ЛАЗЕР ПОВЕРХНОСТНОГО ИЗЛУЧЕНИЯ С ВЕРТИКАЛЬНЫМ РЕЗОНАТОРОМ С ПЕРЕСТРОЙКОЙ ДЛИНЫ ВОЛНЫ И СПОСОБ ЕГО ИЗГОТОВЛЕНИЯ

... 1. Полупроводниковый лазер поверхностного излучения с вертикальным резонатором с перестройкой длины волны, содержащий a) подложку; b) нижнее зеркало, сформированное над подложкой отражателем Брегга; c) активный элемент, который содержит i) слой генерирования света, излучающий свет при воздействии на него инжекционного тока при приложении прямого смещения, ii) первую легированную n-область растекания тока над подложкой и под слоем генерирования света, iii) первую легированную p-область растекания тока над слоем генерирования света, iv) токовые апертуры, расположенные между каждой соседней областью, и v) устройство управления активным элементом посредством напряжения смещения, прикладываемого между легированной n-областью растекания тока и легированной p-областью растекания тока с возможностью инжектирования тока в слой, генерирующий свет, для генерирования света; d) элемент регулировки фазы, который содержит i) слой модуляции, расположенный над первой легированной p–областью растекания тока ...

Lichtaussendende Vorrichtung fähig zur Auswahl der Polarisationsrichtung, optisches Übertragungssystem und Steuerungsverfahren von Polarisationsmodulation

Steuerschaltung eines optischen Halbleitermodulators

Polarisationsmodenselektiver Halbleiterlaser, Lichtquelle und optisches Kommunikationssystem unter Verwendung dieses Lasers

Halbleiterlaser und Modulationsverfahren

Verfahren zur Erzeugung ultrakurzer optischer Impulse

Optoelektronische integrierte Schaltung mit einem Langwellensender

Kompensierte Laserstruktur für analoge Übertragungssysteme.

Halbleiterlaser mit variabler Oszillationswellenlänge.

Optischer Verstärker mit verbesserter Linearität

Anordnung zur optischen Verbindung

Optischer Halbleiterverstärker mit verkürzter Gewinn-Erholungszeit.

Optisch pumpbare oberflächenemittierende Halbleiterlaservorrichtung

Oberflächenemittierende Halbleiterlaservorrichtung mit einem mittels einer Pumpstrahlungsquelle optisch pumpbaren Vertikalemitter (20), der eine strahlungserzeugende Schicht (14) und einen externen Resonator aufweist, dadurch gekennzeichnet, daß zumindest eine Modulationsstrahlungsquelle (30) zur Modulation der Ausgangsleistung der oberflächenemittierenden Halbleiterlaservorrichtung vorgesehen ist, die eine kantenemittierende Halbleiterstruktur (15) mit einer strahlungserzeugenden aktiven Schicht umfaßt, und die so angeordnet ist, daß sie im Betrieb Strahlung emittiert, die in die strahlungserzeugende aktive Schicht (14) des Vertikalemitters (20) eingekoppelt wird und dort eine mittels der Pumpstrahlungsquelle erzeugte Besetzungsinversion zumindest teilweise abbaut.

Halbleiterlaser

FREQUENZSYNTHETISIERER

VORRICHTUNG ZUM MODULIEREN DES AUSGANGS EINES HALBLEITERLASERS

AUTOMATISCHE VORSPANNUNGSSTEUERSCHALTUNG FUER INJEKTIONSLASER

Halbleiterlaservorrichtung und optoelektronisches Strahlumlenkelement für eine Halbleiterlaservorrichtung

Es wird eine Halbleiterlaservorrichtung (100) angegeben mit einer kantenemittierenden Halbleiterlaserdiode (1), die im Betrieb Laserlicht (10) entlang einer horizontalen Richtung (91) abstrahlt, einem Reflektorelement (29), das einen ersten Teil (11) des Laserlichts in eine vertikale Richtung (92) umlenkt, während sich ein zweiter Teil (12) des Laserlichts in horizontaler Richtung weiter ausbreitet, und einem Detektorelement (3), das zumindest teilweise in einem Strahlengang des zweiten Teils des Laserlichts angeordnet ist.Weiterhin wird ein optoelektronisches Strahlumlenkelement (7) für eine Halbleiterlaservorrichtung (100) angegeben.

Anpassungsschaltungen auf optoelektronischen Vorrichtungen

Die vorliegende Erfindung verändert die Frequenzantwort einer optoelektronischen Vorrichtung, um eine Treiberschaltung anzupassen, die die optoelektronische Vorrichtung treibt. Die optoelektronische Vorrichtung ist auf einem ersten Substrat gebildet. Eine Anpassungsschaltung ist auch auf dem ersten Substrat gebildet und mit der optoelektronischen Vorrichtung gekoppelt, um ihre Frequenzantwort zu verändern. Die Anpassungsschaltung liefert eine präzise und wiederholbare Menge einer Induktivität an eine optoelektronische Vorrichtung.

Laseroszillator

Optical scanning system

The optical scanning system according to the invention uses as light source a semiconductor laser diode (10), and it can continually change the spot size of the laser beam emitted by the semiconductor laser diode in order continually to change the size of a point. The laser diode has a semiconductor substrate, a main electrode (11) and a beam-size adjusting device (12). The strength and the diameter of the laser beam emitted by the semiconductor laser diode are modulated as a function of an image signal and for the scanning the laser beam is deflected by a rotating polygonal mirror (20), runs through a scanner lens (30) and scans a scanned surface (40) in order to record an image which is represented by the image signal. ...

Halbleiter-Injektionslaser

EINRICHTUNG ZUR FREQUENZVERSCHIEBUNG IN EINEM OPTISCHEN FELD MIT EINER GEPULSTEN LASERQUELLE

METHOD OF AND AN ARRANGEMENT FOR MODULATING DIRECTLY A SEMICONDUCTOR LASER

... 1363029 Lasers HITACHI Ltd 9 Oct 1972 [8 Oct 1971] 46532/72 Heading H1C A semi-conductor laser modulator has its bias current adjusted to a value producing an output beam with a particular TE mode, and a modulating current of a selected value is superposed on the bias current so as to cause the output beam to change to a different TE mode, the output beam being applied through an optical path capable of transmitting one only of the modes. A stripe electrode semi-conductor is used which is either a GaAs PN junction, Fig. 1 (not shown), or a GaAs-GaApAs double heterostructure, Fig. 2a (not shown). Two of the modes TE 00 , TE 01 , TE 02 are preferably used, Fig. 1b the intensities shown being across the beam emitting region of the semiconductor face. Mode selection in the optical path may be effected by a pair of optical fibres 22, 24, Fig. 3b, aligned with the beam emitting region of the semi-conductor face so as to pass the two peaks, respectively, of a TE o1 mode beam 20. Due to the phase ...

DISTRIBUTED FEEDBACK SEMICONDUCTOR LASER

LIGHT EMITTING DEVICE

LASERS

LASER DEVICES

MULTIBEAM EMITTING DEVICE

A plurality of semiconductive light-emitting elements monolithically formed on a semiconductor substrate are formed so that the directions of emission of the lights emitted from the elements differ from one another. By this means, the beams appear to be emitted from a common point Po and can readily be used as the light source of a plural beam scanning apparatus. …… ...

Semiconductor device

Optical integrated circuit

A semiconductor laser suitable for incorporation into integrated circuits by providing the laser device with a short resonator dimensioned so as to restrict the power consumption of the device to about 1 mW or less. This is made possible by improving the optical confinement, carrier confinement and the reflectivity of end faces in the lasing cavity with a short length and a narrow stripe width of the cavity. Double-layered mirrors are formed at the two opposed ends of the resonator by depositing a film of dielectric insulating material directly on each end and covering the film with a layer of metal.

Vertical cavity surface emitting laser

Vertical cavity surface emitting laser

Distributed feedback semiconductor laser

A distributed feedback semiconductor laser which has periodic corrugations on a light emitting layer or an adjoining layer in the direction of travel of light and performs laser oscillation by the injection of current into the light emitting layer. In accordance with the present invention, a semiconductor having an energy gap larger than that of light emitting layer is formed so as to be extended from a current injection region. The semiconductor is formed uniformly and sufficiently distributed in the current injection region.

PHASE MODULATOR

PULSED LASER

VARIABLE EMISSION STRIP WIDTH SEMICONDUCTOR LASER

... 1496599 Electroluminescence NORTHERN TELECOM Ltd 13 Aug 1975 [17 Sept 1974] 33750/75 Heading C4S [Also in Division H1] In a stripe electrode semi-conductor heterostructure laser, the width of the ribbon output beam is controlled by applying a potential to one or more auxiliary electrodes. With a suitably limited current between the main electrodes of the semiconductor, such control enables the laser to switch from a non-lasing to a lasing condition as the width of the output beam is reduced, and vice versa. The laser consists basically of confining layers 21 and 23 of AlGaAs, Fig. 3, a GaAs laser active layer 22, and a GaAs capping layer 24, the layers being epitaxially grown on a substrate layer 20. The layers 20, 21 and layers 22, 23, 24 are of opposite conductivity type. Dopants may be Al, Te, Ge or Sn. In Fig. 3 a zinc diffusion zone 27 is provided, together with main and auxiliary electrodes 28a, 28b which are formed by evaporating Au/Ge, followed by Au, in windows 26 in an oxide layer ...

MAINTAIN A DESIRED EFFICIENCY OF OPTICAL EMITTERS WITH EXTREMES TEMPERATURES

OPTICAL SELECTION UNIT

ELECTRICALLY MODULATED DIODE LASER

INTERFEROMETRISCHE EINRICHTUNG ZUR MESSUNG DER LAGE EINES REFLEKTIERENDEN OBJEKTES

INTERFEROMETRISCHE EINRICHTUNG ZUR MESSUNG DER LAGE EINES REFLEKTIERENDEN OBJEKTES

Trägermodul mit Überbrückungselement für ein Halbleiterelement

Carrier module (1) for at least one semiconductor element (3) having a passively and/or actively cooled carrier (4) which has a positive carrier contact (5) and a negative carrier contact (6), with a device (2) for bridging the at least one semiconductor element (3) arranged on the carrier (4), comprising at least one first printed circuit board (7) with at least one bridging element (8), wherein at least one positive contact (9) which is electrically conductively connected to the positive carrier contact (5) and at least one negative contact (11) which is electrically conductively connected to the negative carrier contact (6) are provided on a first printed circuit board (7) and the bridging element (8) is electrically conductively connected to the positive contact (9) and to the negative contact (11) of the first printed circuit board (7), wherein the first printed circuit board (7) is thermally conductively and releasably connected to the carrier (4).

OPTICAL GENERATOR FOR THE TRANSMISSION OF A MICROWAVE SIGNAL.

PHASE MODULATION.

LIGHT WITH ANIMAL END OF SEMICONDUCTOR DEVICE.

WITH A HIGH FREQUENCY SOURCE OF DIODE LASER MODULATED.

PROCEDURE AND DEVICE FOR THE GENERATION OF PULSES

FASHION-COUPLED SOURCE OF DIODE LASER PULSE

Arrangement for the information transfer or ranging

POLARISATION SWITCHING IN ACTIVE DEVICES

Wavelength control of an external-cavity tuneable laser

Current-controlled polarization switching vertical cavity surface emitting laser

MAINTAINING DESIRABLE PERFORMANCE OF OPTICAL EMITTERS AT EXTREME TEMPERATURES

A current blocking structure to improve semiconductor laser performance

Toggling optoelectronic device and method

TECHNIQUES FOR BIASING LASERS

FIXING DC BIAS IN NON-LINEAR DEVICE

Intelligent fiberoptic transmitters and methods of operating and manufacturing the same

Integrated semiconductor laser with electronic directivity and focusing control

FIBRE COMMUNICATION SYSTEM

PHASE MODULATION

POLARIZATION TRANSFORMER AND CURRENT SENSOR USING THE SAME

A method for fabricating a transformer of linearly polarized light to elliptically polarized light is disclosed. The method involves twisting a birefringent fiber through angles that depend on the desired final polarization. This technique obviates the need to splice fibers, as in common practice. The polarization can be fine-tuned by heating the fiber to cause the core and the cladding of the fiber to interdiffuse. Also disclosed is a current sensor using the transformer of polarized light which is based on the Faraday Effect in a Sagnac interferometer.

MULTI-BEAM LASER POWER CONTROL CIRCUIT AND IMAGE FORMING APPARATUS USING THE SAME

A disclosed multi-beam laser power control circuit includes a light receiving element receiving power output from semiconductor lasers to control output power of a semiconductor laser array having plural semiconductor lasers, automatic power control circuits (APC circuits) controlling emission power output from semiconductor lasers based on received corresponding automatic power control execution signals so as to be set to predetermined emission power based on output from the light receiving element, and APC execution signal input terminals inputting the corresponding automatic power control execution signals, wherein, when plural APC execution signals input to the corresponding APC execution signal input terminals are overlapped, the automatic power control circuits (APC circuits) to be preferentially operated is determined based on input timings of the APC execution signals and operated.

METHOD AND APPARATUS FOR THE OPERATION OF A DISTRIBUTED FEEDBACK LASER

Optical Communication System, Particularly in the Subscriber Area An optical communication system in which transmission takes place in a single optical-waveguide mode by means of low-cost optical transmitters and receivers although two or more modes could propagate in the optical waveguide (1) at the operating wavelength, is supplemented by optical-waveguide sections (2, 3) between the transmitters (S, S1, S2) and receivers (E, E1, E2) and the optical waveguide (1) which are "single-mode" at the operating wavelength and contain the optical connectors (4, 5). This eliminates the need for connectors at the junctions between the optical-waveguide sections (2, 3) and the optical waveguide (1), so that no modal noise and modal dispersion can occur as a result of mode conversion. (Fig. 1) ...

BEAM SCANNING USING RADIATION PATTERN DISTORTION

BEAM SCANNING USING RADIATION PATTERN DISTORTION A laser beam scanner in which a single-lobe propogates radiation pattern through an electrically variable asymmetric electrical charge distribution. Because the electrical charge distribution determines the real and imaginary parts of the refractive index of the material through which the radiation pattern propogates the radiation pattern may be deflected by changing the charge distribution profile.

OPTICAL BEAM SCANNING BY PHASE DELAYS

A light beam scanner of the moving interference fringe pattern type which includes a body of semiconductor material having a source of coherentradiation and wave guides for guiding the coherent radiation along a plurality of spatially displaced paths which are optically uncoupled, and a device associated with the spatially displaced paths for producing relative phase changes between radiation in the different paths whereby interference fringes in the far field are spatially scanned. In addition, wavelength modulation of the laser over a range of about 80.ANG. can be achieved. The source of the coherent radiation can be a single laser or a plurality of optically coupled lasers, and the optical uncoupling can be achieved by spatial displacement of the paths or by insertion of a high loss medium between the paths ...

METHOD AND APPARATUS FOR GENERATING FREQUENCY MODULATED PULSES

A method and apparatus are provided for generating short (e.g., picosecond) pulses using a 2 section 1553 nm DBR laser without gain switching nor external modulation. The center wavelength of the DBR section is modulated at 0.5 GHz to generate a constant amplitude frequency modulated optical wave. Large group velocity dispersion is then applied with a chirped fiber Bragg grating to convert the FM signal to a pulse stream.

OPTICAL CIRCUIT ARRANGEMENT

VARIABLE STRIPE WIDTH SEMICONDUCTOR LASER

PHASE-CONTROL IN AN EXTERNAL-CAVITY TUNEABLE LASER

The present invention relates to a single-mode external-cavity tuneable laser including a gain medium, a tuneable element and a channel allocation grid element. The channel allocation grid element is preferably a FP etalon, which is structured and configured to define a plurality of equally spaced transmission peaks corresponding to the ITU channel grid, e.g., 200, 100, 50 or 25 GHz. The tuneable element, preferably a tuneable mirror, serves as the coarse tuning element that discriminates between the peaks of the grid etalon. The tuneable laser of the invention has a relatively short cavity length of not more than 15 mm, preferably not larger than 12 mm. It has been found that the FP etalon introduces a phase non-linearity in the external cavity, which induces a compression of the cavity modes, i.e., a reduction in the cavity mode spacing, in correspondence to the etalon transmission peaks. Mode compression increases with the decrease of the FWHM bandwidth of the grid FP etalon, hereafter ...

