Abstract: Semiconductor electrooptic medium shows behavior different from a medium based on quantum confined Stark Effect. A preferred embodiment has a type-II heterojunction, selected such, that, in zero electric field, an electron and a hole are localized on the opposite sides of the heterojunction having a negligible or very small overlap of the wave functions, and correspondingly, a zero or a very small exciton oscillator strength. Applying an electric field results in squeezing of the wave functions to the heterojunction which strongly increases the overlap of the electron and the hole wave functions, resulting in a strong increase of the exciton oscillator strength. Another embodiment of the novel electrooptic medium includes a heterojunction between a layer and a superlattice, wherein an electron and a hole in the zero electric field are localized on the opposite sides of the heterojunction, the latter being effectively a type-II heterojunction.

Abstract: The invention aims at realizing a 1300-nm-band direct modulation laser, having a single lateral mode, in which a chip light power of several milliwatts and a low current operation are simultaneously realized. Also, the invention aims at realizing a laser light source excellent in economy as well by realizing output characteristics of a vertical cavity surface light emitting laser. A distributed Bragg reflector laser is constructed in the form of a semiconductor laser having a multilayer structure formed on a predetermined semiconductor substrate. The multilayer structure includes an active region for emitting a laser beam, and a distributed Bragg reflector layer. A length of the active region falls within the range of 10 to 100 ?m, and a laser light beam is generated in accordance with ON/OFF of current injection to the active region.

Abstract: A high-power laser system includes a laser master oscillator, a plurality of fiber laser amplifiers producing intermediate output beamlets, a combiner for combining the intermediate beamlets into a combined output beam, and a piston error controller for minimizing errors related to beam combination that may degrade the quality of the combined output beam. A piston error controller processes a sample of the combined output beam using a Diffractive Optical Element to isolate a signal representing the total piston error of the combined beam. The controller uses amplitude modulation based on Hadamard code words to tag each non-reference intermediate beamlet with a unique code sequence orthogonal to those used for the other beamlets. For each intermediate beamlet, the associated piston error contribution is recovered using a Hadamard decoder. A very small phase dither is also introduced to allow the sign or direction of the piston error to be recovered.

Abstract: It is made possible to provide an optical waveguide system that has a coupling mechanism capable of selecting a wavelength and has the highest possible conversion efficiency, and that is capable of providing directivity in the light propagation direction. An optical waveguide system includes: a three-dimensional photonic crystalline structure including crystal pillars and having a hollow structure inside thereof; an optical waveguide in which a plurality of metal nanoparticles are dispersed in a dielectric material, the optical waveguide having an end portion inserted between the crystal pillars of the three-dimensional photonic crystalline structure, and containing semiconductor quantum dots that are located adjacent to the metal nanoparticles and emit near-field light when receiving excitation light, the metal nanoparticles exciting surface plasmon when receiving the near-field light; and an excitation light source that emits the excitation light for exciting the semiconductor quantum dots.

Abstract: A high-power laser system includes a laser master oscillator, a plurality of fiber laser amplifiers producing intermediate output beamlets, a diffractive optical element for combining the intermediate beamlets into a combined output beam, and one or more error controllers for minimizing errors related to beam combination that may degrade the quality of the combined output beam. A piston error controller uses phase modulation to tag each non-reference intermediate beamlet with a unique dither signal harmonically unrelated to those used for the other beamlets. For each intermediate beamlet, the associated piston error is recovered using a synchronous detector, and an error control signal proportional to the piston error is supplied to a phase modulator to control the piston error for that beamlet. A tilt error controller uses amplitude modulation based on Hadamard code words to tag each non-reference intermediate beamlet with a unique code sequence orthogonal to those used for the other beamlets.

