Abstract: A vertical cavity surface emitting laser (VCSEL) device includes a pair of diffusion Bragg reflectors (DBRs) sandwiching therebetween a multiple quantum well (MQW) comprising active layers. The bottom DBR includes a lower layer structure having AlAs layers having a higher thermal conductivity and AlGaAs layers in pair and an upper layer structure acting anti-oxidation layers and having a pair of AlGaAs layers having different Al contents. A selectively oxidized AlAs layer disposed as the top layer of the bottom DBR comprises an Al-oxidized area and a non-oxidized layer for confinement of current injection path.

Abstract: A semiconductor device including a substrate, a mesa post overlying the substrate and having a substantially cylindrical shape, a resin member surrounding the mesa post and a stress moderating member received in the mesa post for moderating stress between the mesa post and the resin member. The stress applied to the mesa post is reduced because the entire volume of the resin member is divided by the stress moderating member and each of the divided resin members reduces the stress.

Abstract: A vertical cavity surface emitting semiconductor laser (VCSEL) device has p-type and n-type DBRs sandwiching therebetween a resonant cavity including an active layer. Each the DBRs has a plurality of layer pairs each including a Alx1Ga1-x1As high-reflectivity layer and an Alx2Ga1-x2As low-reflectivity layer and an Alx3Ga1-x3As slope content layer interposed between each of the high-reflectivity layers and adjacent low-reflectivity layer. The slope content layers in the vicinity of the active layer has an Al content x3 wherein 0<x3≦0.3 and 0.55≦x3<1 and an impurity concentration of 3×1017 cm−3 or above.

Abstract: A surface emitting semiconductor laser device of oxidized-Al current confinement structure has a resonant wavelength of a fundamental transverse mode, which is set shorter than or equal to a peak-gain wavelength of the laser device at a specified temperature. The surface emitting semiconductor laser device emits in a single-transverse mode.

Abstract: There is provided a surface emitting laser device of fundamental lateral mode oscillation that suppresses a resistor increase and that is favorable in reliability. A GaAs layer 16 having such a thickness as to exhibit a high reflection factor with respect to oscillation wavelength is formed on an upper DBR mirror. In addition, a groove having such a depth that the GaAs layer located directly under it has such a thickness as to exhibit a low reflection factor with respect to oscillation wavelength is formed on the GaAs layer in such a position as to stride an extension line of a boundary between an Al oxide layer and an AlAs layer. As a result, laser oscillation can be conducted only in a post region surrounded by the groove.

Abstract: A method for fabricating a surface-emission semiconductor laser on a p-type substrate includes the step of interposing an Au film between an AuGeNi film or AuGe film of an n-side electrode and a compound semiconductor layer of an n-type DBR, followed by annealing to form an Au alloy in the n-side electrode. The presence of the Au alloy film improves the adherence between the n-side electrode and the compound semiconductor layer to improve an injection current vs. applied voltage characteristic.

Abstract: A semiconductor device including a substrate, a mesa post overlying the substrate and having a substantially cylindrical shape, a resin member surrounding the mesa post and a stress moderating member received in the mesa post for moderating stress between the mesa post and the resin member. The stress applied to the mesa post is reduced because the entire volume of the resin member is divided by the stress moderating member and each of the divided resin members reduces the stress.

Abstract: A surface emitting semiconductor laser device including a substrate, a bottom DBR, and a mesa post having a layer structure, the layer structure including a top DBR including a plurality of pairs, each of said pairs including an Al-containing high-reflectivity layer and an Al-containing low-reflectivity layer, an active layer structure sandwiched between the DBRs for emitting laser, and a current confinement layer disposed within or in a vicinity of one of the DBRs, the current confinement layer including a central current injection area and an annular current blocking area encircling the central current injection area, the annular current blocking area being formed by selective oxidation of Al in an AlxGa1−xAs layer (0.95≦X<1) having a thickness below 60 nm, the Al-containing low-reflectivity layer including Al at an atomic ratio not more than 0.8 and below 0.9.

Abstract: A surface-emitting semiconductor laser device having reduced device resistance, a method for fabricating the device and a surface-emitting semiconductor laser array employing the device are provided. The laser device comprises a lower reflector layer structure and an upper reflector layer structure, formed on a p-type semiconductor substrate. An etching blocking layer, a current confinement layer, and an active layer are formed in that order from below between the lower and upper reflector layer structures. The portion over the etching blocking layer is formed into a mesa shape.

Abstract: A wafer stage having a built-in heater therein mounts a heat conductive disk which mounts thereon an object wafer having an AlAs layer therein. The heat conductive disk has a thermal conductivity equal to or higher than 100 watts/K/meter. The Al-oxidized area in the AlAs layer has excellent in-plane uniformity for the width thereof due to desirable heat distribution of the wafer caused by the heat conductive disk.

Abstract: A surface emission semiconductor laser device includes a GaAs substrate and a layer structure having a plurality of constituent layers including an active layer, a pair of cladding layers, and a pair of multilayer semiconductor mirrors. One of the multilayer mirrors includes an AlAs layer having an Al-oxidized area forming a current confinement structure. At least one of the constituent layers, such as active layer or one of the multilayer mirrors, has an oxygen density of 1×1018 cm−3 or less. The laser device suppresses reduction of the optical output power with time.

