Abstract: A semiconductor light emitting diode (LED) and a method of manufacturing the same are provided. The LED includes a first semiconductor layer; a plurality of active elements spaced apart on the first semiconductor layer and each having a width less than a width of the first semiconductor layer; and a second semiconductor layer disposed on the plurality of active elements.

Abstract: A method of forming and a random Distributed Bragg Reflector (DBR) is disclosed. The random DBR includes a substrate and a plurality of alternating layers of lattice-matched nanoporous GaN (NP-GaN) and GaN formed on a top surface of the substrate, wherein at least one of the alternating layers has a thickness of ?/4n and an adjacent one of the alternating layers does not have a thickness of ?/4n, wherein ? is a wavelength of incident radiation and n is the refractive index of a particular layer of the plurality of alternating layers.

Abstract: A manufacturing method of a light emitting diode apparatus is provided. This method includes forming a light emitting diode on the substrate, forming a light leakage preventing layer to surround the side surface of the light emitting diode, etching a region corresponding to the light emitting diode in the substrate, and bonding a wavelength converting material to a lower portion of the light emitting diode in the etched region, in which the wavelength converting material includes a semiconductor layer including a quantum well layer.

Abstract: A quantum cascade laser has an active layer, a first and second cladding layer, and an optical guide layer. The active layer has a plurality of injection quantum well regions and a plurality of light-emitting quantum well regions. The each of the injection quantum well regions and the each of the light-emitting quantum well regions are alternatively stacked. The first and second cladding layers are provided to interpose the active layer from both sides, and have a refractive index lower than an effective refractive index of the each of the light-emitting quantum well regions. The optical guide layer is disposed to divide the active layer into two parts. The optical guide layer has a refractive index higher than the effective refractive index of the each of the light-emitting quantum well regions, and has a thickness greater than the thickness of all well layers of quantum well layers.

Abstract: A semiconductor laser wafer includes a substrate, a first semiconductor layer, an active layer, a second semiconductor layer, and a composition evaluation layer. The active layer is provided on the first semiconductor layer; multiple periods of pairs of a light-emitting multi-quantum well region and an injection multi-quantum well region are stacked in the active layer; the light-emitting multi-quantum well region is made of a first compound semiconductor and a second compound semiconductor. The second semiconductor layer is provided on the active layer. The composition evaluation layer is provided above the active layer and includes a first film and a second film; the first film is made of the first compound semiconductor and has a first thickness; and the second film is made of the second compound semiconductor and has a second thickness.

Abstract: Provided is a technique for manufacturing a semiconductor light-emitting element for which it is possible to dramatically increase light emission efficiency to a greater degree than in the past. An AlInN film provided on a GaN epitaxial film that is formed on a substrate, wherein: the AlInN film is formed by lamination of AlInN layers; between the laminated AlInN layers, there is provided a cap layer that comprises GaN, AlN, or AlGaN, and has a thickness of 0.1-10 nm; a super lattice structure is formed; the total thickness exceeds 200 nm; and the root-mean-square height RMS is 3 nm or less. A method for forming an AlInN film, the method being such that: a step for forming an AlInN layer is repeated a plurality of times, said step involving using any of an organometallic vapor phase growth method, a molecular beam epitaxy method, and a sputtering method to form the AlInN layer to a thickness of 200 nm or less by epitaxial growth in an atmosphere of 700-850° C.

Abstract: A light receiving element (1) according to an embodiment of the disclosure includes a semiconductor layer (20) in which a photodiode having a PIN structure is provided in a mesa portion having a pillar shape. The photodiode includes a first conductive layer (21), an optical absorption layer (23), and a second conductive layer (24) having a light incident surface. In the light receiving element (1), the semiconductor layer (20) includes, in the vicinity of an interface between the first conductive layer (21) and the optical absorption layer (23), a constricted portion (26) that is the most constricted of the first conductive layer (21). The interface has an end exposed on an internal surface of the constricted portion (26).

Abstract: In embodiments described herein, a light emitting diode device comprises an emission device with an emission region and a bottom contact layer. The emission region comprises n cascading emission layers, where n is a whole and positive number. The n cascading emission layers comprise at least one superlattice structure. In an embodiment, a tunnel junction is spaced between a first superlattice structure and a second superlattice structure. In an embodiment, light extraction is enhanced with a trapezoidal shaped chip, a roughened exit interface, and encapsulation of the chip with a hemispherical shaped polymer. In an embodiment, the superlattice structure may be repeated periods of InAs/AlGaInSb. In another embodiment, the superlattice may be repeated periods of InAs/GaInSb/InAs/AlAsSb. In another embodiment, between the bottom contact layer and the emission region is a tunnel junction where the bottom contact layer and the tunnel junction form an n-type anode layer.

