Abstract: A method of manufacturing a surface-emitting laser that allows precise alignment of the center position of a surface relief structure and that of a current confinement structure and formation of the relief structure by means of which a sufficient loss difference can be introduced between the fundamental transverse and higher order transverse mode. Removing the dielectric film on the semiconductor layers and the first-etch stop layer along the second pattern, using a second- and third-etch stop layer are conducted in single step after forming the confinement structure. The relief structure is formed by three layers including a lower, middle and upper layer, and total thickness of three layers is equal to the optical thickness of an odd multiple of ¼ wavelength (?: oscillation wavelength, n: refractive index of the semiconductor layer). The layer right under the lower layer is the second-etch stop layer and the first-etch stop layer is laid right on this etch stop layer.

Abstract: An optical device includes a gallium and nitrogen containing substrate comprising a surface region configured in a (20-2-1) orientation, a (30-3-1) orientation, or a (30-31) orientation, within +/?10 degrees toward c-plane and/or a-plane from the orientation. Optical devices having quantum well regions overly the surface region are also disclosed.

Abstract: The present disclosure involves a light-emitting device. The light-emitting device includes an n-doped gallium nitride (n-GaN) layer located over a substrate. A multiple quantum well (MQW) layer is located over the n-GaN layer. An electron-blocking layer is located over the MQW layer. A p-doped gallium nitride (p-GaN) layer is located over the electron-blocking layer. The light-emitting device includes a hole injection layer. In some embodiments, the hole injection layer includes a p-doped indium gallium nitride (p-InGaN) layer that is located in one of the three following locations: between the MQW layer and the electron-blocking layer; between the electron-blocking layer and the p-GaN layer; and inside the p-GaN layer.

Abstract: In the semiconductor laser including a diffraction grating in which a first diffraction grating region with a first pitch, a second diffraction grating region with a second pitch and a third diffraction grating region with the first pitch, an anti-reflection film coated on an end facet to the light-emitting side, and a reflection film coated on an opposite end facet, the first diffraction grating region is greater than the third diffraction grating region, and the second diffraction grating region is formed, in such a manner that phases of the first and third diffraction grating regions are shifted in a range of equal to or more than 0.6 ? to equal to or less than 0.9 ?, phases are successive on a boundary between the first and second diffraction grating regions and the phases are successive on a boundary between the second and third diffraction grating regions.

Abstract: A quantum cascade laser 1 includes a semiconductor substrate, an active layer 15 that is disposed on the semiconductor substrate and has a cascade structure in which a unit layered structure 16 including a quantum well light emitting layer and an injection layer is stacked in multiples to alternately stack the quantum well light emitting layer and the injection layer, and a diffraction grating layer 20 disposed on the active layer.

Abstract: A semiconductor laser device generates blue-violet light with an emission wavelength of 400 to 410 nm. The device includes an n-type group III nitride semiconductor layer, an active layer laminated on the n-type semiconductor layer and having an InGaN quantum well layer, a p-type group III nitride semiconductor layer laminated on the active layer, and a transparent electrode contacting the p-type semiconductor layer and serving as a clad. The n-type semiconductor layer includes an n-type clad layer and an n-type guide layer disposed between the clad layer and the active layer. The guide layer includes a superlattice layer in which an InGaN layer and an AlxGa1-xN layer (0?X<1) are laminated periodically, the superlattice layer contacting the active layer and having an average refractive index of 2.6 or lower. The In composition of the InGaN layer is lower than that of the InGaN quantum well layer.

Abstract: The present invention provides a Group III nitride semiconductor light-emitting device exhibiting improved emission output. The light-emitting device comprises an n-type contact layer on which an n-electrode is formed, a light-emitting layer, an n-type cladding layer formed between the light-emitting layer and the n-type contact layer. The n-type cladding layer has a structure of at least two layers including a first n-type cladding layer closer to the light-emitting layer and a second n-type cladding layer farther from the light-emitting layer than the first n-type cladding layer. The first n-type cladding layer has a Si concentration higher than that of the second n-type cladding layer, and the first n-type cladding layer has a thickness smaller than that of the second n-type cladding layer.

