Abstract: The present invention provides quantum cascade lasers and amplifier that operate in a frequency range of about 1 Terahertz to about 10 Terahertz. In one aspect, a quantum cascade laser of the invention includes a semiconductor heterostructure that provides a plurality of lasing modules connected in series. Each lasing module includes a plurality of quantum well structure that collectively generate at least an upper lasing state, a lower lasing state, and a relaxation state such that the upper and the lower lasing states are separated by an energy corresponding to an optical frequency in a range of about 1 to about 10 Terahertz. The lower lasing state is selectively depopulated via resonant LO-phonon scattering of electrons into the relaxation state.

Abstract: A nitride semiconductor laser device has a group III nitride semiconductor multilayer structure. The group III nitride semiconductor multilayer structure includes an n-type semiconductor layer, a p-type semiconductor layer and a light emitting layer held between the n-type semiconductor layer and the p-type semiconductor layer, and the p-type semiconductor layer is formed by successively stacking a p-side guide layer, a p-type electron blocking layer in contact with the p-side guide layer and a p-type cladding layer in contact with the p-type electron blocking layer from the side closer to the light emitting layer. The p-side guide layer is formed by stacking a layer made of a group III nitride semiconductor containing Al and a layer made of a group III nitride semiconductor containing no Al.

Abstract: A semiconductor laser device that can be operated at high power and that has a structure which can suppress kink, reduce loss and stabilize the direction of polarization simultaneously, and in which an optical pattern decreases monotonously as receding from an active layer and the crystal composition can be easily controlled. A plurality of layers of high refractive index different in the composition from that of the cladding layer are introduced being dispersed over a range wider than the spot size for directing light closer to the lower cladding layer of the semiconductor laser and stabilizing the direction of polarization. The electric field intensity is decreased monotonously as receding from the active layer for the optical pattern.

Abstract: A semiconductor optical amplification device is disclosed that has a gain spectrum of a wide bandwidth. The semiconductor optical amplification device includes an InP substrate and an active layer on the InP substrate. The active layer has a quantum well structure formed by alternately stacking a barrier layer and a well layer, the barrier layer is formed from a tensile-strained InGaAs film, and the well layer is formed from a compressively-strained InGaAs film.

Abstract: A semiconductor laser (101) includes a first cladding layer (103), an active layer (105) and a second cladding layer (108). A window region (115) including fluorine, that is, an impurity element with higher electronegativity than nitrogen, is formed in the vicinity of a front end face (113) and a rear end face (114) of a laser resonator. The window region (115) is formed by exposing the front end face (113) and the rear end face (114) to carbon fluoride (CF4) plasma. The effective band gap of a portion of the active layer (105) disposed in the window region (115) is larger than the effective band gap of another portion of the active layer, and hence, it functions as an end face window structure for suppressing COD.

Abstract: A high-power surface emitting laser capable of recycling electrons and holes by inserting a tunnel junction between quantum wells is provided. The laser includes an active layer with a plurality of quantum wells and a plurality of barriers alternately sandwiched between the plurality of quantum wells wherein a tunnel junction is inserted into the barrier between the quantum wells.

Abstract: A semiconductor light-emitting transistor device, including: a bipolar pnp transistor structure having a p-type collector, an n-type base, and a p-type emitter; a first tunnel junction coupled with the collector, and a second tunnel junction coupled with the emitter; and a collector contact coupled with the first tunnel junction, an emitter contact coupled with the second tunnel junction, and a base contact coupled with the base; whereby, signals applied with respect to the collector, base, and emitter contacts causes light emission from the base by radiative recombination in the base.

Abstract: An n-type cladding layer structure which has good luminescence properties without the use of substances corresponding to RoHS Directive and a high Cl-doping efficiency, i.e. which facilitates the manufacture of a semiconductor optical element and device with low crystal defects and high reliability, and an active layer and a p-type cladding layer therefor are provided. The n-type layer being lattice matched to an InP substrate and containing Group II-VI compound as a main ingredient is a Group II-VI compound semiconductor, in which the Group II elements consist of Mg, Zn, and Be and the Group VI elements consist of Se and Te. The n-type layer of the present invention is characterized by a large energy gap, high energy of the bottom of a conduction band that is effective for suppress the Type II luminescence, high carrier concentration, and low crystal defects attributed to a good quality crystallinity.