Abstract: A diode laser comprises an n-type first cladding layer, an n-type first waveguide layer arranged on the first cladding layer, an active layer suitable for radiation generation and arranged on the first waveguide layer, a p-type second waveguide layer arranged on the active layer, a p-type second cladding layer which is arranged on the second waveguide layer, an n-type first intermediate layer being formed as a transition region between the first waveguide layer and the active layer, and a p-type second intermediate layer being formed as a transition region between the second waveguide layer and the active layer. The diode laser according to the invention is characterized in that the asymmetry ratio of the thickness of the first intermediate layer to the sum of the thickness of the first intermediate layer and the thickness of the second intermediate layer is less than or greater than 0.5.

Abstract: A method for manufacturing of a waveguide for guiding an electro-magnetic wave comprising: forming a first waveguide layer, a sacrificial layer and a protection layer on a first wafer, patterning to define a pattern of a first waveguide part and a supporting structure in the first waveguide layer; exposing the sacrificial layer on the first waveguide part while the protection layer still covers the sacrificial layer on the supporting structure; removing the sacrificial layer on the first waveguide part; removing the protection layer; bonding a second wafer to the sacrificial layer of the first wafer such that a second waveguide part is supported by the supporting structure and a gap corresponding to the thickness of the sacrificial layer is formed between the first and second waveguide parts.

Abstract: The invention relates to a quantum cascade laser (300) comprising a gain region (102) inserted between two optical confinement layers (1041, 1042), said gain region (102) having an electron input into the gain region (102) and an electron output from said gain region (102) characterized in that said laser comprises a hole-blocking area (304) on the side of said electron output.

Abstract: To increase the maximum operating temperature of quantum cascade lasers of a terahertz region, a quantum cascade laser element 1000 according to the present invention has a semiconductor superlattice structure sandwiched between a pair of electrodes, the semiconductor superlattice structure has an active region 100 that emits electromagnetic waves of a frequency in a THz region under an external voltage applied through the pair of electrodes for operation, and the active region 100 has plural unit structures 10U, each of which is repeatedly layered over one another. Each of the unit structures 10U has a double quantum well structure formed of a first well layer 10W1 and a second well layer 10W2 separated from each other by a barrier layer, the first well layer 10W1 and the second well layer 10W2 have compositions different from each other, and when the external voltage is not being applied, potential energy for electrons in the second well layer 10W2 is lower than that in the first well layer 10W1.

Abstract: An avalanche diode arrangement (10) comprises an avalanche diode (11) that is coupled to a first voltage terminal (16) and to a first node (13), an event detector (14) for detecting a trigger event of the avalanche diode (11) and being coupled to the first node (13), a quenching circuit (15) that is coupled to the first node (13), and a detection circuit (20) coupled to the first node (13). The detection circuit (20) is configured to provide a detection signal (SVC2) that depends on a value of a node voltage (SVA) at the first node (13).

Abstract: A method of providing an out-of-plane semiconductor structure and a structure fabricated thereby is disclosed. The method comprises acts of: providing a substrate defining a major surface; providing a template layer having a predetermined template thickness on the major surface of the substrate; forming a recess in the template layer having a recess pattern and a recess depth smaller than the template thickness; and epitaxilally growing a semiconductor structure from the recess. A planar shape of the recess pattern formed in the template layer substantially dictates an extending direction of the semiconductor structure.

Abstract: The present invention belongs to the field of semiconductor technology and relates to a polarization-doped enhancement mode HEMT device. The technical solution of the present invention grows the first barrier layer and the second barrier layer that contain gradient Al composition sequentially on the buffer layer. The gradient trends of the two layers are opposite. The three-dimensional electron gas (3DEG) and the three-dimensional hole gas (3DHG) are induced and generated in the barrier layers due to the inner polarization difference respectively. A trench insulated gate structure is at one side of the source which is away from the metal drain and is in contact with the source. First, since the highly concentrated electrons exist in the entire first barrier layer, the on-state current is improved greatly. Second, the vertical conductive channel between the source and the 3DEG are pinched off by the 3DHG, so as to realize the enhancement mode.