DRIVE CIRCUIT AND OPTICAL NETWORK UNIT

Provided are a drive circuit and a customer-side device capable of suppressing the temperature dependency of a light signal in a transmission circuit to achieve satisfactory communication. The drive circuit is provided with a bias current supply circuit whereby a bias current is supplied to a light-emitting element for transmitting a light signal, and a modulation current supply circuit whereby a modulation current with an intensity corresponding to the logical value of the data to be transmitted is supplied to the light-emitting element. The drive circuit has: a first path wherein the bias current flows; a second path containing a path for supplying the modulation current from the modulation current supply circuit to the light-emitting element so that when the bias current flows, the current flows from the bias current supply circuit through the modulation current supply circuit and back to the bias current supply circuit without passing through the light-emitting element; and a third ...

OPTO-ELECTRONIC HYBRID INTEGRATION PLATFORM, OPTICAL SUB-MODULE, OPTO-ELECTRONIC HYBRID INTEGRATION CIRCUIT, AND PROCESS FOR FABRICATING PLATFORM

An opto-electronic hybrid integrated circuit of the present invention satisfy a low-loss optical waveguide function, an optical bench function and a high-frequency electrical wiring function. The circuit includes a substrate such as a silicon substrate, a dielectric optical waveguide part arranged in a recess of the substrate, and an optical device mounting part formed on a protrusion of the substrate. An electrical wiring part is disposed on the dielectric layer. The optical device is mounted on the substrate. An optical sub-module includes the optical device which is possible to mount on the substrate.

SEMICONDUCTOR OPTICAL DEVICE

... : The present invention relates to an improvement for a semiconductor optical device having a region in which semiconductor or carriers in the semiconductor and light interact. For example, an active region for a semiconductor laser, an optical wave guide region of an optical modulator, etc. has a quantum well structure comprising a well region and a barrier region. A semiconductor optical device is disclosed which greatly improves the degree of freedom for the design of the device such as the thickness and the selection of material without deteriorating the quantum effect. This is achieved by introducing a super lattice super-layer structure into the barrier region of the quantum well structure or defining the strain for the well region and the barrier region.

PULSED LASER

... - 5 - O.Z. 0050/40811 In order to generate precisely square-wave laser light pulses, a laser diode is fed by a current pulse generator which comprises a timing pulse generator and a power stage, which is driven by the latter and which is followed by a single-pole driver stage of high current having a rise time of a few nanoseconds for the laser diode which is connected in the circuit of a battery of capacitors.

METHOD OF OPERATING A SEMICONDUCTOR LASER AS A MODE-LOCKED SEMICONDUCTOR LASER AND DEVICES FOR IMPLEMENTING THE METHOD

A semiconductor laser (1) is known that is monolithically integrated on a substrate (2) and whose cavity (41) has a branched structure that is simply contiguous in a topological sense. The semiconductor laser (1) includes a plurality of regions (8-11) that enclose the cavity (41). According to the invention, the semiconductor laser (1) is operated as a mode-locked semiconductor laser, with an alternating current flowing through at least one region in addition to a direct current. The frequency of the alternating current corresponds to the reciprocal of the round-trip time or an integral multiple of this reciprocal of the light pulses generated by the alternating current in the semiconductor laser (1).

OPTICAL GENERATOR, PARTICULARLY FOR TRANSMITTING MICROWAGE SIGNALS

... : Générateur optique, notamment pour le transport d'un signal hyperfréquence. Un laser (4) est polarisé au voisinage du coude (8) de sa courbe caractéristique (6). Il reçoit en outre, sous forme électrique, une onde de base appliquée à une entrée (14) du générateur et une onde locale fournie par un oscillateur local (16) et il mélange ces ondes en additionnant leurs fréquences pour moduler l'onde lumineuse qu'il émet. L'invention trouve notamment application dans les systèmes de télécommunications. FIGURE A PUBLIER : Fig.1 ...

DRIVE CIRCUIT FOR A SOLID STATE OPTICAL EMITTER DEVICE

The present invention relates to a circuit for driving a solid state optical emitter device such as a laser diode, and in particular a circuit which limits the maximum current which may be drawn through the device. The circuit comprises a current supply path and a current return path to which the optical emitter may be connected, and current limit means (20) to limit a maximum current (Imax) that may flow through one of the current paths. The current limit means (20) has a current mirror with an input portion (21) and an output portion (23), the circuit being arranged so that when a first current (I R) flows through the input portion (21) the second portion (23) is predisposed to supply a second current (I O) up to a maximum which mirrors the first current (I R). The maximum current (Imax) through the paths is thereby limited in accordance with the maximum of the second current (I O).

DATA ENCODED OPTICAL PULSE GENERATOR

The apparatus and method according to the present invention includes a semiconductor laser-modulator which is used to simultaneously generate optical pulses and encode data. The optical data output from the lasermodulator are soliton pulses in RZ format suitable for transmission in long distance optical communications.

Method for the Generation of Ultra-Short Optical Pulses

TUNABLE EXTERNAL CAVITY DIODE LASER

An external cavity laser system composed of a semiconductor diode laser (10), a temperature control (30) and injection current control (40) means the diode laser, an external cavity (60) with a wavelength selector and means for controlling the laser temperature (20), laser injection current and the wavelength selector (110) to obtain arbitrary frequencies within the tuning range of the laser.

OPTICAL COMMUNICATION MODULE

A Peltier cooler is situated in a module casing, and combined with a metallic block, on which a lens is mounted. A thermistor, an electroabsorption modulator integrated DFB laser (a laser unit), a monitoring photosensor are mounted on the metallic block. A signal line of a co-planar structure which is connected with a signal input pin supplied with an external signal is laid on a ceramic substrate, under which a pedestal is formed. A part of the ceramic substrate on the pedestal is removed, and an amplifier is mounted on the pedestal in condition that it approximates to the laser unit. The laser unit is connected with the amplifier by an Au wire, and the amplifier is connected with the signal line by another Au wire. According to the aforementioned configuration, an electrical length between the signal pin and the laser unit can be shortened, and a compact optical communication module having an excellent performance in a high bit rate communication can be provided.

Halbleiter-Laser

Optischer Sender

Sender zur Übertragung von Informationen über Laserstrahlen

Halbleiter-Injektionslaser

Vorrichtung zum Abtasten von Objekten mittels der Strahlen eines Injektionslasers und Verfahren zu ihrem Betrieb

OPTICAL SELECTION UNIT FOR SCANNING A WITH OF A RADIATION-REFLECTING INFORMATION STRUCTURE OF PROVIDED RECORDING CARRIER.

PROCEDURE AND CIRCUIT OF PILOTAGE OF NOT LINEAR AN ELECTRONIC THRESHOLD DEVICE.

Tunable laser, optical network device and optical network system

The invention discloses a tunable laser, an optical network device and an optical network system, and relates to the technical field of fiber optical communication. The tunable laser having a direct modulation function is low in cost without adding an expensive external modulator, and wavelengths can be tuned in a wide range. The tunable laser comprises: a coupled cavity and a modulation area. The coupled cavity is provided with three output ends, at least an output end's opposite end of the coupled cavity is the modulation area, any output end's end face of the coupled cavity is opposite to the end face of the modulation area, and the output end's end face and the end face of the modulation area forms an acute angle. The coupled cavity is used to generate specific frequency optical signals and send the optical signals to the modulation area. The modulation area is used to adjust strength of the specific frequency optical signals sent by the coupled cavity. The tunable laser is used in ...

Light emitting semiconductor methods and devices

A method for producing light emission from a two terminal semiconductor device with improved efficiency, includes the following steps: providing a layered semiconductor structure including a semiconductor drain region comprising at least one drain layer, a semiconductor base region disposed on the drain region and including at least one base layer, and a semiconductor emitter region disposed on a portion of the base region and comprising an emitter mesa that includes at least one emitter layer; providing, in the base region, at least one region exhibiting quantum size effects; providing a base/drain electrode having a first portion on an exposed surface of the base region and a further portion coupled with the drain region, and providing an emitter electrode on the surface of the emitter region; applying signals with respect to the base/drain and emitter electrodes to obtain light emission from the base region; and configuring the base/drain and emitter electrodes for substantial uniformity ...

LASER HAS SEMICONDUCTOR HAS RECONCILABLE SPECTRUM OF PROFIT

METHOD FOR MODULATING SEMICONDUCTOR LASERS

Semiconductor source optical pulse to gain switching and soliton transmission system.

Improvements with the devices laser with semiconductor

Source laser à semi-conducteur modulée à fréquence élevée

Un laser semi-conducteur 2 constitue une source monolithique dont l'intensité est modulée à une fréquence située dans le domaine des hyperfréquences, typiquement de 10-20 à 100 GHz. Il est basé sur le couplage des modes longitudinaux du laser, la modulation d'intensité étant donnée par le battement des différents modes du laser. L'optimisation et la commande du laser sont permises par une division de la cavité optique 6, 8, 10 du laser en sections successives 20, 22, 24. L'invention s'applique notamment aux télécommunications.

Device with laser with semiconductors of which the wavelength is reconcilable

L'invention concerne un dispositif à laser à semiconducteurs dont la longueur d'onde est accordable. Selon l'invention, il comprend un substrat semiconducteur (1) d'un premier type de conductivité, une couche active (6) en semi-conducteur au-dessus du substrat (1) qui produit de la lumière en réponse à un courant injecté, une couche d'accord (8) en semi-conducteur au-dessus du substrat (1) dont l'indice de réfraction (100) change en réponse au champ électrique une couche d'espacement (7) en un semiconducteur d'un second type de conductivité, interposée entre la couche (6) et la couche (8), des facettes opposées avant et arrière de résonateur aux deux extrémités des couches (6) et (8) et ayant des réflectivités différentes, une électrode côté première conductivité pour fournir un champ électrique à la couche (8), une électrode côté première conductivité (10) pour injecter du courant dans la couche (6) et une électrode (11) côté seconde conductivité commune aux électrodes d'application du ...

MONOLITHIC SEMICONDUCTOR STRUCTURE Of a BIPOLAR TRANSISTOR HAS HETEROJUNCTION AND Of a LASER

Wavelength tunable laser device, optical module, and method of controlling wavelength tunable laser

Provided is a power saving and highly reliable wavelength tunable laser device. A wavelength tunable laser device 10 of the present invention includes: a wavelength tunable laser 11 including: a laser resonator including a light source 111 and wavelength tunable mechanisms 112 and 113; and light loss control units 114 a and 114 b; a temperature detecting element 12 detecting a temperature of the wavelength tunable laser 11; and a controller 13, wherein the controller 13 obtains temperature information a of the wavelength tunable laser 11 from the temperature detecting element 12, calculates wavelength tunable control parameters d and e and light loss control parameters b 1 and b 2 based on the temperature information a, controls the wavelength tunable mechanisms 112 and 113 based on the wavelength tunable control parameters d and e, and controls light loss control units 114 a and 114 b based on the light loss control parameters b 1 and b 2.

Frequency stabilized laser system

A laser stabilization system includes laser source having first and second ends; first waveguide portion having first and second ends, first end of first waveguide portion coupled to first end of laser source; second waveguide portion having first and second ends, first end of second waveguide portion coupled to second end of laser source; micro-cavity coupled between second end of first waveguide portion and second end of second waveguide portion, micro-cavity having resonant frequency; and electronic locking loop coupled between micro-cavity and laser source, wherein electronic locking loop electronically locks laser source to resonant frequency of micro-cavity; wherein first waveguide portion is optical locking loop coupled between micro-cavity and laser source, wherein optical locking loop optically locks laser source to resonant frequency of micro-cavity; micro-cavity stabilization loop coupled with micro-cavity, wherein micro-cavity stabilization loop stabilizes resonant frequency of micro-cavity to reference frequency; and output for outputting light from system.

Optical semiconductor device, and manufacturing method thereof

The optical semiconductor device includes a spot-size converter formed on a semiconductor substrate. The spot-size converter has a multilayer structure including a light transition region. The multilayer structure includes a lower core layer, and an upper core layer having a refractive index higher than that of the lower core layer. The width of the upper core layer is gradually decreased and the width of the lower core layer is gradually increased in the light transition region. Both sides and an upper side of the multilayer structure are buried by a semi-insulating semiconductor layer in the light transition region. Light incident from one end section of the spot-size converter is propagated to the upper core layer. The light transits from the upper core layer to the lower core layer in the light transition region, is propagated to the lower core layer, and exits from the other end section thereof.

Wavelength tunable laser diode

A wavelength tunable laser diode (LD) is disclosed. The LD provides a SG-DFB region and a CSG-DBR region. The SG-DFB region shows a gain spectrum with a plurality of gain peaks, while, the CSG-DBR region shows a reflection spectrum with a plurality of reflection peaks. The LD may emit light with a wavelength at which the one of the gain peaks and one of the reflection peaks coincides. In the present LD, both the gain spectrum and the reflection spectrum are modified by adjusting the temperature of the SG-DFB region and that of the CSG-DBR region independently.

Semiconductor optical integrated device

A semiconductor optical integrated device includes a substrate having a main surface with a first and second regions arranged along a waveguiding direction; a gain region including a first cladding layer, an active layer, and a second cladding layer arranged on the first region of the main surface; and a wavelength control region including a third cladding layer, an optical waveguide layer, and a fourth cladding layer arranged on the second region of the main surface and including a heater arranged along the optical waveguide layer. The substrate includes a through hole extending from a back surface of the substrate in the thickness direction and reaching the first region. A metal member is arranged in the through hole. The metal member extends from the back surface of the substrate in the thickness direction and is in contact with the first cladding layer.

Method to switch emission wavelength of tunable laser diode

The method to change the emission wavelength of a tunable LD is disclosed. In an ordinary state, the method monitors conditions not only relating to determine the emission wavelength but conditions independent of the emission wavelength by an ordinary A/D-C implemented within the controller. Responding to an instruction to switch the emission wavelength, the controller only monitors the former conditions affecting the determination of the emission wavelength. The sampling rate of the ordinary A/D-C is equivalently enhanced without installing an additional A/D-C.

Method and system for communicating with a laser power driver

A system for controlling a plurality of laser diodes includes an optical transmitter coupled to the laser diode driver for each laser diode. An optical signal including bi-phase encoded data is provided to each laser diode driver. The optical signal includes current level and pulse duration information at which each of the diodes is to be driven. Upon receiving a trigger signal, the laser diode drivers operate the laser diodes using the current level and pulse duration information to output a laser beam.

Directly Modulated Laser for PON Applications

In an embodiment, a distributed Bragg reflector (DBR) laser includes a gain section and a passive section. The gain section includes an active region, an upper separate confinement heterostructure (SCH), and a lower SCH. The upper SCH is above the active region and has a thickness of at least 60 nanometers (nm). The lower SCH is below the active region and has a thickness of at least 60 nm. The passive section is coupled to the gain section, the passive section having a DBR in optical communication with the active region.

Tunable multi-wavelength semiconductor laser array for optical communications based on wavelength division multiplexing

Techniques, devices and systems for optical communications based on wavelength division multiplexing (WDM) that use tunable multi-wavelength laser transmitter modules.

Hybrid silicon laser-quantum well intermixing wafer bonded integration platform for advanced photonic circuits with electroabsorption modulators

Photonic integrated circuits on silicon are disclosed. By bonding a wafer of compound semiconductor material as an active region to silicon and removing the substrate, the lasers, amplifiers, modulators, and other devices can be processed using standard photolithographic techniques on the silicon substrate. A silicon laser intermixed integrated device in accordance with one or more embodiments of the present invention comprises a silicon-on-insulator substrate, comprising at least one waveguide in a top surface, and a compound semiconductor substrate comprising a gain layer, the compound semiconductor substrate being subjected to a quantum well intermixing process, wherein the upper surface of the compound semiconductor substrate is bonded to the top surface of the silicon-on-insulator substrate.

PULSE GENERATOR CIRCUIT, RELATED SYSTEM AND METHOD

An embodiment pulse generator circuit comprises a first electronic switch coupled between first and second nodes, and a second electronic switch coupled between the second node and a reference node. An LC resonant circuit comprising an inductance and a capacitance is coupled between the first and reference nodes along with charge circuitry comprises a further inductance in a current flow line between a supply node and an intermediate node in the LC resonant circuit. Drive circuitry of the electronic switches repeats, during a sequence of switching cycles, charge time intervals, wherein the capacitance in the LC resonant circuit is charged via the charge circuit, and pulse generation time intervals, wherein a pulsed current is provided to the load via the first and second nodes. The charge and pulse generation time intervals are interleaved with oscillation time intervals where the LC resonant circuit oscillates at a resonance frequency. 1. A pulse generator circuit comprising:a first node and a second node configured to apply a pulse signal to an electrical load coupled therebetween;a first electronic switch coupled between the first node and the second node;a second electronic switch coupled between the second node and a reference node;an LC resonant circuit comprising a series connection of an inductance and a capacitance having an intermediate node therebetween, the LC resonant circuit coupled between the first node and the reference node;charge circuitry comprising a further inductance in a current flow line between a supply node and the intermediate node in the LC resonant circuit; and 'charge time intervals, wherein the first electronic switch is closed and the second electronic switch is open and the capacitance in the LC resonant circuit is charged via the charge circuit.', 'drive circuitry of the first electronic switch and the second electronic switch, the drive circuitry configured to repeat switching cycles of a sequence of switching cycles comprising2. ...

