Abstract: An optical semiconductor device has a semiconductor substrate, an optical semiconductor region and a heater. The optical semiconductor region is provided on the semiconductor substrate and has a width smaller than that of the semiconductor substrate. The heater is provided on the optical semiconductor region. The optical semiconductor region has a cladding region, an optical waveguide layer and a low thermal conductivity layer. The optical waveguide layer is provided in the cladding region and has a refractive index higher than that of the cladding region. The low thermal conductivity layer is provided between the optical waveguide layer and the semiconductor substrate and has a thermal conductivity lower than that of the cladding region.

Abstract: An optical semiconductor device has a semiconductor substrate, an optical semiconductor region and a heater. The optical semiconductor region is provided on the semiconductor substrate and has a width smaller than that of the semiconductor substrate. The heater is provided on the optical semiconductor region. The optical semiconductor region has a cladding region, an optical waveguide layer and a low thermal conductivity layer. The optical waveguide layer is provided in the cladding region and has a refractive index higher than that of the cladding region. The low thermal conductivity layer is provided between the optical waveguide layer and the semiconductor substrate and has a thermal conductivity lower than that of the cladding region.

Abstract: [Object of the Invention] An object of the present invention is to provide a method for processing contact portions between a valve plate and a suction valve and/or discharge valve of a reciprocating compressor to prevent the suction valve and/or the discharge valve from sticking on the valve plate at the portions contacting the valve plate, the productivity thereof being higher than that of the conventional method.

Abstract: A wavelength tunable semiconductor laser includes: a first facet having reflectivity of 10% or more; a second facet; a wavelength selection portion between the first facet and the second facet; and an optical absorption region between the first facet and the wavelength selection portion. Another wavelength tunable semiconductor laser includes: a first facet having reflectivity of 10% or more to inside of the semiconductor laser; a second facet for output; a wavelength selection portion having diffraction gratings and positioned between the first and the second facet; an optical absorption region located between the first facet and the wavelength selection portion.

Abstract: Provided is a specific structure for a compressor valve plate device, which can ensure smooth operation of a suction valve in terms of suction valve sticking force due to lubricant oil, and can be mass-produced at low cost with high efficiency. The compressor valve plate device comprises; a valve plate having a suction hole and a discharge hole; a suction valve; and a discharge valve. At least a part of a gas filling chamber capable of introducing and filling gas with a higher pressure than suction gas pressure in a suction chamber between the valve plate and the suction valve is constituted in the valve plate, while a communication hole communicating with a surface at the valve closing side of the suction valve is provided to the valve plate. At least a part of a gas introduction route for introducing the higher-pressure gas into the communication hole is formed on the discharge valve formed from a thin plate.

Abstract: A method for tuning a semiconductor laser including a plurality of wavelength selection portions, each of which has a periodic wavelength characteristic, including: controlling a value of a refractive index controlling means of the wavelength selection portions to achieve a desired output wavelength of the laser; and shifting the value when the value is equal to or excess of a predetermined value to a basal value side until achieving the desired output wavelength, the basal value being a value without applying refractive index variation by the refractive index controlling means, the predetermined value being a value for shifting one period of the periodic wavelength characteristic.

Abstract: A method of controlling a wavelength-tunable laser selecting an oscillation wavelength with a combination of a plurality of wavelength selection portions of which wavelength peak is different from each other, comprising: a first step of confirming a control direction of the wavelength selection portion in a case where a setting value is changed from a first setting value for achieving the first wavelength to a second setting value for achieving the second wavelength; a second step of setting a setting value that is shifted from the second setting value in a direction that is opposite of a pre-determined changing direction on the wavelength selection portion as a prepared setting value, when the control direction confirmed in the first step is opposite to the pre-determined changing direction; and a third step of changing the prepared setting value set in the second step to the second setting value.

Abstract: A semiconductor laser device includes: a semiconductor laser; a carrier that has a carrier side face facing with a longitudinal direction of the semiconductor laser, has a carrier edge area, and has a first bonding area that is the closest to a first end of the semiconductor laser and a second bonding area that is the closet to a second end of the semiconductor laser; a first thermal conduction portion that has a first thermal resistance and couples between the first bonding area and an outer connection terminal; and a second thermal conduction portion that has a second thermal resistance smaller than the first thermal resistance and couples between the second bonding area and an outer connection terminal, wherein the first end side of the semiconductor laser is closer to the carrier side face than the second end side of the semiconductor laser.

Abstract: Provided is a semiconductor laser which has a low operating current and stably oscillates even for high-temperature output. The semiconductor laser is provided with a substrate (10); an n-type clad layer (12) arranged on the substrate (10); an active layer (13) arranged on the n-type clad layer (12); a p-type clad layer (14), which is arranged on the active layer (13) and composed of a compound containing Al and has a stripe-shaped ridge structure to be a current channel; a current block layer (16), which is arranged on the surface of the p-clad layer (14) excluding an upper surface of the ridge structure and composed of a compound containing Al and has an Al composition ratio not more than that of the p-type clad layer (14); and a light absorption layer (17), which is arranged on the current block layer (16) and absorbs light at the laser oscillation wavelength.

Abstract: A tunable laser module includes a tunable laser section including a gain medium and a wavelength filter having a periodic characteristic which brings about a discontinuous variation of an oscillation wavelength, and a monitoring section adapted to output a monitoring signal which periodically varies in response to the oscillation wavelength of the tunable laser section. The monitoring section includes a monitoring wavelength filter having a periodic characteristic which defines the monitoring signal. The relationship between the period of the wavelength filter and the period of the monitoring wavelength filter is set such that the monitoring signal varies when the oscillation wavelength varies discontinuously.