Abstract: A quantum cascade laser may include a substrate, and a semiconductor layer adjacent the substrate and defining an active region. The active region may have an elongate shape extending laterally across the substrate and having first and second lowest injector states with an energy spacing greater than 20 meV. In some embodiments, the active region may have a thickness less than or equal to 1.3 ?m and a length greater than or equal to 20 ?m. The quantum cascade laser may also include an optical grating adjacent the active region and configured to emit a continuous wave laser output through the substrate. The optical grating may include a curved grating pattern.

Abstract: An active layer of a quantum cascade laser includes an active layer includes a plurality of emission regions and a plurality of injection regions. Each emission region includes an injection barrier layer, and an light-emitting quantum well layer that has at least two well layers, and that emits infrared light by undergoing an intersubband transition. Each injection region includes an extraction barrier layer, and a relaxation quantum well layer that creates an energy level for relaxing the energy of carriers from the each emission region. One of adjacent two well layers in the light-emitting quantum well layer of the each emission region on the side of the extraction barrier layer is deeper than a second well layer on the side of the injection barrier layer. The each emission region and the injection region are alternately stacked.

Abstract: A GaN based semiconductor light-emitting device is provided. The light-emitting device includes a first GaN based compound semiconductor layer of an n-conductivity type; an active layer; a second GaN based compound semiconductor layer; an underlying layer composed of a GaN based compound semiconductor, the underlying layer being disposed between the first GaN based compound semiconductor layer and the active layer; and a superlattice layer composed of a GaN based compound semiconductor doped with a p-type dopant, the superlattice layer being disposed between the active layer and the second GaN based compound semiconductor layer.

Abstract: Disclosed herein are multi-layered optically active regions for semiconductor light-emitting devices (LEDs) that incorporate intermediate carrier blocking layers, the intermediate carrier blocking layers having design parameters for compositions and doping levels selected to provide efficient control over the carrier injection distribution across the active regions to achieve desired device injection characteristics. Examples of embodiments discussed herein include, among others: a multiple-quantum-well variable-color LED operating in visible optical range with full coverage of RGB gamut, a multiple-quantum-well variable-color LED operating in visible optical range with an extended color gamut beyond standard RGB gamut, a multiple-quantum-well light-white emitting LED with variable color temperature, and a multiple-quantum-well LED with uniformly populated active layers.

Abstract: Novel ICL layering designs, ridge waveguide architectures, and processing protocols that will significantly lower the optical losses and improve the power conversion efficiencies of interband cascade lasers designed for both DFB single-mode and high-power applications. The semiconductor top cladding and metal contact layers are eliminated or significantly reduced. By instead using a dielectric or air top clad, or dielectric or air layers to supplement a thin top clad, in conjunction with lateral current injection and weak index-guiding, the present invention will substantially reduce the internal loss of such ICLs, resulting in lower lasing threshold, higher efficiency, and higher maximum power.

Abstract: A method for producing a quantum cascade laser includes the steps of forming a laser structure including a mesa structure and a buried region embedding the mesa structure; forming a mask on the laser structure, the mask including a first pattern that defines a ?/4 period distribution Bragg reflector structure and a second pattern that defines a 3?/4 period distribution Bragg reflector structure; and forming a first distribution Bragg reflector structure, a second distribution Bragg reflector structure, and a semiconductor waveguide structure by dry-etching the laser structure through the mask, the semiconductor waveguide structure including the mesa structure that has first and second end facets. The first distribution Bragg reflector structure is optically coupled to the first end facet. The second distribution Bragg reflector structure is optically coupled to the second end facet. Here, ? denotes a value of an oscillation wavelength of the quantum cascade laser in vacuum.

Abstract: A quantum cascade laser and its method of fabrication are provided. The quantum cascade laser comprises one or more p-type electrical isolation regions and a plurality of electrically isolated laser sections extending along a waveguide axis of the laser. An active waveguide core is sandwiched between upper and lower n-type cladding layers and the active core and the upper and lower n-type cladding layers extend through the electrically isolated laser sections of the quantum cascade laser. A portion of the upper n-type cladding layer comprises sufficient p-type dopant to have become p-type and to have become an electrical isolation region, which extends across at least a part of the thickness upper n-type cladding layer along a projection separating the sections of the quantum cascade laser.

Abstract: A semiconductor optical device includes an active layer, the active layer including a plurality of quantum well layers having gain peak wavelengths different from one another in a layering direction thereof, and a plurality of barrier layers, wherein the quantum well layers and the barrier layers are alternately layered over each other, and an n-type dopant has been added in the plurality of quantum well layers having gain peak wavelengths different from one another and in the plurality of barrier layers.

