Abstract: A nitride semiconductor light-emitting device includes: a first conductivity-type nitride semiconductor layer, an active layer located over the first conductivity-type nitride semiconductor layer, a second conductivity-type nitride semiconductor layer located over the active layer, a current constriction layer located in a part of the second conductivity-type nitride semiconductor layer, and a transparent conductive layer located on the second conductivity-type nitride semiconductor layer and transparent to light generated from the active layer.

Abstract: There is provided a fluid detection device that detects a flow velocity or a flow rate of a fluid flowing through a piping, the fluid detection device including: a sound detection unit that detects a sound from the piping, and outputs a frequency signal; a signal processing unit that calculates a strength ratio of the frequency signal on the basis of the frequency signal and a predetermined reference frequency signal; and a data conversion unit that obtains the flow velocity or the flow rate on the basis of the strength ratio of the frequency signal and a predetermined fluid characteristic function.

Abstract: Provided is a wireless sensor node which includes a sensor to convert a physical quantity into an electric signal to measure the physical quantity, a filter to extract a signal containing a predetermined frequency from the electric signal, a transmitter to transmit data based on the frequency extracted by the filter, a receiver to receive a command to be transmitted from an outside in a wireless manner, and a control unit to control a frequency to be extracted by the filter based on the command.

Abstract: Provided is a wireless sensor node which includes a sensor to convert a physical quantity into an electric signal to measure the physical quantity, a filter to extract a signal containing a predetermined frequency from the electric signal, a transmitter to transmit data based on the frequency extracted by the filter, a receiver to receive a command to be transmitted from an outside in a wireless manner, and a control unit to control a frequency to be extracted by the filter based on the command.

Abstract: There is provided a fluid detection device that detects a flow velocity or a flow rate of a fluid flowing through. a piping, the fluid detection. device including: a sound detection unit that detects a sound from the piping, and outputs a frequency signal; a signal processing unit that calculates a strength ratio of the frequency signal on the basis of the frequency signal and a predetermined reference frequency signal; and a data conversion unit that obtains the flow velocity or the flow rate on the basis of the strength ratio of the frequency signal and a predetermined fluid characteristic function.

Abstract: To suppress occurrence of axial hole burning in a phase shift portion of a diffraction grating, provided is a semiconductor optical device including: a diffraction grating layer including a diffraction grating and a phase shift portion; and an optical waveguide layer including an active layer that has a gain with respect to an emission wavelength and an optical waveguide region that has no gain with respect to the emission wavelength. The optical waveguide region is formed at least on the lower side of the phase shift portion.

Abstract: A core of an optical waveguide and a core of a waveguide type optical device are adjacently disposed, and a layer is continuously formed at one end of the core of the waveguide type optical device, wherein an effective refractive index of the layer decreases toward a long axis direction of the optical waveguide stripe.

Abstract: Provided is a semiconductor electroluminescent device with an InGaAlAs-based well layer having tensile strain, or a semiconductor electroluminescent device with an InGaAsP-based well layer having tensile strain and with an InGaAlAs-based barrier layer which is high-performance and highly reliable in a wide temperature range. In a multiple-quantum well layer of the semiconductor electroluminescent device, a magnitude of interface strain at an interface between the well layer and the barrier layer is smaller than a magnitude of critical interface strain determined by a layer thickness value which is larger one of a thickness of the well layer and a thickness of the barrier layer.

Abstract: Provided is a semiconductor electroluminescent device with an InGaAlAs-based well layer having tensile strain, or a semiconductor electroluminescent device with an InGaAsP-based well layer having tensile strain and with an InGaAlAs-based barrier layer which is high-performance and highly reliable in a wide temperature range. In a multiple-quantum well layer of the semiconductor electroluminescent device, a magnitude of interface strain at an interface between the well layer and the barrier layer is smaller than a magnitude of critical interface strain determined by a layer thickness value which is larger one of a thickness of the well layer and a thickness of the barrier layer.

