Abstract: In an electrochemical gas sensor (10), a first sensing element (21) is stored in a first storage portion (31). A moisture permeable film (24) is disposed in a first introduction inlet (31A) of the first storage portion (31). The moisture permeable film (24) substantially prevents a to-be-detected gas from permeating therethrough. A second sensing element (22) is disposed in a space into which water vapor and the to-be-detected gas contained in a target gas flow. In such a configuration, the electrochemical gas sensor (10) is capable of detecting a to-be-detected gas having a concentration of 0 or more and 1 ppm or less.

Abstract: In a method for fabricating a semiconductor laser device, a plurality of grooves are formed in a surface of one conductive type of an InP layer. The InP layer is thermally treated in an atmosphere including at least a gas containing phosphorus and a gas containing arsenic in a mixed state, thereby forming a plurality of active regions made of InAsP in the plurality of grooves. An other conductive type of semiconductor layer is formed after the active regions are formed.

Abstract: A semiconductor laser includes a substrate; and a multilayered film formed on the substrate and including an active layer. The multilayered film includes a stripe structure that extends in a longitudinal direction of a resonator and has a tapered portion in which a width of a stripe changes in a tapered manner; and a first side face and a second side face that sandwich the stripe structure. At least one side face of the first side face and the second side face is inclined with respect to a principal surface of the substrate.

Abstract: A semiconductor laser device includes an InP substrate and a multi-layered structure formed on the InP substrate, wherein the multi-layered structure includes at least a plurality of active regions for outputting a laser beam, and the plurality of active regions each are provided in each of a plurality of grooves dented toward the InP substrate.

Abstract: The semiconductor laser device according to the present invention includes: a semiconductor substrate; an active layer having a stripe structure formed on the semiconductor substrate; and a buried layer formed on the semiconductor substrate and in a vicinity of the active layer, the buried layer including Fe and Ti.

Abstract: A semiconductor laser element including: a three-dimensional photonic crystal structure which has a light confining effect and includes alternating first and second refractive index changing layers, where refractive index of light periodically changes in a first direction in each first refractive index changing layer and periodically changes in a second direction in each second refractive index changing layer; and an active unit which is disposed in a portion having a predetermined refractive index inside the three-dimensional photonic crystal structure, and generates a laser beam in response to reception of electric power.

Abstract: A semiconductor laser element including: a three-dimensional photonic crystal structure which has a light confining effect and includes alternating first and second refractive index changing layers, where refractive index of light periodically changes in a first direction in each first refractive index changing layer and periodically changes in a second direction in each second refractive index changing layer; and an active unit which is disposed in a portion having a predetermined refractive index inside the three-dimensional photonic crystal structure, and generates a laser beam in response to reception of electric power.

Abstract: A semiconductor laser device includes a substrate, a p-type cladding layer and a n-type cladding layer provided on the substrate, and an active layer provided between the p-type cladding layer and the n-type cladding layer, having at least two barrier layers and at least two well layers, the barrier layers and the well layers being disposed alternately. Band offsets in a conduction band between the barrier layers and the well layers are provided so as to increase from the n-type cladding layer aide toward the p-type cladding layer side.

Abstract: A semiconductor laser device includes an InP substrate and a multi-layered structure formed on the InP substrate, wherein the multi-layered structure includes at least a plurality of active regions for outputting a laser beam, and the plurality of active regions each are provided in each of a plurality of grooves dented toward the InP substrate.

Abstract: A semiconductor laser includes a substrate; and a multilayered film formed on the substrate and including an active layer. The multilayered film includes a stripe structure that extends in a longitudinal direction of a resonator and has a tapered portion in which a width of a stripe changes in a tapered manner; and a first side face and a second side face that sandwich the stripe structure. At least one side face of the first side face and the second side face is inclined with respect to a principal surface of the substrate.

Abstract: A semiconductor laser element including: a three-dimensional photonic crystal structure which has a light confining effect and includes alternating first and second refractive index changing layers, where refractive index of light periodically changes in a first direction in each first refractive index changing layer and periodically changes in a second direction in each second refractive index changing layer; and an active unit which is disposed in a portion having a predetermined refractive index inside the three-dimensional photonic crystal structure, and generates a laser beam in response to reception of electric power.