Abstract: A laser source (10) for generating a continuously wavelength tunable light (12) includes a gain media (16), an optical output coupler (36F), a cavity collimator (38A), a diffraction grating (30), a grating beam (54), and a beam attacher (56). The diffraction grating (30) is spaced apart from the cavity collimator (38A) and the grating (30) cooperates with the optical output coupler (36F) to define an external cavity (32). The grating (30) includes a grating face surface (42A) that is in a grating plane (42B). The beam attacher (56) retains the grating beam (54) and allows the grating beam (54) and the grating (30) to effectively pivot about a pivot axis (33) that is located approximately at an intersection of a pivot plane (50) and the grating plane (42B).

Abstract: A fiber laser system includes a predominately single spatial mode, linearly polarized master oscillator providing a set of optical pulses and a polarization-maintaining optical isolator optically coupled to the master oscillator. The fiber laser system also includes a fiber amplifier optically coupled to the optical isolator and including a power amplifier comprising a double clad gain fiber, one or more pump lasers, and a pump coupler. The fiber laser system further includes a pulse compression stage optically coupled to the fiber amplifier. The pulse compression stage includes a volume holographic phase grating. Moreover, the fiber laser system includes a nonlinear frequency conversion stage optically coupled to the pulse compression stage.

Abstract: A high-power laser system includes a laser master oscillator, a plurality of fiber laser amplifiers producing intermediate output beamlets, a diffractive optical element for combining the intermediate beamlets into a combined output beam, and one or more error controllers for minimizing errors related to beam combination that may degrade the quality of the combined output beam. A piston error controller uses phase modulation to tag each non-reference intermediate beamlet with a unique dither signal harmonically unrelated to those used for the other beamlets. For each intermediate beamlet, the associated piston error is recovered using a synchronous detector, and an error control signal proportional to the piston error is supplied to a phase modulator to control the piston error for that beamlet. A tilt error controller uses amplitude modulation based on Hadamard code words to tag each non-reference intermediate beamlet with a unique code sequence orthogonal to those used for the other beamlets.

Abstract: An external cavity type semiconductor laser that has a larger output and a more excellent single mode characteristic than a conventional external cavity type semiconductor laser is provided. The external cavity type semiconductor laser has a laser diode 11, a window glass 16, a grating, and a lens. The external cavity type semiconductor laser has several modifications over the conventional one. A first modification is that the window glass 16 is inclined to a beam emission surface 19 of a laser diode 11 for a predetermined angle. A second modification is that arrangements of the laser diode 11 and so forth are adjusted so that a S wave reaches the grating. A third modification is that when an output power of the laser diode 11 is 45 mW or less, a kink is suppressed.

Abstract: A Littrow-type external-cavity diode laser optical axis displacement correction method and device to easily, inexpensively, and accurately correct displacement of optical axis in Littrow-type ECDLs is provided. In the Littrow-type ECDL optical axis displacement correction device and method, a means for introducing a laser beam, a jig 36 for integrally fixing a diffraction grating 33 and a prism 35 into which the laser beam is introduced in a predetermined arrangement, and a rotary shaft 34 capable of integrally rotating the diffraction grating 33 and the prism 35 are included. By the rotation of the diffraction grating 33 and the prism 35 around the rotary shaft 34, the wavelength of the incident light can be changed, and the optical axis of the output light 39 is not changed by the change of the wavelength.

Abstract: Double Bragg grating scanner receivers (DBS) and methods thereof based on spinning high-efficiency transmitting or reflecting holograms in photo-thermo-refractive (PTRG) glass provides unlimited field of view while incident angle for all components do not exceed approximately 45 degrees. The devices and methods are highly tolerable to high power laser radiation and has no restriction for the use in any laser systems working in visible and near IR spectral regions. Rate of scanning by DBS is higher compared to known mechanical scanners because the use of thin glass plates with recorded holograms and spinning instead of rocking. The components described herein are holographic optical devices (reflecting and transmitting volume gratings) for visible and near IR spectral regions with absolute diffraction efficiency exceeding approximately 95% and high thermal, optical and mechanical stability.

Abstract: Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.