Abstract: A vertical cavity surface emitting laser device and a vertical cavity surface emitting laser array are provided for suppressing heat generation in and an increased operating voltage of the device. The vertical cavity surface emitting laser device is formed with a bottom DBR mirror layer structure and a top DBR mirror layer structure on a semiconductor substrate. An active layer and a current confinement layer are interposed between the two mirror layer structures. A portion, including the top DBR mirror layer structure and an underlying region extending at least to a lower end surface of the current confinement layer, is formed in a columnar mesa structure. An upper end surface of the mesa structure has an area larger than a cross section of the mesa structure near the current confinement layer.

Abstract: A semiconductor laser device in which a ridge structure including a layer comprised of an Al-containing compound semiconductor is formed at an upper portion, with both side portions of the layer being oxidized, and the laser-beam emitting face of the ridge structure is a non-oxidized area. As this reduces the ratio of defective cleaved faces, the production cost of the semiconductor laser device becomes lower, and because of the lower threshold current, the degradation of the characteristics over a long operational period does not likely occur.

Abstract: A vertical cavity surface emitting laser (VCSEL) device includes a pair of diffusion Bragg reflectors (DBRs) sandwiching therebetween a multiple quantum well (MQW) comprising active layers. The bottom DBR includes a lower layer structure having AlAs layers having a higher thermal conductivity and AlGaAs layers in pair and an upper layer structure acting anti-oxidation layers and having a pair of AlGaAs layers having different Al contents. A selectively oxidized AlAs layer disposed as the top layer of the bottom DBR comprises an Al-oxidized area and a non-oxidized layer for confinement of current injection path.

Abstract: A surface emitting semiconductor laser device has a layered structure of semiconductor materials formed on a substrate 1. The layered structure has an upper reflector layered structure (5), a lower reflector layered structure (2), and a light-emitting layer (4) interposed therebetween. A current injection path (3e) is formed in close proximity to the light-emitting layer (4). An upper electrical contact (7a), which is annular in plan configuration, is formed on the upper surface of the upper reflector layered structure (5). The outside of the upper electrical contact (7a) is coated with a dielectric film (8) and a metallic film (9). The metallic film (9) is formed being in contact with the upper electrical contact (7a), and the inside of the upper electrical contact (7a) serves as a laser light emission window.

Abstract: A passivation layer suppresses an output end face of a semiconductor laser having a band of an oscillation wavelength of 980 nm from being degraded and contributes to securance of the long-term reliability of the semiconductor laser. In a passivation layer, for a semiconductor laser, having a two-layered structure and constituted by a first thin film directly formed on the output end face of the semiconductor laser and a second thin film formed on a surface of the first thin film, the thickness of the first thin film is set such that, in a calculation expression for calculating the reflectance of the passivation layer by a matrix method, a differential coefficient obtained when the calculation expression is differentiated by the film thickness of the first thin film is zero.

Abstract: A surface emitting semiconductor laser device comprising: a layered structure in which a light-emitting layer is disposed between a pair of reflector layered structures formed by hetero junction of a plurality of semiconductor materials, the layered structure being formed on a substrate and an impurity being doped into the reflector layered structure; wherein in the reflector layered structure the doping concentration of said impurity into a region positioned in the vicinity of the light-emitting layer is relatively smaller than the doping concentration of said impurity into other regions spaced from the light-emitting layer; and at the same time, in the reflector layered structure the region positioned in the vicinity of said light-emitting layer has a relatively smaller energy gap difference &Dgr;Eg between the semiconductor materials forming the region than the energy gap difference &Dgr;Eg between the semiconductor materials forming the other regions, and the driving voltage can be reduced without the det

Abstract: A waveguide-type variable-sensitivity semiconductor photodetector has a waveguide photodetector area and an optical attenuation area formed on an n-InP substrate. The optical attenuation area includes a GaInAs optical waveguide layer having a bandgap energy of 0.85 eV, a pair of upper and lower cladding layers each having a bandgap energy of 1.35 eV and an intermediate layer disposed at the heterojunction interface between the optical waveguide layer and the upper cladding layer and having a bandgap energy of 1.0 eV. A pile-up of halls at the heterojunction interface is prevented by the intermediate layer to improve the linearity of the output optical signal to the input optical signal.

Abstract: A waveguide type semiconductor photodetector device comprises a photosensitive section including a photo-absorption layer for converting a signal light into an electric signal, and an optical attenuation section including an optical attenuation layer made of a bulk crystal for attenuating incident light. Assuming that E.sub.g.ATT and E.sub.in are bandgap energy of the optical attenuation layer and optical energy of the incident light signal, respectively, E.sub.in +50 meV.ltoreq.E.sub.g,ATT .ltoreq.E.sub.in +100 meV holds. The optical absorption layer and the optical attenuation layer are made of GaInAs and GaInAsP, respectively, for adapting to incident light of a 1.55 mm wavelength.

Abstract: The present invention gives rise to a 1.3 .mu.m tensile-strained quantum well laser having a quantum well active layer which can be structurally specified as In.sub.1-x Ga.sub.x As.sub.y P.sub.1-y with X between 0.42 and 0.55 and Y between 0.8 and 0.75. The InGaAsP active layer needs to have a tensile stress between 1.0 and 1.5% and can be fabricated without any substantial phase-separation between InP and GaAs. The 1.3 .mu.m tensile-strained quantum well laser is equipped with a remarkably meager threshold current density of less than 0.2 kA/cm.sup.2. The preferable tensile strain ranges between from 1.2 to 1.4% or thereabout.