LASER DRIVER INCORPORATING CLAMPING CIRCUIT WITH FREEWHEELING DIODE

A level-shifter includes an input node coupled to a laser driver input receiving a trigger signal, the input node receiving a signal indicating generation of a laser drive-pulse. A p-channel transistor has a source coupled to a supply node, a drain coupled to an output node, and a gate coupled to the input node. An n-channel transistor has a drain coupled to the drain of the p-channel transistor, a source coupled to ground, and a gate coupled to the input node. A first switch couples the input node to the output node. Another p-channel transistor has a source coupled to the supply node, a drain coupled to the output node by a second switch, and a gate coupled to the input node. The first switch closes and second switch opens when the signal is low, and the first switch opens and second switch closes when the signal is high. 1. A system comprising: an input node capacitively coupled to a laser driver and configured to receive a signal therefrom indicative of generation of a laser drive pulse; and', 'an inverter having an input coupled to the input node and an output coupled to an output node, the inverter having adjustable threshold voltage that increases when the signal on the input node goes high and decreases when the signal on the input node returns low., 'a level shifter, comprising2. The system of claim 1 , wherein the level shifter further comprises:a buffer having an input coupled to the output node; anda current source generating a current proportional to absolute temperature, the current source biasing the buffer with the current proportional to absolute temperature.3. The system of claim 1 , wherein the inverter comprises:a first p-channel transistor having a source coupled to a supply node, a drain coupled to the output node, and a gate coupled to the input node;an n-channel transistor having a drain coupled to the output node, a source coupled to ground, and a gate coupled to the input node;a first switch selectively coupling the input node to the output ...

Method of evaluating initial parameters and target values for feedback control loop of wavelength tunable system

A method of determining initial parameters and target values for tuning an emission wavelength of a wavelength tunable laser capable of emitting laser light in a substantial wavelength range is disclosed. The method iterates an evaluation of initial parameters and target values at target wavelengths in a preset order. The evaluation includes steps of supplying empirically obtained parameters to the t-LD, confirming whether the t-LD generates an optical beams, determining the initial parameters and the target values by carrying out feedback loops of the AFC and the APC when the t-LD generates the optical beam, or shifting the wavelength range so as to exclude the current target wavelength when the t-LD generates no optical beam.

EXTERAL CAVITY LASER INCORPORATING A RESETABLE PHASE SHIFTER

An apparatus including an external cavity laser with an optical cavity, the optical cavity bounded by optical reflectors. The optical cavity can include an optical gain module capable of amplifying light, a tunable endless optical phase shifter and a wavelength-tunable optical filter. The apparatus can also include an electronic control module connected to enable adjustment of a phase shift accumulated by the light propagating through the tunable endless optical phase shifter and connected to enable adjustment of a passband wavelength of the wavelength tunable optical filter. Another apparatus as described above with no wavelength-tunable optical filter present. 1. An apparatus comprising: an optical gain module capable of amplifying light,', 'a tunable endless optical phase shifter, and', 'a wavelength-tunable optical filter; and, 'an external cavity laser with an optical cavity, the optical cavity bounded by optical reflectors, wherein the optical cavity includesan electronic control module connected to enable adjustment of a phase shift accumulated by the light propagating through the tunable endless optical phase shifter and connected to enable adjustment of a passband wavelength of the wavelength tunable optical filter.2. The apparatus of claim 1 , wherein the electronic control module is capable of adjusting the accumulated phase shift and the passband wavelength in parallel.3. The apparatus of claim 1 , wherein the electronic control module is able to cause a phase shift accumulated by the light propagating through the tunable endless optical phase shifter to vary with an amount of a multiple of 2π radians without causing a substantial change in lasing optical power.4. The apparatus of claim 1 , wherein the tunable endless optical phase shifter includes:a first optical switch;a second optical switch; andfirst and second optical waveguide paths, each optical waveguide path optically connecting a corresponding optical output of the first optical switch to a ...

Laser driver with variable resistor and variable capacitance element, and optical transmitter including the same

A laser driver includes a differential amplifier and a driver. The differential amplifier includes a first series circuit and a second series circuit each including a resistor, a transistor, and a current source that are connected in series to each other, a variable resistor connected between emitters of the transistors, and a variable capacitance element connected in parallel to the variable resistor. The differential amplifier generates a driving signal having amplitude proportional to amplitude of a differential signal externally input to the transistors. The driver generates a driving current in response to the driving signal for driving the semiconductor laser connected in series to the driver. The laser driver changes frequency characteristics of the differential amplifier by adjusting the variable resistor and the variable capacitance element to correct frequency characteristics of the semiconductor laser. The laser driver may improve eye opening of an optical signal output from the semiconductor laser.

Wavelength tunable laser device and laser module

A wavelength tunable laser device includes: a laser cavity formed of a grating and a reflecting mirror including a ring resonator filter; a gain portion; and a phase adjusting portion. The grating creates a first comb-shaped reflection spectrum. The ring resonator filter includes a ring-shaped waveguide and two arms and creates a second comb-shaped reflection spectrum having peaks of a narrower full width than peaks in the first comb-shaped reflection spectrum at a wavelength interval different from that of the first comb-shaped reflection spectrum. One of the peaks in the first comb-shaped reflection spectrum and one of the peaks in the second comb-shaped reflection spectrum are overlapped on a wavelength axis, and a spacing between cavity modes is narrower than the full width at half maximum of the peaks in the first comb-shaped reflection spectrum.

TUNABLE LASER AND MANUFACTURING METHOD FOR TUNABLE LASER

A wavelength tunable laser includes: a heating layer, a dielectric layer, reflectors, a transport layer, a support layer, and a substrate layer. The heating layer is located above the transport layer; the transport layer is located above the support layer, and the transport layer includes an upper cladding layer, a waveguide layer, and a lower cladding layer from top to bottom; the reflector is located in the transport layer; the support layer has a protection structure, where the protection structure forms a hollow structure together with the transport layer and the substrate layer, and the hollow structure has a support structure; and the substrate layer is located below the support layer. The heating layer, the reflector, and a part of the transport layer form a suspended structure to prevent heat dissipation. Thus thermal tuning efficiency can be improved, and power consumption can be lowered. 1. A wavelength tunable laser , comprising:a substrate layer;a support layer disposed above the substrate layer and having a protection structure;a transport layer disposed above the support layer and comprising a lower cladding layer, a waveguide layer and an upper cladding layer, wherein the protection structure forms a hollow structure together with the transport layer and the substrate layer, and the hollow structure includes a support structure;a heating layer disposed above the transport layer; anda reflector disposed in the transport layer.2. The laser according to claim 1 , further comprising:in a first direction, a gap between the support structure and the protection structure, wherein the first direction is a transmission direction of light in the waveguide layer.3. The laser according to claim 1 , further comprising:in a second direction, a gap between the support structure and the protection structure, wherein the second direction is perpendicular to the transmission direction of light in the waveguide layer.4. The laser according to claim 1 , wherein the ...

OPTICAL APPARATUS, MANUFACTURING METHOD OF DISTRIBUTED BRAGG REFLECTOR LASER DIODE AND MANUFACTURING METHOD OF OPTICAL APPARATUS

Provided are an optical apparatus, a manufacturing method of a distributed Bragg reflector laser diode, and a manufacturing method of the optical apparatus, the an optical apparatus including a cooling device, a distributed Bragg reflector laser diode having a lower clad including a recess region on one side of the cooling device and connected to another side of the cooling device, and an air gap between the cooling device and the distributed Bragg reflector laser diode, wherein the air gap is defined by a bottom surface of the lower clad in the recess region and a top surface of the cooling device. 1. An optical apparatus comprising:a cooling device;a distributed Bragg reflector laser diode having a lower clad comprising a recess region on one side of the cooling device and connected to another side of the cooling device; andan air gap between the cooling device and the distributed Bragg reflector laser diode,wherein the air gap is defined by a bottom surface of the lower clad in the recess region and a top surface of the cooling device.2. The optical apparatus of claim 1 , wherein the distributed Bragg reflector laser diode comprises:a waveguide comprising a passive waveguide on one side of the lower clad and an active waveguide on another end of the lower clad;an upper clad on the waveguide;a first upper electrode on the upper clad of the active waveguide; anda second upper electrode on the upper clad of the passive waveguide,wherein the recess region is disposed below the second upper electrode.3. The optical apparatus of claim 2 , wherein the distributed Bragg reflector laser diode further comprises gratings disposed in the lower clad below the second upper electrode claim 2 ,wherein the gratings are disposed in a depth equal to or greater than 5 μm from the bottom surface of the lower clad in the recess region.4. The optical apparatus of claim 1 , further comprising:bumps between the lower clad and the other side of the cooling device,wherein the cooling ...

WAVELENGTH-TUNABLE LIGHT SOURCE AND WAVELENGTH CONTROL METHOD FOR THE SAME

A wavelength-tunable light source includes a wavelength-tunable laser including a first region and a second region each of which includes at least one of heaters, a frequency locker configured to receive output light of the wavelength-tunable laser and output two electric control signals whose phases are mutually different by 90° and having frequency period with respect to frequency of the output light, a thermal electric cooler on which the wavelength-tunable laser and the frequency locker are mounted, and a controller configured to control temperature of the heaters, and the thermal electric cooler on the basis of any one of the two electric control signals. 1. A wavelength-tunable light source comprising:a wavelength-tunable laser including a first region and a second region each of which includes at least one of heaters;a frequency locker configured to receive output light of the wavelength-tunable laser and to output two electric control signals whose phases are mutually different by 90°, the two electric control signals having frequency period with respect to frequency of the output light;a thermal electric cooler on which the wavelength-tunable laser and the frequency locker are mounted; anda controller configured to control temperature of the heaters and the thermal electric cooler on a basis of any one of the two electric control signals.2. The wavelength-tunable light source according to claim 1 ,wherein the frequency period of one of the two electric control signals and the frequency period of the other of the two electric control signals are 50 GHz.3. The wavelength-tunable light source according to claim 1 , whereinthe controller includes a look-up table,the look-up table includes a plurality of reference frequencies and a control data set for each of the plurality of reference frequencies, and a setting temperature of the thermal electric cooler;', 'a temperature coefficient of the two electric control signals with respect to temperature of the thermal ...

Method to determine operating conditions of wavelength tunable laser diode and to control optical transmitter providing wavelength tunable laser diode

A method to control a wavelength tunable laser diode (tunable LD) is disclosed. The tunable LD includes a SG-DFB region and a CSG-DBR region to tune the emission wavelength thereof. The CSG-DBR region includes three segments, where the refractive indices of respective segments are variable by heaters provided therein. When the electrical power supplied to two segments is optionally selected, the power supplied to the rest segment is corrected by an offset from a value reflecting physical dimensions of the heaters. The offset is determined such that the tunable LD shows the best side mode suppression ratio (SMSR).

Common Cathode Laser Driving Circuit

A method for biasing a tunable laser during burst-on and burst-off states through a common-cathode laser driving circuit includes delivering a bias current to an anode of a gain-section diode having a shared substrate with the laser, and receiving a burst mode signal indicative of a burst-on state or a burst-off state. When the burst mode signal is indicative of the burst-off state, the method includes sinking a sink current away from the anode of the gain-section diode. The sink current is less than the bias current delivered to the anode of the gain-section diode. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method includes ceasing the sinking of the sink current away from the anode of the gain-section diode, and delivering an overshoot current to the anode of the gain-section diode to accelerate heating of the gain-section diode. 1. A method comprising:delivering, by a laser driving circuit, a bias current to an anode of a gain-section diode disposed on a shared substrate of a tunable laser;receiving, at the laser driving circuit, a burst mode signal indicative of a burst-on state or a burst-off state;when the burst mode signal is indicative of the burst-off state, sinking, by the laser driving circuit, a sink current away from the bias current at the anode of the gain-section diode, the sink current less than the bias current delivered to the anode of the gain-section diode; andwhen the burst mode signal is indicative of the burst-on state, modulating, by the laser driving circuit, the tunable laser by a capacitively coupled modulation stage of the laser driving circuit to the anode of the gain-section diode, resulting in an alternating current (AC) modulation current.2. The method of claim 1 , further comprising claim 1 , when the burst mode signal transitions to be indicative of the burst-on state from the burst-off state:ceasing, by the laser driving circuit, the sinking of the sink current away ...

OPTICAL MODULE

An optical module includes a laser transmitter driver chip, a Distributed Bragg reflection (DBR) raster, a laser transmitter, a first resistor, a first capacitor, a second resistor, a second capacitor and a power source. The first resistor is connected between a power source and a differential signal output positive terminal of the laser transmitter; the first capacitor is connected between the differential signal output positive terminal and the a positive terminal of the laser transmitter; the second resistor is connected between the power source and a differential signal output negative terminal of the laser transmitter driver chip; the second capacitor is connected between the differential signal output negative terminal and a negative terminal of the laser transmitter; and the negative terminal of the laser transmitter and a negative terminal of the DBR raster are grounded. 1. An optical module , comprising:a laser transmitter driver chip comprising a differential signal output positive terminal and a differential signal output negative terminal;a laser transmitter comprising a positive terminal and a negative terminal;a first capacitor electrically connecting the differential signal output positive terminal and the positive terminal of the laser transmitter;a power source;a Distributed Bragg reflection (DBR) raster comprising a negative terminal.2. The optical module according to claim 1 , wherein:the negative terminal of the laser transmitter is grounded.3. The optical module according to claim 1 , further comprising:the negative terminal of the DBR raster electrically connecting to the negative terminal of the laser transmitter.4. The optical module according to claim 1 , wherein:the negative terminal of the DBR raster is grounded.5. The optical module according to claim 1 , further comprising:a first resistor electrically connecting the power source and the differential signal output positive terminal; anda second resistor electrically connecting the power ...

DML Driver

The DML driver includes: a post driver which supplies a driving current to the LD; and a pre-driver which drives the post driver in response to a modulated signal. The pre-driver has a transistor, a peaking inductor, a peaking inductor, a group delay inhibition inductor, and a peaking capacitor. 14.-. (canceled)5. A DML driver comprising:a post driver configured to supply a driving current to a laser diode; and a first transistor, wherein the inputted modulated signal is configured to be input into a gate of the first transistor or a base of the first transistor;', 'a first resistor, wherein a first end of the first resistor is connected to a first power supply voltage;', 'a first inductor, wherein a first end of the first inductor is connected to a second end of the first resistor, wherein a second end of the first inductor is connected to a drain of the first transistor or a collector of the first transistor;', 'a second inductor, wherein a first end of the second inductor is connected to the drain of the first transistor or the collector of the first transistor, wherein a second end of the second inductor is connected to an input terminal of the post driver;', 'a third inductor, wherein a first end of the third inductor is connected to a source of the first transistor or an emitter of the first transistor, wherein a second end of the third inductor is connected to a second power supply voltage; and', 'a capacitor, wherein a first end of the capacitor is connected to the source of the first transistor or the emitter of the first transistor, wherein a second end of the capacitor is connected to the second power supply voltage., 'a pre-driver configured to drive the post driver in response to an inputted modulated signal, the pre-driver including6. The DML driver according to claim 5 , wherein the pre-driver further includes a second resistor between the source of the first transistor or the emitter of the first transistor and the first end of the third inductor as ...

Distributed reflector laser

A distributed reflector (DR) laser may include a distributed feedback (DFB) region and a distributed Bragg reflector (DBR). The DFB region may have a length in a range from 30 micrometers (μm) to 100 μm and may include a DFB grating with a first kappa in a range from 100 cm−1 to 150 cm−1. The DBR region may be coupled end to end with the DFB region and may have a length in a range from 30-300 μm. The DBR region may include a DBR grating with a second kappa in a range from 150 cm−1 to 200 cm−1. The DR laser may additionally include a lasing mode and a p-p resonance frequency. The lasing mode may be at a long wavelength side of a peak of a DBR reflection profile of the DBR region. The p-p resonance frequency may be less than or equal to 70 GHz.

