Abstract: A method and system for determining deformation in a cable, where a sensing optical fiber arrangement is applied along the cable. The method includes injecting a forward pulse pump signal in the optical fiber in a forward direction of the optical fiber and injecting a reverse probe signal in the optical fiber in a reverse direction of the optical fiber. A stimulated Brillouin backscattering is measured and, based on the Brillouin backscattering measurement, information is provided about a deformation of the cable. The forward pulse pump signal is provided as a sum of a stationary signal component and an interrogation pulse component, the stationary signal component has an energy below a Brillouin activation level and the interrogation pulse signal component has an energy which results in that the sum of the stationary signal component and the interrogation pulse signal component exceeds the Brillouin activation level.

Abstract: Systems and methods for ring laser gyroscopes (RLGs) are provided. An RLG includes a traveling-wave resonator cavity with three or more mirrors and a gain medium positioned in the traveling-wave resonator cavity between two of the three or more mirrors. The gain medium is a solid-state gain medium or a nonlinear optical medium. The RLG further includes a first pump laser and a second pump laser to pump the gain medium in different directions and generate first and second lasing signals that traverse the traveling-wave resonator cavity in a opposite directions. The RLG further includes first and second photodetectors to measure levels of the first and second lasing signals. The RLG further includes at least one processor configured to adjust a power level of the first pump laser and/or a power level of the second pump laser based on the measured power levels of the first and second lasing signals.

Abstract: Methods and apparatus for tuning a photonics-based component. An opto-electrical detector is configured to output an electrical signal based on a measurement of light intensity of the photonics-based component, the light intensity being proportional to an amount of detuning of the photonics-based component. Analog-to-digital conversion (ADC) circuitry is configured to output a digital signal based on the electrical signal output from the opto-electrical detector. Feedback control circuitry is configured to tune the photonics-based component based, at least in part, on the digital signal output from the ADC circuitry.

Abstract: The invention is concerned with a structured optical fibre sensor, comprising a light source (1), a detection system (2) and a Bragg grating optical fibre (3) connected to said source and said system. The light source is a wavelength-tunable laser emission device (1) comprising a cavity (CA) delimited by a first and a second Sagnac mirror (M1, M2). The cavity comprises an amplifying medium (AM) and a tunable spectral filter using the Vernier effect (F), said filter (F) comprising at least three resonant rings (R1, R2, RN?1, RN) arranged in cascade, each resonant ring integrating a wavelength-tunable reflectivity loop mirror (MBR).

Abstract: A single longitudinal mode ring Raman laser including: a pump source outputting a pump light power, resonantly coupled to a first ring resonator; a optical measurement and piezo-actuator for stabilising the resonant coupling of the pump light power to a first ring resonator; a first ring resonator including a Raman gain medium, wherein the Raman gain medium receives the pump light power and undergoes Raman lasing generating resonated Stokes power at the corresponding Stokes output wavelength; the first ring resonator acting as a feedback loop for the pump light power and the resonated Stokes power and outputting a portion of the Stokes power as the laser output.

Abstract: An FEL includes a feedback device for feeding back emitted illumination radiation.

Abstract: A pulse stretching fiber oscillator (or laser cavity) may comprise a chirped fiber Bragg grating (CFBG) and an optical circulator arranged such that a first portion of a beam that is transmitted through the CFBG continues to propagate through the laser cavity while a second portion of the beam that is reflected from the CFBG is stretched and chirped by the CFBG and directed out of the laser cavity by the optical circulator. Accordingly, a configuration of the CFBG and the optical circulator in the laser cavity may enable pulse stretching contemporaneous with outcoupling, which may prevent deleterious nonlinear phase from accumulating prior to stretching.

Abstract: To provide an optical element that can be more easily aligned with an optical fiber, an optical element includes one grating coupler optically coupled to an optical fiber, a waveguide connected to the grating coupler, a multimode interferometer connected to the waveguide on the opposite side to the grating coupler, and a waveguide inserted between two input/output ports on the branched side of the multimode interferometer.

Abstract: An optoelectronic semiconductor chip includes a p-type semiconductor region, an n-type semiconductor region, an active layer disposed between the p-type semiconductor region and the n-type semiconductor region and formed as a multiple quantum well structure and having alternating quantum well layers and barrier layers, the quantum well layers emitting a first radiation in a first wavelength range, and at least one further quantum well layer disposed outside the multiple quantum well structure that emits a second radiation in a second wavelength range, wherein the first wavelength range is in an infrared spectral range invisible to a human eye, and the second wavelength range includes wavelengths at least partially visible to the human eye.

