Abstract: A laser is disclosed including a gain section having a distributed feedback grating imposed thereon. An absorption section is embedded in the gain section such that the first and second portions of the distributed feedback grating extend on either side of the electro-absorption section. A controller imposes a substantially DC bias signal on the first and second gain electrodes and imposes a modulation signal encoding digital data on the modulation electrode to generate a frequency modulated signal. In some embodiments, the first and second portions are biased above the lasing threshold and the absorption section is modulated below the lasing threshold to modulate loss in the absorption section.

Abstract: A manufacturing method of an opto-electric hybrid module which is capable of suppressing losses in cost, and an opto-electric hybrid module obtained thereby. An optical waveguide portion W1 including protrusions 4 for the positioning of an electric circuit portion E1, and the electric circuit portion E1 including through holes 8 for fitting engagement with the protrusions 4 are produced individually. An optical element 11 is mounted on the electric circuit portion E1. Thereafter, an inspection is performed to verify the mounting state of the optical element 11. When the appropriate mounting is verified, the through holes 8 in the electric circuit portion E1 are brought into fitting engagement with the protrusions 4 for the positioning of the electric circuit portion E1, whereby the electric circuit portion E1 with the optical element 11 mounted thereon and the optical waveguide portion W1 are integrated with each.

Abstract: A high-power narrow-linewidth fiber laser system includes a seed oscillator with multiple resonant cavities and an amplifier stage. The seed oscillator includes a gain fiber, a pump source to introduce pump light into the gain fiber, a single-mode output fiber arranged at the end of the active gain fiber, a first resonant cavity including the active gain fiber, and a second resonant cavity including the active gain fiber. The first and second resonant cavities cooperate to minimize the synchronization of longitudinal modes and thereby reduce modal beating. The amplifier preferably includes an active multimode gain fiber capable of supporting a single fundamental mode at the signal wavelength, wherein the single mode output fiber of the seed oscillator and the multimode gain fiber of the amplifier are mode-matched and coupled without a mode converter.

Abstract: Since the absorption of a fundamental wave by a fiber increases if it is tried to obtain a wavelength conversion light of watt-class high output, the fiber length needs to be shortened. However, since oscillation efficiency conversely decreases if the fiber length is shortened, it is difficult to obtain a high-output fundamental wave. Thus, by reflecting an excitation light incident on the fiber in the fiber, the excitation light is efficiently absorbed to amplify the fundamental wave with a high gain. Further, by shortening the fiber length, the absorption of the fundamental wave is also reduced to improve a fundamental wave output. Consequently, a wavelength converter capable of ensuring a stable high output up to watt-class is achieved.

Abstract: An optical device including: an optical waveguide; and a plurality of diffraction grating layers provided along the optical waveguide, wherein each of the diffraction grating layers comprises a diffraction grating, each diffraction grating comprising a discontinuous first semiconductor layer and a second semiconductor layer burying the first semiconductor layer, the first and second semiconductor layers having different refractive indices, the plurality of diffraction grating layers comprise at least two diffraction grating layers being different from each other in terms of the length of a region where the diffraction grating is provided, and the diffraction gratings in an overlap region of the plurality of diffraction grating layers have the same phase and period is provided.

Abstract: A method and apparatus may comprise a seed laser, along with an amplifier laser amplifying the output of the seed laser. A bandwidth metrology module may provide a bandwidth measurement and a bandwidth error signal may be provided using a bandwidth set point. A differential timing system responsive to the error signal can selectively adjust a differential firing time between the seed laser and amplifier laser. A beam dimension and center wavelength control system may adjust a beam dimension, within the cavity of the seed laser, to select bandwidth, and may adjust center wavelength at the same time, using a plurality of beam expansion prisms and at least one other prism or other optical element in the cavity to select center wavelength.

Abstract: Apparatus and methods of controlling a frequency-converted diode laser system are disclosed. The diode laser systems can include embodiments of thermally coupled elements facilitating temperature stabilization. Aspects of some methods include monitoring the output of a stabilized diode laser system to reduce noise of the output laser beam. Other aspects of some methods include adjusting the temperature of a frequency converter based on noise in the output beam, and/or the current provided to drive the diode laser. Systems incorporating such control aspects, and others, are also disclosed.

Abstract: A light source includes a semiconductor laser diode and a narrow spectral and spatial bandwidth reflector in optical communication with respect to the semiconductor diode laser and aligned with the output beam of the diode laser, such that a portion of the light in the output beam is reflected back into the laser.