METHOD TO TUNE EMISSION WAVELENGTH OF WAVELENGTH TUNABLE LASER APPARATUS AND LASER APPARATUS

A method to tune an emission wavelength of a wavelength tunable laser apparatus is disclosed. The laser apparatus implements, in addition to a wavelength tunable laser diode (t-LD) integrating with a semiconductor optical amplifier (SOA), a wavelength monitor including an etalon filter. The current emission wavelength is determined by a ratio of the magnitude of a filtered beam passing the etalon filter to a raw beam not passing the etalon filter. The method first sets the SOA in an absorbing mode to sense stray component disturbing the wavelength monitor, then correct the ratio of the beams by subtracting the contribution from the stray component. 1. A method to tune an emission wavelength of a laser apparatus that includes a wavelength tunable laser diode (t-LD) integrating a laser diode (LD) with a semiconductor optical amplifier (SOA) , and a wavelength monitor to sense the emission wavelength of the t-LD , the wavelength monitor disposed in one of a front side and a rear side of the t-LD , the wavelength monitor including an optical filter , a first photodiode (PD) to sense a raw beam not transmitting through the optical filter , and a second PD to sense a filtered beam split from the raw beam and transmitting through the optical filter , the method comprising steps of:evaluating a first stray component and a second stray component by the first PD and the second PD, respectively, the first stray component and the second stray component originating to an optical beam output from another of the front side and the rear side not disposing the wavelength monitor;sensing the raw beam and the filtered beam by the first PD and the second PD, respectively; andcalculating a ratio of the filtered beam subtracted with the second stray component to the raw beam subtracted with the first stray component,wherein the SOA is integrated in the front side of the t-LD and the wavelength monitor is disposed in the front side of the t-LD, and setting the SOA in an absorbing mode;', ...

Method for controlling tunable wavelength laser

In the method for controlling a tunable wavelength laser, information designating an oscillation wavelength is inputted. A driving condition for causing laser oscillation at a first wavelength is acquired from a memory. A control value of wavelength characteristics of the etalon and a difference between the first wavelength and a second wavelength are referred to, and a control value of wavelength characteristics of the etalon for causing laser oscillation at the second wavelength is calculated. The control value of wavelength characteristics of the etalon are assigned to the tunable wavelength laser, and a wavelength is controlled so that a wavelength sensing result becomes a first target value. Information indicating a wavelength shift amount from the designated oscillation wavelength is inputted. The wavelength sensing result is calculated as a second target value. The wavelength is controlled so that the wavelength sensing result becomes the second target value.

Optical modulator having reflection layers

An optical modulator is provided, including a lower reflection layer, an active layer formed on the lower reflection layer, and an upper reflection layer formed on the active layer. The active layer includes a multiple quantum well structure including a quantum well layer and a quantum barrier layer. The upper reflection layer includes a dielectric material. A plurality of micro cavity layers are included in the upper reflection layer.

Adjustable Termination Circuit for High Speed Laser Driver

Disclosed is a circuit having a high speed laser driver circuit, a semiconductor laser electrically connected to the high speed laser driver circuit, and an adjustable termination circuit electrically connected between the high speed laser driver circuit and the semiconductor laser, where the adjustable termination circuit is configured to control an output impedance seen by the semiconductor laser as a function of an input current provided to the adjustable termination circuit.

LASER DRIVING CIRCUIT, LASER DRIVING METHOD, AND DEVICE USING LASER LIGHT

A laser driving circuit, a laser driving method, and a device using laser light that can reduce speckle noise caused by laser light as coherent light are provided. 1. A projection apparatus comprising:a high-frequency superimposing section in a laser driving circuit, the high-frequency superimposing section is configured to receive a clock signal input from circuitry that is external to the laser driving circuit; anda signal processing system configured to generate an input video signal, the high-frequency superimposing section is configured to change amplitude of a high-frequency signal in accordance with a level of the input video signal.2. The projection apparatus according to claim 1 , wherein the clock signal is synchronized with the input video signal before the high-frequency superimposing section receives the clock signal.3. The projection apparatus according to claim 1 , further comprising:a light source unit in an optical system, the light source unit configured to receive laser driving current from the laser driving circuit.4. The projection apparatus according to claim 3 , further comprising:laser driving video current generation sections in the laser driving circuit, the laser driving video current generation sections are configured to output the laser driving current to the light source unit.5. The projection apparatus according to claim 3 , wherein the light source unit is controllable by the laser driving current to emit different wavelengths of light.6. The projection apparatus according to claim 3 , wherein the high-frequency signal is of a frequency that exceed a band of the video signal on the laser driving current.7. The projection apparatus according to claim 3 , wherein the high-frequency superimposing section is configured to superimpose the high-frequency signal onto the laser driving current. This is a Continuation application of U.S. patent application Ser. No. 14/349,592, filed Apr. 3, 2014, which is a National Stage Entry of Application ...

GENERATION OF OUTPUT LASER PULSES HAVING A TUNABLE CENTRAL WAVELENGTH

In a device for generating output laser pulses having a tunable central wavelength, based on parametric amplification, a laser system is to be provided that has less complexity, but that nevertheless provides great tunability for the wavelength, permits rapid switching of the wavelength, and allows the spectral bandwidth of the emitted pulses to be adjusted. This is attained in that for adjustability of the bandwidth of the output laser pulses, an optical device is provided that is designed to influence the spectral phase of the pump pulses as a function of the spectral phase of the seed pulses. 1. A device for generating output laser pulses having a tunable central wavelength , based on parametric amplification , comprising:an optical pump pulse generator having an adjustable repetition rate for generating pump pulses,a fiber-based optical parametric oscillator having a feedback device and a parametric amplifying medium, embodied to receive the pump pulses and convert the latter using parametric generation to a wavelength-shifted idler pulse and a signal pulse wavelength-shifted thereto, and,a dispersive feedback device designed to feed back the idler pulse or the signal pulse via a resonator, so that the idler pulse or the signal pulse then may be used as seed pulse for the parametric amplification,wherein,for adjustability of the bandwidth of the output laser pulses, an optical device is provided that is designed to influence the spectral phase of the pump pulses as a function of the phase of the seed pulses.2. The device according to claim 1 , wherein the optical device is embodied to influence the spectral phase of the pump pulses following pulse generation.3. The device according to claim 1 , wherein the optical device is arranged in the optical path between pump pulse generator and fiber-based optical parametric oscillator for influencing the spectral phase of the pump pulses.4. The device according to claim 1 , wherein the optical device is embodied as glass ...

Blue Laser Aiming Device

A laser aiming device includes a laser generator and a module activating the laser generator to generate a non-continuous laser beam in order to form a bright spot of light in a flickering manner that a flickering interval of the bright spot of light is short enough not to be noticed by a human eye. A pulse width modulation (PWM) of the control module modulates the laser beam in form of rectangular pulse wave to control an output power of the non-continuous laser beam being not exceed 5 mW continuous wave. 1. A laser aiming device , comprising:a laser generator, anda control module activating said laser generator to generate a non-continuous laser beam in order to form a bright spot of light in a flickering manner that a flickering interval of said bright spot of light is short enough not to be noticed by a human eye.2. The laser aiming device claim 1 , as recited in claim 1 , wherein said laser generator is a blue laser generator to generate said non-continuous laser beam in blue color with an output power thereof being not exceed 5 mW continuous wave.3. The laser aiming device claim 1 , as recited in claim 1 , wherein said control module comprises a pulse width modulation (PWM) to activate said laser generator in an on-and-off manner so as to enable said laser generator to generate said non-continuous laser beam.4. The laser aiming device claim 2 , as recited in claim 2 , wherein said control module comprises a pulse width modulation (PWM) activating said laser generator in an on-and-off manner so as to enable said laser generator to generate said non-continuous laser beam.5. The laser aiming device claim 3 , as recited in claim 3 , further comprising an output power controller operatively linked to said control module claim 3 , wherein said pulse width modulation modulates said laser beam in form of rectangular pulse wave that said output power controller selectively adjusts a pulse duration of said rectangular pulse wave in each period thereof.6. The laser ...

METHOD FOR CONTROLLING WAVELENGTH-TUNABLE LASER

The method for controlling a wavelength-tunable laser comprises a first step of acquiring a driving condition of the wavelength-tunable laser for laser oscillation at a first wavelength, and a second step of calculating according to the driving condition of the first wavelength and a wavelength difference between the first wavelength and a second wavelength different from the first wavelength a control value or target value of a wavelength characteristic of the second wavelength in the wavelength detection unit, so as to calculate a driving condition for driving the wavelength-tunable laser, the second step including a step of selecting according to the wavelength difference one of etalon slopes having respective gradients identical and opposite to a gradient of an etalon slope used for controlling the first wavelength. 14.-. (canceled)5. A method for controlling a wavelength-tunable laser comprising a wavelength detection unit having an etalon , the method comprising:a first step of acquiring from a memory a first driving condition for laser-oscillating the wavelength-tunable laser at a first wavelength;a second step of computing a second driving condition for oscillating the wavelength-tunable laser at a second wavelength with reference to the first driving condition and a wavelength difference between the first and second wavelengths; anda third step of detecting with the wavelength detection unit an output wavelength of the wavelength-tunable laser driven according to the second driving condition and performing according to a result thereof feedback control for correcting the driving conditions of the wavelength-tunable laser;the method further comprising a step, before the third step, of determining whether or not to reverse a correction sign for the correction in the feedback control with respect to a correction sign in the first driving condition.6. The method for controlling a wavelength-tunable laser according to claim 5 , wherein the correction sign is ...

Independent control of emission wavelength and output power of a semiconductor laser

Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms.

Laser

A vertical cavity surface emitting laser (VCSEL) configured to operate in a gain switching regime includes a cavity that is terminated by reflectors at both ends for enabling a standing wave of optical radiation therebetween. The cavity comprises at least one quantum well, each of the quantum wells located at a position where a value of a standing wave factor for each quantum well is between zero and one, 0<ξ<1.

DFB WITH WEAK OPTICAL FEEDBACK

A distributed feedback plus reflection (DFB+R) laser includes an active section, a passive section, a low reflection (LR) mirror, and an etalon. The active section includes a distributed feedback (DFB) grating and is configured to operate in a lasing mode. The passive section is coupled end to end with the active section. The LR mirror is formed on or in the passive section. The etalon includes a portion of the DFB grating, the passive section, and the LR mirror. The lasing mode of the active section is aligned to a long wavelength edge of a reflection peak of the etalon.

OPTICAL PULSE OUTPUT APPARATUS AND METHOD FOR CONTROLLING WIDTH AND INTENSITY OF OPTICAL PULSE

An optical pulse output apparatus and method for controlling a width and an intensity of an optical pulse are provided. The optical pulse output apparatus may include a laser driver to control an optical pulse output by a laser, based on a plurality of channel signals, and a channel delay unit to delay at least one of the plurality of channel signals. 1. An optical pulse output apparatus , comprising:a laser driver to drive a laser to output an optical pulse based on a plurality of channel signals, the optical pulse having a width;a channel delay unit to change an amount of time by which at least one of the plurality of channel signals is delayed; andthe laser driver to further drive the laser to output an optical pulse having a changed width which is changed in accordance with the changed amount of time.23-. (canceled)4. The optical pulse output apparatus of claim 1 , wherein the channel delay unit changes the amount of time by increasing the amount of time claim 1 , and wherein the laser driver further drives the laser to output an optical pulse having an increased width which is increased in accordance with the increased amount of time.5. The optical pulse output apparatus of claim 1 , wherein claim 1 , when the channel delay unit does not delay the at least one channel signal claim 1 , the laser driver determines the width of the optical pulse claim 1 , based on a width of each of the plurality of channel signals.6. The optical pulse output apparatus of claim 1 , further comprising:a maximum current controller to control a maximum current of the laser driver.7. The optical pulse output apparatus of claim 6 , wherein the laser driver determines an intensity of the optical pulse claim 6 , based on the maximum current.8. The optical pulse output apparatus of claim 6 , wherein claim 6 , when the maximum current increases claim 6 , the laser driver increases the intensity of the optical pulse.910-. (canceled)11. An optical pulse output method claim 6 , comprising: ...

DFB WITH WEAK OPTICAL FEEDBACK

A distributed feedback plus reflection (DFB+R) laser includes an active section, a passive section, a low reflection (LR) mirror, and an etalon. The active section includes a distributed feedback (DFB) grating and is configured to operate in a lasing mode. The passive section is coupled end to end with the active section. The LR mirror is formed on or in the passive section. The etalon includes a portion of the DFB grating, the passive section, and the LR mirror. The lasing mode of the active section is aligned to a long wavelength edge of a reflection peak of the etalon. 1. A distributed feedback plus reflection (DFB+R) laser , comprising:a distributed feedback (DFB) section configured to operate in a lasing mode;a high reflection (HR) mirror coupled to a rear of the DFB section;a passive section coupled to a front of the DFB section; anda low reflection (LR) mirror formed at a front of the passive section;wherein the passive section, a portion of the DFB section at the front of the DFB section, and the LR mirror form an etalon having a reflection profile with periodic peaks and valleys, and wherein the lasing mode of the DFB section is aligned to a long wavelength edge of one of the periodic peaks of the reflection profile of the etalon.2. The DFB+R laser of claim 1 , wherein the LR mirror has a reflectivity of 15% or less.3. The DFB+R laser of claim 1 , wherein the LR mirror has a reflectivity of 10% or less.4. The DFB+R laser of claim 1 , wherein the passive section is configured to impart a phase shift of about 20 degrees to light propagating in the DFB+R laser.5. The DFB+R laser of claim 1 , wherein the HR mirror has a reflectivity of 30% or more.6. The DFB+R laser of claim 1 , further comprising a modulation contact coupled to the DFB section and configured to provide a modulation signal to the DFB section to modulate the DFB section claim 1 , wherein modulation of the DFB section modulates cavity loss of the DFB+R laser and increases carrier-photon resonance ...

Pulsed bias current for gain switched semiconductor lasers for amplified spontaneous emission reduction

Gain switched laser diode pulses are used as seed pulses for optical pulse generation. ASE is reduced by applying a prebias to the laser diodes at an amplitude less than that associated with a laser diode threshold. An electrical seed pulse having an amplitude larger than that associated with laser threshold is applied within about 10-100 ns of the prebias pulse. The resulting laser diode pulse can be amplified in a pumped, rare earth doped optical fiber, with reduced ASE.

Tunable laser with high thermal wavelength tuning efficiency

A monolithically integrated thermal tunable laser comprising a layered substrate comprising an upper surface and a lower surface, and a thermal tuning assembly comprising a heating element positioned on the upper surface, a waveguide layer positioned between the upper surface and the lower surface, and a thermal insulation layer positioned between the waveguide layer and the lower surface, wherein the thermal insulation layer is at least partially etched out of an Indium Phosphide (InP) sacrificial layer, and wherein the thermal insulation layer is positioned between Indium Gallium Arsenide (InGaAs) etch stop layers.

DISCRETE WAVELENGTH TUNABLE LASER

A multisection digital supermode-distributed Bragg reflector (MSDS-DBR) comprising: a plurality P of digital supermode Bragg reflector (DS-DBR) grating sections arranged along a waveguide; wherein each DS-DBR grating section is configured to pass or reflect light over a given spectral region, the given spectral region being different from the spectral regions of the other DS-DBR grating sections; wherein each DS-DBR grating section comprises a plurality M of grating sub-regions, each sub-region corresponding to a spectral sub-band within the spectral region of the DS-DBR grating section, and wherein each grating sub-region includes a positive electrical contact and a negative electrical contact; said grating sub-region being configured to pass or reflect light of its spectral sub-band when an electrical bias is provided between its positive and negative electrical contacts. 1. A reflector comprising:one or more digital supermode Bragg reflector (DS-DBR) grating sections arranged along a waveguide; whereineach DS-DBR grating section is configured to pass or reflect light over a given spectral region, the given spectral region being different from the spectral regions of the other DS-DBR grating sections;wherein each DS-DBR grating section comprises a plurality of grating sub-regions, each grating sub-region corresponding to a spectral sub-band within the spectral region of the DS-DBR grating section, andwherein each grating sub-region includes a positive electrical contact and a negative electrical contact; said grating sub-region being configured to pass or reflect light of its spectral sub-band when an electrical bias is provided between its positive and negative electrical contacts.2. The reflector of claim 1 ,wherein the one or more DS-DBR grating sections include at least two DS-DBR grating sections, wherein the reflector comprises a common electrode structure shared between two or more of the DS-DBR grating sections; 'the common electrode structure includes a ...

Tunable Waveguide Devices

Methods, systems, and apparatus, including a laser including a layer having first and second regions, the first region including a void; a mirror section provided on the layer, the mirror section including a waveguide core, at least part of the waveguide core is provided over at least a portion of the void; a first grating provided on the waveguide core; a first cladding layer provided between the layer and the waveguide core and supported by the second region of the layer; a second cladding layer provided on the waveguide core; and a heat source configured to change a temperature of at least one of the waveguide core and the grating, where an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core.