Abstract: A high Q whispering gallery mode resonator with ion-implanted voids is described. A resonator device includes a resonator disk formed of an electrooptic material. The resonator disk includes a top surface, a bottom surface substantially parallel to the top surface, and a side structure between the top surface and the bottom surface. The side structure includes an axial surface along a perimeter of the resonator disk, where a midplane passes through the axial surface dividing the axial surface into symmetrical halves. The whispering gallery mode resonator disk includes voids localized at a particular depth from the top surface. At least one of the voids localized at the particular depth from the top surface is located at an outer extremity towards the perimeter of the resonator disk. The resonator device can further include a first electrode on the top surface and a second electrode on the bottom surface.

Abstract: An integrated polarization splitter and rotator (PSR) employs the TE0 and TE1 modes of propagating light, rather than the TE0 and TM0 modes used in conventional prior art PSR. The integrated PSR exhibits appreciably flatter wavelength response because it does not require a directional coupler to de-multiplex incoming polarizations. The PSR allows tuning of the TM0 loss to reduce polarization dependent loss (PDL). This integrated polarization splitter and rotator is applicable to all integrated platforms including Silicon-on-Insulator (SOI) and III-V semiconductor compound systems. The PSR may be very compact (12×2 ?m2), and provides low loss (<0.3 dB across the C-band) and ultra-broadband operation. The PSR also affords better control of polarization dependent losses.

Abstract: A tunable optical comb generator having a source laser configured to generate a continuous wave (CW) light at a first wavelength; and a microresonator coupled to the source laser and configured to receive the CW light and generate an optical signal having a plurality of output wavelengths corresponding to the first wavelength. The generator includes a microresonator tuning device coupled to the microresonator and configured to tune the microresonator to compensate the microresonator for wavelength shifts. A control circuit is coupled to the microresonator tuning device and configured to generate a control signal to control the microresonator tuning device based on the optical signal. Multiple microresonators in the form of microrings may be included to tune the generator. A heater coupled to the microresonators may be used to adjust the microresonators.

Abstract: An optoelectronic component including an optical waveguide integrated into a plane of the component. The optical waveguide configured to guide optical radiation in the plane. The component including a coupling element connected to the waveguide and coupling optical radiation into the waveguide along the main coupling path. The degree of coupling efficiency of the coupling element is less than one in respect to the main coupling path. The coupling element outputs optical loss radiation along a secondary coupling path. The optical loss radiation is proportional to the radiation transferred along the main coupling path. The optoelectronic component includes a detector connected to the coupling element that registers the optical loss radiation and produces a detector signal. The optoelectronic component includes a control unit configured to influence at least one operating variable of the optoelectronic component based on the detector signal.

Abstract: Methods and apparatus optically measure acceleration, without Sagnac-effect corruption, without requiring slow light and without moving parts. Each optical accelerometer includes at least one measurement cell and at least one reference cell. Two optical signals traverse the cells in opposite directions around a figure-8-configured optical path and then interfere to produce an output signal. The reference cells have different indices of refraction than the measurement cells. Acceleration differentially affects speeds of the optical signals traversing the measurement and reference cells through differentially affecting the indices of refraction of the measurement and reference cells. These differences are evident in changes in the interference in the output signal, thereby enabling measurement of the acceleration. Several embodiments, including optical bench, vertical slab multi-pass, toroidal prism, planar waveguide, cylindrical waveguide, wound waveguide and optical fiber, are described.

Abstract: A laser source including a germanium-based semiconductor layer, including a suspended membrane formed of a tensilely stressed central portion and including an optical amplification section, and a plurality of tensioning arms. It includes an integrated waveguide, which participates in forming an optical cavity and which is located level with the carrier layer and at distance from the suspended membrane, the waveguide including a coupling section located facing the optical application section, which is suitable for allowing evanescent-wave optical coupling to the latter, and at least one curved section, which extends the coupling section, and which is arranged so that the integrated waveguide is placed at distance, in orthogonal projection, from the tensioning arms.