Abstract: A laser device including a gain medium that has a gain, a waveguide for propagating an electromagnetic wave, and a resonant structure comprised of the waveguide. The gain medium extends in the propagation direction, and is sandwiched, at the top and bottom surfaces in the thickness direction thereof, between a first cladding and a second cladding of negative dielectric constant media. The gain medium is provided with a lateral structure adjacent to at least one of the side surfaces thereof in the width direction perpendicular to the propagation direction and the thickness direction. The lateral structure includes a positive dielectric constant medium which is sandwiched, at its top and bottom surfaces in the thickness direction thereof, between the negative dielectric constant media. The waveguide is comprised of the gain medium, the lateral structure, the first cladding and the second cladding.

Abstract: There has been a problem that pumping light leaks from a part having a coating at the joint of a double-clad fiber added with a rare earth and a general single-mode fiber, and heat is generated partly from the fiber by this energy thus causing deterioration of the fiber. Deterioration of a fiber due to residual excitation light can be prevented by preventing residual excitation light in a double-clad fiber from exiting to a single-mode fiber, and the reliability is enhanced. Output of oscillation light can be increased because output of excitation light is not limited. Furthermore, a laser display having a high color reproducibility can be achieved by employing a light source combining a fiber laser light source and a wavelength conversion module.

Abstract: Vertical cavity surface emitting lasers are disclosed, one example of which includes a substrate upon which a lower mirror layer is formed. An active region and upper mirror layer are disposed, in that order, on the lower mirror layer. In particular, the upper mirror layer includes a plurality of DBR layers formed on the active region. The upper mirror layer additionally includes a photonic crystal formed on the plurality of DBR layers and having a periodic structure that contributes to the definition of a central defect. As a consequence of this structure, the photonic crystal has a reflectivity that is wavelength dependent, and the central defect enables the VCSEL to propagate a single mode.

Abstract: Exemplary embodiments provide tunable laser devices, methods for making the laser devices and methods for tuning the laser devices. The tunable laser devices can include an optically pumped semiconductor laser heterostructure, on which a distributed-feedback (DFB) laser grating having variable grating spacings (or chirps) can be formed. The optically pumped semiconductor laser heterostructure can be an optically pumped type-II quantum well laser structure. The emission wavelength of the tunable laser devices can be tuned by changing positions of the region illuminated by the pump laser and with respect to the chirped DFB grating. The disclosed laser devices and methods can provide tunable laser emission with a combination of narrow linewidth and high output power that can be used for remote sensing applications and/or spectroscopic applications across the entire mid infrared (IR) spectral region.

Abstract: A widely tunable laser structure with at least two different sampled or superstructure gratings is provided. The widely tunable laser only requires as much tuning currents as gratings. In the case of two gratings, two tuning currents, instead of 3 tuning currents in a typical laser, are needed. Alternatively, the laser structure can be denoted a sampled or superstructure grating tunable laser with wide tunability characteristics, with a limited amount of needed tuning parameters, e.g., two currents.

Abstract: A first light feedback element is arranged at an optical distance L1 from a front facet of a semiconductor laser from which an output light is emitted on an optical path of the output light. An i-th light feedback element is arranged at an optical distance Li from the front facet on the optical path of the output light, where i=2 to n, n is a positive integer not less than 2, and Li>L1. L1 and Li satisfies ((M?1)+0.01)<(Li/L1)<(M?0.01), where M is a positive integer not less than 2, satisfying (M?1)<(Li/L1)?M.

Abstract: A laser module includes a semiconductor laser element and a feedback optical component forming an external cavity with the semiconductor laser element. Even if a ratio of a current threshold of the laser module changing according to a polarized state of returned light from the feedback optical component to a current threshold of the semiconductor laser element is in an arbitrary range within a predetermined range, a total value of a relative intensity noise occurring between a first frequency determined according to a cavity length of the external cavity and at least equal to or more than a frequency band of using a laser light and a second frequency calculated by multiplying the first frequency by a predetermined number is equal to or more than ?40 dB.