Wavelength Stabilizer For TWDM-PON Burst Mode DBR Laser

An optical network unit (ONU) comprising a media access controller (MAC) configured to support biasing a laser transmitter to compensate for temperature related wavelength drift receiving a transmission timing instruction from an optical network control node, obtaining transmission power information for the laser transmitter, estimating a burst mode time period for the laser transmitter according to the transmission timing instruction, and calculating a laser phase fine tuning compensation value for the laser transmitter according to the burst mode time period and the transmission power information, and forwarding the laser phase fine tuning compensation value toward a bias controller to support biasing a phase of the laser transmitter. 1. A method implemented in a passive optical network (PON) comprising:transmitting an optical signal in the PON via a laser transmitter utilizing time and wavelength division multiplexing (TWDM); anddynamically compensating for a red-shift in a wavelength of the optical signal associated with an increase in temperature of the laser transmitter associated with a duration of an optical signal burst,wherein compensation is performed by introducing a blue-shift wavelength bias to the laser transmitter.2. The method of claim 1 , wherein compensating for the red-shift in the wavelength comprises:obtaining optical transmission power information based on real-time measurement of photo-current across a photodiode of the laser transmitter;estimating a burst mode time period according to received timeslot instructions; andcalculating an injection current for use as the blue-shift wavelength bias to compensate for the wavelength red-shift based on the estimated burst mode time period and the optical transmission power information.3. The method of claim 2 , wherein calculating the injection current for use as the blue-shift wavelength bias is performed by a media access controller (MAC).4. The method of claim 3 , wherein compensating for the red- ...

Switching Circuit for Burst-mode Tunable Laser

A method () for tuning a tunable laser () includes delivering a bias current (I) to an anode of a distributed Bragg reflector (DBR) section diode (D) disposed on a shared substrate of the tunable laser and receiving a burst mode signal () indicative of a burst-on state or a burst-off state. When the burst mode signal is indicative of the burst-off state, the method includes offsetting the bias current at the anode of the DBR section diode by one of sourcing a push current with the bias current to the anode of the DBR section diode or sinking a pull current away from the bias current at the anode of the DBR section diode. When the burst mode signal is indicative of the burst-on state, the method also includes ceasing any offsetting of the bias current at the anode of the DBR section diode. 1. A method for tuning a tunable laser , the method comprising:delivering, by a switching circuit, a bias current to an anode of a distributed Bragg reflector (DBR) section diode disposed on a shared substrate of the tunable laser;receiving, at the switching circuit, a burst mode signal indicative of a burst-on state or a burst-off state; sourcing a push current with the bias current to the anode of the DBR section diode; or', 'sinking a pull current away from the bias current at the anode of the DBR section diode; and, 'when the burst mode signal is indicative of the burst-off state, offsetting, by the switching circuit, the bias current at the anode of the DBR section diode by one ofwhen the burst mode signal is indicative of the burst-on state, ceasing, by the switching circuit, any offsetting of the bias current at the anode of the DBR section diode.2. The method of claim 1 , wherein:the bias current at the anode of the DBR section diode causes the tunable laser to transmit on a first channel associated with a working wavelength when the burst mode signal is indicative of the burst-on state; andthe offsetting of the bias current at the anode of the DBR section diode causes the ...

DISTRIBUTED REFLECTOR LASER

A distributed reflector (DR) laser may include a distributed feedback (DFB) region and a distributed Bragg reflector (DBR). The DFB region may have a length in a range from 30 micrometers (μm) to 100 μm and may include a DFB grating with a first kappa in a range from 100 cmto 150 cm. The DBR region may be coupled end to end with the DFB region and may have a length in a range from 30-300 μm. The DBR region may include a DBR grating with a second kappa in a range from 150 cmto 200 cm. The DR laser may additionally include a lasing mode and a p-p resonance frequency. The lasing mode may be at a long wavelength side of a peak of a DBR reflection profile of the DBR region. The p-p resonance frequency may be less than or equal to 70 GHz. 1. A distributed reflector (DR) laser , comprising:a distributed feedback (DFB) region;a distributed Bragg reflector (DBR) region coupled end to end with the DFB region;a lasing mode at a long wavelength side of a peak of a DBR reflection profile of the DBR region; anda p-p resonance frequency in a range from 50-60 gigahertz (GHz); andan intrinsic resonant frequency (Fr) in a range from 15-38 GHz.2. The DR laser of claim 1 , wherein the length of the DFB region is 50 μm claim 1 , the first kappa of the DFB grating is 120 cm claim 1 , the length of the DBR region is 200 μm claim 1 , and the second kappa of the DBR grating is 180 cm.3. The DR laser of claim 1 , wherein the DFB region has a first stop-band that is wider than a second stop-band of the DBR region.4. The DR laser of claim 3 , wherein the first stop-band of the DFB region is 8 nanometers (nm) in width and the second stop-band of the DBR region is 5 nm in width.5. The DR laser of claim 1 , wherein the DFB region further comprises a multiple quantum well (MQW) structure having a large linewidth enhancement factor α.6. The DR laser of claim 5 , wherein the linewidth enhancement factor an of the MQW structure is greater than or equal to 4.7. The DR laser of claim 6 , wherein the ...

Drive circuit

A drive circuit includes a GaN FET having a source connected to an anode of an LD and a drain connected to a power source of the LD, a gate drive having an output port connected to a gate of the GaN FET and a negative voltage port connected to the source of the GaN FET to receive an input voltage at a positive voltage port and output the input voltage from the output port in response to a signal with a predetermined level, a capacitor between the positive and negative voltage ports of the gate drive, a diode on a power source line connecting the positive voltage port of the gate drive and a VDD power source for outputting a voltage less than the breakdown voltage at a voltage Vgs of the GaN FET, and a semiconductor switch between the source of the GaN FET and the ground.

METHODS FOR PRODUCING A LASER PULSE AND DEVICES FOR PRODUCING A DRIVER CONTROL SIGNAL

In methods and devices for generating a laser pulse of an excitation laser that is actuated by a driver in response to a triggering time of a trigger signal, the driver actuation signal is generated taking into account the time interval between the triggering time and a preceding triggering time. 1. A method for producing a laser pulse of an excitation laser , the method comprising:receiving an actuation time of an actuation signal or a laser pulse,controlling the excitation laser by a driver, andproducing a driver control signal taking into account a time interval of the actuation time or laser pulse with respect to a previously received actuation time or laser pulse.2. The method of claim 1 , wherein the driver control signal is produced taking into account properties of an optical amplifier controlled by the excitation laser.3. The method of claim 1 , wherein producing the driver control signal comprises compensating for a digitally encoded pulse shape with a digitally encoded compensation signal claim 1 , wherein the digitally encoded compensation signal is dependent on the time interval and the compensated digitally encoded pulse shape is converted into an analog signal.4. The method of claim 3 , comprising reading the digitally encoded compensation signal in accordance with the time interval from a compensation signal store.5. The method of claim 3 , further comprising resetting the compensation signal in a time-delayed manner with respect to the actuation time.6. The method of claim 3 , further comprising resetting the compensation signal at the end of the produced pulse shape.7. The method of claim 1 , wherein producing the driver control signal comprises producing a pulse shape from a digitally encoded pulse shape by digital to analog conversion that is compensated for with a compensation signal claim 1 , wherein the compensation signal is dependent on the time interval.8. The method of claim 7 , wherein the compensation signal is a time-dependent factor in ...

Laser clock signal generators

A laser clock signal generator for controlling a laser beam generator to generate pulse laser radiation is provided. The laser clock signal generator includes a clock signal specification input arranged to receive an external clock specification signal, a basic clock signal generator configured to generate a basic clock signal based on the external clock specification signal and output the basic lock signal at a clock signal output to the laser beam generator, and a controller configured to control the basic clock generator, for example, to be synchronized with the external clock specification signal. The laser clock signal generator also includes an overclocking protector arranged between the basic clock generator and the clock signal output.

GENERATING LASER PULSES

A laser pulse generator includes a pulse shape generation device and a clock unit. The generation device includes a pulse shape repository, a digital-to-analog converter (DAC), a first terminal for connecting a start signal line, a second terminal for connecting a clock signal line, and a third terminal for connecting a pulse line. The first and second terminals are connected to the pulse shape repository and the DAC such that when a predefined start signal is present, data is transferred from the pulse shape repository to the DAC and converted by the DAC into an output pulse, for example, at a rate of a clock signal. The output pulse is supplied at the third terminal for actuating a driver of a laser diode. The clock unit is connected to the second terminal via the clock signal line and includes a reset terminal connected to the start signal line. 1. A laser pulse generator comprising: a pulse shape repository storing data,', 'a digital/analogue converter (DAC) connected to the pulse shape repository,', 'a first connection for connecting a start signal line of a start signal path,', 'a second connection for connecting a clock signal line, and', 'a third connection for connecting a pulse line,', 'wherein the first and second connections are connected to the pulse shape repository and the DAC, wherein the pulse shape repository is arranged to direct pulse shape data to the DAC upon receiving a predetermined start signal, and wherein the DAC is configured to convert the pulse shape data into an output pulse and to provide the output pulse to the third connection to control a driver of a laser diode; and, 'a pulse shape generation device havinga clock unit connected to the second connection by the clock signal line and configured to output a clock signal to the pulse shape generation device, wherein the clock unit comprises a reset connection connected to the start signal path.2. The laser pulse generator of claim 1 , wherein the DAC is configured to convert the pulse ...

Independent Control of Emission Wavelength and Output Power of a Semiconductor Laser

Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms. 120-. (canceled)21. A method of driving a semiconductor laser , comprising:applying a laser injection current to the semiconductor laser to generate a laser output power targeting a predetermined output power; andapplying a tuning current to a tuning element to generate a laser emission wavelength targeting a predetermined laser emission wavelength; wherein the semiconductor laser and the tuning element are configured to control the laser emission wavelength and the laser output power of the semiconductor laser independently of one another.22. The method of claim 21 , further comprising:varying the laser injection current while maintaining an approximately consistent submount temperature such that the laser output power is linearly dependent on the laser injection current.23. The method of claim 22 , wherein the laser output power is linearly dependent on the laser injection current when the laser injection current exceeds a laser threshold current.24. The method of claim 23 , further comprising:determining a laser slope efficiency based at least in part on the linear ...

Quantum cascade laser

A quantum cascade laser includes a semiconductor substrate, an optical waveguide formed on a first surface of the semiconductor substrate, and a temperature adjusting member. The optical waveguide includes a first region and a second region located on one side with respect to the first region in the optical waveguide direction of the optical waveguide. The first region generates a first light having a first wavelength, and the second region generates a second light having a second wavelength. The optical waveguide generates an output light having a frequency corresponding to a difference between the first wavelength and the second wavelength by difference-frequency generation. A recess for suppressing heat transfer between the first region and the second region is formed at a second surface of the semiconductor substrate. The temperature adjusting member includes a first temperature adjusting member for adjusting the temperature of the second region.

QUANTUM DOT SOA-SILICON EXTERNAL CAVITY MULTI-WAVELENGTH LASER

A hybrid external cavity multi-wavelength laser using a QD RSOA and a silicon photonics chip is demonstrated. Four lasing modes at 2 nm spacing and less than 3 dB power non-uniformity were observed, with over 20 mW of total output power. Each lasing peak can be successfully modulated at 10 Gb/s. At 10BER, the receiver power penalty is less than 2.6 dB compared to a conventional commercial laser. An expected application is the provision of a comb laser source for WDM transmission in optical interconnection systems. 1. An optical cavity , comprising: 'a single optical port configured to provide an optical output beam;', 'a substrate having a surface, said surface having situated thereon 'a filter element in optical communication with said first mirror element, said filter element configured to pass an optical beam having a selected optical wavelength therethrough; and', 'a first mirror element comprising a submicron silicon waveguide, said first mirror element having a first transmittance and a first reflectivity, said first mirror element forming a first optical reflector situated at a first end of the optical cavity, said first mirror element in optical communication with said single optical port; and'}an optical gain medium comprising a second mirror element having a second transmittance and a second reflectivity, said second mirror element forming a second optical reflector situated at a second end of the optical cavity.2. The optical cavity of claim 1 , wherein said substrate is silicon.3. The optical cavity of claim 1 , wherein said optical gain medium comprises a quantum dot reflective semiconductor optical amplifier.4. The optical cavity of claim 1 , wherein said first mirror element is a Sagnac loop mirror.5. The optical cavity of claim 1 , wherein said first mirror element is a broadband reflector.6. The optical cavity of claim 1 , wherein said first mirror element has a reflectivity that increases as the selected wavelength is increased.7. The optical ...

HIGH POWER AND HIGH QUALITY LASER SYSTEM AND METHOD

A laser system is provided that includes a modulated laser, which is configured to generate an amplitude modulated laser signal, comprising a first amplitude modulation. The first amplitude modulation is based on a data signal. Moreover, the laser system includes an optical modulator, which is configured to receive the amplitude modulated laser signal as an input signal, and modulate the amplitude modulated laser signal with a second amplitude modulation, based on the data signal, resulting in an amplitude modulated output laser signal. 1. A laser system comprising:a modulated laser, configured to generate an amplitude modulated laser signal, comprising a first amplitude modulation, wherein the first amplitude modulation is based on a data signal; and receive the amplitude modulated laser signal as an input signal; and', 'modulate the amplitude modulated laser signal with a second amplitude modulation, based on the data signal, resulting in an amplitude modulated output laser signal., 'an optical modulator, configured to2. The laser system of claim 1 ,wherein the amplitude modulated output laser signal comprises one or more of an enhanced modulation depth or a higher extinction ratio than the amplitude modulated laser signal.3. The laser system of claim 1 , 'a Fabry-Perot Laser, and', 'wherein the modulated laser is one of: a single longitudinal mode laser, wherein the single longitudinal mode laser is one of: a distributed feedback laser, a distributed bragg reflector laser, a distributed reflector laser, a single wavelength vertical cavity laser, or an external cavity laser; or'}wherein the optical modulator is an electro-absorption modulator.4. The laser system of claim 1 , generating a first control signal for controlling the first amplitude modulation, based upon the data signal; and', 'generating a second control signal for controlling the second amplitude modulation, based upon the data signal., 'further comprising a driver, the driver configured for5. The ...

Burst Mode Laser Driving Circuit

A method ( 900 ) includes a gain current (I GAIN ) to an anode of a gain-section diode (D 0 ) disposed on a shared substrate of a tunable laser ( 310 ), delivering a modulation signal to an anode of an Electro-absorption section diode (D 2 ) disposed on the shared substrate of the tunable laser, and receiving a burst mode signal ( 330 ) indicative of a burst-on state or a burst-off state. When the burst mode signal is indicative of the burst-off state, the method includes sinking a sink current (I SINK ) away from the gain current at the anode of the gain-section diode. When the burst mode signal transitions to be indicative of the burst-on state from the burst-off state, the method includes ceasing the sinking of the sink current away from the gain current and delivering an overshoot current (I OVER ) to the anode of the gain-section diode.

Fast tunable integrated laser

An apparatus includes a wavelength-tunable laser and an electronic controller. The electronic controller is configured to control the wavelength-tunable laser such that an output wavelength of the wavelength-tunable laser performs a zigzag in time. The wavelength-tunable laser is capable of rapidly and densely scanning wavelengths across a broad spectral range.

Angled dbr-grating laser/amplifier with one or more mode-hopping regions

A semiconductor laser device is disclosed that includes a laser resonator situated to produce a laser beam, with the laser resonator including an angled distributed Bragg reflector (a-DBR) region including first and second ends defining an a-DBR region length corresponding to a Bragg resonance condition with the first end being uncleaved and including a first mode hop region having a first end optically coupled to the a-DBR region first end and extending a first mode hop region length associated with the a-DBR region length to a second end so as to provide a variable longitudinal mode selection for the laser beam.

SEMICONDUCTOR LASER, ELECTRONIC APPARATUS, AND METHOD OF DRIVING SEMICONDUCTOR LASER

In a semiconductor laser according to an embodiment of the present disclosure, a ridge part has a structure in which a plurality of gain regions and a plurality of Q-switch regions are each disposed alternately with each of separation regions being interposed therebetween in an extending direction of the ridge part. The separation regions each have a separation groove that separates from each other, by a space, the gain region and the Q-switch region adjacent to each other. The separation groove has a bottom surface at a position, in a second semiconductor layer, higher than a part corresponding to a foot of each of both sides of the ridge part. 1. A semiconductor laser comprising , on a semiconductor substrate:a first semiconductor layer of a first conductivity type;an active layer;a second semiconductor layer of the first conductivity type;a third semiconductor layer of a second conductivity type, in order; anda ridge part formed in the second semiconductor layer and the third semiconductor layer, and extending in a stacked in-plane direction,the ridge part having a structure in which a plurality of gain regions and a plurality of Q-switch regions are each disposed alternately with each of separation regions being interposed therebetween in an extending direction of the ridge part,the separation regions each having a separation groove that separates from each other, by a space, the gain region and the Q-switch region adjacent to each other,the separation groove having a bottom surface at a position, in the second semiconductor layer, higher than a part corresponding to a foot of each of both sides of the ridge part.2. The semiconductor laser according to claim 1 , whereinthe second semiconductor layer includes a first different-composition-ratio semiconductor layer having a composition ratio different from a composition ratio of another part of the second semiconductor layer, andthe bottom surface is a portion of a top surface of the first different-composition- ...