Abstract: A laser system comprises first and second laser sub-cavities each including a gain medium arranged to produce volume gain gratings. The laser system further includes a beam combiner arranged to combine emission from each cavity and direct emission from one cavity to the other. As a result a stale, phase-locked coherently combined emission system is provided.

Abstract: Using sampled Bragg grating structure, the present invention proposes a distributed feedback (DFB) semiconductor laser based on reconstruction-equivalent-chirp technology. Namely, the Bragg grating in the said DFB semiconductor laser cavity is a sampled Bragg grating, in which there is an equivalent grating corresponding to the original ordinary DFB grating as feedback for lasing. The laser wavelength of the said semiconductor laser located within the operation bandwidth of the said equivalent grating. The said equivalent grating is designed and fabricated using REC technology and has equivalent chirps, one equivalent phase shift or multiple equivalent phase shifts. The said sampled Bragg grating has multiple ghost gratings and the wavelength spacing between neighboring ghost gratings is inversely proportional to the sampling period and the effective refractive index of the said semiconductor laser.

Abstract: A CS optical pulse train generation method, which is able to change the half width of an optical pulse constituting a CS optical pulse train, and which is compact and has low power consumption. A distributed Bragg reflector semiconductor laser utilized in this method is one which is constituted comprising an optical modulation region, a gain region, a phase control region, and a distributed Bragg reflector region. Current is injected into the gain region by way of a p-side electrode and a n-side common electrode by a constant current source, forming the population inversion required for laser oscillation. Optical modulation required to manifest mode locking is carried out in the optical modulation region. A diffraction grating is formed in the distributed Bragg reflector region.

Abstract: The present invention relates to an external-cavity laser module comprising a thermoelectric cooler (TEC) including an upper carrier plate having an upper surface, said TEC being configured to stabilize the temperature of the upper surface at a substantially constant temperature. The laser module further comprises a laser assembly mounted on an optical bench, which is in thermal coupling with said upper surface, said laser assembly comprising a gain medium for emitting an optical beam into the external cavity and an end mirror.

Abstract: An apparatus comprising a laser source configured to emit a light beam along a first path, an optical beam steering component configured to steer the light beam from the first path to a second path at an angle to the first path, and a diffraction grating configured to reflect back at least a portion of the light beam along the second path, wherein the angle determines an external cavity length. Included is an apparatus comprising a laser source configured to emit a light beam along a first path, a beam steering component configured to redirect the light beam to a second path at an angle to the first path, wherein the optical beam steering component is configured to change the angle at a rate of at least about one Kilohertz, and a diffraction grating configured to reflect back at least a portion of the light beam along the second path.

Abstract: A robust, quickly tunable narrow-linewidth entangled photon source system based on Spontaneous Parametric Down Conversion (SPDC) of the pump light in periodically polled LiNbO3 (PPLN) waveguides. The photon source provides narrow-linewidth, entangled output photons having a wavelength in the telecom C-Band wavelength. To tailor the output spectrum of the output photons, the PPLN waveguide is arranged between two end waveguides having LiNbO3-embedded Bragg gratings, thereby forming a tunable Fabry-Perot cavity. The resulting narrow output linewidth of the output photons makes the system desirable for use in a long-distance quantum key distribution (QKD) system.

Abstract: A surface emitting laser diode includes a ring-shaped first semiconductor layer including an n-type clad layer, a ring-shaped active layer provided on the first semiconductor layer, and a ring-shaped second semiconductor layer which is provided on the active layer and includes a p-type clad layer and a grating layer including grating units continuously arranged in a circumferential direction, each grating unit including a plurality of regions having different refractive indices and being adjacent to each other in the circumferential direction.

Abstract: According to aspects of an embodiment of the disclosed subject matter, a line narrowed high average power high pulse repetition laser micro-photolithography light source bandwidth control method and apparatus are disclosed which may comprise a bandwidth metrology module measuring the bandwidth of a laser output flight pulse beam pulse produced by the light source and providing a bandwidth measurement; a bandwidth error signal generator receiving the bandwidth measurement and a bandwidth setpoint and providing a bandwidth error signal; an active bandwidth controller providing a fine bandwidth correction actuator signal and a coarse bandwidth correction actuator signal responsive to the bandwidth error. The fine bandwidth correction actuator and the coarse bandwidth correction actuator each may induce a respective modification of the light source behavior that reduces bandwidth error. The coarse and fine bandwidth correction actuators each may comprise a plurality of bandwidth correction actuators.