Abstract: The present invention relates to the tailoring the reflectivity spectrum of a sampled-grating distributed Bragg reflector (SGDBR) by applying digital sampling theory to choose the way each reflector is sampled. The resulting mirror covers a larger wavelength span and has peaks with a larger, more uniform, coupling constant (?) than the mirrors produced using conventional approaches. The improved mirror also retains the benefits of the sample grating approach. Additionally, most of the embodiments are relatively simple to manufacture.

Abstract: A gas discharge laser system bandwidth control mechanism and method of operation for controlling bandwidth in a laser output light pulse generated in the gas discharge laser system is disclosed which may comprise a bandwidth controller which may comprise an active bandwidth adjustment mechanism; a controller actively controlling the active bandwidth adjustment mechanism utilizing an algorithm implementing bandwidth thermal transient correction based upon a model of the impact of laser system operation on the wavefront of the laser light pulse being generated and line narrowed in the laser system as it is incident on the bandwidth adjustment mechanism. The controller algorithm may comprises a function of the power deposition history in at least a portion of an optical train of the gas discharge laser system, e.g., a linear function, e.g., a combination of a plurality of decay functions each comprising a respective decay time constant and a respective coefficient.

Abstract: External cavity laser (ECL) systems and methods for measuring the wavelength of the ECL by using a portion of the positional light received by the position sensitive detector (PSD) to determine the position of a wavelength tuning element (such as a diffraction grating or an etalon), for determining the longitudinal laser mode or power output of the laser from a portion of the laser light received by a beam-shearing mode sensor, and by using a non-output beam(s) from a transmissive diffraction grating in the ECL to monitor the external cavity laser.

Abstract: The disclosed invention is an external cavity laser with a volume holographic VHG output coupler. The facet of the VHG is coated with a very high reflectivity coating (HR close to 100%) for the purpose of reflecting the second harmonic (SH) light generated intra-cavity. The HR coating for the SH light has also an anti-reflection (AR) coating at the fundamental wavelength. The reflected second harmonic (SH) light is either reflected directly out of the cavity by the VHG or back to the cavity towards the optics that deflect the SH light out of the cavity.

Abstract: A method is presented for shaping the spectral response of volume holographic grating elements by applying controlled thermal energy. The methods allow generating continuous or discontinuous grating periods from a fixed grating period. The methods are applicable to optical feedback into optical sources such as light emitting diodes, lasers and other general optical filtering applications.

Abstract: A projection video display includes a light source including an OPS-laser delivering laser radiation in multiple transverse modes (a multiple-transverse-mode OPS-laser). The display includes a spatial light modulator for spatially modulating the radiation from the multiple-transverse-mode OPS-laser in accordance with a portion of an image to be displayed. Projection optics project the spatially modulated light on a screen on which the image is to be displayed. In one example the OPS-laser is a diode-laser array pumped OPS-laser and is one of three lasers, one delivering red light, one delivering blue light, and the other delivering green light. The lasers are time modulated such that the spatial light modulator receives light from each of the lasers separately. The OPS laser is directly time modulated by periodically turning the diode-laser array on and off.

Abstract: Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.

Abstract: Apparatus is disclosed for optically steering an optical beam, the apparatus comprising a pair of optical prism components arranged together with a diffraction grating so as to allow efficient coupling of an array of spectrally and spatially offset laser diodes to a common optical fiber. A method of optically steering at least one of a series of optical beams is disclosed, the method comprising providing a pair of optical prism components comprising a thermo-optic material; actuating at least one of the components so as to steer at least one of the series of optical beams received from an array of spatially and spectrally offset lasers.

Abstract: A wavelength detector detecting a change of a wavelength of a laser light with high accuracy, such that the wavelength detector includes a diffraction grating diffracting a laser light, photodetectors positioned symmetrically with respect to a 0-order diffracted light diffracted by the diffraction grating, and respective light incidence surfaces of the photodetectors that have a same shape and that are divided into a plurality of areas. The wavelength detector detects the change of the wavelength based on a value obtained by dividing a difference between (i) a sum of light intensities measured by all of the plurality of divided areas of a first photodetector and (ii) a sum of light intensities measured by all of the plurality of divided areas of a second photodetector, by a sum of light intensities measured by all of the plurality of divided areas of both photodetectors.