Abstract: A DFB quantum cascade laser element that can reliably CW-oscillate a single-mode light even at room temperature or a temperature in proximity thereof is provided. In a quantum cascade laser element 1, a top-grating approach for which a diffraction grating 7 is formed on a laminate 3 is adopted, and thus in comparison with a buried-grating approach, deterioration in temperature characteristics of the laser element and decline in the yield and reproducibility are suppressed. In addition, since the thickness of a cladding layer 5 located between an active layer 4 and the diffraction grating 7 is within a range of 42±10% of the oscillation wavelength, weakening of light seeping from the active layer 4 to the diffraction grating 7 or an increase in light leakage is prevented. Consequently, by the quantum cascade laser element 1, a single-mode light can be reliably CW-oscillated even at room temperature or a temperature in proximity thereof.

Abstract: On a GaAs substrate (1), are formed a DBR (Distributed Bragg Reflector) (3), and a light-emitting layer (5) made of a plurality of layers of AlyGazIn1-y-zP (0?y?1, 0?z?1) above the DBR (3). A semiconductor layer or a plurality of semiconductor layers (6)-(10) having a number of layers of 1 or more are formed on the light-emitting layer (5), and a grating pattern for scattering light is formed on a surface of the semiconductor layer (9) by photolithography and by etching with a sulfuric acid/hydrogen peroxide based etchant. Thus, a semiconductor device small in radiation angle dependence of light emission wavelength, as well as a manufacturing method therefor, are provided.

Abstract: An indirect semiconductor laser having an indirect semiconductor used as the material of an active layer is used, instead of a conventional direct semiconductor laser so as to obtain a reproducing optical source, in order to reduce optical interference noise of the laser caused in the optical head in an optical disc apparatus, and to eliminate the necessity of high frequency wave convolution, thereby it is possible to reduce the cost.

Abstract: A quantum cascade laser structure in accordance with the invention comprises a number of cascades (100), each of which comprises a number of alternately arranged quantum wells (110a to 110j) and barrier layers (105 to 105j). The material of at least one quantum well (110a to 110j) as well as the material of at least one barrier layer (105 to 105j) is under mechanical strain, with the respective strain being either a tensile strain or a compression strain. The quantum wells (110a to 110j) and barrier layers (105 to 105j) are engineered in the quantum cascade laser structure in accordance with the invention so that existing strains are largely compensated within a cascade (100). In the quantum cascade laser structure in accordance with the invention, each material of the quantum wells (110a to 110j) has only one constituent material and the material of at least one barrier layer (105d, 105e, 105f) has at least two constituent materials (111a, 111b, 112a, 112b, 113a, 113b).

Abstract: Semiconductor lasers, such as VCSELs having active regions with flattening layers associated with nitrogen-containing quantum wells are disclosed. MEE (Migration Enhanced Epitaxy) is used to form a flattening layer upon which a quantum well is formed and thereby enhance smoothness of quantum well interfaces and to achieve narrowing of the spectrum of light emitted from nitrogen containing quantum wells. A cap layer is also formed over the quantum well.

Abstract: An intersubband quantum cascade laser structure includes multiple coupled laser stages, wherein each stage has a multilayer structure including an electron injector, an active region with at least one quantum well, and an electron reflector. Electrons injected from the injector into the active region at a high energy level relax to a lower energy level with the emission of a photon at, for example, mid-infrared wavelengths. The reflector reflects electrons at the higher energy level at which they were injected and transmits electrons from the lower energy level after emission of a photon. Multiple layers of semiconductor are formed on each side of the multistage structure to provide conduction across the device and to provide optical confinement of the photons emitted.

Abstract: A semiconductor light emitting device including an active layer interposed between an n-type cladding layer and a p-type cladding layer employs an AlxGa1-xN (AlGaN) layer having an Al composition ratio x satisfying 0.01?x<0.06 as the n-type cladding layer. As the Al composition ratio x decreases below 0.06, the AlGaN layer increases in refractive index. Thus, the near field pattern (NFP) in the vertical direction can spread out, and full width at half maximum of FFP in the vertical direction can be minimized. Further, since lattice mismatch with a GaN substrate is reduced with decreasing Al composition ratio, the AlGaN layer can be thick without causing cracks or dislocations, and spreading of light into the GaN substrate can be minimized.

Abstract: A highly portable, high-powered infrared laser source is produced by intermittent operation of a quantum cascade laser power regulated to a predetermined operating range that permits passive cooling. The regulation process may boost battery voltage allowing the use of more compact, low-voltage batteries.