Abstract: Provided are a Bragg grating and a spectroscopy device including the same. The Bragg grating is disposed at each of opposite ends of a resonator for reflecting light of a certain wavelength band and includes a core member extending from a waveguide of the resonator in a lengthwise direction of the waveguide; a plurality of first refractive members protruding from the core member and spaced apart from each other along the lengthwise direction; and a second refractive member filling spaces between the first refractive members and having a refractive index different from a refractive index of the first refractive members.

Abstract: Methods and apparatus optically measure acceleration, without Sagnac-effect corruption, without requiring slow light and without moving parts. Each optical accelerometer includes at least one measurement cell and at least one reference cell. Two optical signals traverse the cells in opposite directions around a figure-8-configured optical path and then interfere to produce an output signal. The reference cells have different indices of refraction than the measurement cells. Acceleration differentially affects speeds of the optical signals traversing the measurement and reference cells through differentially affecting the indices of refraction of the measurement and reference cells. These differences are evident in changes in the interference in the output signal, thereby enabling measurement of the acceleration. Several embodiments, including optical bench, vertical slab multi-pass, toroidal prism, planar waveguide, cylindrical waveguide, wound waveguide and optical fiber, are described.

Abstract: Methods and apparatus optically measure acceleration, without Sagnac-effect corruption, without requiring slow light and without moving parts. Each optical accelerometer includes at least one measurement cell and at least one reference cell. Two optical signals traverse the cells in opposite directions around a figure-8-configured optical path and then interfere to produce an output signal. The reference cells have different indices of refraction than the measurement cells. Acceleration differentially affects speeds of the optical signals traversing the measurement and reference cells through differentially affecting the indices of refraction of the measurement and reference cells. These differences are evident in changes in the interference in the output signal, thereby enabling measurement of the acceleration. Several embodiments, including optical bench, vertical slab multi-pass, toroidal prism, planar waveguide, cylindrical waveguide, wound waveguide and optical fiber, are described.

Abstract: A device includes a substrate feature disposed over a substrate. The substrate feature has a first length extending along a first direction and a second length extending along a second direction. The first length is greater than the second length. The device also includes a first material feature disposed over the substrate. The first material feature has a first surface in physical contact with the substrate feature and a second surface opposite to the first surface. The first surface has a third length extending along the first direction and a fourth length extending along the second direction. The third length is greater than the fourth length. The second surface has a fifth length extending along the first direction and a sixth length extending along the second direction. The sixth length is greater than the fifth length.

Abstract: This invention describes algorithmic and computational approaches to optimize the design and performance of microresonator based ultra-low noise lasers including a reflector or filter comprised of multiple (?3) microresonator rings with different ring radii coupled together through bus waveguides. The enhanced reflector/filter design optimization provides more control over the key parameters, including the suppression ratio of unwanted modes over both a wide wavelength range (supporting wide wavelength tunability) and over the narrow range around the laser wavelength (improving laser singlemode and noise performance), while also enabling the design of specific reflector/filter bandwidth and effective length (delay), supporting the design of an ultra-low noise laser with specific operating performance parameters.

Abstract: A ring laser includes a large-core rare-earth-doped fiber ring-connected with a free-space path having an electro-optic switch, output coupler, and intracavity band-pass filter to enforce lasing operation in narrow wavelength range. In some cavity-dumped modes, the laser is configured in a similar manner, except that an output coupler is omitted since the optical power is extracted from the laser cavity by the electro-optic switch itself. The same laser can be configured to operate in Q-switched and/or cavity-dumping modes as well as in hybrid modes (e.g., partial Q-switch, followed by cavity dumping, or even CW). In some embodiments, the laser can be used as, or inject laser light into, a regenerative solid-state amplifier, or a Raman laser, or can be also used to generate visible, ultra-violet, mid-infrared, and far-infrared (THz) radiation via nonlinear wavelength conversion processes. The various embodiments can use a power oscillator or seed-plus-amplifier MOPA configuration.

Abstract: This invention provides ultra-low noise lasers with exceptional performance through the use of ultra-low loss microresonator based filters/reflectors including multiple (?3) microresonator rings with different ring radii. The ultra-low loss microresonators provide a long effective laser cavity length enabling very narrow linewidth laser operation, with multiple (?3) microresonators providing extremely high selectivity of the lasing mode over a very wide wavelength range; supporting single wavelength and widely tunable wavelength laser operation. The highly selective and also low loss filter/reflector supports high output power operation of the lasers.