Abstract: A DFB laser element includes an active layer 4 having a multiple quantum well structure including a plurality of well layers 4B having different thicknesses, a diffraction grating layer 6 that is optically coupled to the active layer 4, and a pair of cladding layers with the active layer 4 and the diffraction grating layer 6 interposed therebetween. An effective refractive index of the diffraction grating layer 6 is high, and a thickness of the well layer 4B increases as a distance from the diffraction grating layer 6 increases. In this structure, it is possible to reduce dependence on temperature when the DFB semiconductor laser element is miniaturized.

Abstract: There is provided a nanostructure semiconductor light emitting device including a base layer formed of a first conductivity-type semiconductor, a first insulating layer disposed on the base layer and having a plurality of first openings exposing partial regions of the base layer, a plurality of nanocores disposed in the exposed regions of the base layer and formed of the first conductivity-type semiconductor, an active layer disposed on surfaces of the plurality of nanocores positioned to be higher than the first insulating layer, a second insulating layer disposed on the first insulating layer and having a plurality of second openings surrounding the plurality of nanocores and the active layer disposed on the surfaces of the plurality of nanocores, and a second conductivity-type semiconductor layer disposed on the surface of the active layer positioned to be higher than the second insulating layer.

Abstract: According to one embodiment of the invention, a semiconductor laser device includes a plurality of first unit stacked bodies and a plurality of second stacked bodies. The plurality of first unit stacked bodies have an emission region including a first quantum well layer and capable of emitting a first infrared light by an intersubband transition, and an electron injection region capable of transporting an electron relaxed to a mini-band level in the emission region to a downstream unit stacked body. The plurality of second unit stacked bodies have an emission region including a second quantum well layer and capable of emitting a second infrared light by an intersubband transition, and an electron injection region capable of transporting an electron relaxed to a mini-band level in the emission region of the second quantum well layer to a downstream unit stacked body. The second quantum well layer has at least one well width different from a well width of the first quantum well layer.

Abstract: A method for producing a quantum cascade laser includes the steps of growing a stacked semiconductor layer including a core layer; forming an insulating mask on the stacked semiconductor layer; forming a mesa structure including the core layer by etching the stacked semiconductor layer through the insulating mask; growing a buried layer on a side surface of the mesa structure using the insulating mask by supplying a halogen-based substance and a gas containing a raw material, the buried layer having a thickness larger than a height of the mesa structure; producing a substrate product including the mesa structure and a buried region by processing of the buried layer using a chemical-mechanical polishing method; and after removal of the insulating mask, producing a distributed reflection structure by etching the mesa structure and the buried region of the substrate product using a mask.

Abstract: Device comprising a high brightness broad-area edge-emitting semiconductor laser and method of making the same. The device includes an edge-emitting semiconductor laser, said laser having a multi-layered waveguide, and said waveguide comprising at least one layer with an active region that emits light under electrical injection, and at least one aperiodic layer stack.

Abstract: An improved longwave infrared quantum cascade laser. The improvement includes a strained InxGa1-xAs/AlyIn1-yAs composition, with x and y each between 0.53 and 1, an active region emitting at a wavelength equal to or greater than 8 ?m, an energy spacing E54 equal to or greater than 50 meV, an energy spacing EC4 equal to or greater than 250 meV, and an optical waveguide with a cladding layer on each side of the active region. Each cladding layer has a doping level of about 2·1016 cm?3. The optical waveguide also has a top InP layer with a doping level of about 5·1016 cm?3 and a bottom InP layer with a doping level of about 5?1016 cm?3. Additionally, the optical waveguide has a plasmon layer with a doping level of about 8·1018 cm?3.

Abstract: A method of providing an out-of-plane semiconductor structure and a structure fabricated thereby is disclosed. The method comprises acts of: providing a substrate defining a major surface; providing a template layer having a predetermined template thickness on the major surface of the substrate; forming a recess in the template layer having a recess pattern and a recess depth smaller than the template thickness; and epitaxially growing a semiconductor structure from the recess. A planar shape of the recess pattern formed in the template layer substantially dictates an extending direction of the semiconductor structure.

Abstract: To improve performance of a semiconductor device. For example, on the assumption that a superlattice layer is inserted between a buffer layer and a channel layer, a concentration of acceptors introduced into nitride semiconductor layers forming a part of the superlattice layer is higher than a concentration of acceptors introduced into nitride semiconductor layers forming the other part of the superlattice layer. That is, the concentration of acceptors introduced into the nitride semiconductor layers having a small band gap is higher than the concentration of acceptors introduced into the nitride semiconductor layers having a large band gap.

