Abstract: A device includes one or more reflector components. Each reflector component comprises layer pairs of epitaxially grown reflective layers and layers of a non-epitaxial material, such as air. Vias extend through at least some of the layers of the reflector components. The device may include a light emitting layer.

Abstract: In a VCSEL, a first multilayer film reflector, an active layer having a light emitting central region, a second multilayer film reflector, and a transverse mode adjustment layer are layered in this order. The first multilayer film reflector has a quadrangle current injection region with an intersection of diagonal lines corresponding to the light emitting central region. The second multilayer film reflector has a light emitting window provided in a region corresponding to one diagonal line of the current injection region and a pair of grooves provided with the light emitting window in between. The transverse mode adjustment layer is provided correspondingly to the light emitting window, and reflectance of a peripheral region thereof is lower than that of a central region thereof.

Abstract: Light emitting systems are disclosed. The light emitting system includes an electroluminescent device that emits light at a first wavelength. The light emitting system further includes an optical cavity that enhances emission of light from a top surface of the light emitting system and suppresses emission of light from one or more sides of the light emitting system. The optical cavity includes a semiconductor multilayer stack that receives the emitted first wavelength light and converts at least a portion of the received light to light of a second wavelength. The semiconductor multilayer stack includes a II-VI potential well. The integrated emission intensity of all light at the second wavelength that exit the light emitting system is at least 10 times the integrated emission intensity of all light at the first wavelength that exit the light emitting system.

Abstract: Provided is a method of manufacturing a surface-emitting laser capable of preventing characteristics fluctuations within the plane and among wafers and oscillating in a single fundamental transverse mode. The method includes after performing selective oxidation: exposing a bottom face of a surface relief structure by etching a second semiconductor layer with a first semiconductor layer where a pattern of the surface relief structure has been formed as an etching mask and a third semiconductor layer as an etching stop layer; and exposing a top face of the surface relief structure by etching the first semiconductor layer where the pattern of the surface relief structure has been formed, with the second semiconductor layer and the third semiconductor layer as etching stop layer.

Abstract: A two-dimensional photonic crystal surface-emitting laser light source producing a beam without side lobes is provided. A window-shaped electrode having a central window devoid of the electrode material is provided on a device substrate. A mount surface electrode smaller than the electrode including the window is provided on a mount surface. The distance between the substrate and the active layer is larger than that between the mount surface and the active layer. When a voltage is applied, electric charges are injected into the active layer and emission is obtained. Light having a specific wavelength is amplified by a two-dimensional photonic crystal and extracted through the window without side lobes due to interference. The positioning of the active layer close to the mount surface significantly enhances the heat-radiating effect.

Abstract: There is described a high speed vertical-cavity surface-emitting laser (VCSEL) comprising a substrate and first and second distributed Bragg reflectors (DBRs) disposed on the substrate, each comprising a stack of layers of alternating refractive index. A resonant cavity is disposed between the DBRs and an active region disposed in the resonant cavity. The resonant cavity is formed of material having low refractive index and has an optical thickness in a direction perpendicular to the substrate of ½?, where ? is the wavelength of light emitted by the VCSEL.

Abstract: A semiconductor device is provided that has a VCSEL and a protection diode integrated therein and that has an additional intrinsic layer. The inclusion of the additional intrinsic layer increases the width of the depletion region of the protection diode, which reduces the amount of capacitance that is introduced by the protection diode. Reducing the amount of capacitance that is introduced by the protection diode allows the VCSEL to operate at higher speeds.

Abstract: Provided is a wavelength tunable external cavity laser (laser beam) generating device. The wavelength tunable external cavity laser generating devices includes: an optical amplifier, a comb reflector, and an optical signal processor connected in series on a first substrate; and an external wavelength tunable reflector disposed on a second substrate adjacent to the first substrate and connected to the optical amplifier, wherein the comb reflector includes: a waveguide disposed on the first substrate; a first diffraction grating disposed at one end of the waveguide adjacent to the optical amplifier; and a second diffraction grating disposed at the other end of the waveguide adjacent to the optical signal processor, wherein the optical amplifier, the comb reflector, and the optical signal processor constitute a continuous waveguide.

Abstract: A method of manufacturing a laser diode array capable of inhibiting electric cross talk is provided. The method of manufacturing a laser diode array includes a processing step of forming a peel layer containing an oxidizable material and a vertical resonator structure over a first substrate sequentially from the first substrate side by crystal growth, and then selectively etching the peel layer and the vertical resonator structure to the first substrate, thereby processing into a columnar shape, a peeling step of oxidizing the peel layer from a side face, and then peeling the vertical resonator structure of columnar shape from the first substrate, and a rearrangement step of jointing a plurality of vertical resonator structures of columnar shape obtained by the peeling step to a surface of a metal layer of a second substrate formed with the metal layer on the surface.