Abstract: A testing method of a wavelength-tunable laser having a resonator including wavelength selection portions having wavelength property different from each other includes a first step of controlling the wavelength-tunable laser so as to oscillate at a given wavelength according to an initial setting value, a second step of tuning the wavelength property of the wavelength selection portions and detecting discontinuity point of gain-condition-changing of the wavelength-tunable laser, and a third step of obtaining a stable operating point of the wavelength selection portion according to a limiting point of an oscillation condition at the given wavelength, the limiting point being a point when the discontinuity point is detected.

Abstract: A compressor includes a cylinder block including cylinder bores and pistons within the cylinder bores. A front housing opposes a first cylinder block end face to form a crank chamber accommodating a piston driving mechanism. A valve plate opposes a second cylinder block end face and includes suction and discharge holes. A rear housing includes suction and discharge chambers and opposes the second cylinder block end face with the valve plate there between. Strap-shaped suction valves on the valve plate end face oppose the cylinder block, thereby opening and closing the suction holes at tip portions. Discharge valves on the valve plate end face oppose the rear housing to open and close the discharge holes. Through-bolts join the front housing, the crank chamber, the cylinder block, the valve plate, and the rear housing. The valve plate includes grooves extending from holes accommodating the through-bolts to portions abutting the suction valves.

Abstract: A laser device includes a resonator having a gain region, a first wavelength selection portion having a periodical peak in wavelength characteristics and a second wavelength selection portion having a periodical peak in wavelength characteristics in a wavelength range smaller than a variable range of an oscillation wavelength at a period different from the first wavelength selection portion, the oscillation wavelength selected with a single direction changing of a refractive index of the second wavelength selection portion changing in a single direction; a storing portion storing a setting value of a refractive index of the second wavelength selection portion for selecting an oscillation wavelength according to an oscillation wavelength to be attained within an extent from a maximum value to a minimum value of the refractive index over the plurality of the ranges; and a controller giving the setting value to the resonator.

Abstract: An optical device includes an optical element, a detector and a controller. The optical element has an optical waveguide. Refractive index of the optical waveguide is controlled by a heater. A temperature of the optical element is controlled by a temperature control device. The detector detects a current flowing in the heater and/or a voltage applied to the heater. The controller controls an electrical power provided to the heater so as to be kept constant according to the detection result of the detector.

Abstract: A method of controlling a semiconductor laser that has a plurality of wavelength selection portions having a different wavelength property from each other and is mounted on a temperature control device, including: a first step of correcting a temperature of the temperature control device according to a detected output wavelength of the semiconductor laser; and a second step of controlling at least one of the wavelength selection portions so that changing amount differentials between each wavelength property of the plurality of the wavelength selection portions is reduced, the changing amount differential being caused by correcting the temperature of the temperature control device.

Abstract: An optical semiconductor device includes an optical semiconductor element, a metal pattern and at least one thermal conductive material. The optical semiconductor element has a first optical waveguide region and a second optical waveguide region. The second optical waveguide region is optically coupled to the first optical waveguide region and has a heater for changing a refractive index of the second optical waveguide region. The metal pattern is provided on an area to be thermally coupled to a temperature control device. The thermal conductive material couples the metal pattern with an upper face of the first optical waveguide region of the optical semiconductor element. The thermal conductive material is electrically separated from the first optical waveguide region.

Abstract: An optical semiconductor device has a semiconductor substrate, a semiconductor region and heater. The semiconductor region has a stripe shape demarcated with a top face and a side face thereof. The stripe shape has a width smaller than a width of the semiconductor substrate. An optical waveguide layer is located in the semiconductor region. A distance from a lower end of the side face of the semiconductor region to the optical waveguide layer is more than half of the width of the semiconductor region. The heater is provided above the optical waveguide layer.

Abstract: A tunable laser module includes a tunable laser section including a gain medium and a wavelength filter having a periodic characteristic which brings about a discontinuous variation of an oscillation wavelength, and a monitoring section adapted to output a monitoring signal which periodically varies in response to the oscillation wavelength of the tunable laser section. The monitoring section includes a monitoring wavelength filter having a periodic characteristic which defines the monitoring signal. The relationship between the period of the wavelength filter and the period of the monitoring wavelength filter is set such that the monitoring signal varies when the oscillation wavelength varies discontinuously.

Abstract: An optical semiconductor device includes an optical semiconductor element, a metal pattern and at least one thermal conductive material. The optical semiconductor element has a first optical waveguide region and a second optical waveguide region. The second optical waveguide region is optically coupled to the first optical waveguide region and has a heater for changing a refractive index of the second optical waveguide region. The metal pattern is provided on an area to be thermally coupled to a temperature control device. The thermal conductive material couples the metal pattern with an upper face of the first optical waveguide region of the optical semiconductor element. The thermal conductive material is electrically separated from the first optical waveguide region.

Abstract: Provided is a high-power red semiconductor laser having a laser element in which a temperature rise is suppressed with improved heat dissipation characteristics thereof, and which accordingly needs not be enlarged in heat dissipation area. An n-AlGaInP cladding layer, an AlGaInP optical guide layer, an MQW active layer, an AlGaInP optical guide layer, a p-AlGaInP first cladding layer, an AlGaInP etching stop layer, an n-AlGaInP block layer, a p-AlGaAs second cladding layer, a p-GaAs contact layer and a p-electrode are stacked on the top surface of a tilted n-GaAs substrate. An n-electrode is formed on the back surface of the n-GaAs substrate. The heat dissipation characteristics of the laser element are improved, because the second cladding layer contains AlGaAs, which has a higher heat conductivity.