Abstract: A semiconductor laser has an optical cavity comprising and active layer disposed between an n-side barrier layer and a p-side barrier layer. The active layer comprises alternating layers of a first and second material, and the n-side barrier layer and p-side barrier layer each comprise alternating layers of the first material and a third material. The materials are selected such that the layers of the second and third materials form quantum wells between the layers of the first material. A band gap Eg of the second material is arranged such that a proportion of electrons and holes that recombine across the band gap Eg recombine to emit photons at the lasing wavelength, the proportion decreasing with increasing temperature of the optical cavity.

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

Abstract: Concatenated distributed feedback lasers having multiple laser sections laid out in series are disclosed. The concatenated distributed feedback lasers utilize quantum cascade core designs to produce optical gain in the mid- infrared region and may generate several wavelengths simultaneously or sequentially. Methods of making along with methods of using such devices are also disclosed.

Abstract: An epitaxial structure for a III-Nitride based optical device, comprising an active layer with anisotropic strain on an underlying layer, where a lattice constant and strain in the underlying layer are partially or fully relaxed in at least one direction due to a presence of misfit dislocations, so that the anisotropic strain in the active layer is modulated by the underlying layer.

Abstract: A semiconductor light emitting device includes a light guiding structure, a light emitting layer disposed within the light guiding structure, and a structure for discharging excess electric charge within the device. The device may be excited by an electron beam, as opposed to an optical beam, to create electron-hole pairs. The light emitting layer is configured for light generation without requiring a p-n junction, and is therefore not embedded within nor part of a p-n junction. Doping with p-type species is obviated, reducing device loss and permitting operation at a short wavelengths, such as below 300 nm. Various structures, such as a top-side cladding layer, are disclosed for discharging beam-induced charge. A single device may be operated with multiple electron beam pumps, either to enable a relatively thick active layer or to drive multiple separate active layers. Cooperatively curved end facets accommodate for possible off-axis resonance within the active region(s).

Abstract: A group-III nitride semiconductor laser device comprises: a laser structure including a semiconductor region and a support base having a semipolar primary surface of group-III nitride semiconductor; a first reflective layer, provided on a first facet of the region, for a lasing cavity of the laser device; and a second reflective layer, provided on a second facet of the region, for the lasing cavity. The laser structure includes a laser waveguide extending along the semipolar surface. A c+ axis vector indicating a <0001> axial direction of the base tilts toward an m-axis of the group-III nitride semiconductor at an angle of not less than 63 degrees and less than 80 degrees with respect to a vector indicating a direction of an axis normal to the semipolar surface. The first reflective layer has a reflectance of less than 60% in a wavelength range of 525 to 545 nm.

Abstract: A quantum cascade laser includes a semiconductor substrate including a principal surface; a mesa waveguide disposed on the principal surface of the semiconductor substrate, the mesa waveguide including a light emitting region and an upper cladding layer disposed on the light emitting region, the mesa waveguide extending in a direction orthogonal to a reference direction; and a current blocking layer formed on a side surface of the mesa waveguide. The light emitting region includes a plurality of core regions and a plurality of buried regions. The core regions and the buried regions are alternately arranged in the reference direction. The core region at a central portion of the mesa waveguide has a width larger than a width of the core region at a peripheral portion of the mesa waveguide in the reference direction.

Abstract: Group III nitride-based laser diodes comprise an n-side cladding layer formed of n-doped (Al,In)GaN, an n-side waveguide layer formed of n-doped (Al)InGaN, an active region, a p-side waveguide layer formed of p-doped (Al)InGaN, and a p-side cladding layer formed of p-doped (Al,In)GaN. Optical mode is shifted away from high acceptor concentrations in p-type layers through manipulation of indium concentration and thickness of the n-side waveguide layer. Dopant and compositional profiles of the p-side cladding layer and the p-side waveguide layer are tailored to reduce optical loss and increased wall plug efficiency.

Abstract: A tuneable laser source includes a first confinement layer forming a Bragg reflector for a pump wave; an active layer made of non-linear semiconducting material, the refraction index of the active layer being greater than the refraction index of the first confinement layer; a second confinement layer, the refraction index of the second confinement layer being less than the refraction index of the active layer; a base with a first width; and a ribbon with a second width less than the first width. The second width is less than 10 ?m; the active layer includes at least one plane of quantum boxes capable of emitting a pump wave and the ribbon includes at least the part of the active layer including the quantum boxes plane and the second confinement layer.