Abstract: A laser includes an active ring, a passive waveguide, and a reflector. The active ring is to generate light. The passive waveguide is associated with the active ring to capture generated light. The reflector is associated with the passive waveguide to cause captured light from the waveguide to be coupled into the active ring to trigger domination of unidirectional lasing in the active ring to generate light.

Abstract: An optical coherence tomography system utilizes an optical swept laser that has improved coherence length in the swept optical signal. This is accomplished using an intra-cavity element that extracts the tunable optical signal at the optimal location within the laser's resonant cavity. Generally this location is between the intracavity tuning element and the cavity's gain element so that light coming from the tuning element is extracted. In general in lasers, the gain element adds noise and chirp and this degrades the tunable optical signal's coherence length.

Abstract: An optical semiconductor device includes a ring waveguide, and a serpentine waveguide configured to be optically connected to the ring waveguide and surround at least a part of the ring waveguide in a serpentine form. In the optical semiconductor device, the serpentine waveguide heats the ring waveguide by absorbing input light propagated from the ring waveguide to the serpentine waveguide.

Abstract: A compact laser is provided for in accordance with an exemplary embodiment in the present disclosure includes a compact resonator structure using a non-planar geometry of bulk components. The laser includes a preferred rotational direction of lasing modes and employs bulk components for establishing the preferred rotational direction of lasing modes within resonator. In some embodiments, the preferred rotational direction of lasing modes is established using a reflective element that is outside the resonator structure. In some embodiments, the reflective element induces polarization shifts in the reflected light that are compensated for by a wave plate, which may be outside the resonator structure.

Abstract: An optical semiconductor device includes a ring laser including a ring resonator in which an optical gain element having an optical gain by current injection is provided, a waveguide optically coupled to the ring laser, and a reflector provided at an end portion of the waveguide and configured to reverse the advancing direction of light outputted from the ring laser and propagating in the waveguide.

Abstract: An apparatus includes an optical ring resonator, first and second optical couplers, and control circuitry. The first optical coupler is configured to modulate an input optical signal traversing an optical waveguide, by tuning cross-coupling of energy between the optical waveguide and the ring resonator with a first variable coupling coefficient. The second optical coupler is configured to tune cross-coupling of energy between the ring resonator and an auxiliary optical signal, different from the input optical signal, with a second variable coupling coefficient. The control circuitry is configured to modulate the first coupling coefficient with a first control signal so as to modulate the input optical signal, and to modulate the second coupling coefficient with a second control signal, so as to retain a constant electrical-field complex envelope in the ring resonator.

Abstract: A laser includes an active ring, a passive waveguide, and a reflector. The active ring is to generate light. The passive waveguide is associated with the active ring to capture generated light. The reflector is associated with the passive waveguide to cause captured light from the waveguide to be coupled into the active ring to trigger domination of unidirectional lasing in the active ring to generate light.

Abstract: A wavelength converter includes an optical resonator that is optically coupled to a waveguide. The refractive index of the optical resonator is dynamically changed, such as by injecting free carriers into the resonator. This effectively changes that optical path length of the light, thus converting the wavelength.

Abstract: An intracavity laser absorption infrared spectroscopy system for detecting trace analytes in vapor samples. The system uses a spectrometer in communications with control electronics, wherein the control electronics contain an analyte database that contains absorption profiles for each analyte the system is used to detect. The system can not only detect the presence of specific analytes, but identify them as well. The spectrometer uses a hollow cavity waveguide that creates a continuous loop inside of the device, thus creating a large path length and eliminating the need to mechanically adjust the path length to achieve a high Q-factor. In a preferred embodiment, the laser source may serve as the detector, thus eliminating the need for a separate detector.

Abstract: The invention relates to a laser device comprising at least three linear laser gain volumes (12) for a gas to be excited, connecting elements (20) for connecting adjacent laser gain volumes, the laser gain volumes being mechanically coupled to other, and forming a common volumetric space, excitation means (50) for the laser gain volumes for exciting the gas in the laser gain volumes for generating a laser light, mirrors (22) arranged in the connecting elements for reflecting laser light between the laser gain volumes, a totally reflecting rear mirror (44), and a partially reflecting output coupler (42) for coupling out a laser beam. The laser gain volumes are arranged in the shape of an open or closed ring surrounding a free central space (8) between them. The invention also relates to a method for marking an object.