Abstract: An 830 nm broad area semiconductor laser having a distributed Bragg reflector (DBR) structure. The semiconductor laser supports multiple horizontal transverse modes of oscillation extending within a plane perpendicular to a crystal growth direction of the laser, in a direction perpendicular to the length of the resonator of the laser. The resonator includes a diffraction grating in the vicinity of the emitting facet of the laser. The width of the diffraction grating in a plane perpendicular to the growth direction and perpendicular to the length of the resonator is different at first and second locations along the length of the resonator. The width of the diffraction grating along a direction which is perpendicular to the length of the resonator increases with increasing distance from the front facet of the semiconductor laser.

Abstract: A vertical cavity surface emitting laser element as described herein can suppress of any dislocation, when a distributed Bragg reflector (DBR) mirror is formed on the onto a substrate (1). The vertical cavity surface emitting laser can be designed so that an average of strain in the DBR mirror (2) and a layer thickness of the DBR mirror (2) are in reference to a curvature of the substrate (1) in order to satisfy a predetermined condition, and then nitrogen can be added into the DBR mirror (2) with a composition that corresponds to a designed average of strain in the DBR mirror (2). For example, the average composition of nitrogen can be designed to be between 0.028% and 0.390%.

Abstract: It is an object of the invention to provide a VCSEL having both a high beam quality or a low M2-factor, respectively, and a reduced mirror thickness which improves the heat dissipation due to the reduced thickness and the production cost. It is suggested to employ a Bragg-reflector in combination with a metal reflector terminating the distal side of the Bragg-reflector as seen from the laser cavity, wherein the metal reflector layer is localized at the center around the optical axis.

Abstract: Methods and apparatus for improved single-mode selection in a quantum cascade laser. In one example, a distributed feedback grating incorporates both index-coupling and loss-coupling components. The loss-coupling component facilitates selection of one mode from two possible emission modes by periodically incorporating a thin layer of “lossy” semiconductor material on top of the active region to introduce a sufficiently large loss difference between the two modes. The lossy layer is doped to a level sufficient to induce considerable free-carrier absorption losses for one of the two modes while allowing sufficient gain for the other of the two modes. In alternative implementations, the highly-doped layer may be replaced by other low-dimensional structures such as quantum wells, quantum wires, and quantum dots with significant engineered intraband absorption to selectively increase the free-carrier absorption losses for one of multiple possible modes so as to facilitate single-mode operation.

Abstract: Provided are a distributed feedback laser diode and a manufacturing method thereof. The distributed feedback laser diode includes a first area having a first grating layer disposed in a longitudinal direction, a second area disposed adjacent to the first area and having a second grating layer disposed in the longitudinal direction, and an active layer disposed over the first and second areas. Coupling coefficients of the first and second grating layers are made different in the first and second areas by a selective area growth method. The distributed feedback laser diode includes grating layers each having an asymmetric coefficient and is implemented within an optimal range capable of obtaining both a high front facet output and stable single mode characteristics. Thus, high manufacturing yield and low manufacturing cost can be achieved.

Abstract: An apparatus includes an extended cavity vertical cavity surface emitting laser producing light and having an active region, a first reflector position adjacent to a first side of the active region, an extended cavity positioned adjacent to a second side of the active region, and a second reflector reflecting a first portion of the light into the extended cavity and transmitting a second portion of the light, a planar waveguide positioned adjacent to the extended cavity vertical cavity surface emitting laser, and a horizontal coupler structured to couple the second portion of light from the extended cavity vertical cavity surface emitting laser into the waveguide.

Abstract: High-power, phased-locked, laser arrays as disclosed herein utilize a system of optical elements that may be external to the laser oscillator array. Such an external optical system may achieve mutually coherent operation of all the emitters in a laser array, and coherent combination of the output of all the lasers in the array into a single beam. Such an “external gain harness” system may include: an optical lens/mirror system that mixes the output of all the emitters in the array; a holographic optical element that combines the output of all the lasers in the array, and an output coupler that selects a single path for the combined output and also selects a common operating frequency for all the coupled gain regions.