Abstract: A semiconductor laser diode capable of improving reliability and mass-productivity is disclosed. The semiconductor laser diode comprises a first clad layer; a first optical guide layer disposed on the first clad layer; an active layer disposed on the first optical guide layer; a second optical guide layer disposed on the active layer; and a second clad layer disposed on the second optical guide layer, having a greater band gap energy than the second optical guide layer, the band gap energy decreasing as being farther from the second optical guide layer.

Abstract: A semiconductor device having high reliability, a long lifetime and superior light emitting characteristics by applying a novel material to a p-type cladding layer is provided. A semiconductor device includes a p-type semiconductor layer on an InP substrate, in which the p-type semiconductor layer has a laminate structure formed by alternately laminating a first semiconductor layer mainly including Bex1Mgx2Znx3Te (0<x1<1, 0<x2<1, 0<x3<1, x1+x2+x3=1) and a second semiconductor layer mainly including Bex4Mgx5Znx6Te (0<x4<1, 0<x5<1, 0<x6<1, x4+x5+x6=1).

Abstract: An object of the invention is to achieve a high output gain waveguide semiconductor laser device exhibiting high reliability by suppressing growth of <100>DLD. A semiconductor laser device includes a semiconductor laser structure of a gain waveguide formed on a semiconductor substrate in which two grooves extending in an oscillation direction thereof are formed, wherein a current injection stripe is arranged between the two grooves. Preferably, a quantum well constituting an active layer of the semiconductor laser device is composed of GaAs.

Abstract: The present invention relates to the field of distributed feedback semiconductor lasers. More specifically, the invention makes it possible to develop single-mode distributed feedback lasers with a production rate close to 100% using a simple and robust technology. To this end, the invention involves introducing radiative losses on just one of the two predominant modes of a DFB laser obtained by index modulation by defining a particular refractive index profile of the active area.

Abstract: A quantum cascade source, such as a QC laser, is provided comprising a plurality of repeat units each including an active region and an injector region. The active region includes at least two quantum wells that, in response to an applied electrical bias, provide a first, second, and third electron energy level, each resulting from a respective quantum well excited state. The first and second energy levels are configured so that an electron transition from the first energy level to the second energy level emits a photon of a selected wavelength. The second and third energy levels are configured so that an electron transition from the second energy level to the third energy level comprises a nonradiative transition to empty the second energy level sufficiently quickly to promote a population inversion between the first and second energy levels.

Abstract: A semiconductor light-emitting element includes a nitride-based Group III-V compound semiconductor, wherein the semiconductor light-emitting element has a structure in which an active layer including one or a plurality of well layers is sandwiched between a p-side cladding layer and an n-side cladding layer, and the composition of at least one of the well layers of the active layer is modulated in the direction perpendicular to the thickness direction of the least one of the well layers.

Abstract: A bipolar quantum cascade (QC) laser includes a p-n junction disposed adjacent to an active/injection region of semiconductor layers. Systems that make use of such QC lasers and methods for manufacturing such QC lasers are also described.

Abstract: A semiconductor laser device includes an active layer, a pair of guiding layers sandwiching the active layer, and a pair of cladding layers sandwiching the active layer and the pair of guiding layers. The pair of guiding layers are InGaAsP lattice-matched to GaAs. The pair of cladding layers are AlGaAs. The Al composition ratios of the pair of AlGaAs cladding layers are 0.4 or less. The Al composition ratios are set such that the refractive indices of the pair of AlGas cladding layers do not exceed those of the pair of InGaAsP guiding layers.

Abstract: A method and structure for producing lasers having good optical wavefront characteristics, such as are needed for optical storage includes providing a laser wherein an output beam emerging from the laser front facet is essentially unobstructed by the edges of the semiconductor chip in order to prevent detrimental beam distortions. The semiconductor laser structure is epitaxially grown on a substrate with at least a lower cladding layer, an active layer, an upper cladding layer, and a contact layer. Dry etching through a lithographically defined mask produces a laser mesa of length lc and width bm. Another sequence of lithography and etching is used to form a ridge structure with width w on top of the mesa. The etching step also forming mirrors, or facets, on the ends of the laser waveguide structures. The length ls and width bs of the chip can be selected as convenient values equal to or longer than the waveguide length lc and mesa width bm, respectively.

Abstract: A device includes a multiple quantum well with potential barriers and quantum wells, and an electric field element for applying an electric field thereto. The multiple quantum well includes at least two regions A and a region B disposed therebetween. The region A includes a plurality of energy levels, and a carrier is transported from a specific energy level i to a specific energy level f in the region A through one of the potential barriers by photon-assisted tunneling. The region B includes a plurality of energy levels, and an energy relaxation is performed with a relaxation time shorter than a transit time of the carrier in the region A from a specific energy level e to a specific energy level g in the region B. When an electric field is applied, electric current flows through the multiple quantum well and light is emitted or absorbed in the region A.