Abstract: A tunable fiber ring laser with a gain clamped semiconductor optical amplifier is a ring laser source working at room temperature. The laser has an inner cavity disposed inside an outer cavity. A pair of circulators disposed in the inner cavity is configured to assure counter-propagation of light between the inner cavity and the outer cavity. A gain-clamped semiconductor optical amplifier (GC-SOA) is formed by combining a semiconductor optical amplifier (SOA) and a fixed filter in conjunction with the pair of circulators. A Fiber Fabry-Perot Tunable Filter (FFP-TF) is disposed in the outer cavity and connects to the pair of circulators via a polarization controller and a fused coupler.

Abstract: A ring resonator is connected to an optical amplifier. The ring resonator and optical amplifier are contained within the optical path of an optical resonator formed by a first and second reflector. The optical coupler branches part of the light conducting from the optical amplifier to the ring resonator within the optical resonator off to an output optical waveguide.

Abstract: A normal-dispersion fiber laser is operated using parameters in which dissipative solitons exist with remarkably large pulse duration and chirp, along with large pulse energy. A low-repetition-rate oscillator that generates pulses with large and linear chirp can thus replace the standard oscillator, stretcher, pulse-picker and preamplifier in a chirped-pulse fiber amplifier.

Abstract: An apparatus for generating a pulse train with an adjustable time interval is provided. The apparatus, being an annular optical cavity structure, includes a seed source receiving end, a pump source receiving end, an optical coupler, an optical combiner, a gain fiber, an optical path time regulator and a beam splitter. Thus, the apparatus is capable of generating a pulse train with an adjustable time interval to increase material processing quality and speed.

Abstract: A high energy semiconductor laser capable of high optical efficiency includes a master oscillator coupled to a plurality of slave oscillators, each producing a laser beam that is substantially at the same wavelength as the output beam from the master oscillator. The outputs of the slave oscillators are then coherently combined to a single monochromatic beam having an optical power which is substantially greater than that of beam output from the master oscillator. The slave oscillators can be configured as ring resonators. A suitable ring oscillator can be built by arranging one or more semiconductor diode laser gain media, two or more reflecting mirrors, and at least one semireflective mirror in a ring configuration. A suitable ring oscillator can also be built by machining a solid block to include one or more semiconductor diode laser high gain regions.

Abstract: A ring laser-resonator generating plane-polarized fundamental-frequency radiation includes an optically nonlinear crystal configured for type-II second-harmonic generation of fundamental-frequency radiation. The resonator is configured such that fundamental-frequency radiation circulating either clockwise or counter-clockwise therein makes two passes through the optically nonlinear crystal per round-trip in the resonator in opposite directions, with polarization planes perpendicular to each other. This arrangement forces unidirectional circulation of radiation in the resonator during which second-harmonic radiation is not generated by the crystal.

Abstract: A light source apparatus includes a laser oscillator equipped with a first optical resonator, a plurality of second optical resonators including input portions respectively connected in parallel to the first optical resonator, a plurality of light extraction units configured to extract a light beam from an output portion of each second optical resonator, and a light multiplexing unit configured to multiplex the light beam extracted from each light extraction unit, wherein the light source apparatus causes the light multiplexing unit to output a multiplexed light beam passed through the plurality of second optical resonators, an optical member having refractive index dispersion and an optical amplification medium are disposed in each of the plurality of second optical resonators, and the optical amplification media of the plurality of second optical resonators are different from each other in maximum gain wavelength.

Abstract: System and method for operating a single unit of light-amplifying medium, structured to produce light with a complex spatial spectrum including multitude of high-order spatial modes, in external cavity configured, in conjunction with an optical etalon installed intra-cavity, to reduce spatial spectrum of such light to provide an output containing smaller number of high-order spatial modes and, optionally, only the lowest spatial mode at power levels on the order of 1 W or higher (for example, tens or hundreds of Watts).

Abstract: In at least one embodiment, a wavelength-tunable light source includes at least one fiber-based partial section and at least one delay section. For a wavelength ? of at least one portion of a radiation emitted by the light source as a function of time t, the relationship ?(t)=?(t??) holds true. In this case, ? is a specific period of time. Furthermore, the delay section includes one or more oligomode fibers.

Abstract: A laser includes an active ring, a passive waveguide, and a reflector. The active ring is to generate light. The passive waveguide is associated with the active ring to capture generated light. The reflector is associated with the passive waveguide to cause captured light from the waveguide to be coupled into the active ring to trigger domination of unidirectional lasing in the active ring to generate light.