Abstract: In the optical integrated devices with ridge waveguide structure based on the conventional technology, there occur such troubles as generation of a recess in a BJ section to easily cause a crystal defect due to the mass transport phenomenon of InP when a butt joint (BJ) is grown, lowering of reliability of the devices, and lowering in a yield in fabrication of devices. In the present invention, a protection layer made of InGaAsP is provided on the BJ section. The layer has high etching selectivity for the InP cladding layer and remains on the BJ section even after mesa etching.

Abstract: A laser diode has a horizontal cavity and a mirror attached to the horizontal cavity at an angle of substantially 45° or substantially 135°. The laser diode is mounted on a stem substantially horizontally with taking light vertically emitted to the horizontal cavity as an optical signal, and light horizontally emitted as an optical signal for monitoring, respectively. A photodetector is mounted on the stem substantially orthogonally and so as to let in the optical signal for monitoring.

Abstract: In the optical integrated devices with ridge waveguide structure based on the conventional technology, there occur such troubles as generation of a recess in a BJ section to easily cause a crystal defect due to the mass transport phenomenon of InP when a butt joint (BJ) is grown, lowering of reliability of the devices, and lowering in a yield in fabrication of devices. In the present invention, a protection layer made of InGaAsP is provided on the BJ section. The layer has high etching selectivity for the InP cladding layer and remains on the BJ section even after mesa etching.

Abstract: A conventional semiconductor laser diode is small in optical power at a constant operating current and limited in ridge width when integrated with an optical device, which forces the integration to be performed by lowering the original characteristic and makes it difficult to reduce cost and power consumption. In a semiconductor laser diode, widening of the ridge width is made possible by lowering the difference in refractive indexes between the ridge and other components, diffusion current and increase in the difference of refractive indexes are prevented by forming approximately vertical grooves along both sides of the ridge, and deterioration in characteristics due to regrowth is prevented by forming a diffraction grating on the ridge. The semiconductor laser diode is integrated with an optical device such as electroabsorption type optical modulator without increase of growth cycles and without restriction of the ridge width by using a tapered waveguide.

Abstract: The present invention provides an ultra-mini and low cost refractive index measuring device applicable to biochemical measurements of an extremely minute amount of a sample. The refractive index measuring device uses a photonic crystal without any requirement of an external spectrograph or the like. The micro sensor device according to the present invention includes a light source emitting light with a single wavelength, a microcavity in which a resonant wavelength varies depending on a position thereof. A refractive index of a material to be measured is measured based on positional information by detecting a transmitting position of light changing in response to a change of a refractive index of the measured material. The micro sensor device according to the present invention enables measurement of a refractive index of a material to be measured without using a large-scale spectrograph.

Abstract: A core of an optical waveguide and a core of a waveguide type optical device are adjacently disposed, and a layer is continuously formed at one end of the core of the waveguide type optical device, wherein an effective refractive index of the layer decreases toward a long axis direction of the optical waveguide stripe.

Abstract: A conventional semiconductor laser diode is small in optical power at a constant operating current and limited in ridge width when integrated with an optical device, which forces the integration to be performed by lowering the original characteristic and makes it difficult to reduce cost and power consumption. In a semiconductor laser diode, widening of the ridge width is made possible by lowering the difference in refractive indexes between the ridge and other components, diffusion current and increase in the difference of refractive indexes are prevented by forming approximately vertical grooves along both sides of the ridge, and deterioration in characteristics due to regrowth is prevented by forming a diffraction grating on the ridge. The semiconductor laser diode is integrated with an optical device such as electroabsorption type optical modulator without increase of growth cycles and without restriction of the ridge width by using a tapered waveguide.

Abstract: The present invention provides an ultra-mini and low cost refractive index measuring device applicable to biochemical measurements of an extremely minute amount of a sample. The refractive index measuring device uses a photonic crystal without any requirement of an external spectrograph or the like. The micro sensor device according to the present invention includes a light source emitting light with a single wavelength, a microcavity in which a resonant wavelength varies depending on a position thereof. A refractive index of a material to be measured is measured based on positional information by detecting a transmitting position of light changing in response to a change of a refractive index of the measured material. The micro sensor device according to the present invention enables measurement of a refractive index of a material to be measured without using a large-scale spectrograph.