Abstract: A surface-emission laser device comprises an active layer, cavity spacer layers provided at both sides of the active layer, reflection layers provided at respective sides of the cavity spacer layers, the reflection layers reflecting an oscillation light oscillated in the active layer and a selective oxidation layer. The selective oxidation layer is provided between a location in the reflection layer corresponding to a fourth period node of the standing wave distribution of the electric field of the oscillating light and a location in the reflection layer adjacent to the foregoing fourth period node in the direction away from the active layer and corresponding to an anti-node of the standing wave distribution of the electric field of the oscillation light.

Abstract: A vertical cavity surface emitting laser includes, a lower DBR layer; an upper DBR layer; an active layer existing between the lower DBR layer and the upper DBR layer; and a laser emitting region provided on a surface layer of the upper DBR layer, in which the upper DBR layer includes a doped first semiconductor multilayer film layer and an undoped second semiconductor multilayer film layer; an electrode provided on the upper DBR layer is formed in a region which is on an upper part of the first semiconductor multilayer film layer and is surrounded by the second semiconductor multilayer film layer; the laser emitting region is formed on a surface layer of the second semiconductor multilayer film layer; and the surface layer of the first semiconductor multilayer film layer is formed by a contact layer and the second semiconductor multilayer film layer is stacked on the contact layer.

Abstract: A laser device includes a substrate, a lower cladding layer on the substrate, an active layer on the lower cladding layer and having a disordered portion spaced from an end face of a resonator of the laser device, an upper cladding layer located on the active layer, and a diffraction grating located in a portion of a layer lying above or below the active layer, with respect to the substrate. The disordered portion intersects a boundary between a diffraction grating section, in which the diffraction grating is located, and a bulk section, in which no diffraction grating is located.

Abstract: A surface-emitting laser includes a surface relief structure provided on an upper multilayer reflector, the surface relief structure including a region of a first laminate, a region of a second laminate that has a larger optical thickness than the first laminate, and a region of a third laminate that has a larger optical thickness than the first laminate and the second laminate.

Abstract: The present invention includes a vertical-cavity surface-emitting semiconductor laser diode having a resonator with a first distributed Bragg reflector, an active zone which has a p-n junction and is embedded into a semiconductor layer sequence, and a second distributed Bragg reflector. The semiconductor laser diode has an emission wavelength ?, wherein a periodic structure is arranged within the resonator as an optical grating made of semiconductive material and dielectric material, the main plane of extension of which is arranged substantially perpendicularly to the direction of emission of the semiconductor laser diode. The periodic structure is in direct contact with at least one of the semiconductor layers embedding the active zone and with at least one of the two distributed Bragg reflectors.

Abstract: One embodiment of the present invention provides a system that facilitates adjusting the wavelengths of lasers via temperature control. This system includes a chip with an active face upon which active circuitry and signal pads reside. A thermal-control mechanism provides localized thermal control of two lasers mounted upon the active face of the chip. By individually controlling the temperature of the lasers, the thermal-control mechanism controls the wavelengths emitted by each respective laser. By creating a temperature gradient that causes a temperature difference between two or more lasers, the system can cause the lasers to emit different wavelengths.

Abstract: Disclosed is a semiconductor light emitting device. The semiconductor light emitting device includes a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer, a plurality of isolation layers formed along an outer peripheral portion of the light emitting structure below the light emitting structure, a metal layer interposed between the isolation layers, and a second electrode layer formed below the light emitting structure.

Abstract: A surface-emitting semiconductor laser device is provided that includes an edge-emitting laser integrated in a semiconductor material with various reflectors and a diffractive lens. The edge-emitting laser has a first section comprising an active MQW region, a second section comprising a passive region and a third section comprising a semi-insulating or un-doped semiconductor bulk layer. This configuration ensures that the injection current will pass through all of the layers of the active region, thereby preventing the occurrence of optical losses due to un-injected areas of the MQW active region. In addition, the inclusion of the passive region ensures that there is no current passing through the interface between the active MQW region and the regrown semiconductor bulk layer. The latter feature improves performance and device reliability.

Abstract: A semiconductor laser that includes: a substrate; a first semiconductor multilayer reflector of a first conductive type formed on the substrate; an active region formed on the first semiconductor multilayer reflector; a second semiconductor multilayer reflector of a second conductive type formed on the active region; and an intermediate semiconductor layer of a first conductive type or a second conductive type formed under the first semiconductor multilayer reflector or above the second semiconductor multilayer reflector.