Abstract: An optical module includes a substrate, a waveguide body disposed on the substrate and including an optical waveguide for propagating light, and a photodetector. A curved portion for radiating light propagating through the optical waveguide from the optical waveguide is provided in a part of the optical waveguide, and the photodetector receives light radiated by the curved portion.

Abstract: To provide an optical waveguide having an optical waveguide core enclosed with clads, which is independent of a polarization direction. In the optical waveguide, an optical waveguide core is enclosed with clads, and a sectional shape of the core in a direction crossing a light traveling direction is quasi-square, and a cross section of the core decreases from the light incoming end to the outgoing end in the light traveling direction.

Abstract: In a distributed feedback semiconductor laser includes an InP substrate and a multiple layer structure formed on a main surface of the InP substrate, the multiple layer structure includes at least an active layer for emitting laser light and a periodical structure for distributed feedback of the laser light, and the periodical structure includes a plurality of semiconductor regions each having a triangular cross section in a direction perpendicular to the main surface of the InP substrate and parallel to a cavity length of the distributed feedback semiconductor laser, the triangular cross section projecting toward the InP substrate.

Abstract: In a distributed feedback semiconductor laser includes an InP substrate and a multiple layer structure formed on a main surface of the InP substrate, the multiple layer structure includes at least an active layer for emitting laser light and a periodical structure for distributed feedback of the laser light, and the periodical structure includes a plurality of semiconductor regions each having a triangular cross section in a direction perpendicular to the main surface of the InP substrate and parallel to a cavity length of the distributed feedback semiconductor laser, the triangular cross section projecting toward the InP substrate.

Abstract: A disc rotor formed of flaky graphite cast iron in which the natural frequency of the disc rotor is set by the graphite length in the flaky graphite cast iron structure.For preventing resonant vibrations ascribable to the self-excited vibrations of the component parts of disc brakes, such as pads, the natural frequency of the disc rotor are shifted from the frequency of excited vibrations of the component parts of disc brakes, such as pads.

Abstract: The semiconductor laser device of the invention includes: a strained quantum well structure including a well layer and a barrier layer, and a semiconductor substrate for supporting the strained quantum well structure. In the semiconductor laser device, at least one of the well layer and the barrier layer is composed of a mixed crystal where an atomic ordering is generated.

Abstract: A strained multiple quantum well semiconductor laser including a semiconductor substrate, a multiple quantum well active layer including a plurality quantum well layers and a plurality of barrier layers, and a multilayer structure including the above multiple quantum well active layer is provided. Each barrier layer is interposed between two of the multiple quantum well active layers. The multilayer structure is formed upon the semiconductor substrate. Herein, at least one of the plurality of barrier layers is thicker than the other barrier layers, thereby serving as a layer absorbing strain which is stored in the barrier layers due to a difference between the lattice constant of semiconductor substrate and the lattice constant each quantum well layer.

Abstract: The semiconductor laser comprises a Sn doped InP substrate 1, n-InGaAsP wave guide layer 2, 5 nm thick InGaAs well layer 3, 3.5 nm thick undoped InGaAsP layer 4, 3 nm thick p-InGaAsP modulation doping layer 5, 3.5 nm thick undoped InGaAsP layer 6, a modulation doping quantum well layer 7 with ten wells, a 90 nm thick p-InGaAsP layer 8, a p-InP clad layer 9 (Zn=7.times.10.sup.17 cm.sup.-3), p-n-p current block layer 10, and a mesa-shaped active layer region 11. An Au/sn n-electrode 12 and if Au/Zn p-electrode 13 are formed by vapor deposition to complete the laser structure.

Abstract: A heat exchanger for recovering heat from exhaust gases which includes a plurality of separately divided portions, a fluid passage mechanism for a fluid disposed within each of the portions, a bypass mechanism for the fluid for bypassing each of the portions and a valve mechanism for selectively operating the fluid passage mechanism or the bypass mechanism. The plurality of portions may constitute at least two chambers separately provided in the heat exchanger or at least two parts independently provided ion the heat exchanger. In addition, discharge means for discharging the fluid in the plurality of portions is provided.