Abstract: Methods for producing surface-emitting semi-conductor lasers with tunable waveguiding are disclosed. The laser comprises an active zone containing a pn-transition, surrounded by a first n-doped semiconductor layer and at least one p-doped semiconductor layer. In addition to a tunnel junction on the p-side of the active zone, the tunnel junction borders a second n-doped semi-conductor layer with the exception of an area forming an aperture. An n-doped layer is provided between the layer provided for the tunnel junction and the at least one p-doped semiconductor layer. The tunnel junction may be arranged in a maximum or minimum of the vertical intensity distribution of the electric field strength. This enables surface-emitting laser diodes to be produced in high yields with stabilization of the lateral single-mode operation, high performance and wave guiding properties.

Abstract: An interband self-mode-locked (SML) semiconductor laser utilizes an active waveguide structure that includes an active waveguide section and one or more passive waveguide sections that together enhances self-mode-locking. The SML laser operation is based on enhanced Kerr lens mode-locking by vertically optically combining the active section with one or more passive waveguide sections.

Abstract: A semiconductor laser diode comprises a p-n junction. The p-n junction comprises a substrate, an n-type semiconductor layer, a p-type semiconductor layer, and a quantum well. The quantum well is disposed between the n-type semiconductor layer and the p-type semiconductor layer. The substrate is formed from a first material system, the n-type semiconductor layer is formed from a second material system, the p-type semiconductor layer is formed from a third material system, and the quantum well is formed from a fourth material system. The second material system is different from the third material system. The second material system and the third material system are selected such that there is an increase in the rate of recombinations of the electrons from the n-type semiconductor layer and the holes from the p-type semiconductor layer in the quantum well. This results in a lower turn-on voltage for the semiconductor laser diode.

Abstract: A quantum cascade laser 1, which generates infrared light or other light of a predetermined wavelength by making use of intersubband transitions in a quantum well structure, is arranged by forming, on a GaAs substrate 10, an AlGaAs/GaAs active layer 11 having a cascade structure in which quantum well light emitting layers and injection layers are laminated alternately. Also, at the GaAs substrate 10 side and the side opposite the GaAs substrate 10 side of active layer 11, is provided a waveguide structure, comprising waveguide core layers 12 and 14, each being formed of an n-type GaInNAs layer, which is a group III-V compound semiconductor that contains N (nitrogen), formed so as to be lattice matched with the GaAs substrate 10, and waveguide clad layers 13 and 15, each formed of an n++-type GaAs layer. A quantum cascade laser, with which the waveguide loss of generated light in the laser is reduced, is thereby realized.

Abstract: A quantum cascade laser 1, which generates infrared light or other light of a predetermined wavelength by making use of intersubband transitions in a quantum well structure, is arranged by forming, on a GaAs substrate 10, an AlGaAs/GaAs active layer 11 having a cascade structure in which quantum well light emitting layers and injection layers are laminated alternately. Also, at the GaAs substrate 10 side and the side opposite the GaAs substrate 10 side of active layer 11, is provided a waveguide structure, comprising waveguide core layers 12 and 14, each being formed of an n-type GaInNAs layer, which is a group III-V compound semiconductor that contains N (nitrogen), formed so as to be lattice matched with the GaAs substrate 10, and waveguide clad layers 13 and 15, each formed of an n++-type GaAs layer. A quantum cascade laser, with which the waveguide loss of generated light in the laser is reduced, is thereby realized.

Abstract: A nitride-based semiconductor laser device, includes: a first cladding layer of a first conductivity type; an active layer formed above the first cladding layer; an overflow-preventing layer of a second conductivity type formed on the active layer; and a second cladding layer of the second conductivity type formed above the overflow-preventing layer. The active layer includes three barrier layers and two well layers so that each well layer can be inserted between the corresponding ones of the three barrier layers and two of the three barrier layers are located on the outer sides of both well layers, thereby constituting a double-layered quantum well layer. The thickness of each well layer is set within a range of 2 to 5 nm.

Abstract: A surface emitting semiconductor laser diode of a tunnel junction type includes a semiconductor substrate, a first reflector, a second reflector, an active region disposed in series between the first and second reflectors, and a tunnel junction region disposed in series between the first and second reflectors. The tunnel junction region includes a first semiconductor layer of a first conductive type and a second semiconductor layer of a second conductive type that forms a junction with the first semiconductor layer, the first semiconductor layer being composed of a supper-lattice layer that at least partially includes aluminum and is partially oxidized.