VERNIER EFFECT DBR LASERS INCORPORATING INTEGRATED TUNING ELEMENTS

Disclosed is a Vernier effect DBR laser that has uniform laser injection current pumping along the length of the laser. The laser can include one or more tuning elements, separate from the laser injection element, and these tuning elements can be used to control the temperature or modal refractive index of one or more sections of the laser. The refractive indices of each diffraction grating can be directly controlled by temperature changes, electro optic effects, or other means through the one or more tuning elements. With direct control of the temperature and/or refractive indices of the diffraction gratings, the uniformly pumped Vernier effect DBR laser can be capable of a wider tuning range. Additionally, uniform pumping of the laser through a single electrode can reduce or eliminate interfacial reflections caused by, for example, gaps between metal contacts atop the laser ridge, which can minimize multi-mode operation and mode hopping. 1. A semiconductor laser comprising: two or more grating sections, each grating section including a one or more diffraction gratings, each grating section including a reflection spectrum comprising a plurality of peaks with a wavelength spacing; and', 'one or more tuning sections;', 'an optical gain region;, 'a plurality of sections includinga first electrode disposed on the optical gain region and at least one of the two or more grating sections; andone or more second electrodes, each second electrode disposed on at least one of the one or more tuning sections.2. The laser of claim 1 , further comprising:a trench located at least partially between the first electrode and at least one of the one or more second electrodes.3. The laser of claim 2 , wherein the trench is associated with at least one of the one or more second electrodes claim 2 , and an injection of a current into the at least one of the one or more second electrodes generates heat.4. The laser of claim 1 , wherein the two or more grating sections include a first ...

Laser temperature compensation system and driving method thereof

An optical transmitter and a method for driving the optical transmitter include emitting an optical signal using a laser having a lasing cavity with a first section and a second section, performing, using a first heater thermally coupled to the first section, a first temperature control on the first section using a first control signal, and performing, using a second heater thermally coupled to the second section, a second temperature control on the second section using a second control signal. The first temperature control is independent from the second temperature control.

METHOD FOR PHYSICAL RANDOM NUMBER GENERATION USING A VERTICAL CAVITY SURFACE EMITTING LASER

A method for physical random number generation includes the steps of: modulating the gain of a vertical-cavity surface-emitting laser periodically from the lower threshold to the upper threshold and back; maintaining the gain per round trip positive for a longer period than the round trip time of the cavity; maintaining the net gain per round trip negative for a longer period than the round trip time of the cavity, in order to create optical pulses of random amplitude; detecting the optical pulses; converting the optical pulses into electrical analog pulses; and digitising the electrical analog pulses into random numbers. 1. A method for physical random number generation comprising the steps of:modulating the gain of a vertical-cavity surface-emitting laser periodically from below threshold to above threshold and back;maintaining gain per round trip positive for a longer period than the round trip time of the cavity;maintaining net gain per round trip negative for a longer period than the round trip time of the cavity, to create optical pulses of random amplitude;detecting the optical pulses;converting the optical pulses into electrical analog pulses; anddigitising the electrical analog pulses into random numbers.2. The method according to claim 1 , wherein the step of detecting optical pulses is performed by a fast photodiode3. The method according to claim 2 , wherein the step of modulating gain is performed by an electrical pulse driver.4. The method according to claim 1 , wherein the step of modulating gain is performed by an electrical pulse driver. The present application is a § 371 national stage of International Application PCT/ES2017/070734, filed Nov. 6, 2017, which is hereby incorporated herein by reference in its entirety.The present invention relates to random number generators (RNGs), in particular to generators based on the random dynamics observed in gain-switched laser cavities.Random numbers are by definition unpredictable, and a sequence of random ...

Semiconductor laser, semiconductor laser array and method of manufacturing semiconductor laser

A semiconductor laser in which a PD unit monitoring an optical output is integrated is provided. A semiconductor laser (100) includes: a DFB unit including a back surface side first cladding layer (3), a first diffraction grating layer (9), a light emitting layer (1) having a first MQW structure and emitting a laser beam, a front surface side first cladding layer (6), and a first contact layer (12) which are stacked; a DBR unit including a back surface side second cladding layer (4) having a resistivity higher than that of the back surface side first cladding layer (3), a second diffraction grating layer (10) reflecting part of the laser beam toward the DFB unit, a first core layer (2a) guiding a remnant of the laser beam and having an effective bandgap energy smaller than that of the first MQW structure, and a front surface side second cladding layer (7) having a resistivity higher than that of the front surface side first cladding layer (6) which are stacked; and a PD unit including a back surface side third cladding layer (5), a second core layer (2b) having a second MQW structure absorbing the remnant of the laser beam guided by the first core layer (2a), a front surface side third cladding layer (8), and a second contact layer (14) which are stacked.

Two-section semiconductor laser with modulation-independent grating section to reduce chirp

A two-section semiconductor laser includes a gain section and a modulation-independent grating section to reduce chirp. The modulation-independent grating section includes a diffraction grating for reflecting light and forms a laser cavity with the gain section for lasing at a wavelength or range of wavelengths reflected by the diffraction grating. The gain section of the semiconductor laser includes a gain electrode for driving the gain section with at least a modulated RF signal and the grating section includes a grating electrode for driving the grating section with a DC bias current independent of the modulation of the gain section. The semiconductor laser may thus be directly modulated with the modulated RF signal without the modulation significantly affecting the index of refraction in the diffraction grating, thereby reducing chirp.

Method for manufacturing semiconductor device, semiconductor device and system for manufacturing semiconductor device

A method for manufacturing a semiconductor device includes forming a lower light confinement layer on a substrate, a light absorption layer on the lower light confinement layer, and an upper light confinement layer on the light absorption layer; and removing parts of these layers to form an optical modulator, forming a laser section having a diffraction grating in a portion of the substrate where the optical modulator is not present, forming a diffusion constraining layer, which constrains diffusion of a dopant, on the upper light confinement layer, and forming a contact layer on the laser section and the diffusion constraining layer. The same dopant is present in the contact layer and the upper light confinement layer.

INDEPENDENT CONTROL OF EMISSION WAVELENGTH AND OUTPUT POWER OF A SEMICONDUCTOR LASER

Methods for driving a tunable laser with integrated tuning elements are disclosed. The methods can include modulating the tuning current and laser injection current such that the laser emission wavelength and output power are independently controllable. In some examples, the tuning current and laser injection current are modulated simultaneously and a wider tuning range can result. In some examples, one or both of these currents is sinusoidally modulated. In some examples, a constant output power can be achieved while tuning the emission wavelength. In some examples, the output power and tuning can follow a linear relationship. In some examples, injection current and tuning element drive waveforms necessary to achieve targeted output power and tuning waveforms can be achieved through optimization based on goodness of fit values between the targeted and actual output power and tuning waveforms. 1. A method of driving a laser having a tuning element and a waveguide , the method comprising:applying a first waveform to the tuning element of the laser, the laser including a resistive cladding, the resistive cladding having a reduced thickness that forms a trench, wherein the reduced thickness creates a resistor that generates heat in response to the first waveform, wherein the generated heat affects the waveguide of the laser;applying a second waveform to the waveguide of the laser; andmodulating the first waveform simultaneously with modulating the second waveform to change one or more of an emission wavelength and an output power of the laser such that a change of one is independent from a change of the other.2. The method of claim 1 , wherein the first waveform is different from the second waveform.3. The method of claim 1 , further comprising modulating first and second waveforms at non-harmonic frequencies.4. The method of claim 1 , wherein at least one of the first waveform and the second waveform is sinusoidal.5. The method of claim 1 , further comprising ...

LASER, PASSIVE OPTICAL NETWORK SYSTEM, APPARATUS AND WAVELENGTH CONTROL METHOD

The present invention provide a laser, where the laser is divided into a laser region and a grating adjustment region through a first electrical isolation layer; the laser region is configured to generate optical signals, where the optical signals include an optical signal with a wavelength corresponding to a “0” signal and an optical signal with a wavelength corresponding to a “1” signal; the grating adjustment region is configured to adjust a wavelength of the grating adjustment region by controlling current of the grating adjustment region, so that the optical signal with the wavelength corresponding to the “1” signal of the laser region passes through the grating adjustment region, and the optical signal with the wavelength corresponding to the “0” signal of the laser region returns to the laser region, thereby implementing suppression to chirp of a directly modulated laser. 1. A laser , wherein the laser comprises: a laser region and a grating adjustment region; wherein the laser is divided into the laser region and the grating adjustment region by a first electrical isolation layer;the laser region is configured to generate optical signals, wherein the optical signals comprise an optical signal with a wavelength corresponding to a “0” signal and an optical signal with a wavelength corresponding to a “1” signal; andthe grating adjustment region is configured to adjust a wavelength of the grating adjustment region by controlling current of the grating adjustment region, so that the optical signal with the wavelength corresponding to the “1” signal of the laser region passes through the grating adjustment region, and the optical signal with the wavelength corresponding to the “0” signal of the laser region returns to the laser region.2. The laser according to claim 1 , wherein the laser region comprises: a first current generating unit and a first optical signal generating unit claim 1 , and the first current generating unit comprises: a first electrode sub-layer ...

HORIZONTAL CAVITY SURFACE EMITTING LASER DEVICE

A horizontal cavity surface emitting laser device includes an active layer configured to generate light to be emitted in one direction along the one surface of a semiconductor substrate and in another direction opposite to the one direction. The device also includes a rear distributed Bragg reflector unit configured to reflect the light. The rear distributed Bragg reflector unit includes a waveguide layer configured to guide light and a distributed Bragg reflector configured to reflect the light in the waveguide layer. The device further includes an optical component configured to guide, in a direction different from the one direction and the other direction, the light emitted from an end of the rear distributed Bragg reflector unit in the one direction. The device further includes a front reflecting mirror configured to reflect the light emitted from the active layer in the other direction toward another surface side of the semiconductor substrate. 1. A horizontal cavity surface emitting laser device , comprising:an active layer formed over one surface of a semiconductor substrate, the active layer being configured to generate light to be emitted in one direction along the one surface of the semiconductor substrate and in another direction opposite to the one direction;a rear distributed Bragg reflector unit formed at an end of the active layer in the one direction and configured to reflect the light emitted from the active layer, the rear distributed Bragg reflector unit comprising a waveguide layer configured to guide light and a distributed Bragg reflector configured to reflect the light in the waveguide layer;an optical component configured to guide, in a direction different from the one direction and the other direction, the light emitted from an end of the rear distributed Bragg reflector unit in the one direction; anda front reflecting mirror formed over the one surface side, the front reflecting mirror being configured to reflect the light emitted from the ...

Distributed bragg reflector tunable laser diode

Provided is a distributed Bragg reflector tunable laser diode including a substrate provided with a gain section having an active waveguide from which a gain of laser light is obtained and a distributed reflector section having a passive waveguide connected to the active waveguide, wherein the distributed reflector section includes gratings disposed on or under the passive waveguide, a current injection electrode disposed on the passive waveguide and configured to provide a current into the passive waveguide to electrically tune a wavelength of the laser light, and a heater electrode disposed on the current injection electrode and configured to heat the passive waveguide to thermally tune the wavelength of the laser light, wherein the gratings, the current injection electrode, and the heater electrode vertically overlap each other.

Tunable Multi-Mode Laser

A widely tunable multi-mode semiconductor laser containing only two electrically active sections, being an optical gain section and a tunable distributed Bragg reflector section adapted to reflect at a plurality of wavelengths, wherein the gain section is bounded by the tunable distributed Bragg reflector section and a broadband facet reflector, and wherein the tunable distributed Bragg reflector section comprises a plurality of discrete segments capable of being selectively tuned, wherein the reflection spectra of one or more segments of the tunable distributed Bragg reflector section can be tuned lower in wavelength to reflect with the reflection spectrum of a further segment of the tunable distributed Bragg reflector section to provide a wavelength range of enhanced reflectivity. An optical transmitter comprising a light source that is such a widely tunable multi-mode semiconductor laser.

Process of forming epitaxial substrate and semiconductor optical device

A process of forming a semiconductor optical device is disclosed. The semiconductor optical device provides a waveguide structure accompanied with a heater for varying a temperature of the waveguide structure. The process includes steps of: (a) forming a striped mask on a semiconductor substrate; (b) selectively growing a dummy layer on the semiconductor substrate; (c) removing the patterned mask; (d) burying the dummy layer by a supplemental layer; (e) exposing a portion of the dummy layer by etching a portion of the supplemental layer; (f) and removing the dummy layer by immersing the dummy layer within a solution that shows an etching rate for the dummy layer enough faster than an etching rate for the supplemental layer and the substrate so as to leave a void in a region the dummy layer had existed.

Active Mode Centre Control

There is disclosed a DBR laser and a method of use. The DBR laser comprises a phase section in a cavity of the DBR laser and configured to adjust an optical path length of the cavity. A DBR section comprises a frequency tuning system configured to adjust a Bragg frequency of the DBR section. A detector is configured to detect laser light transmitted through the DBR section. A controller is configured: to cause the phase section to apply a dither to the optical path length of the cavity or cause the frequency tuning system to apply a dither to the Bragg frequency of the DBR section; to use the detector to monitor intensity of light transmitted from the laser cavity via the DBR section during application of the dither; to determine a deviation from longitudinal mode centre operation on the basis of the monitored intensity; and to cause the frequency tuning system to adjust the Bragg frequency of the DBR section in order to reduce said deviation, or cause the phase section to adjust the optical path length of the cavity in order to reduce said deviation. 1. A distributed Bragg reflector , DBR , laser , the DBR laser comprising:a phase section in a cavity of the DBR laser and configured to adjust an optical path length of the cavity;a DBR section comprising a frequency tuning system configured to adjust a Bragg frequency of the DBR section;a detector configured to detect laser light transmitted through the DBR section; to cause the phase section to apply a dither to the optical path length of the cavity or cause the frequency tuning system to apply a dither to the Bragg frequency of the DBR section;', 'to use the detector to monitor intensity of light transmitted from the laser cavity via the DBR section during application of the dither;', 'to determine a deviation from longitudinal mode centre operation on the basis of the monitored intensity; and', 'to cause the frequency tuning system to adjust the Bragg frequency of the DBR section in order to reduce said deviation, ...

Tuneable DBR Laser Without External Frequency Locker

In accordance with one aspect of the present application there is provided a DBR, laser. The DBR laser comprises a phase section in a cavity of the DBR laser configured to adjust an optical path length of the cavity. The laser also comprises a DBR section comprising a frequency tuning system, the frequency tuning system comprising a resistance heater configured to apply heat to a grating of the DBR section in order to adjust a Bragg frequency of the DBR section. A detector is configured to detect laser light transmitted through the DBR section. A controller is configured: to cause the phase section to apply a dither to the optical path length of the cavity or cause the frequency tuning system to apply a dither to the Bragg frequency of the DBR section; to use the detector to monitor intensity of light transmitted from the laser cavity via the DBR section during application of the dither; to determine a deviation from longitudinal mode centre operation on the basis of the monitored intensity; to cause the phase section to adjust the optical path length of the cavity in order to reduce said deviation; to determine an output frequency of the DBR laser on the basis of a resistance of the resistance heater; and to control the output frequency of the DBR laser by controlling power to the resistance heater. 1. A distributed Bragg reflector , DBR , laser , the DBR laser comprising:a phase section in a cavity of the DBR laser and configured to adjust an optical path length of the cavity;a DBR section comprising a frequency tuning system, the frequency tuning system comprising a resistance heater configured to apply heat to a grating of the DBR section in order to adjust a Bragg frequency of the DBR section;a detector configured to detect laser light transmitted through the DBR section; and cause the phase section to apply a dither to the optical path length of the cavity or cause the frequency tuning system to apply a dither to the Bragg frequency of the DBR section;', 'use ...