Abstract: A semiconductor laser includes an optical waveguide formed on a semiconductor substrate and capable of generating gain by current injection, and a diffraction grating having a phase shift and provided along the optical waveguide over the overall length of the optical waveguide on the semiconductor substrate. The semiconductor laser is configured such that a Bragg wavelength in a region in the proximity of each of the opposite ends of the optical waveguide is longer than a Bragg wavelength in a region in the proximity of the phase shift in a state in which current injection is not performed for the optical waveguide.

Abstract: A laser source (10) for emitting a set of sequential, different wavelength output beams (12) includes a gain medium (16), a feedback assembly (26) and a control system (30). The gain medium (16) includes a first facet (16A), and the gain medium (16) generates a beam (12A) that exits the first facet (16A). The feedback assembly (26) includes a feedback device (40) and a device mover (42). The feedback device (40) is positioned in the path of the beam (12A) that exits the first facet (16A) and the feedback device (40) redirects at least a portion of the beam (12A) back to the gain medium (16). The device mover (42) continuously adjusts an angle of incidence (?) of the beam (12A) on the feedback device (40). The control system (30) selectively directs pulses of power to the gain medium (16) as the device mover (42) is continuously adjusting the angle of incidence (?) of the beam (12A).

Abstract: In accordance with the present invention, a compact laser system with nearly continuous wavelength scanning is presented. In some embodiments, the compact laser system can be scanned over a broad range. In some embodiments, the compact laser system can be scanned at high scan rates. In some embodiments, the compact laser system can have a variable coherence length. In particular, embodiments with wavelength scanning over 140 nm with continuously variable scan rates of up to about 1 nm/?s, and discrete increase in scan rates up to about 10 nm/?s, and variable coherence lengths of from 1 mm to about 30 mm can be achieved.

Abstract: An illumination light source is provided with a laser light source having a laser medium with a specified gain region, and a reflector having a narrow band reflection characteristic. A part of a laser light emitted from the laser light source is reflected and fed back by the reflector, so that an oscillation wavelength of the laser light source is fixed at a reflection wavelength. A peak of a gain region of the laser medium is shifted from the reflection wavelength by a change of an oscillation characteristic of the laser light source, so that the oscillation wavelength of the laser light source is changed from the reflection wavelength. Thus, an oscillation spectrum of the laser light source is spread to reduce speckle noise.

Abstract: An active layer (18) is formed over a semiconductor substrate having a pair of facets (15A, 15B) mutually facing opposite directions. An upper cladding layer (19) is formed on the active layer, having a refractive index lower than that of the active layer. A diffraction grating (25) is disposed in the upper cladding layer on both sides of a distributed feedback region in a waveguide region (22), the waveguide region extending from one facet to the other of the semiconductor substrate. End regions (22B) are defined at both ends of the waveguide region and the distributed feedback region (22A) is disposed between the end regions. Low refractive index regions (26) are disposed in the upper cladding layer on both sides of each of the end regions of the waveguide region, the low refractive index regions having a refractive index lower than that of the upper cladding layer.

Abstract: A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. Such an invention, as disclosed herein, uses diffraction gratings to increase gain, stored energy density, and pumping efficiency of solid-state laser gain media, such as, but not limited to rods, disks and slabs. By coupling predetermined gratings to solid-state gain media, such as crystal or ceramic laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

Abstract: A tunable laser comprises a gain section and two or more reflectors. At least one of the reflectors is a Bragg grating comprising a reduced strength section comprising a base order periodic pattern of marks and spaces from at which at least some of the marks or spaces are missing. This enables the reflective strength of the grating to be controlled relative to the other reflector. The Bragg grating may be a phase change grating with individual sections being reduced in strength by line removal.

Abstract: A Bragg grating has a local reflection strength which varies with position along the length of the grating so as to generate a non-uniform wavelength reflection spectrum, enabling compensation for a non-uniform gain profile of the gain section of a tunable laser. In another aspect, a Bragg comb grating is modulated by an envelope function which can also compensate for a non-uniform gain profile. The comb grating may be a phase change grating, with the envelope function shape being controlled by the length between phase changes and/or size of the phase changes.