Abstract: The present invention describes a self mode locking laser and a method for self mode locking a laser. The laser (1) comprises a resonator terminated by first (3) and second (4) mirrors and folded by a third mirror (5). The third mirror comprises a single distributed Bragg reflector (17) upon which is mounted a multilayer semiconductor gain medium (18) and which includes at least one quantum well layer and an optical Kerr lensing layer (22). Self mode locking may be achieved by configuring the laser resonator such that the lensing effect of the Kerr lensing layer acts to reduce an astigmatism deliberately introduced to the cavity mode. The self mode locking of the laser may be further enhanced by selecting the length of the resonator such that a round trip time of a cavity mode is matched with an upper-state lifetime of one or more semiconductor carriers located within the gain medium.

Abstract: Embodiments relate to a semiconductor laser having a multilayer structure including a ridge and two material removal areas adjacent to the ridge on either side, the multilayer structure being arranged on a substrate and a layer expansion plane being defined by a surface of the substrate, the ridge having at least one active region and at least the active region being spatially limited by passages between the ridge and the material removal areas in one dimension of the layer expansion plane, the active region having a layer structure for forming an interband cascade laser.

Abstract: A quantum cascade laser includes a semiconductor region having a main surface including first and second regions arranged in a first axis direction; a stacked semiconductor layer disposed on the second region, the stacked semiconductor layer including a core layer and an upper cladding layer disposed on the core layer; and a distributed Bragg reflector disposed on the first region, the distributed Bragg reflector including at least one semiconductor wall having a side surface extending in a second axis direction perpendicular to the main surface of the semiconductor region, the semiconductor wall including the core layer and the upper cladding layer. The side surface of the semiconductor wall is optically coupled to an end facet of the stacked semiconductor layer. The side surface of the semiconductor wall includes a side surface of the core layer having a recess portion depressed from a side surface of the upper cladding layer in the semiconductor wall.

Abstract: The optoelectronic arrangement comprises a semiconductor nanowire intended to participate in the processing, notably in a reception and/or an emission, of a light concerned and a mirror reflecting the light concerned. The semiconductor nanowire comprises a first section and a second section, and the mirror surrounds, at least longitudinally, the first section of the semiconductor nanowire, said second section extending out of the mirror.

Abstract: Disclosed is a semiconductor light emitting device. The semiconductor light emitting device includes a light emitting structure having a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first and second conductive semiconductor layers. The active layer includes a plurality of well layers and barrier layers. An outermost barrier layer of the barrier layers includes a plurality of first layers; and a plurality of second layers.

Abstract: A semiconductor light emitting element includes an n-type light guide layer containing a group III nitride semiconductor, an active layer, and a p-type light guide layer, in which the n-type light guide layer includes a semiconductor superlattice layer which is a stack of superlattice layers, the semiconductor superlattice layer having a structure in which group III nitride semiconductors A and group III nitride semiconductors B are alternately stacked, each of the semiconductors A and each of the semiconductors B being stacked in each of the superlattice layers, a relationship Eg (A)>Eg (B) holds, the semiconductor A is a film containing AlInN, and the film contains oxygen (O) at a concentration of at least 1×1018 cm?3, the semiconductor A has a film thickness of at most 5 nm, and a current is injected in a stacking direction of the superlattice layers.

Abstract: The invention provides a laser converter for converting a laser radiation of shorter wavelength to a laser radiation of longer wavelength using a single stage conversion. The laser converter comprises a laser diode for emitting a laser radiation in a first wavelength range, a cylindrical microlens for transferring and focusing the laser radiation to a laser chip and the laser chip for absorbing the laser radiation and emitting the laser radiation in a second wavelength range.

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 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: A hybrid external cavity laser and a method for configuring the laser having a stabilized wavelength is disclosed. The laser comprises a semiconductor gain section and a volume Bragg grating, wherein a laser emission from the semiconductor gain section is based on a combination of a reflectivity of a front facet of the semiconductor gain section and a reflectivity of the volume Bragg grating and the reflectivity of the semiconductor gain section and the volume Bragg grating are insufficient by themselves to support the laser emission. The hybrid cavity laser further comprises an etalon that provides further wavelength stability.