Abstract: The present invention provides a semiconductor laser excellent in the current injection efficiency. In an inner stripe type semiconductor laser according to the present invention, a p type cladding layer 309 has a superlattice structure composed of GaN layers and Al0.1Ga0.9N layers, which are alternately layered on each other. The p type cladding layer 309 has a portion of high dislocation density and a portion of low dislocation density. That is, the dislocation density is relatively low in a region directly above an opening of the current-confining region 308, whereas the dislocation density is relatively high in a region directly above a current-confining region 308.

Abstract: A nitride semiconductor laser element comprises a nitride semiconductor substrate and a nitride semiconductor layer laminated thereon, wherein the nitride semiconductor substrate has a high dislocation density region and a low dislocation density region containing lower dislocation than that of the high dislocation density region, and has at least one recess formed in at least the high dislocation density region, the nitride semiconductor layer has a first nitride semiconductor layer in which the grown film thickness in the lateral direction from the side faces of the recess in the substrate is greater than the grown film thickness in the heightwise direction from a region other than the recess, and a second nitride semiconductor layer that is disposed on the first nitride semiconductor layer and contains indium, and the first nitride semiconductor layer and second nitride semiconductor layer have recess over the recess in the nitride semiconductor substrate.

Abstract: A semiconductor laser device comprising: a first cladding layer of a first conductivity type; an active layer provided on the first cladding layer and having a quantum well structure; an overflow blocking layer of a second conductivity type provided on the overflow blocking layer. The active layer includes a region having an impurity concentration is 3×1017 cm?3 or more and having a thickness of 30 nm or less between the overflow blocking layer and a well layer in the active layer closet to the overflow blocking layer.

Abstract: The semiconductor layer structure comprises a superlattice (9) composed of alternately stacked layers (9a, 9b) of III-V semiconductor compounds of a first composition (a) and at least one second composition (b). The layers (9a, 9b) of the superlattice (9) contain dopants in predetermined concentrations, with regard to which the concentrations of the dopants are different at least two layers of a same composition in the superlattice (9), the concentration of the dopants is graded within at least one layer (9a, 9b) of the superlattice (9), and the superlattice (9) comprises layers that are doped with different dopants or comprise at least one layer (9a, 9b) that is undoped. The electrical and optical properties of the superlattice (9) can be adapted to given requirements in the best possible manner in this way.

Abstract: The invention relates to an optically pumped multilayered modulator having surface-normal geometry. The multilayer structure comprises an absorber section through which an optical signal (401) to be modulated is coupled from an input (401) to an output (400). The multilayer structure further comprises control means for supplying a control signal for controlling the transmission characteristics of the absorber section. The control signal is generated by an in-plane waveguide-type laser integrated monolithically with the saturable absorption region. The in-plane control laser includes waveguide regions (405) and multiple-quantum-well layers (409) used as a gain medium. The laser beam is adapted to travel through the absorber section in order to modulate the transmission characteristics of the absorber section.

Abstract: The invention provides a light-emitting device, where the active region thereof may be escaped from being damaged by the plasma process. The device is first formed with a semiconductor layer on the semiconductor substrate, next provided with an etching mask. Using the mask, the semiconductor layer on the substrate is dry-etched to form a periodic structure with grooves and mesas. The active regions are buried within the grooves by the OMVPE method.

Abstract: A method for converting a Type 2 quantum well semiconductor material to a Type 1 material. A second layer of undoped material is placed between first and third layers of selectively doped material, which are separated from the second layer by undoped layers having small widths. Doping profiles are chosen so that a first electrical potential increment across a first layer-second layer interface is equal to a first selected value and/or a second electrical potential increment across a second layer-third layer interface is equal to a second selected value. The semiconductor structure thus produced is useful as a laser material and as an incident light detector material in various wavelength regions, such as a mid-infrared region.

Abstract: A mid-infrared emitting indirect bandgap quantum well semiconductor laser with an optical waveguide structure having an active waveguide core. The active waveguide core comprises at least one repetition of a sub-region comprising in the following order a first wide bandgap layer, a first conduction band layer of InAs, a valence band layer of Ga(1-x)InxSb where x?0.7, preferably of InSB (ie. x=1), having a thickness of less than 15 Angstroms, a second conduction band layer of InAs and a second wide bandgap barrier layer. The barrier layers co-operate to provide electrical confinement for the carriers within the intervening conduction band and valence band layers and optical confinement in the active core region is provided by the optical waveguide structure.