Abstract: A mode hop-free tunable laser including a gain medium, a microfabricated blazed grating, defining an external cavity of a given length, the blazed grating lying in a general plane and including a plurality of elongate beams carrying mutually parallel respective reflection surfaces spaced apart from one another with a predefined pitch, and actuating elements designed so as to allow displacements of the assembly with respect to a grating support within a plane substantially parallel to the grating general plane, and including actuation elements designed so as to apply a stretching and a displacement of the assembly in a direction transverse to said reflection surfaces, the blazed grating being arranged relative to an incident light beam provided by the gain medium so that the incident light beam impinges on the reflection surfaces with a substantially normal incident angle.

Abstract: According to aspects of an embodiment of the disclosed subject matter, method and apparatus are disclose that may comprise adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, without utilizing any beam magnification control, or adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for other than bandwidth control, and adjusting a differential timing between gas discharges in the seed laser and amplifier laser for bandwidth control, based on the error signal, or for control of another laser operating parameter other than bandwidth, while utilizing beam magnification control for bandwidth control based on the error signal.

Abstract: A method of operating a laser projection system is provided. The projection system comprises an external cavity laser, an optical intensity monitor, laser projection optics, and a controller. The external cavity laser comprises a laser diode, an intra-cavity wavelength conversion device, and a wavelength selective element. According to the method, the position of the wavelength selective element is adjusted relative to an optical axis Z of the external cavity laser to optimize output intensity. Specifically, the position of the wavelength selective element is adjusted by (i) tilting the wavelength selective element about its wavelength selective axis Y to reflect a wavelength of interest along an optimum path in an XZ plane of the external laser cavity and (ii) tipping the wavelength selective element about its wavelength insensitive axis X to reflect the wavelength of interest along an optimum path in a YZ plane of the external laser cavity. Additional embodiments are disclosed and claimed.

Abstract: A laser having a laser cavity is disclosed that does not require conventional dielectric mirrors or as-grown reflectors. Instead, a diffraction grating and total internal reflection system is used to define a laser cavity. Within the laser cavity, the laser emission travels in a zigzag pattern. The diffraction grating provides a highly reflective “mirror” diffracting beams at a forward angle and back angle that “tunes” the process of total internal reflection. The diffraction grating also directs a small percentage of the incident radiation approximately normal to the upper face of the semiconductor (more generally, at an angle less than the critical angle), to provide an output laser beam. The laser can be used in an electron tube and laser display system.

Abstract: A laser beam multiplexer capable of easily multiplexing a plurality of laser beams is provided. A laser beam multiplexer includes a multiplexing element having a hollow portion with a sectional elliptical shape, in which the multiplexing element includes: a plurality of light-incident apertures guiding laser beams from outside toward one of two focal points of the hollow portion, a reflective layer arranged on a wall surface of the hollow portion, and multiplexing a plurality of incident laser beams while reflecting the plurality of laser beams, and a light-emitting aperture guiding laser beams multiplexed by the reflective layer toward outside.

Abstract: The hologram recording technology expected to realize ultrahigh-density information recording is one of the post Blu-ray Disc technology. When we think about developing a drive based on this technology and suitable for consumer electronics, it is considered most desirable from the viewpoint of upward compatibility to solve the problem of the BD-compatibility. The problem in sharing the laser light source between the hologram recording device and the current optical disc device, however, is that the hologram recording requires a high-coherent, single-mode light beam, while the current optical discs requires a low-coherent, multi-mode light beam. In point of the coherence of the light source, the above two cases require the light beams of the characteristics opposite to each other, and this presents an important task.

Abstract: Provided is a self-pulsating laser diode including: a distributed feedback (DFB) section serving as a reflector; a gain section connected to the DFB section and having an as-cleaved facet at one end; a phase control section interposed between the DFB section and the gain section; and an external radio frequency (RF) input portion applying an external RF signal to at least one of the DFB section and the gain section.

Abstract: A method of controlling a semiconductor laser that has a plurality of wavelength selection portions having a different wavelength property from each other and is mounted on a temperature control device, including: a first step of correcting a temperature of the temperature control device according to a detected output wavelength of the semiconductor laser; and a second step of controlling at least one of the wavelength selection portions so that changing amount differentials between each wavelength property of the plurality of the wavelength selection portions is reduced, the changing amount differential being caused by correcting the temperature of the temperature control device.