Abstract: A quantum cascade laser and method of making are disclosed. The quantum cascade laser includes a plurality stages configured in a cascade structure, each stage having a quantum well emission layer and an injection layer, each stage having an upper laser level and a lower laser level. A scattering barrier is located in the quantum well emission layer, the scattering barrier being positioned such that interface roughness (IFR) scattering at the lower laser level is greater than IFR scattering at the upper laser level. The scattering barrier may be located to maximize IFR scattering for the lower laser level and/or minimize IFR scattering for the upper laser level.

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: To raise the upper limit of the temperature range in which a quantum cascade laser (QCL) element for THz range operates at a single frequency. In a quantum cascade laser element in one embodiment of the present invention, each unit structure 10U in the active region 10 is provided with the first to fourth well layers 10W1-10W4 that are stacked in this order and separated from one another by at least one barrier layer 10B. During application of a first bias electric field for lasing, the structure of electronic energy levels has a reception, upper lasing, lower lasing, and depopulation levels and emits electromagnetic waves at a first frequency. During application of a second bias electric field that is weaker than the first bias electric field, the overlap integral is 0.15 or less between electronic wavefunctions for the unnecessary upper lasing and unnecessary lower lasing levels, thereby stimulated emissions of electromagnetic waves are suppressed at frequencies other than the first frequency.

Abstract: A multicolor photonic crystal laser array comprises pixels of monolithically grown gain sections each with a different emission center 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 center wavelength) that was determined purely by the photonic crystal geometry. This approach can be extended to cover the entire visible spectrum.

Abstract: In one aspect, semiconductor lasers are provided. A semiconductor laser described herein comprises substrate and a cavity formed on the substrate, the cavity comprising an asymmetric Mach-Zehnder (AMZ) interferometer structure positioned between two straight waveguide segments, the straight waveguide segments and first and second arms of the AMZ interferometer structure comprising epitaxial semiconductor layers, wherein the second arm of the AMZ interferometer structure has a temperature control architecture independent of the first arm.

Abstract: Provided are a quantum dot laser diode and a method of manufacturing the same. The method of manufacturing a quantum dot laser diode includes the steps of: forming a grating structure layer including a plurality of gratings on a substrate; forming a first lattice-matched layer on the grating structure layer; forming at least one quantum dot layer having at least one quantum dot on the first lattice-matched layer; forming a second lattice-matched layer on the quantum dot layer; forming a cladding layer on the second lattice-matched layer; and forming an ohmic contact layer on the cladding layer. Consequently, it is possible to obtain high gain at a desired wavelength without affecting the uniformity of quantum dots, so that the characteristics of a laser diode can be improved.

Abstract: To raise the upper limit of the temperature range in which a quantum cascade laser (QCL) element for THz range operates at a single frequency. In a quantum cascade laser element in one embodiment of the present invention, each unit structure 10U in the active region 10 is provided with the first to fourth well layers 10W1-10W4 that are stacked in this order and separated from one another by at least one bather layer 10B. During application of a first bias electric field for lasing, the structure of electronic energy levels has a reception, upper lasing, lower lasing, and depopulation levels and emits electromagnetic waves at a first frequency. During application of a second bias electric field that is weaker than the first bias electric field, the overlap integral is 0.15 or less between electronic wavefunctions for the unnecessary upper lasing and unnecessary lower lasing levels, thereby stimulated emissions of electromagnetic waves are suppressed at frequencies other than the first frequency.

Abstract: An ultrashort pulse and ultrahigh power laser diode device capable of outputting pulse laser light having higher peak power with a simple composition and a simple structure is provided. The laser diode device includes: a laminated structure composed of a first compound semiconductor layer containing n-type impurity, an active layer having a quantum well structure, and a second compound semiconductor layer containing p-type impurity; a first electrode electrically connected to the first compound semiconductor layer; and a second electrode electrically connected to the second compound semiconductor layer, wherein the second compound semiconductor layer is provided with an electron barrier layer having a thickness of 1.5*10?8 m or more, and driving is made by a pulse current having a value 10 or more times as large as a threshold current value.

Abstract: An optoelectronic semiconductor chip, based on a nitride material system, comprising at least one active quantum well, wherein during operation electromagnetic radiation is generated in the active quantum well, the active quantum well comprises N successive zones in a direction parallel to a growth direction z of the semiconductor chip, N being a natural number greater than or equal to 2, the zones are numbered consecutively in a direction parallel to the growth direction z, at least two of the zones have average aluminium contents k which differ from one another, and the active quantum well fulfils the condition: 50??(35?k(z))dz?2.5N?1.5?dz?120.