Abstract: A multi-wavelength laser source is provided including a pump laser unit, a gain section and an output. The pump laser unit generates an energy signal, which is applied to the gain section. The gain section includes a gain medium with having a superstructure grating forming a distributed Fabry-Perot-like structure. The superstructure grating causes a multi-wavelength laser signal to be generated when the energy signal is applied to the gain medium. The multi-wavelength laser signal is then released at the output.

Abstract: A VCSEL waveguide grating coupler is provided such that a first and second mirror are positioned to define a resonant cavity between them. The waveguide grating coupler further includes a waveguide having a first grating formed as a part of the waveguide to couple light of a first polarization mode into the waveguide. A second grating is formed on the waveguide grating coupler and is orthogonal to the first grating. The second grating is operative to enhance the light coupled to the waveguide by creating a loss difference between light of the first polarization mode and light of a second polarization mode, so that light of the first polarization mode lases preferentially within the VCSEL.

Abstract: A light source module for use in display systems is provided herein. According to one exemplary embodiment, the light source module includes a plurality of coherent light sources, and a diffraction grating in optical communication with the coherent light source, the diffraction grating being configured to provide feedback to the coherent light source to produce a plurality of spectra over a broad spectrum.

Abstract: A semiconductor laser has first and second diffractive grating regions. The first diffractive grating region has segments, has a gain, and has first discrete peaks of a reflection spectrum. The second diffractive grating region has segments combined to each other, and has second discrete peaks of a reflection spectrum. Each segment has a diffractive grating and a space region. Pitches of the diffractive grating are substantially equal to each other. A wavelength interval of the second discrete peaks is different from that of the first discrete peaks. A part of a given peak of the first discrete peaks is overlapped with that of the second discrete peaks when a relationship between the given peaks of the first discrete peaks and the second discrete peaks changes.

Abstract: The present invention is directed to a laser resonator emitting visible radiation with reduced speckle noise, wherein said optical resonator is formed by at least two mirrors at both ends of a visible radiation emitting lasing material, wherein that optical resonator enhances multimode operation, so that said visible radiation emitting lasing material emits a spectrally broadened visible radiation, wherein the enveloping function of said spectrally broadened visible radiation has a full width at half maximum (FWHW) within 1 nm to 15 nm.

Abstract: The invention describes the method and apparatus for enhancement of coupling efficiency in effective-ridge laterally-coupled surface-etched grating waveguide structures, where a slab waveguide has a sequence of the periodic parallel segmented trenches etched from its top surface, such that the segments of intact material having higher refractive index than that in the surrounding segments of periodic trenches form the effective ridges which confine the optical field in and around these ridges, on one hand, and provide bidirectional coupling for the confined modes experiencing Bragg reflection from the segments of the periodic trenches, on the other.

Abstract: A light source device generates irradiation light that is irradiated onto a predetermined face, the light source device including: a laser light source that emits laser light; a diffractive optical element that diffracts the laser light; a diffusion optical element that has an incidence face into which the laser light is incident and a light emission face from which the laser light from the incidence face is emitted, and that diffuses the laser light; and unit structures that are two-dimensionally arrayed on at least one of the incidence face and the light emission face of the diffusion optical element, and that cause the light which is perpendicularly incident into the diffusion optical element to refract at one time, and then emit this light toward the predetermined face.

Abstract: A volume Bragg laser including a resonator comprising photo-thermo-refractive (PTR) volume diffractive elements that can be used in a laser emitting window of transparency of PTR glass to provide control of the lasers spectral and angular parameters, and methods, devices, apparatus and systems related thereto. The high efficiency volume Bragg gratings recorded in photo-thermo-refractive (PTR) glass preferably has an absolute diffraction efficiency exceeding approximately 95% in transmitting and reflecting modes is used for selection of a transverse and longitudinal mode for thermal, optical and mechanical stabilization of the volume Bragg lasers and coherent coupling of different lasers. Robustness, compactness, thermal and laser stability along with the ability to place several elements in the same space allows the use of sophisticated optical system according to the invention in fields of military lasers, optical communications, data storage and processing, and the like.