Tunable laser source

A tunable transmission optical filter is optically coupled between a laser section and semiconductor optical amplifier (SOA) section of a tunable laser device. The optical filter may be tuned to provide a high transmission near the lasing peak while suppressing a significant portion of back-propagating amplified spontaneous emission (ASE) of the SOA section. Without the optical filter, the laser output spectrum may develop side lobes of higher intensity after the ASE is amplified and reflected in the forward direction by the laser gain and mirror sections. While lessening the side lobes, the optical filter simultaneously transmits the laser peak for amplification by the SOA section.

DISCRETE WAVELENGTH TUNABLE LASER

A multisection digital supermode-distributed Bragg reflector (MSDS-DBR) comprising: a plurality P of digital supermode Bragg reflector (DS-DBR) grating sections arranged along a waveguide; wherein each DS-DBR grating section is configured to pass or reflect light over a given spectral region, the given spectral region being different from the spectral regions of the other DS-DBR grating sections; wherein each DS-DBR grating section comprises a plurality M of grating sub-regions, each sub-region corresponding to a spectral sub-band within the spectral region of the DS-DBR grating section, and wherein each grating sub-region includes a positive electrical contact and a negative electrical contact; said grating sub-region being configured to pass or reflect light of its spectral sub-band when an electrical bias is provided between its positive and negative electrical contacts. 1. A discrete wavelength tunable laser comprising:a reflective semiconductor optical amplifier having a back facet, an output facet, and a highly reflective broadband mirror on the back facet; anda DS-DBR grating coupled to the output facet, the DS-DBR grating comprising a plurality of grating sections arranged along a waveguide,each of the grating sections being configured to pass or reflect light over a given spectral region, the given spectral region being different from the spectral regions of the other DS-DBR grating sections,each of the grating sections including a positive electrical contact and a negative electrical contact, each of the grating sections being configured to pass or reflect light of its spectral region when an electrical bias is applied to its positive and negative electrical contacts.2. The tunable laser of claim 1 , further comprising a broadband output mirror claim 1 , the DS-DBR grating being between the reflective semiconductor optical amplifier and the broadband output mirror claim 1 , wherein the tunable laser is configured to lase at a wavelength in a spectral ...

Tunable Laser With High Thermal Wavelength Tuning Efficiency

A monolithically integrated thermal tunable laser comprising a layered substrate comprising an upper surface and a lower surface, and a thermal tuning assembly comprising a heating element positioned on the upper surface, a waveguide layer positioned between the upper surface and the lower surface, and a thermal insulation layer positioned between the waveguide layer and the lower surface, wherein the thermal insulation layer is at least partially etched out of an Indium Phosphide (InP) sacrificial layer, and wherein the thermal insulation layer is positioned between Indium Gallium Arsenide (InGaAs) etch stop layers.

Tunable Semiconductor Lasers

A tunable semiconductor laser having, in one embodiment, a higher bias voltage end, a lower bias voltage end, and an optically active gain region comprising a band-gap configured to emit light at an emission wavelength that is tunable when an electric field is generated across the optically active gain region by applying a bias voltage thereto, an electron quantum well (QW) layer positioned closer to the higher bias voltage end than the lower voltage bias end, and a hole QW layer positioned closer to the lower bias voltage end than the higher bias voltage end and comprising a type-II band alignment with the electron QW layer such that the band-gap is determined by an energy difference between a ground electron state in the electron QW layer and a ground hole state in the hole QW layer, wherein the emission wavelength is redshifted upon an increase in a bias voltage applied to the optically active gain region. 1. A tunable semiconductor laser comprising:a higher bias voltage end;a lower bias voltage end; and a band-gap configured to emit light at an emission wavelength that is tunable when an electric field is generated across the optically active gain region by applying a bias voltage thereto;', 'at least a first electron quantum well (QW) layer positioned closer to the higher bias voltage end than the lower bias voltage end; and', 'at least a first hole QW layer positioned closer to the lower bias voltage end than the higher bias voltage end and comprising a type-II band alignment with the first electron QW layer such that the band-gap is determined by an energy difference between a ground electron state in the first electron QW layer and a ground hole state in the first hole QW layer,', 'wherein the emission wavelength is redshifted upon an increase in a bias voltage applied to the optically active gain region., 'an optically active gain region comprising2. The tunable semiconductor laser of claim 1 , further comprising a plurality of the optically active gain ...

Circuit for Driving a Laser and Method Therefor

The present disclosure is directed toward circuits for driving one or more laser diodes with a series of current pulses, where the energy required for each current pulse is generated and stored on a pulse-by-pulse basis. Laser-driver circuits in accordance with the present disclosure include a charge-storage inductor that is electrically coupled with a power supply and a charge-storage capacitor that is electrically coupled with a laser-diode string. The electrical coupling between the inductor and capacitor is controlled by one or more switches having on- and off-states that determine whether the inductor is charged by the power supply, charges the capacitor, or whether the charged capacitor generates a current pulse in the laser-diode string. By controlling the states of the switches, the energy provided to the laser-diode string can be controlled on a pulse-by-pulse basis.

Passive waveguide structure with alternating gainas/alinas layers for mid-infrared optoelectronic devices

Disclosed is a semiconductor optical emitter having an optical mode and a gain section, the emitter comprising a low loss waveguide structure made of two alternating layers of semiconductor materials A and B, having refractive indexes of Na and Nb, respectively, with an effective index N o of the optical mode in the low loss waveguide between Na and Nb, wherein No is within a 5% error margin of identical to a refractive index of the gain section and wherein the gain section is butt-jointed with the low loss waveguide, and wherein the size and shape of the optical mode(s) in the low loss waveguide and gain section are within a 10% error margin of equal. Desirably, at least one of the semiconductor materials A and B has a sufficiently large band gap that the passive waveguide structure blocks current under a voltage bias of 15 V.

Directly modulated laser drive circuit

A driver circuit 11 includes a plurality of cascode-connected NMOS transistors, a modulating signal V GN1 is applied to a gate terminal of a lowermost stage transistor T N1 located at a lowermost stage out of the NMOS transistors, and an upper stage bias potential V GN2 that is a sum of a minimum gate-source voltage V GN1min and a maximum drain-source voltage V DS1max of a transistor (T N1 ) located immediately below an upper stage transistor located at an upper stage above the lowermost stage transistor of the NMOS transistors is applied to the upper stage transistor T N2 .

Monolithic wide wavelength tunable mid-ir laser sources

A monolithic tunable mid-infrared laser has a wavelength range within the range of 3-14 μm and comprises a heterogeneous quantum cascade active region together with at least a first integrated grating. The heterogeneous quantum cascade active region comprises at least one stack, the stack comprising two, desirably at least three differing stages. Methods of operating and calibrating the laser are also disclosed.

LASER SOURCE AND METHOD OF MANUFACTURING SUCH

A laser source for emitting radiation in a given emission spectral band, centered on a given emission angular frequency, the central emission angular frequency is provided. The laser source comprises a laser cavity comprising a gain section having a known frequency dependent Group Delay Dispersion, and a GTI mirror arranged at one end of the gain section, having a known frequency dependent Group Delay Dispersion. The gain section and the GTI mirror are formed into a same laser medium, the laser medium having a known frequency dependent Group Delay Dispersion, and the gain section and the GTI mirror are separated by a gap of predetermined width filled with a dielectric medium thus forming a two parts laser cavity. Further, the GTI GDD at least partly compensates the sum of the Gain GDD and the material GDD in the emission spectral band. 1. A laser source for emitting radiation in a given emission spectral band , centered on a given emission angular frequency , comprising:a laser cavity comprising a gain section having a known frequency dependent Group Delay Dispersion, and a GTI mirror arranged at one end of the gain section, and having a known frequency dependent Group Delay Dispersion, wherein:the gain section and the GTI mirror are formed into a same laser medium, said laser medium having a known frequency dependent Group Delay Dispersion, thus forming a two parts laser cavity;the gain section and the GTI mirror are separated by a gap of predetermined width (a) filled with a dielectric medium; andthe GTI GDD at least partly compensates the sum of the Gain GDD and the material GDD in said emission spectral band.2. The laser source according to claim 1 , wherein the dielectric medium comprises graphene.3. The laser source according to claim 1 , wherein the dielectric medium is air.4. The laser source according to claim 1 , wherein the width (a) of the gap is smaller than nc/(nd2ω) where nd is the refractive index of the dielectric medium and c is the speed of light ...

METHOD AND DEVICE FOR GENERATING SHORT OPTICAL PULSES

An embodiment of the invention relates to a method for generating short optical pulses comprising the steps of: 1. Method for generating short optical pulses comprising the steps of:operating a single section semiconductor laser in a nonlinear regime to emit chirped optical pulses at an output facet of the laser cavity, andcompressing the chirped optical pulses outside the laser cavity using a dispersive element in order to generate the short optical pulses;wherein the single section semiconductor laser is operated with a DC injection current; andwherein the injected DC current is such that the generated optical intensity within the laser causes nonlinear effects inside the gain medium of the laser's cavity.2. Method of wherein the single section semiconductor laser is operated in a transverse fundamental single mode where the longitudinal mode phases are locked.3. (canceled)4. (canceled)5. Method of wherein the nonlinear effects cause the longitudinal mode phases to be locked.6. Method of wherein the nonlinear effects within the gain medium cause mutual injection locking through the generation of side bands and lead to a correlation between the phases of the laser cavity modes.7. Method of whereinthe chirped optical pulses are generated with an edge-emitting semiconductor laser having a multi-layered waveguide,said waveguide comprising at least one layer with an active region that emits light under electrical injection, and at least one aperiodic layer stack.8. Optical device for generating short optical pulses claim 1 , the device comprising:a single section semiconductor laser capable of being operated in a nonlinear regime and generating chirped optical pulses at an output facet of the laser cavity,an electrical control unit connected to the single section semiconductor laser for operating the laser in the nonlinear regime, anda dispersive element being optically connected with the laser, the dispersive element being configured to compress the chirped optical ...

DIRECTLY MODULATED LASER FOR PON APPLICATION

In an embodiment, a laser includes a gain section. The gain section includes an active region, an upper separate confinement heterostructure (SCH), and a lower SCH. The upper SCH is above the active region and has a thickness of at least 60 nanometers (nm). The lower SCH is below the active region and has a thickness of at least 60 nm. 1. A laser comprising: an active region;', 'an upper separate confinement heterostructure (SCH) above the active region having a thickness of at least 60 nanometers (nm); and', 'a lower SCH below the active region having a thickness of at least 60 nm., 'a gain section comprising2. The laser of claim 1 , further comprising a gain electrode coupled to the gain section claim 1 , the gain electrode configured to be coupled to a direct modulation source providing a modulation signal having a data rate of about 10 gigabits per second or higher.3. The laser of claim 2 , wherein in response to application of the modulation signal to the gain electrode claim 2 , the laser is configured to generate an optical signal having a frequency modulation profile exhibiting both transient chirp and adiabatic chirp claim 2 , a ratio of transient chirp to adiabatic chirp being in a range from 1:3 to 1:4.4. The laser of claim 1 , wherein a modulation signal applied to the gain section has a modulation swing of at least 40 milli amps peak-to-peak (mApp).5. The laser of claim 4 , wherein the gain section has a length of 300 micrometers (um) or less.6. The laser of claim 5 , wherein the modulation signal applied to the gain section has a modulation swing of about 60 mApp and the gain section has a length of about 200 um.7. The laser of claim 1 , wherein the laser has a reach of 21 kilometers or more with a bit error rate of about 1×10−3.8. The laser of claim 1 , wherein the thickness of the upper SCH is less than 125 nm and the thickness of the lower SCH is less than 125 nm.9. The laser of claim 1 , wherein the laser comprises a distributed Bragg reflector ( ...

Access communication subsystem with object/intelligent appliance-to-object/intelligent appliance interaction

An intelligent subsystem can connect with one or more objects or intelligent appliances, wherein the intelligent subscriber (access) subsystem includes a fuzzy logic algorithm or an artificial intelligence algorithm or a machine learning algorithm. The object at least includes a radio module and a sensor/bio-sensor module. The intelligent appliance at least includes a processor module and a radio module.

DUAL WAVELENGTH LASING DEVICE

A semiconductor lasing device () for emitting radiation at multiple distinct wavelengths, the device () comprising an active layer () having first portion () and a second portion (), the first and second portions () being separated by a Bragg grating () extending through the entire depth of the active layer (), the first portion () defining a first lasing cavity () for emitting electromagnetic radiation at a first wavelength λand the first and second portions () together defining a second lasing cavity () for emitting electromagnetic radiation at a second wavelength λ. 1. A dual wavelength semiconductor lasing device comprising an active layer , the active layer comprising a first portion and a second portion , the first and second portions being separated by grating , the first portion defining a first lasing cavity for emitting electromagnetic radiation at a first wavelength and the first and second portions together defining a second lasing cavity for emitting electromagnetic radiation at a second wavelength , wherein the grating has a high reflectivity with respect to the first wavelength and a high transmissivity with respect to the second wavelength and comprises a plurality of channels extending through the entire depth of the active layer , said first portion of the device comprising a first pair of electrical contacts for driving the first lasing cavity and the second portion of the device comprising a second pair of electrical contacts for driving the second lasing cavity.2. A lasing device according to claim 1 , wherein the channels extend to a depth at least equal to a substantially full depth of an optical mode at the first wavelength and at least equal to a substantially full depth of an optical mode at the second wavelength.3. A lasing device according to claim 1 , wherein the active layer is disposed on a substrate.4. A lasing device according to claim 3 , wherein a cladding layer is disposed intermediate the active layer and the substrate.5. A ...

Semiconductor DBR Laser

A semiconductor distributed Bragg reflector laser configured for single longitudinal mode operation, having an optical waveguide comprising an optical gain section, a first reflector being a first distributed Bragg reflector (DBR) section comprising a grating configured to produce a reflection spectrum having one or more first reflective peaks, and a second reflector, wherein the first DBR section is configured to compensate for thermal chirp that is induced inhomogeneously along the length of the DBR section, in use. 1. A semiconductor distributed Bragg reflector laser configured for single longitudinal mode operation , having an optical waveguide comprisingan optical gain section,a first reflector being a first distributed Bragg reflector (DBR) section comprising a grating configured to produce a reflection spectrum having one or more first reflective peaks, anda second reflector,wherein the first DBR section is configured to compensate for thermal chirp that is induced inhomogeneously along the length of the DBR section, in use.2. The semiconductor distributed Bragg reflector laser according to claim 1 , wherein the laser is configured for the full width half maximum of the first reflective peak to be narrower than five times the longitudinal mode spacing at the operating wavelength or across the range of operating wavelengths.3. The semiconductor distributed Bragg reflector laser according to claim 1 , wherein the grating of the first DBR section has a built-in effective chirp.4. The semiconductor distributed Bragg reflector laser according to claim 3 , wherein the built-in effective chirp is less than 0.5% along the first DBR section.5. The semiconductor distributed Bragg reflector laser according to claim 3 , wherein the built-in effective chirp is selected from the group consisting of:an exponential growth function along the length of the first DBR section away from the gain section,a linear growth function along the length of the first DBR section away from ...

METHODS OF DRIVING LASER DIODES, OPTICAL WAVELENGTH SWEEPING APPARATUS, AND OPTICAL MEASUREMENT SYSTEMS

An optical wavelength sweeping apparatus is disclosed. The optical wavelength sweeping apparatus includes a laser diode having an active region including a thickness of less than 1 μm, a cross-section of less than 7 μm, and a ratio of active region volume to total laser diode volume of less than 1/300, and a pulse generator coupled to the laser diode. The pulse generator is configured and operable to provide a current drive pulse to the laser diode to selectively and rapidly heat the active region and immediate vicinity to provide a peak increase in temperature of 30° C. or more at an end of the current pulse and to perform a wavelength sweep of emitted optical radiation which is greater than 5 nm. Methods of driving a laser diode and optical systems are disclosed, as are other aspects. 1. A method of driving a laser diode , comprising:{'sup': '2', 'providing a laser diode having an active region including a thickness of less than 1 μm, an active region cross-section of less than 7 μm, and a ratio of active region volume to total laser diode volume of less than 1/300; and'}selectively and rapidly heating the active region and immediate vicinity by applying a current pulse to provide a peak increase in temperature of the active region and immediate vicinity of 30° C. or more at an end of the current pulse and to perform a wavelength sweep of emitted optical radiation which is greater than 5 nm.2. The method of claim 1 , wherein the laser diode is a telecommunication distributed feedback laser diode.3. The method of claim 1 , wherein the selectively and rapidly heating comprises applying a current pulse amplitude of greater than about five times larger than a maximum declared continuous DC drive current of the laser diode.4. The method of claim 1 , wherein the selectively and rapidly heating comprises application of a short-duration current drive pulse having a pulse duration of less than 50 μs claim 1 , less than 10 μs claim 1 , less than 5 μs claim 1 , less than 2 μ ...