Abstract: A vertical cavity surface emitting laser includes an active layer that includes a quantum well, a first cladding layer and a second cladding layer between which the active layer is interposed. A first multilayer reflector layer is arranged on a side of the first cladding layer opposite to that on which the active layer is arranged. A second multilayer reflector layer is arranged on a side of the second cladding layer opposite to that on which the active layer is arranged. At least one of the first cladding layer and the second cladding layer includes a low activity energy layer having a band gap that is smaller than a smallest band gap of an optical confinement layer for forming the quantum well of the active layer and larger than a band gap of the quantum well.

Abstract: A disclosed vertical cavity surface emitting laser device emits light orthogonally in relation to a substrate and includes a resonator structure including an active layer; and semiconductor multilayer reflectors disposed in such a manner as to sandwich the resonator structure between them and including a confinement structure which confines an injected current and transverse modes of oscillation light at the same time. The confinement structure has an oxidized region which surrounds a current passage region. The oxidized region is formed by oxidizing a part of a selective oxidation layer which includes aluminum and includes at least an oxide. The selective oxidation layer is at least 25 nm in thickness. The semiconductor multilayer reflectors include an optical confinement reducing section which reduces optical confinement in a transverse direction. The optical confinement reducing section is disposed on the substrate side in relation to the resonator structure.

Abstract: Provided is a distributed feedback-laser diode (DFB-LD) and manufacturing method thereof. The DFB-LD includes a substrate; a lower clad layer having a grating on the substrate; an active waveguide extended in a first direction on the lower clad layer; an upper clad layer on the active waveguide; a signal pad on the upper clad layer; and at least one ground pad spaced apart from the active waveguide, the upper clad layer, and the signal pad in a second direction crossing the first direction, the at least one ground pad being coupled to the lower clad layer.

Abstract: A semiconductor laser device generates blue-violet light with an emission wavelength of 400 to 410 nm. The device includes an n-type group III nitride semiconductor layer, an active layer laminated on the n-type semiconductor layer and having an InGaN quantum well layer, a p-type group III nitride semiconductor layer laminated on the active layer, and a transparent electrode contacting the p-type semiconductor layer and serving as a clad. The n-type semiconductor layer includes an n-type clad layer and an n-type guide layer disposed between the clad layer and the active layer. The guide layer includes a superlattice layer in which an InGaN layer and an AlxGa1-xN layer (0?x<1) are laminated periodically, the superlattice layer contacting the active layer and having an average refractive index of 2.6 or lower. The In composition of the InGaN layer is lower than that of the InGaN quantum well layer.

Abstract: A device including one or more layers with lateral regions configured to facilitate the transmission of radiation through the layer and lateral regions configured to facilitate current flow through the layer is provided. The layer can comprise a short period superlattice, which includes barriers alternating with wells. In this case, the barriers can include both transparent regions, which are configured to reduce an amount of radiation that is absorbed in the layer, and higher conductive regions, which are configured to keep the voltage drop across the layer within a desired range.

Abstract: A laser source (340) comprises a first frame (356), a laser (358), and a first mounting assembly (360). The laser (358) generates an output beam (354) that is directed along a beam axis (354A). The first mounting assembly (360) allows the laser (358) to expand and contract relative to the first frame (356) along a first axis and along a second axis that is orthogonal to the beam axis, while maintaining alignment of the output beam (354) so the beam axis (354A) is substantially coaxial with the first axis. The first mounting assembly (360) can include a first fastener assembly (366) that couples the laser (358) to the first frame (356), and a first alignment assembly (368) that maintains alignment of the laser (358) along a first alignment axis (370) that is substantially parallel to the first axis.

Abstract: A semiconductor laser includes a semiconductor nanowire of a first conductivity type provided over a substrate, a light emitting layer provided around the semiconductor nanowire and insulated at an upper end and a lower end thereof, a cladding layer of a second conductivity type different from the first conductivity type, the cladding layer being provided at an outer periphery of the light emitting layer, a first electrode electrically coupled to an end portion of the semiconductor nanowire, a second electrode electrically coupled to an outer periphery of the cladding layer, a first reflection mirror provided at a one-end portion side of the semiconductor nanowire, and a second reflection mirror provided at the other end portion side of the semiconductor nanowire.

Abstract: To realize a nitride semiconductor laser element having improved internal quantum efficiency.

Abstract: An optoelectronic component includes a semiconductor layer sequence having an optoelectronically active region; a dielectric layer on the semiconductor layer sequence; and a metal layer on the dielectric layer, wherein an adhesion layer is arranged between the dielectric layer and the metal layer, the adhesion layer being covalently bonded to the dielectric layer and to the metal layer.