Abstract: The present invention provides a semiconductor optical element applicable to an EC-LD or an SLD, and an external cavity laser having the semiconductor optical element. The semiconductor optical element has a pair of cleavage surfaces, and comprises a semiconductor substrate 11 having a base surface and a planer structure provided on the base surface and provided with a waveguide 1G having an active layer. The waveguide 1G has an end surface with low reflectivity and another end surface with certain reflectivity.

Abstract: The invention relates to an article comprising a length of an optical fiber and a package, the optical fiber comprising a fiber Bragg grating dispersed over a FBG-section of the length of the optical fiber, the package comprising a carrier with a carrier surface for supporting at least a supported part of the optical fiber including the FBG-section. The invention further relates to an apparatus comprising the article, to its use and to a method of manufacturing such an article. The object of the present invention is to seek to provide an optimized (e.g. elongate) package having a relatively low sensitivity to mechanical vibrations from the environment. This is achieved by providing that the carrier surface for supporting the optical fiber comprising a fiber Bragg grating is convex in a longitudinal direction of the optical fiber during use of the article.

Abstract: A nitride semiconductor laser element, comprises a substrate and a nitride semiconductor layer in which a first semiconductor layer, an active layer, and a second semiconductor layer are laminated in this order on the substrate, wherein recessed and raised portions are formed in the first semiconductor layer and/or the second semiconductor layer, a semiconductor layer that embeds the recessed and raised portions are formed on the semiconductor layer in which said recessed and raised portions are formed, the semiconductor layer in which the recessed and raised portions are formed is equipped with a side face having a first region extending downward and a second region extending farther downward continuously from the first region, and the second region has a greater slope with respect to the normal direction of the substrate than the first region.

Abstract: Disclosed is a laser system comprising: A laser assembly (101) comprising a plurality of emitters; first and second light feedback devices (208, 232) forming respective external cavities with the laser assembly; a dispersive device (205) for redirecting respective portions of the light from the laser assembly to the first and second feedback devices (208, 232), wherein the first feedback device (232) is adapted to reflect a feedback portion of the redirected beam back onto the dispersive device (205) and to generate the output beam (233) from an output part of the first redirected beam, —an imaging device (213) for generating an optical Fourier transform of the plurality of emitters at a Fourier plane (235). The dispersive device (205) is positioned displaced from said Fourier plane (235) by a predetermined displacement (d) in a direction along said principle axis (230).

Abstract: A light source apparatus includes: a light emitter; a pair of electrodes for driving the light emitter; and an external resonant cavity that reflects part of the light emitted from a light-exiting end surface of the light emitter. The light emitter includes an active layer that generates light, an internal resonant cavity, and a diffractive optical layer that diffracts light having a predetermined wavelength. The external resonant cavity includes an external mirror that reflects the light having the predetermined wavelength. The internal resonant cavity, the external resonant cavity, and the diffractive optical layer form a laser resonant cavity that allows the light generated in the active layer to achieve laser oscillation.

Abstract: A spatial coupling provided between an amplified-light waveguide and an output-light waveguide includes a wavelength selecting element that selectively transmits a light having a desired wavelength band out of a spontaneous emission light generated in the amplified-light waveguide and a lens unit that couples the spontaneous emission light to the wavelength selecting unit. An input-side light reflecting unit provided between a semiconductor pumping laser and the amplified-light waveguide and an output-side light reflecting unit formed on an output side of the spatial coupling unit form a laser resonator.

Abstract: The invention describes the method and apparatus for enhanced efficiency in a laterally-coupled distributed feedback (LC-DFB) laser. In a device featuring the effective ridge design, lateral confinement of the guided optical modes is provided by a surface etched grating, which also serves as a DFB element of the laser. Coupling and quantum efficiency of such a LC-DFB laser both improve with an increase of the lateral mode order. In accordance with this invention, a dramatic enhancement of the laser efficiency is achievable by designing it to operate in one of the higher order modes, notably the first order mode, while all the other lateral modes, including the zero order mode, are suppressed through gain-loss discrimination.

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 light source device includes: a laser light source emitting a laser beam of a prescribed wavelength; a nonlinear optical element, disposed facing a light emergence surface of the laser light sources which converts an emission wavelength of the laser beam emitted from the laser light source and causes the laser beam to emerge; a volume phase grating, disposed facing an emergence surface of the laser beam of the converted wavelength converted by the nonlinear optical element, which has formed in an interior thereof a Bragg grating structure which selectively reflects a laser beam of an emission wavelength; and a first dielectric multilayer, provided on a light emergence surface of the volume phase gratings which transmits the laser beam of the converted wavelength and reflects the laser beam of the emission wavelength.