Abstract: Provided is a distributed feedback semiconductor laser structure including: a first clad layer; a first ridge waveguide formed on the first clad layer; an active layer formed on the first ridge waveguide; a second ridge waveguide formed on the active layer; a second clad layer formed on the second ridge waveguide; an ohmic contact layer formed on the second clad layer; and a plurality of gratings formed in at least one of the first and second clad layers, making a predetermined angle with the first ridge waveguide or the second ridge waveguide, and periodically arranged in a longitudinal direction of the first or second ridge waveguide. As a result, a general hologram lithography process capable of mass production is applied to the present invention so that process time can be reduced. Also, a distributed feedback semiconductor laser structure using a quantum-dot active layer that does not require an additional process for obtaining a pure single-wavelength is provided.

Abstract: A resonator cavity (10A) and method are provided. The resonator cavity (10A) includes at least one gain medium (16) and end reflectors (12, 14) which define together longitudinal modes of light in the cavity, and further includes an intra-cavity beam coupler assembly (20). The beam coupler assembly (20) is configured to split light impinging thereon into a predetermined number of spatially separated light channels, and to cause phase locking and at least partial coherent combining of the light channels, having common longitudinal and transverse modes, in a double pass through the beam coupler assembly (20). The resonator cavity (10A) is configured and operable to produce at least one output combined light channel of a predetermined intensity profile.

Abstract: An optical modulator and related methods are described. In accordance with one embodiment, the optical modulator comprises a horizontal waveguide grating structure (WGS) receiving an incident radiation beam propagating in a non-horizontal direction. The WGS includes a horizontal waveguiding layer along which a lateral propagation mode is guided, the lateral propagation mode having a vertically extending mode profile. The optical modulator further comprises a multiple quantum well (MQW) layer sufficiently proximal to the horizontal waveguiding layer to be within a vertical extent of the mode profile of the lateral propagation mode. The optical modulator further comprises an electric field source applying a time-varying electric field to the MQW layer. The optical modulator modulates the incident radiation beam according to the time-varying electric field to generate a modulated radiation beam propagating in one of a transmitted direction and a reflected direction.

Abstract: A powerful fiber laser system is configured with at least one large-area multi-clad rare-earth doped fiber, which is configured with a MM core capable of propagating a single mode laser emission at a first wavelength, and with at least one pumping assembly capable of generating an optical pump output at a wavelength shorter than the first wavelength of the rare-earth doped fiber. The pumping assembly has a plurality SM fiber lasers coupled to a SM-MM combiner which is operative to lunch the pump output into the cladding of the rare-earth doped fiber so that the powerful fiber laser system is operative to deliver a power of up to 20 kW.

Abstract: A fiber Chirped Pulse Amplification (CPA) laser system includes a fiber mode-locking oscillator for generating a laser for projecting to a fiber stretcher for stretching a pulse width of the laser. The fiber CPA laser system further includes a multistage amplifier for amplifying the laser and a high-order dispersion compensating compressor for compensating high order dispersions and compressing the pulse width of the laser. The high-order dispersion compensating compressor further includes a pair of gratings coupled with a pair of prisms, a grating pair engraved on the surfaces of a pair of prisms, a chirped grating pair and a phase modulator consists of a grating and a deformable mirror, for generating a negative group velocity dispersion (GVD) and a negative third order dispersion (TOD) for the laser.

Abstract: A surface-emission laser diode includes a distributed Bragg reflector tuned to wavelength of 1.1 ?m or longer, wherein the distributed Bragg reflector includes an alternate repetition of a low-refractive index layer and a high-refractive index layer, with a heterospike buffer layer having an intermediate refractive index interposed therebetween with a thickness in the range of 5-50 nm.