Abstract: Semiconductor structures for laser devices are provided. The semiconductor structures have a quantum cascade laser structure comprising an electron injector, an active region, and an electron extractor. The active region comprises an injection barrier, a multiquantum well structure, and an exit barrier. The multiquantum well structure can comprise a first barrier, a first quantum well, a second barrier, a second quantum well, and a third barrier. The energies of the first and second barrier are less than the energy of the third barrier. The energy difference between the energy of the second barrier and the energy of the third barrier can be greater than 150 meV and the ratio of the energy of the third barrier to the energy of the second barrier can be greater than 1.26.

Abstract: An optoelectronic device having an active layer that includes a multiplicity of structural elements spaced apart from one another laterally, wherein the structural elements each have a quantum well structure including at least one barrier layer composed of Inx1Aly1Ga1-x1-y1N, wherein 0?x1?1, 0?y1?1 and x1+y1?1, and at least one quantum well layer composed of Inx2Aly2Ga1-x2-y2N, wherein 0?x2?1, 0?y2?1 and x2+y2?1.

Abstract: A light oscillation device has a self oscillation semiconductor laser that has a double quantum well separated confinement heterostructure made of GaInN/GaN/AlGaN materials and that includes a saturable absorber section which is applied with a negative bias voltage and a gain section into which a gain current is injected, a light separation unit that separates a portion of laser light beams from the self oscillation semiconductor laser, a light sensing element that senses the laser light beams separated by the light separation unit, and a current control circuit which controls a current injected into the gain section of the self oscillation semiconductor laser based on an amount of the laser light beams which are sensed by the light sensing element.

Abstract: A method for preparing a VCSEL can use MBE for: growing a first conduction region over a first mirror region; growing an active region over the first conduction region opposite of the first mirror region, including: (a) growing a quantum well barrier having In1-xGaxP(As); (b) growing an transitional layer having one or more of GaP, GaAsP, or GaAs; (c) growing a quantum well layer having In1-zGazAsyP1-y; (d) growing another transitional layer have one or more of GaP, GaAsP, or GaAs; (e) repeating processes (a) through (d) over a plurality of cycles; and (f) growing a quantum well barrier having In1-xGaxP(As); growing a second conduction region over the active region opposite of the first conduction region, wherein: x ranges from 0.77 to 0.50; y ranges from 0.7 to 1; and z ranges from 0.7 to 0.99.

Abstract: Implementations and techniques for coupled asymmetric quantum confinement structures are generally disclosed.

Abstract: Semiconductor structures for laser devices are provided. The semiconductor structures have a quantum cascade laser structure comprising an electron injector, an active region, and an electron extractor. The active region comprises an injection barrier, a multiquantum well structure, and an exit barrier. The multiquantum well structure can comprise a first barrier, a first quantum well, a second barrier, a second quantum well, and a third barrier. The energies of the first and second barrier are less than the energy of the third barrier. The energy difference between the energy of the second barrier and the energy of the third barrier can be greater than 150 meV and the ratio of the energy of the third barrier to the energy of the second barrier can be greater than 1.26.

Abstract: A quantum cascade laser includes a substrate having first, second, third, and fourth regions; a stacked semiconductor layer including n-type lower and upper conductive layers, a core layer having a mesa structure, and a cladding layer; first and second buried layers disposed on side surfaces of the core layer and above the substrate; a first electrode disposed on the upper conductive layer above the first region; and a second electrode disposed on the lower conductive layer above the fourth region. The core layer is disposed on the lower conductive layer above the second region. The upper conductive layer is disposed on the first buried layer and the core layer. The cladding layer is disposed on the upper conductive layer above the second region, The substrate and the cladding layer are formed of an undoped or semi-insulating semiconductor. The first and second buried layers are formed of a semi-insulating semiconductor.

Abstract: A quantum cascade laser 1 includes a semiconductor substrate, an active layer 15 that is disposed on the semiconductor substrate and has a cascade structure in which a unit layered structure 16 including a quantum well light emitting layer and an injection layer is stacked in multiples to alternately stack the quantum well light emitting layer and the injection layer, and a diffraction grating layer 20 disposed on the active layer.