Abstract: In an element wherein a plurality of ridges (16, 36) are arranged in parallel, supports (17, 37) are formed to sandwich each of the ridges (16, 36). More specifically, on an outer side of the ridge (16) in the element, the first support (17a) is formed, and on an inner side in the element, the second support (17b) is formed. On an outer side of the ridge (36) in the element, the first support (37a) is formed, and on an inner side in the element, the second support (37b) is formed. Thus, even when a resist is applied on an element surface and spin-coating is performed at the time of manufacturing the element, the resist on the inner side than the ridges (16, 36) in the element can be prevented from flowing into a groove between the ridges to a certain extent by means of the second supports (17b, 37b), and a resist film thickness on the inner sides of the ridges (16, 36) in the element can be prevented from being considerably small compared with that on the outer sides in the element.

Abstract: A semiconductor optical device has a semiconductor substrate, and an active layer which is formed above the semiconductor substrate, the active layer having a plurality of quantum wells formed from a plurality of barrier layers and a plurality of well layers sandwiched among the plurality of barrier layers. At least one well layer of the plurality of well layers is formed from an InxaGa(1-xa)As film, and a composition ratio xa of the In takes any one value within a range from approximately 0.05 to approximately 0.20. Accordingly, the semiconductor optical device is formed as a strained well layer in which lattice distortion bought about in the well layer takes any one value within a range from approximately 0.35% to approximately 1.5%, and the strained well layer is formed so as to have a bandgap wavelength different from those of the other well layers.

Abstract: An active layer is formed by arranging a plurality of quantum-well layers and a plurality of barrier layers alternatively. An amount of band discontinuity in a conduction band between a barrier layer that is sandwiched by the quantum-well layers and adjacent quantum-well layers is equal to or more than 26 meV and less than 300 meV, so that an overflow of injected carriers due to a thermal excitation between the quantum-well layers is intentionally caused to make the carrier density uniform between the quantum-well layers.

Abstract: A waveguide PIN photodiode is provided. The waveguide PIN photodiode includes a lower light guide layer, a light absorption layer, an upper light guide layer, and a cladding layer. The lower light guide is formed on a substrate, and the light absorption layer is formed on the lower light guide layer. The upper light guide layer is formed on the light absorption layer, and the cladding layer is formed on the upper light guide layer. The lower light guide layer, the light absorption layer, and the upper light guide layer constitute a core layer, which is an optical waveguide, and graded index distribution is symmetrically formed in a depth direction, centering around the light absorption layer having a highest refractive index.

Abstract: An interband self-mode-locked (SML) semiconductor laser utilizes an active waveguide structure that includes an active waveguide section and one or more passive waveguide sections that together enhances self-mode-locking. The SML laser operation is based on enhanced Kerr lens mode-locking by vertically optically combining the active section with one or more passive waveguide sections.

Abstract: The invention provides a semiconductor unit and a semiconductor apparatus having a low electric resistance as a whole, even when the electric resistance of a functional layer or a semiconductor substrate is high. A method of making the semiconductor unit and apparatus is also provided. An electrooptic apparatus and an electronic apparatus are also provided. A semiconductor apparatus includes a predetermined substrate and a semiconductor unit bonded to the substrate. The semiconductor unit includes a highly conductive layer and a functional layer including a semiconductor element.

Abstract: A high power laser system including: a plurality of emitters each including a large area waveguide and a plurality of quantum well regions optically coupled to the large area waveguide, wherein each of the quantum well regions exhibits a low modal overlap with the large area waveguide; a collimator optically coupled to the emitters; a diffraction grating optically coupled through the collimator to the emitters; and, an output coupler optically coupled through the diffraction grating to the emitters.

Abstract: An optical modulator comprises a first waveguide layer and a barrier layer, and a quantum well layer sandwiched between the first waveguide layer and the barrier layer, where the quantum well layer has a graded composition that varies the bandgap energy of the quantum well layer between a minimum bandgap energy and the bandgap energy of at least one of the first waveguide layer and the barrier layer.

Abstract: A cavity is formed by a lower multilayer mirror and an upper multilayer mirror and an active layer is arranged between the lower multilayer mirror and the upper multilayer mirror in a surface-emitting laser element. A relaxation oscillation frequency at a bias point in the cavity is set to exceed an optical communication frequency for modulating a laser light output from the surface-emitting laser element.