Abstract: The invention relates to a two-stage laser system well fit for semiconductor aligners, which is reduced in terms of spatial coherence while taking advantage of the high stability, high output efficiency and fine line width of the MOPO mode. The two-stage laser system for aligners comprises an oscillation-stage laser (50) and an amplification-stage laser (60). Oscillation laser light having divergence is used as the oscillation-stage laser (50), and the amplification-stage laser (60) comprises a Fabry-Perot etalon resonator made up of an input side mirror (1) and an output side mirror (2). The resonator is configured as a stable resonator.

Abstract: A widely tunable laser is described where a compound semiconductor gain chip is coupled to a waveguide filter fabricated on silicon. The filter has two resonators with different free-spectral-ranges, such that Vernier tuning between the filters can be used to provide a single wavelength of light feedback into the gain chip, where the wavelength is adjustable over a wide range. The coupling between the gain chip and the filter is realized through a microlens whose position can be adjusted using micromechanics and locked in place.

Abstract: A laser device includes a pump source, a ring resonator, a gain medium disposed in the ring resonator, and a holographic output coupler to partially transmit the laser radiation. The gain medium is configured to receive radiation from the pump source and generate laser radiation.

Abstract: A fiber laser having a ring resonance path comprises a pump light source, a Yb-doped optical fiber and a light modulation unit. The pump light source emits a pump light. The Yb-doped optical fiber is coupled with the pump light. The light modulation unit includes a grating pair, a diaphragm and two reflective elements. The grating pair is coupled with the pump light. The diaphragm includes an aperture. The light transmitted by the grating pair partially passes through the aperture and reaches one of the reflective elements to become a reflective light, and the reflective light passes through the aperture and is transmitted through the grating pair and the other reflective element to be coupled back with the ring resonance path.

Abstract: Unidirectionality of lasers is enhanced by forming one or more etched gaps (78, 80) in the laser cavity. The gaps may be provided in any segment of a laser, such as any leg of a ring laser, or in one leg (62) of a V-shaped laser (60). A Brewster angle facet at the distal end of a photonic device coupled to the laser reduces back-reflection into the laser cavity. A distributed Bragg reflector is used at the output of a laser to enhance the side-mode suppression ratio of the laser.

Abstract: A system and method for an electrically pumped laser system is disclosed. The system includes a silicon micro-ring resonator 405. A quantum well 412 formed of a III-V group semiconductor material is optically coupled with the micro-ring resonator 405 to provide optical gain. A trapezoidal shaped buffer 414 formed of a III-V group semiconductor material and doped with a first type of carrier is optically coupled to the quantum well 412. A ring electrode 410 is coupled to the trapezoidal shaped buffer 414. The trapezoidal shaped buffer 414 enables the ring electrode 410 to be substantially isolated from an optical mode of the micro-ring resonator 405.

Abstract: A system and method for controllably chirping electromagnetic radiation from a radiation source includes an optical cavity arrangement. The optical cavity arrangement enables electromagnetic radiation to be produced with a substantially linear chirp rate and a configurable period. By selectively injecting electromagnetic radiation into the optical cavity, the electromagnetic radiation may be produced with a single resonant mode that is frequency shifted at the substantially linear chirp rate. Producing the electromagnetic radiation with a single resonant mode may increase the coherence length of the electromagnetic radiation, which may be advantageous when the electromagnetic radiation is implemented in various applications. For example, the electromagnetic radiation produced by the optical cavity arrangement may enhance a range, speed, accuracy, and/or other aspects of a laser radar system.

Abstract: A semiconductor optical amplifier includes: a laminated structure sequentially including a first compound semiconductor layer composed of GaN compound semiconductor and having a first conductivity type, a third compound semiconductor layer having a light amplification region composed of GaN compound semiconductor, and a second compound semiconductor layer composed of GaN compound semiconductor and having a second conductivity type; a second electrode formed on the second compound semiconductor layer; and a first electrode electrically connected to the first compound semiconductor layer. The laminated structure has a ridge stripe structure. When widths of the ridge stripe structure in a light output end face and the ridge stripe structure in a light incident end face are respectively Wout, and Win, Wout>Win is satisfied. A carrier non-injection region is provided in an internal region of the laminated structure from the light output end face along an axis line of the semiconductor optical amplifier.