Abstract: A semiconductor light-emitting element includes a substrate, a recess in the substrate, and a ridge portion disposed in the recess, the ridge portion having a constant width, in which the recess has a width that varies in the longitudinal direction of the ridge portion, the ridge portion is formed of a compound semiconductor multilayer structure including an active layer, and the active layer has a thickness that varies in the longitudinal direction of the ridge portion.

Abstract: A quantum cascade laser includes a plurality of active layers, each of active layers including a first barrier layer, a first quantum well layer, a second barrier layer, a second quantum well layer, a third barrier layer, a third quantum well layer, and a fourth bather layer provided in this order along a predetermined direction; a plurality of injection layers; and a core layer having the active layers and the injection layers, the active layers and the injection layers being alternately provided along the predetermined direction to form a cascade structure. The first quantum well layer has a film thickness larger than a film thickness of the second quantum well layer. The second quantum well layer has the film thickness larger than a film thickness of the third quantum well layer. In addition, the second barrier layer has a film thickness smaller than a film thickness of the third bather layer.

Abstract: An edge-emitting etched-facet optical semiconductor structure includes a substrate, an active multiple quantum well (MQW) region formed on the substrate, a ridge waveguide formed over the MQW region extending in substantially a longitudinal direction between a waveguide first etched end facet disposed in a first window and a waveguide second etched end facet disposed in a second window, and first and second trenches having non-uniform widths extending in substantially the longitudinal direction between the first and second windows.

Abstract: A nitride semiconductor laser diode comprises a substrate; an n-side nitride semiconductor layer containing an n-type impurity and disposed on the substrate; an active layer having a light emitting layer including InxAlyGa1-x-yN (0<x<1, 0?y<1, and 0<x+y<1) and disposed on the n-side nitride semiconductor layer; and a p-side nitride semiconductor layer containing a p-type impurity and disposed on the active layer. The lasing wavelength of the nitride semiconductor laser diode is 500 nm or greater.

Abstract: A quantum cascade semiconductor laser includes a n-type semiconductor substrate, the substrate having a main surface; a mesa waveguide disposed on the substrate, the mesa waveguide including a core layer and an n-type upper cladding layer disposed on the core layer; a first semiconductor layer disposed on a side surface of the mesa waveguide and the main surface of the substrate, the first semiconductor layer being in contact with the side surface of the mesa waveguide; and a second semiconductor layer disposed on the first semiconductor layer. The first semiconductor layer and the second semiconductor layer constitute a burying region embedding the side surfaces of the mesa waveguide. The first semiconductor layer is formed of at least one of a semi-insulating semiconductor and a p-type semiconductor. In addition, the second semiconductor layer is formed of an n-type semiconductor.

Abstract: A method of component assembly on a substrate, and an assembly of a bound component on a substrate. The method comprises the steps of forming a free-standing component having an optical characteristic; providing a pattern of a first binding species on the substrate or the free standing component; and forming a bound component on the substrate through a binding interaction via the first binding species; wherein the bound component exhibits substantially the same optical characteristic compared to the free-standing component.

Abstract: A multicolor photonic crystal laser array comprises pixels of monolithically grown gain sections each with a different emission centre wavelength. As an example, two-dimensional surface-emitting photonic crystal lasers comprising broad gain-bandwidth III-nitride multiple quantum well axial heterostructures were fabricated using a novel top-down nanowire fabrication method. Single-mode lasing was obtained in the blue-violet spectral region with 60 nm of tuning (or 16% of the nominal centre wavelength) that was determined purely by the photonic crystal geometry. This approach can be extended to cover the entire visible spectrum.

Abstract: In the semiconductor laser including a diffraction grating in which a first diffraction grating region with a first pitch, a second diffraction grating region with a second pitch and a third diffraction grating region with the first pitch, an anti-reflection film coated on an end facet to the light-emitting side, and a reflection film coated on an opposite end facet, the first diffraction grating region is greater than the third diffraction grating region, and the second diffraction grating region is formed, in such a manner that phases of the first and third diffraction grating regions are shifted in a range of equal to or more than 0.6 ? to equal to or less than 0.9 ?, phases are successive on a boundary between the first and second diffraction grating regions and the phases are successive on a boundary between the second and third diffraction grating regions.