METHOD FOR GENERATING A COMPRESSED OPTICAL PULSE

There is presented a method of for generating a compressed optical pulse () comprising emitting from a wavelength tunable microcavity laser system (), comprising an optical cavity () with a mechanically adjustable cavity length (L), a primary optical pulse () having a primary temporal width (T) while adjusting the optical cavity length (L) so that said primary optical pulse comprises temporally separated photons of different wavelengths, and transmitting said pulse through a dispersive medium (), so as to generate a compressed optical pulse () with a secondary temporal width (T), wherein the secondary temporal width (T) is smaller than the primary temporal width (T). 1. A method for generating a compressed optical pulse , the method comprising: an optical cavity with a mechanically adjustable cavity length, so as to enable the wavelength tunable microcavity laser system to emit photons of different wavelengths with respect to each other, wherein the optical cavity comprises a microcavity, wherein the length of the microcavity is at least ½ times the reference wavelength and less than 10 times the reference wavelength, wherein the optical cavity comprises a MEMS component, wherein a position of the MEMS component is adjustable and, wherein the cavity length of the optical cavity depends on the position of the MEMS component so that a cavity controller may control the cavity length of the optical cavity by controlling the position of the MEMS component,', 'a photon emitter for emitting photons into the optical cavity,', 'a cavity controller arranged for controlling the length of the optical cavity,, 'providing a wavelength tunable microcavity laser system having a reference wavelength corresponding to a central operating wavelength, comprisingproviding a dispersive medium,emitting a primary optical pulse having a primary temporal width from the wavelength tunable microcavity laser system,adjusting the optical cavity length so that said primary optical pulse comprises ...

VARIABLE BANDGAP MODULATOR FOR A MODULATED LASER SYSTEM

A modulated laser system generally includes a light emission region, a modulation region having a plurality of semiconductive layers, at least one of which includes a quantum well layer having a variable energy bandgap, and an isolation region separating the light emission region and the modulation region. The laser may be an electro-absorption modulated laser, the light emission region may include a distributed feedback laser, and the modulation region may include an electro-absorption modulator. The laser may be manufactured by forming a lower semiconductive buffer layer on a substrate, an active layer including one or more quantum well layers having the variable energy bandgap on or above the lower semiconductive buffer layer, an upper semiconductive buffer layer on or above the active layer, a contact layer on or above the upper semiconductive buffer layer, and an isolation region separating the light emission region and the modulation region. 1. A semiconductor laser comprising:a light emission region;a modulation region comprising a plurality of semiconductive layers, at least one of which comprises one or more quantum well layers having a variable energy bandgap; andan isolation region separating said light emission region and said modulation region.2. The device of claim 1 , wherein said modulation region has a first boundary closest to said isolation region and a second boundary farthest from said isolation region claim 1 , and said variable energy bandgap has a bandgap or bandgap gradient that decreases from said first boundary to said second boundary.3. The device of claim 2 , wherein an energy of said variable energy bandgap along said bandgap gradient is approximately inversely proportional to a distance from said first boundary and/or approximately proportional to an amount of power dissipated at said distance.4. The device of claim 1 , wherein said modulation region has a boundary closest to said isolation region claim 1 , and said one or more quantum ...

LASER EMISSION DEVICE WITH INTEGRATED LIGHT MODULATOR

Laser emission device with integrated light modulator comprising: a multilayer waveguide comprising, on a support layer, a first guiding layer, a first doped layer, a second guiding layer of light amplifying material, and a biasing second doped layer opposite the first doped layer, the waveguide comprising a laser amplification section (), a light modulation section () comprising an extraction zone for radiating the light, a transition section () inserted between the laser amplification section and the light modulation section, a positive first electrode for injecting a pumping current into the laser amplification section, a positive second electrode for injecting a modulation signal into the modulation section, a negative third electrode, and a reference fourth electrode, the second doped layer comprising an electrical insulation situated in the transition section to form a resistive channel. 1. Laser emission device with integrated light modulator comprising:a multilayer waveguide, the waveguide extending along a longitudinal direction of the device,the waveguide comprising, on a support layer made of silicon dioxide,a first guiding layer of silicon,a first doped layer,a second guiding layer of light amplifying material, anda biasing second doped layer opposite the first doped layer,the waveguide comprising, along the longitudinal directiona laser amplification section,a light modulation section comprising an extraction zone for radiating the light of a resonant optical mode towards the exterior of the device,and a transition section inserted in the longitudinal direction, between the laser amplification section and the light modulation section,the device also comprising:a positive first electrode coupled to the laser amplification section, a positive DC potential connected to the positive first electrode to inject a pumping current into the laser amplification section,wherein the device also comprises:a positive second electrode coupled to the light modulation ...

Widely tunable laser control

A tunable laser has a first binary super grating (BSG), a second BSG, and a phase adjuster. The first BSG, the second BSG, and the phase adjuster are optically tuned by changing temperatures of respective heating elements. The tunable laser also includes three temperature sensors, a first sensor to measure the temperature of the first BSG; a second sensor to measure the temperature of the second BSG, and a third sensor to measure the temperature of the phase adjuster. A lasing frequency is determined by a set of values of the three temperature sensors. In some embodiments, instead of a third temperature sensor, a pilot tone is applied to the phase adjuster to lock to a maximum of an aligned pair of peaks.

Intelligent subsystem

An intelligent subsystem coupled with a system-on-chip (comprising a microprocessor/graphic processor), a radio transceiver, a voice processing module/voice processing algorithm, a foldable/stretchable display, a near-field communication device, a biometric sensor and an intelligent learning algorithm is disclosed. The intelligent subsystem can respond to a user's interests and/or preferences. Furthermore, the intelligent subsystem is sensor-aware or context-aware.

Optical Device With Multisection Semiconductor Optical Amplifiers for Achieving Wide Optical Bandwidth and Large Output Power

An optical device includes a first semiconductor optical amplifier having an active region embedded into a waveguide and including a first section intended for amplifying optical signals when it is crossed by a first current smaller than a chosen value inducing amplification over a large optical bandwidth, and a second section intended for amplifying the optical signals amplified by the first section when it is crossed by a second current greater than this chosen value, to deliver output optical signals with a large power. 1. An optical device having a first semiconductor optical amplifier comprising an active region embedded into a waveguide , at least a first section intended for amplifying optical signals when it is crossed by a first current smaller than a chosen value , the chosen value inducing amplification over a large optical bandwidth , and a second section intended for amplifying the optical signals amplified by the first section when it is crossed by a second current greater than the chosen value , to deliver output optical signals with a large power.2. The optical device according to claim 1 , wherein the first and second sections have approximately a same length.3. The optical device according to claim 1 , wherein an active region of the first semiconductor optical amplifier comprises a third section located upward the first section and intended for preamplifying input optical signals when it is crossed by a third current approximately equal to the chosen value claim 1 , in order to feed the first section with preamplified optical signals.4. The optical device according to claim 3 , wherein the first second and third sections have approximately a same length.5. The optical device according to claim 1 , further comprising a second semiconductor optical amplifier comprising an active region embedded into a waveguide and intended for preamplifying input optical signals when it is crossed by a third current approximately equal to the chosen value claim 1 , ...

CIRCUIT AND METHOD OF OPERATING A LASER DIODE

An embodiment circuit includes a diode having a first terminal coupled to a first reference voltage; a first controllable switch coupled between a second terminal of the diode and a second reference voltage; and a capacitive element having a first terminal coupled to the first reference voltage and a second terminal controllably coupled to the second terminal of the diode. 1. A circuit , comprising:a diode having a first terminal controllably coupled to a first reference voltage;a first controllable switch controllable by a first control signal, the first controllable switch being coupled between a second terminal of the diode and a second reference voltage;a capacitive element having a first terminal coupled to form a node with the first reference voltage and a second terminal controllably coupled to the second terminal of the diode; and couple the second terminal of the capacitive element to the first reference voltage in response to the first control signal being at a first amplitude and in response to the second control signal being at a second amplitude different from the first amplitude; and', 'couple the second terminal of the capacitive element to the second terminal of the diode in response to the first control signal being at a third amplitude different from the first amplitude and in response to the second control signal being at a fourth amplitude different from the second amplitude., 'a second controllable switch controllable by a second control signal, the second controllable switch being configured to2. The circuit of claim 1 , wherein fourth amplitude is greater than the first amplitude.3. The circuit of claim 2 , wherein the first amplitude is between about 1V and 2 V claim 2 , and wherein the fourth amplitude is between 3 V and 4 V.4. The circuit of claim 1 , wherein a transition of the first control signal from the first amplitude to the third amplitude is synchronized in time with a transition of the second control signal from the second ...

Tunable U-Laser Transmitter With Integrated Mach-Zehnder Modulator

According to the present invention, a monolithically integrated laser also referred to herein as a U-laser or integrated dual optical emission laser having a first optical emission and a second optical emission where both the first and second optical emissions of the monolithically integrated laser are in optical communication with a modulator or other device is provided. The integrated dual emission laser can be formed with a a light bending portion in variety of configurations including a waveguide in the form of a U-shape, or total internal reflection (TIR) mirrors, curved waveguides, and free-space etched gap mirrors. The integrated dual optical emission laser can also have two laser gain sections one on each arm of the laser to control gain.

A laser driver and method of operating a laser

According to the present invention there is provided a method of operating a laser comprising the steps of; defining an intensity value (K VIDEO red , K VIDEO green , K VIDEO blue ) for a light beam which is to be output from the laser; determining if the defined intensity value is greater than, or less than, a threshold intensity (K TH red , K TH green , K TH blue ) for the laser, wherein the threshold intensity is the intensity of the light which is output from the laser when the input current to the laser is equal to the threshold current (I TH red , I TH green , I TH blue ) of the laser, wherein the threshold current (I TH red , I TH green , I TH blue ) of the laser is an input current value below which the laser would operate in its light emitting region and equal to, or above which, the laser will operate in its laser region; operating the laser using current from at least a DAC current source if the defined intensity value (K VIDEO red , K VIDEO green , K VIDEO blue ) is greater than the threshold intensity (K TH red , K TH green , K TH blue ), wherein the DAC current source operates the laser by inputting to the laser a continuous current which has an amplitude which is greater than the threshold current (I TH red , I TH green , I TH blue ) of the laser, and which has an amplitude such that the laser is operated to output a light beam which has an intensity equal to the defined intensity value (K VIDEO red , K VIDEO green , K VIDEO blue ); and operating the laser using current from the PWM current source only, if the defined intensity value (K VIDEO red , K VIDEO green , K VIDEO blue ) is less than the threshold intensity (K TH red , K TH green , K TH blue ), wherein the PWM current source operates the laser by inputting to the laser a current which has an amplitude which is at least equal to the threshold current value (I TH red , I TH green , I TH blue ) of the laser, and wherein the duration of time over which the PWM current source inputs its current to ...

Integrated semiconductor laser device and semiconductor laser module

An integrated semiconductor laser device includes: a semiconductor laser including a first active layer; a semiconductor optical amplifier including a second active layer and configured to amplify output laser light of the semiconductor laser; and a substrate on which the semiconductor laser and the semiconductor optical amplifier are integrated. The first active layer and the second active layer each include a multiple quantum well structure, and the second active layer includes a larger number of quantum wells than the first active layer.

Tunable Laser And Control Method For Same

A tunable laser is provided, including a first reflector, a second reflector, a phase adjustment area, a gain area, a first detector, a second detector, and a controller. The phase adjustment area is located between the first reflector and the gain area, the gain area is located between the phase adjustment area and the second reflector, a reflectivity of the first reflector is adjustable, and a reflectivity of the second reflector is adjustable. The first detector is configured to convert an optical signal of the first reflector into a first electrical signal. The second detector is configured to convert an optical signal of the second reflector into a second electrical signal. The controller is configured to adjust at least one of the reflectivity of the first reflector or the reflectivity of the second reflector based on the first electrical signal and the second electrical signal.

Electromagnetic energy output system

An apparatus having an excitation source that includes at least one laser diode and also having a handpiece with a disposable, bendable tip cannula is disclosed. The bendable tip can include a pliable material possessing a treatment characteristic of being bendable by a user three or more times without kinking from a generally straight orientation to a self-supporting bent configuration spanning an angle of at least forty degrees while remaining fully operational.

Tunable Waveguide Devices

Methods, systems, and apparatus, including a laser including a layer having first and second regions, the first region including a void; a mirror section provided on the layer, the mirror section including a waveguide core, at least part of the waveguide core is provided over at least a portion of the void; a first grating provided on the waveguide core; a first cladding layer provided between the layer and the waveguide core and supported by the second region of the layer; a second cladding layer provided on the waveguide core; and a heat source configured to change a temperature of at least one of the waveguide core and the grating, where an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core. 1. A laser comprising:a layer having first and second regions, the first region including a void; a waveguide core, at least part of the waveguide core is provided over at least a portion of the void;', 'a grating;', 'a first cladding provided between the layer and the waveguide core, at least a portion of the first cladding being supported by the second region of the layer;', 'a second cladding provided on the waveguide core; and', 'a heat source configured to change a temperature of at least one of the waveguide core or the grating,, 'a mirror section provided on the layer, the mirror section comprisingwherein an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core.2. The laser in accordance with claim 1 , wherein a loss incurred by the optical mode during said propagation in the mirror is less than 7 dB/cm.3. The laser in accordance with claim 2 , wherein a loss incurred by the optical mode during said propagation in the mirror is less than 5 dB/cm.4. The laser in accordance with claim 3 , wherein a ...

Tunable Waveguide Devices

Methods, systems, and apparatus, including a laser including a layer having first and second regions, the first region including a void; a mirror section provided on the layer, the mirror section including a waveguide core, at least part of the waveguide core is provided over at least a portion of the void; a first grating provided on the waveguide core; a first cladding layer provided between the layer and the waveguide core and supported by the second region of the layer; a second cladding layer provided on the waveguide core; and a heat source configured to change a temperature of at least one of the waveguide core and the grating, where an optical mode propagating in the waveguide core of the mirror section does not incur substantial loss due to interaction with portions of the mirror section above and below the waveguide core. 1. A semiconductor laser , comprising:a substrate;a layer formed on the substrate, the layer having first and second regions, the first region of the layer including one or more voids; and a waveguide core, wherein at least part of the waveguide core is provided over a first void,', 'a grating,', 'a first cladding provided between the layer and the waveguide core, wherein at least a portion of the first cladding is provided over at least a portion of the second region of the layer, and', 'a second cladding provided on the waveguide core; and, 'a mirror section provided on the layer, the mirror section comprisinga first electrode and a second electrode, the first electrode being coupled to the second cladding, such that a current flows between the first and second electrodes and through at least a portion of the second cladding, such that heat generated by the current adjusts a temperature of a portion of the waveguide core.2. A semiconductor laser in accordance with claim 1 , wherein the first electrode is coupled to the second cladding at a plurality of locations along the contact layer.3. A semiconductor laser in accordance with claim 1 ...

METHOD FOR FABRICATING AN ELCTRO-ABSORPTION MODULATED LASER AND ELECTRO-ABSORPTION MODULATED LASER

It is provided a method for fabricating an electroabsorption modulated laser comprising generating a single mode laser section and an electroabsorption modulator section, comprising fabricating at least one n-doped layer of the laser section and at least one n-doped layer of the modulator section; generating an isolating section for electrically isolating at least the n-doped layer of the laser section and the n-doped layer of the modulator section from one another. Generating the isolating section comprises epitaxially growing at least one isolating layer and structuring the isolating layer before the generation of the n-doped layer of the laser section and the n-doped layer of the modulator section. 1. A method for fabricating an electroabsorption modulated laser , comprising:generating a single mode laser section and an electroabsorption modulator section, comprising fabricating at least one n-doped layer of the laser section and at least one n-doped layer of the modulator section;generating an isolating section for electrically isolating at least the n-doped layer of the laser section and the n-doped layer of the modulator section from one another,wherein generating the isolating section comprises epitaxially growing at least one isolating layer and structuring the isolating layer before the generation of the n-doped layer of the laser section and the n-doped layer of the modulator section.2. The method as claimed in claim 1 , wherein the laser section is generated to be a DFB laser claim 1 , a DBR laser or a multi-section tunable laser.3. The method as claimed in claim 1 , wherein generating the isolating section comprises epitaxially growing at least one Fe-doped InP layer and at elast one Fe-doped InGaAsP layer.43. The method as claimed in claim 1 , wherein generating the isolating section in addition comprises at least one of:epitaxially growing at least one n-doped InP layer, at least one p-doped InP layer and at least one p-contact layer above the Fe-doped ...