Abstract: A wavelength tunable laser includes a DFB portion including a first optical waveguide provided with a first grating; a DBR portion including a second optical waveguide that is optically coupled to the first optical waveguide and is provided with a plurality of second gratings continuously arranged in a waveguide direction; and a phase shift portion including a third optical waveguide that is optically coupled to the first and second optical waveguides. Each of the second gratings has a grating formation area in which a grating is formed, and a grating phase shift area which shifts the phase of the grating adjacent thereto in the second grating.

Abstract: A two-dimensional photonic crystal laser light is provided. The two-dimensional photonic crystal laser includes a two-dimensional photonic crystal made of a plate-shaped member provided with a periodic arrangement of identically-shaped modified refractive index areas having a refractive index different from that of the plate-shaped member; and an active layer provided on one side of the two-dimensional photonic crystal. The modified refractive index areas are arranged at lattice points of a lattice with a same period at least in two directions; each modified refractive index area is shaped so that a feedback strength is different with respect to directions of two primitive lattice vectors of the lattice; the two-dimensional photonic crystal has a periodic structure of a supercell, which contains a plurality of lattice points; and the sum of the feedback strengths by all modified refractive index areas in the supercell is identical in each direction of the two primitive lattice vectors.

Abstract: The present invention concerns tunable distributed Bragg reflector (DBR) semiconductor lasers, in particular a DBR laser with a branched optical waveguide 5 within which a plurality of differently shaped lasing cavities may be formed, and a method of operation of such a laser. The laser may comprise a phase control section (418), gain section (420, 422), a sampled grating DBR (412) giving a comb-line spectrum and two tunable, chirped DBRs (414, 416) for broadband frequency training and a coupling section (410).

Abstract: A fiber laser of an MOPA type includes an MO which is a laser oscillator for generating seed light, a PA which is a light amplifier connected to a rear stage of the MO, for amplifying and outputting laser light emitted from the MO, and a reflection device which is provided between the MO and the PA. According to the present invention, the MOPA type fiber laser can decrease the peak value of the pulse which is emitted toward the MO or the pump light source by self-oscillation or reflection, and makes it unlikely that the pump light source or the MO will be damaged.

Abstract: A semiconductor laser device includes: a semiconductor laser having a reflector region, a gain region for laser oscillation and a plurality of refraction index controllers, the reflector region having a plurality of segments in which a diffraction region and a space region are coupled to each other, the plurality of segments being separated into a plurality of segment groups having a same optical length, the plurality of refractive index controllers being provided according to each segment group and controlling an equivalent refraction index of each segment group; a wavelength controller controlling an oscillation wavelength of the semiconductor laser by controlling the plurality of the refraction index controllers as at least one of control parameters; and a dither controller inputting a dither signal into only one of the segment groups having the most segments from one of the refractive index controllers according to the segment group.

Abstract: A surface emitting semiconductor laser includes: a substrate; a first semiconductor multilayer reflector of a first conduction type that is formed on the substrate and is composed of stacked pairs of relatively high refractive index layers and relatively low refractive index layers; a cavity region that is formed on the first semiconductor multilayer reflector and includes an active region; and a second semiconductor multilayer reflector of a second conduction type that is formed on the cavity region and is composed of stacked pairs of relatively high refractive index layers and relatively low refractive index layers. A cavity length of a cavity that includes the cavity region and the active region between the first semiconductor multilayer reflector and the second semiconductor multilayer reflector is greater than an oscillation wavelength.

Abstract: A directly driven laser includes multiple contacts, with at least one of the contacts for injecting current into the laser such that the laser reaches at least a lasing threshold and at least one of the contacts for providing a data signal to the laser. In some embodiments a differential data signal is effectively provided to a front and a rear section of the laser, while lasing threshold current is provided to a central portion of the laser.

Abstract: A tunable pulsed laser source comprising a seed source adapted to generate a seed signal and an optical circulator. The optical circulator includes a first port coupled to the seed source, a second port, and a third port. The laser source also includes an amplitude modulator characterized by a first side and a second side. The first side is coupled to the second port of the optical circulator. The laser source further includes a first optical amplifier characterized by an input end and a reflective end including a spectral-domain reflectance filter. The input end is coupled to the second side of the amplitude modulator. Moreover, the laser source includes a second optical amplifier coupled to the third port of the optical circulator.

Abstract: Methods for fabricating semiconductors with enhanced strain. One embodiment includes fabrication of a semiconductor device with an epitaxial structure. The epitaxial structure is formed with one or more semiconductor layers. One or more of the layers includes a dopant including small quantities of Al and repeated delta doping during expitaxial growth to form periods where surfaces are group III rich.