Abstract: A semiconductor device has an active layer, a first semiconductor layer of first conductive type, an overflow prevention layer disposed between the active layer and the first semiconductor layer, which is doped with impurities of first conductive type and which prevents overflow of electrons or holes, a second semiconductor layer of first conductive type disposed at least one of between the active layer and the overflow prevention layer and between the overflow prevention layer and the first semiconductor layer, and an impurity diffusion prevention layer disposed between the first semiconductor layer and the active layer, which has a band gap smaller than those of the overflow prevention layer, the first semiconductor layer and the second semiconductor layer and which prevents diffusion of impurities of first conductive type.

Abstract: A device including one or more layers with lateral regions configured to facilitate the transmission of radiation through the layer and lateral regions configured to facilitate current flow through the layer is provided. The layer can comprise a short period superlattice, which includes barriers alternating with wells. In this case, the barriers can include both transparent regions, which are configured to reduce an amount of radiation that is absorbed in the layer, and higher conductive regions, which are configured to keep the voltage drop across the layer within a desired range.

Abstract: Structures and methodologies to obtain lasing in indirect gap semiconductors such as Ge and Si are provided and involves excitonic transitions in the active layer comprising of at least one indirect gap layer. Excitonic density is increased at a given injection current level by increasing their binding energy by the use of quantum wells, wires, and dots with and without strain. Excitons are formed by holes and electrons in two different layers that are either adjacent or separated by a thin barrier layer, where at least one layer confining electrons and holes is comprised of indirect gap semiconductor such as Si and Ge, resulting in high optical gain and lasing using optical and electrical injection pumping. In other embodiment, structures are described where excitons formed in an active layer confining electrons in the direct gap layer and holes in the indirect gap layer; where layers are adjacent or separated by a thin barrier layer.

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

Abstract: The laser device includes an amplifier including a III-V heterostructure arranged to generate photons, and a waveguide which forms a loop and is optically coupled to the amplifier. The amplifier is arranged facing the waveguide only in the region of a first section of the waveguide.

Abstract: A semiconductor laser element includes: a light emitting layer of a nitride semiconductor that is placed above a substrate of GaN and has a refractive index higher than the substrate, wherein the semiconductor laser element further includes the following layers between the substrate and the light emitting layer in an order from the substrate: a first nitride semiconductor layer of AlGaN; a second nitride semiconductor layer of AlGaN having an Al ratio higher than the first nitride semiconductor layer; a third nitride semiconductor layer of an InGaN; and a fourth nitride semiconductor layer of AlGaN having an Al ratio higher than the first nitride semiconductor layer and having a thickness greater than the second nitride semiconductor layer.

Abstract: [PROBLEM] To manufacture a quantum cascade laser (QCL) element having a reduced threshold current density (Jth) and an increased maximum operating temperature (Tmax). [SOLUTION] One embodiment of the present invention provides a THz-QCL element (1000) with a QCL structure (100), which is a semiconductor superlattice (100A) sandwiched between a pair of electrodes (20, 30). The semiconductor superlattice (100A) (QCL structure (100)) is provided with an active region (10) that emits THz range electromagnetic waves due to the transition of electrons between sub-bands during application of a voltage to the pair of electrodes, for example. The active region (10) has repeating unit structures (10U) of a thickness, which includes sets of a well layer (10W) and a barrier layer (10B) alternatingly laminated with each other, wherein the well layer (10W) is made of AlxGa1-xAs (where 0<x<1), which is a mixed crystal of AlAs and GaAs.

Abstract: An optical light source is provided. The optical light source includes a waveguide including two reflectors arranged spaced apart from each other to define an optical cavity therebetween, an optical gain medium, and a coupling structure arranged to couple light between the optical cavity and the optical gain medium.

Abstract: A nitride semiconductor light-emitting device has a semiconductor ridge, and includes a first inner-layer between an active layer and an n-type cladding and a second inner-semiconductor layer between the active layer and a p-type cladding. The first inner-layer, active layer and second inner-layer constitute a core-region. The n-type cladding, core-region and p-type cladding constitute a waveguide-structure. The active layer and the first inner-layer constitute a first heterojunction inclined at an angle greater than zero with respect to a reference plane of the c-plane of the nitride semiconductor of the n-type cladding. Piezoelectric polarization of the well layer is oriented in a direction from the p-type cladding toward the n-type cladding. The second inner-layer and InGaN well layer constitute a second heterojunction. A distance between the ridge bottom and the second heterojunction is 200 nm or less. The ridge includes a third heterojunction between the second inner-layer and the p-type cladding.