Abstract: Apparatus and methods for altering one or more spectral, spatial, or temporal characteristics of a light-emitting device are disclosed. Generally, such apparatus may include a volume Bragg grating (VBG) element that receives input light generated by a light-emitting device, conditions one or more characteristics of the input light, and causes the light-emitting device to generate light having the one or more characteristics of the conditioned light.

Abstract: A diffraction grating device includes a substrate with a primary surface having a plurality of grating areas that are periodically arranged with a constant period in a predetermined axis direction, the grating area including a first area and a second area, a diffraction grating structure providing a chirped grating whose pitch monotonically changes along the predetermined axis direction, a core layer that is optically coupled with the diffraction grating structure with a coupling coefficient, a plurality of grating portions including the diffraction grating structure and the core layer, the grating portion including a first portion and second portion that are arranged on the first area and the second area, respectively, of the primary surface and a perturbing layer disposed at the first portion or the second portion. The perturbing layer changes the coupling coefficient between the diffraction grating structure and core layer.

Abstract: The subject of the invention is a laser comprising a semiconductor active medium with a population inversion lifetime ?c and a resonant cavity with a lifetime of the photons in the cavity ?p. The cavity includes means for being longitudinally monomode and means so that ?p>?c, such as for example a very long cavity, so as to obtain a laser with a very low intrinsic noise.

Abstract: A second-order multi-mode partial distributed feedback (p-DFB) laser having increased electrical-to-optical power conversion efficiency, stabilized wavelength and narrowed emission linewidth. The laser includes an abbreviated grating housed in the laser cavity that is separated from both the front-end and the back-end of the laser facets.

Abstract: A distributed feedback semiconductor laser may have (1) a controlled complex-coupling coefficient which is not affected by grating etching depth variation, and (2) facet power asymmetry with no facet reflection which eliminates a random effect of facet grating phase. The device comprises a multiple-quantum-well active region, and a complex-coupled grating formed by periodically etching grooves through a part of the active region. The semiconductor materials for a barrier layer where the groove etching is to be stopped, a regrown layer in the etched groove, and a laser cladding layer, are chosen all the same, so as to form an active grating entirely buried in the same material, providing a complex-coupling coefficient which is defined independently of the etching depth. Facet power symmetry may also be provided by composing the laser cavity of two sections (“front” and “back” sections) having different (“front” and “back”) Bragg wavelengths.

Abstract: The present invention relates to a laser source for the infrared wavelength range which comprises a pump laser (1) which emits radiation (PP) which is input radiation to a first optical parametric oscillator (3, 4, 5), whose output radiation (SP) is input radiation to a second step in the form of a second optical parametric oscillator (7, 8, 9) or an optical parametric generator. At least one of the reflective devices of the first optical parametric oscillator consist of a Bragg grating (5) in a bulk material.

Abstract: The present invention provides a laser device wherein one diffraction grating and at least two reflectors are arranged such that two coupled resonators are formed for the light path. This laser device is an arrangement forming a first optical resonator comprising a first and a second reflector including in its light path the diffraction by the grating. The second reflector is arranged perpendicularly to an order of diffraction of the grating. Coupled with the first resonator (A), there is provided a second mirror-reflective resonator between a mirror-reflective surface of the grating and the second reflector. In the case of the grating having an even number of ports, the second resonator needs completion by a third reflector arranged to reflect light from specular reflection by the grating back to the grating. For gratings having an odd number of ports, the second reflector is arranged in parallel to the grating. The laser medium is preferably arranged between the first reflector and the grating.

Abstract: Techniques, apparatus and systems for providing compensation mechanisms for mode-locked lasers and optical amplifiers and a dispersion compensation mechanism to allow a mode-locked laser and an optical amplifier to be optically coupled to each other and to share a common diffraction grating for a dispersion compensation element for the laser and a separate dispersion compensation element for the amplifier.