Abstract: The present invention provides a surface emitting laser having a novel structure which eliminates necessity to provide a low refractive index medium at an interface of a photonic crystal layer on the side of a substrate. A multilayer mirror (1300), an active layer (1200), and a refractive index periodic structure layer (1020) whose refractive index changes periodically are laminated in a direction perpendicular to a substrate (1500). The refractive index periodic structure layer is structured so as to separate a light having a wavelength ? perpendicularly incident on the refractive index periodic structure into at least a transmitted light and a diffracted light. The multilayer mirror is structured so as to have a reflectance with regard to the diffracted light higher than a reflectance with regard to the transmitted light. A resonant mode is realized within a waveguide including the refractive index periodic structure layer and the multilayer mirror.

Abstract: A semiconductor diffraction grating device includes a semiconductor substrate having a principal surface, a semiconductor core layer and a semiconductor cladding layer provided on the principal surface, and a chirped grating structure provided between the semiconductor core layer and the semiconductor cladding layer. The chirped grating structure includes a first region, a second region, and a third region arranged in that order in a predetermined axis direction, the first, second, and third regions including a plurality of projections constituting a chirped grating. The plurality of projections are provided at placement positions arranged with a predetermined pitch in the predetermined axis direction. The coupling coefficient ? of the chirped grating monotonically increases in the predetermined axis direction to a predetermined value in the first region, remains flat in the second region, and monotonically decreases in the predetermined axis direction from the predetermined value in the third region.

Abstract: A Vertical-Cavity Surface-Emitting Laser (VCSEL) device includes a substrate, a first semiconductor multi-layer film of a first conductive type formed on the substrate, an active layer, a second semiconductor multi-layer film of a second conductive type, an electrode pad electrically coupled to the second semiconductor multi-layer film, and a post structure formed on the substrate, the post structure comprising a light emitter, the post structure being continuously surrounded by a first groove, and a second groove being continuously formed outside of the first groove with respect to the post structure.

Abstract: An optical waveguide integrated semiconductor optical device includes a laser and an optical waveguide. The laser includes an active layer and a first cladding layer which are stacked on a second cladding layer. The optical waveguide includes an optical guiding layer and an undoped InP layer which are also stacked on the second cladding layer. A high resistance layer is located between the top surface of the optical guiding layer and a surface of the undoped InP layer and between a side of the first cladding layer and a side of the undoped InP layer.

Abstract: A method to form a an LD with the buried mesa type is disclosed, in which the n-type current blocking layer is stably kept with a distance to the active layer in the buried mesa. The method of the invention includes a step to form the mesa by iterating the RIE and the ashing to obtain in a mesa side a steep edge with the (110) surface. A wet-etching process subsequent to the iterative etching and ashing removes residuals left on the mesa side. Then, the growth of the current blocking layer shows two modes of the horizontal growth of the (110) surface and the vertical growth of the (001) surface comparably.

Abstract: Narrow surface corrugated gratings for integrated optical components and their method of manufacture. An embodiment includes a grating having a width narrower than a width of the waveguide on which the grating is formed. In accordance with certain embodiments of the present invention, masked photolithography is employed to form narrowed gratings having a desired grating strength. In an embodiment, an optical cavity of a laser is formed with a reflector grating having a width narrower than a width of the waveguide. In another embodiment an integrated optical communication system includes one or more narrow surface corrugated gratings.

Abstract: A diode laser and a laser resonator for a diode laser are provided, which has high lateral beam quality at high power output, requires little adjustment effort and is inexpensive to produce. The laser resonator according to the invention comprises a gain section (GS), a first planar Bragg reflector (DBR1) and a second planar Bragg reflector (DBR2), wherein the gain section (GS) has a trapezoidal design and the first planar Bragg reflector (DBR1) is arranged on a first base side of the trapezoidal gain section (GS) and the second planar Bragg reflector (DBR2) is arranged on the opposing base side of the trapezoidal gain section (GS), wherein the width (D1) of the first planar Bragg reflector (DBR1) differs from the width (D2) of the second planar Bragg reflector (DBR2).

Abstract: A Vertical Cavity Surface Emitting Laser capable of decreasing the lowering of the yield due to displacement and separation of a pedestal without enormous increase of the threshold value and more difficult manufacturing process is provided. A base of a mesa spreads over the top face of a lower DBR layer. The base is a non-flat face in which end faces of a plurality of layers are exposed. The non-flat face is generated due to etching unevenness in forming the mesa, and is in a state of a step in which end faces of a low-refractive index layer and a high-refractive index layer included in the lower DBR layer are alternatively exposed. At least one of the layers exposed in the non-flat face in the plurality of low-refractive index layers included in the lower DBR layer is an oxidation inhibition layer.

