Abstract: A semiconductor device includes, an AlGaN electron supply layer having a [000-1] crystalline orientation in a thickness direction to a substrate plane, a GaN electron traveling layer formed on the AlGaN electron supply layer, a gate electrode formed above the GaN electron traveling layer, and a source electrode and a drain electrode between which the gate electrode is located, the source and drain electrode being formed on the GaN electron traveling layer.

Abstract: A method of manufacturing a light emitting diode includes forming an active layer of a nitride semiconductor on a first conductive type of a nitride semiconductor layer, thermally treating the active layer at a first temperature, and forming a second conductive type of a nitride semiconductor layer on the active layer at a second temperature lower than the first temperature.

Abstract: An optical semiconductor device has a heater, an optical waveguide layer, a first electrode and a second electrode. The heater is provided on a first semiconductor region and has more than one heater segment coupled or separated to each other. The optical waveguide layer is provided in the first semiconductor region and receives heat from the heater. The first electrode is coupled to a connecting point of the heater segments adjacent to each other. The second electrodes are electrically common and are coupled to other ends of the heater segments in opposite side of the connecting point respectively.

Abstract: A semiconductor device includes a decoder decoding input signals and generating a control signal from decoded input signals, and a power control circuit detecting a given combination of the input signals applied to the decoder and controlling a supply of power to the decoder.

Abstract: A laser diode drive circuit includes: a duty control amplifier (23) that controls the duty ratio of a main signal for laser control in accordance with a duty control signal; and an AND gate (22) that outputs the duty control signal to the duty control amplifier (23), and outputs a duty control signal that controls the duty ratio of the main signal to be 0% in the duty control amplifier in accordance with a shutdown signal of a laser diode. With this structure, there is no need to input the main signal having the duty ratio controlled to a logic circuit that becomes unstable. Thus, outputs from a semiconductor laser can be shut down, and the output duty can be controlled in a stable manner.

Abstract: A method for manufacturing a semiconductor device having a compound semiconductor layer that is provided on a substrate and includes a cladding layer of a first conductivity type, an activation layer, a cladding layer of a second conductivity type that is the opposite of the first conductivity type, includes the steps of: forming a diffusion source layer on the compound semiconductor layer; forming a first diffusion region in the compound semiconductor layer by carrying out a first heat treatment, so that the first diffusion region includes a light emitting facet for emitting light from the activation layer; removing the diffusion source layer; forming a first SiN film having a refractive index of 1.9 or higher on the compound semiconductor layer; and turning the first diffusion region into the second diffusion region by carrying out a second heat treatment.

Abstract: A field effect transistor includes: a nitride semiconductor layer having a channel layer; a gate electrode including a Schottky electrode that contacts the nitride semiconductor layer and includes a gallium doped zinc oxide (GZO) layer annealed in an inactive gas atmosphere; and ohmic electrodes connecting with the channel layer.

Abstract: A method of controlling a semiconductor laser having a wavelength selection portion, a refractive index of the wavelength selection portion being controllable with a heater including: a starting sequence including a first step for adjusting a heat value of the heater until the heat value of the heater reaches a given value; and a wavelength control sequence including a second step for correcting a wavelength of the semiconductor laser according to a detection result of an oscillation wavelength of the semiconductor laser after the starting sequence.

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 electronic circuit includes a differential amplifier circuit, a first smoothing circuit, a second smoothing circuit and a first switch. The differential amplifier circuit receives a digital input signal and a reference signal. The first smoothing circuit smoothes the digital input signal with a first capacitance value. The second smoothing circuit smoothes the digital input signal with a second capacitance value larger than the first capacitance value. The first switch selects one of output signals from the first smoothing circuit and the second smoothing circuit as the reference signal.

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: A wavelength measuring device includes: light receiving elements that receive light to be measured; a temperature controller that maintains the light receiving elements at different temperatures from one another; and a calculation unit that determines the wavelength of the light to be measured, based on outputs of the light receiving elements.

Abstract: A patch antenna is disclosed that includes a dielectric substrate, a substantially rectangular radiation element formed of a conductive material on the dielectric substrate; and a feeder line connected to a feeding point for feeding to the radiation element. The feeding point has an impedance matching the impedance of the feeder line.

Abstract: An optical communication module includes a receptacle, a chassis and a pressing jig. The receptacle has a photonic device therein and a projection portion. The chassis houses the receptacle. The pressing jig has an engage portion. The engage portion is latched with the chassis with the pressing jig pressing the projection portion of the receptacle to the chassis.

Abstract: A semiconductor light emitting device includes a substrate and a quantum well active layer. The quantum well active layer has a plurality of barrier layers made of GaN-based semiconductor and a well layer made of GaN-based semiconductor sandwiched between the barrier layers and has polarized charge between the barrier layer and the well layer caused by piezo polarization. The well layer has a composition modulation so that a band gap is minimum at an interface between the well layer and one of the barrier layers more far from the substrate than the other.

Abstract: A semiconductor substrate includes: a semiconductor crystal layer grown on one face of a substrate; and a stress relaxation layer, which is formed on the other face opposite to the one face and the side face of the substrate and applies stress to the substrate in the same direction as the direction of stress which the semiconductor crystal layer applies to the substrate. In this case, stress of the semiconductor crystal layer to the substrate is offset. Therefore, warp of the semiconductor substrate and generation of cracks are inhibited.

Abstract: An optical semiconductor device includes a waveguide and a refractive index control portion. The waveguide has one or more first segments, one or more second segments and a plurality of third segments. The first segment has a region that includes a diffractive grating and another region that is a space region combined to the region. The second segment has a region that includes a diffractive grating and another region that is a space region combined to the region. A length of the second segment is different from that of the first segment. The third segment has a region that includes a diffractive grating and another region that is a space region combined to the region. A length of the third segment is shown as L3=L1+(L2?L1)×K1 in which 0.3?K1?0.7, L1 is a length of the first segment, L2 is a length of the second segment and L3 is a length of the third segment. The refractive index control portion controls refractive index of the first segment through the third segments.

Abstract: A semiconductor device includes a pad; an internal circuit; a protection FET that has a drain connected to the pad, and a source connected to a reference potential; a first resistive element that is connected between the drain of the protection FET and the internal circuit, and has a larger resistance value than the value of the series resistance between the drain of the protection FET and the pad; a capacitive element that is connected between the pad and the gate of the protection FET; and a second resistive element that is connected between the gate of the protection FET and the source of the protection FET.

Abstract: In a p-type clad layer, not only a p-type dopant Zn but also Fe is doped. Its Zn concentration is 1.5×1018 cm?3 and the Fe concentration is 1.8×1017 cm?3. In a semi-insulating burying layer, Fe is doped as an impurity generating a deep acceptor level and the concentration thereof is 6.0×1016 cm?3. The Fe concentration in the p-type clad layer is thus three times higher than the Fe concentration in the burying layer.