Abstract: For performing hologram recording or reproduction, an oscillation wavelength half value width ?? of a coherent light source satisfies a relationship of ??<?2/(S×2 sin ?), where a substantial hologram size is S, a substantial cross angle between reference light and signal light is ?, and the oscillation wavelength of the coherent light source is ?. Even when stray light is generated, the coherent light source can suppress generation of an unnecessary interference fringe due to the stray light, and stably record and reproduce holograms.

Abstract: A laser device, includes: a fundamental wave generating portion configured to generate a plurality of fundamental waves having wavelengths which are different from each other in at least one set thereof, the fundamental wave generating portion having a semiconductor laser having a plurality of luminous points, and a Bragg reflection structure; and a nonlinear optical element in which a poling structure adapted to pseudophase matching for the wavelengths of the plurality of fundamental waves emitted from the fundamental wave generating portion, respectively, is formed variatively along a propagating direction of the plurality of fundamental waves.

Abstract: A method for fabricating a distributed Bragg reflector waveguide is disclosed, which includes forming a first distributed Bragg reflector on a substrate; forming a sacrificial pattern on the first distributed Bragg reflector; forming a second distributed Bragg reflector on the sacrificial pattern and the first distributed Bragg reflector; and removing the sacrificial pattern. A distributed Bragg reflector waveguide is also disclosed.

Abstract: For increasing the power emitted by surface emitting lasers and for improving the spatial coherence of the laser beam, emitted in particular by disk lasers, microchip lasers and VCSELs having a relatively wide emitting area, the invention proposes to select a low order transverse cavity mode by means of a mirror structure (12) of high reflectivity, and of high angular selectivity. The mirror structure comprises a multilayer (14) receiving the optical beam (24) and a resonant grating mirror (16) following the multilayer and arranged for highly reflecting the optical beam in a narrow angular range at each side of a determined incidence angle.

Abstract: An integrated optical source includes a Directly Modulated Laser (DML) and a filter which is positioned with the DML on a common substrate. The filter is configured to receive an input signal in the form of a modulated chirped optical signal. The filter is further configured to provide an output optical signal in the form of an amplitude and/or phase modulated optical signal, optimized for long-distance transmission in optical fiber.

Abstract: A color-mixing laser module is disclosed, which is comprised of a laser unit capable of emitting red, blue and green laser beams; a beam combiner, for receiving and converging the laser beams emitted from the laser unit and then directing the converged laser light to illuminate on a light pattern adjusting unit; and the light pattern adjusting unit, capable of receiving the converged laser light from the beam combiner for adjusting the pattern of the same.

Abstract: In a gain-coupled distributed feedback semiconductor laser, a coating of a low reflectivity is provided on a front facet from which laser light is emitted and a coating of a high reflectivity is provided on a rear facet, thus forming asymmetric coatings. The semiconductor laser has a structure in which an absorption diffraction grating is located along an optical waveguide, and the diffraction grating includes a phase shift region.

Abstract: Continuously tunable and precisely wavelength-switchable fiber lasers combine fiber Bragg gratings and the transmissive filtering properties of high finesse fiber Fabry-Perot filters. This laser arrangement adapts to multiple wavelength ranges based on the selections of fiber Bragg grating and gain medium and their arrangement to create a wavelength-modulatable and simultaneously rapidly wavelength-switchable narrow linewidth all-fiber laser design. This laser arrangement further results in narrow-linewidth outputs with fast switching speeds between the selected wavelengths.

Abstract: A planar optical waveguide is formed having sets of locking diffractive elements and means for routing optical signals. Lasers are positioned to launch signals into the planar waveguide that are successively incident on elements of the locking diffractive element sets, which route fractions of the signals back to the lasers as locking feedback signals. The routing means route between lasers and output port(s) portions of those fractions of signals transmitted by locking diffractive element sets. Locking diffractive element sets may be formed in channel waveguides formed in the planar waveguide, or in slab waveguide region(s) of the planar waveguide. Multiple routing means may comprise routing diffractive element sets formed in a slab waveguide region of the planar waveguide, or may comprise an arrayed waveguide grating formed in the planar waveguide. The apparatus may comprise a multiple-wavelength optical source.