Abstract: The present invention provides a Vertical Cavity Surface Emitting Laser including: a first multilayer film reflector; an active layer having a light emission region; a second multilayer film reflector; and a reflectance adjustment layer in this order on a substrate side. The first multilayer film reflector and the second multilayer film reflector have a laminated structure in which reflectance of oscillation wavelength ?x is almost constant without depending on temperature change. The active layer is made of a material with which a maximum gain is obtained at temperature higher than ambient temperature. The reflectance adjustment layer has a laminated structure in which difference ?R(=Rx?Ry) between reflectance Rx of a region opposed to a central region of the light emission region and reflectance Ry of a region opposed to an outer edge region of the light emission region is increased associated with temperature increase from ambient temperature to high temperature.

Abstract: Semiconductor devices are described that include a vertical cavity surface emitting laser (VCSEL) and a structure formed on or near the surface of the VCSEL that acts as a filter that benefits high-frequency VCSEL modulation performance.

Abstract: Provided is a laser device. In the laser device, an active layer is connected to a stem core of a 1×2 splitter on a substrate, a first diffraction grating is coupled to a first twig core of the 1×2 splitter, and a second diffraction grating is coupled to a second twig core of the 1×2 splitter. An active layer-micro heater is designed to supply heat to the active layer. First and second micro heaters are designed to supply heats to the first and second diffraction gratings, respectively, thereby varying a Bragg wavelength.

Abstract: The present disclosure is a vertical-cavity surface-emitting laser (VCSEL) device. A relief structure is formed above or below a light emitting region by partially removing an aluminum composition layer of VCESL through an etching process. Thus, profound static performances are obtained, including low power consumption, biggest operational speed, and high ratio of data transmission to power consumption as 2.9 and 9.2 Gbps/mW under 34 and 12.5 Gbps, respectively.

Abstract: A disclosed surface emitting laser is capable of being manufactured easily, having a higher yield and a longer service lifetime. In the surface emitting laser, a selectively-oxidized layer is included as a part of a low refractive index layer of an upper semiconductor distribution Bragg reflector; the low refractive index layer including the selectively-oxidized layer includes two intermediate layers adjoining the selectively-oxidized layer and two low refractive index layers adjoining the intermediate layers. Al content rate in the intermediate layers is lower than that in the selectively-oxidized layer, and Al content rate in the low refractive index layers is lower than that in the selectively-oxidized layer. This configuration enables providing more control over the thickness and oxidation rate of the oxidized layer, thereby enabling reducing the variation of the thickness of the oxidized layer.

Abstract: A wavelength converter includes a supporting substrate and a ferroelectric substrate, the ferroelectric substrate includes at least one waveguide facing the supporting substrate and at least one wavelength-filtering pattern positioned between the waveguide and the supporting substrate, the waveguide includes a plurality of inverted domains and non-inverted domains configured to convert an infrared light into a green light, and the infrared light emitted from the semiconductor laser enters the waveguide of the wavelength converter. For example, the wavelength-filtering pattern includes a Bragg grating.

Abstract: A surface-emission laser diode comprises a cavity region over a semiconductor substrate and includes an active layer containing at least one quantum well active layer producing a laser light and a barrier layer, a spacer layer is provided in the vicinity of the active layer and formed of at least one material, an upper and lower reflectors are provided at a top part and a bottom part of the cavity region, the cavity region and the upper and lower reflectors form a mesa structure over the semiconductor substrate, the upper and lower reflectors being formed of a semiconductor distributed Bragg reflector having a periodic change of refractive index and reflecting incident light by interference of optical waves, at least a part of the semiconductor distributed Bragg reflector is formed of a layer of small refractive index of AlxGa1-xAs (0<x?1) and a layer of large refractive index of AlyGa1-yAs (0?y<x?1), the lower reflector is formed of a first lower reflector having a low-refractive index layer of AlAs an

Abstract: An optical semiconductor device has a semiconductor substrate, a semiconductor region and heater. The semiconductor region has a stripe shape demarcated with a top face and a side face thereof. The stripe shape has a width smaller than a width of the semiconductor substrate. An optical waveguide layer is located in the semiconductor region. A distance from a lower end of the side face of the semiconductor region to the optical waveguide layer is more than half of the width of the semiconductor region. The heater is provided above the optical waveguide layer.