Abstract: A projection display unit (1) includes a body (10) and an invisible light application unit (30). The body (10) includes a projection optical system and a detection optical system. The projection optical system projects an image onto a projection surface (110). The detection optical system acquires an imaging signal based on invisible light. The invisible light application unit (30) applies the invisible light along a surface in vicinity of the projection surface while being placed on a surface that is an extension of the projection surface. The body (10) is movable with respect to an output opening (31) of the invisible light application unit, and a position of the body is adjustable with respect to the projection surface.

Abstract: A projection display unit (1) includes a body (10) and an invisible light application unit (30). The body (10) includes a projection optical system and a detection optical system. The projection optical system projects an image onto a projection surface (110). The detection optical system acquires an imaging signal based on invisible light. The invisible light application unit (30) applies the invisible light along a surface in vicinity of the projection surface while being placed on a surface that is an extension of the projection surface. The body (10) is movable with respect to an output opening (31) of the invisible light application unit, and a position of the body is adjustable with respect to the projection surface.

Abstract: The reliability of a buried hetero-structure semiconductor laser is improved by preventing an increase in oscillation threshold current and a decrease in external differential quantum efficiency in cases where the semiconductor laser is energized continuously under conditions of high temperature and high optical output. An optical semiconductor laser has an optical waveguide structure comprising an n-type cladding layer, an active layer and p-type cladding layers, and a current narrowing/blocking structure comprising a p-type blocking layer and an n-type blocking layer, wherein concentration of hydrogen contained in the p-type cladding layers is higher than concentration of hydrogen contained in the p-type blocking layer.

Abstract: A distributed feedback laser diode comprises a phase-shifting portion in diffraction gratings. The magnitude of a phase shift in the phase-shifting portion is 8?/40 to 9?/40, ? representing twice the distance between the diffraction gratings. A main mode stands on a lower wavelength side than the center of a stop band when an injected current is of a level of a threshold current, whereas the main mode is shifted to the center of the stop band and a sub mode is suppressed from growing when the injected current is of a level of an operating current.

Abstract: The reliability of a buried hetero-structure semiconductor laser is improved by preventing an increase in oscillation threshold current and a decrease in external differential quantum efficiency in cases where the semiconductor laser is energized continuously under conditions of high temperature and high optical output. An optical semiconductor laser has an optical waveguide structure comprising an n-type cladding layer, an active layer and p-type cladding layers, and a current narrowing/blocking structure comprising a p-type blocking layer and an n-type blocking layer, wherein concentration of hydrogen contained in the p-type cladding layers is higher than concentration of hydrogen contained in the p-type blocking layer.

Abstract: A distributed feedback laser diode comprises a phase-shifting portion in diffraction gratings. The magnitude of a phase shift in the phase-shifting portion is 8 ?/40 to 9 ?/40, ? representing twice the distance between the diffraction gratings. A main mode stands on a lower wavelength side than the center of a stop band when an injected current is of a level of a threshold current, whereas the main mode is shifted to the center of the stop band and a sub mode is suppressed from growing when the injected current is of a level of an operating current.

Abstract: A resist is coated on a substrate. The resist is exposed to a pattern of a plurality of diffraction gratings for setting pitches corresponding respectively to oscillation wavelengths for the plurality of semiconductor lasers and for setting heights of the diffraction gratings which provide an identical coupling coefficient independently of the oscillation wavelengths. The coating is etched in such a manner that the level of etching per unit time is identical. A stripe mask is patterned according to the arrangement of the diffraction gratings. A laser active layer is formed on each of the diffraction gratings by selective MOVPE growth. An electrode is formed on each of the laser active layer on its top surface and the backside of the substrate.

Abstract: An optical semiconductor device comprising a plurality of semiconductor lasers formed on a single substrate is provided, in which each of said semiconductor lasers emits a laser lights having designed different oscillating wavelength. This optical semiconductor device is provided by maintaining the coupling coefficient of each of said semiconductor lasers at a constant value by adjusting the composition of an optical guide layer or the mask width for the MOVPE growth.

Abstract: A resist is coated on a substrate. The resist is exposed to a pattern of a plurality of diffraction gratings for setting pitches corresponding respectively to oscillation wavelengths for the plurality of semiconductor lasers and for setting heights of the diffraction gratings which provide an identical coupling coefficient independently of the oscillation wavelengths. The coating is etched in such a manner that the level of etching per unit time is identical. A stripe mask is patterned according to the arrangement of the diffraction gratings. A laser active layer is formed on each of the diffraction gratings by selective MOVPE growth. An electrode is formed on each of the laser active layer on its top surface and the backside of the substrate.

Abstract: A resist is coated on a substrate. The resist is exposed to a pattern of a plurality of diffraction gratings for setting pitches corresponding respectively to oscillation wavelengths for the plurality of semiconductor lasers and for setting heights of the diffraction gratings which provide an identical coupling coefficient independently of the oscillation wavelengths. The substrate is etched in such a manner that the level of etching per unit time is identical. A stripe mask is patterned according to the arrangement of the diffraction gratings. A laser active layer is formed on each of the diffraction gratings by selective MOVPE growth. An electrode is formed on each of the laser active layer on its top surface and the backside of the substrate.

Abstract: An optical semiconductor device comprising a plurality of semiconductor lasers formed on a single substrate is provided, in which each of said semiconductor lasers emits a laser lights having designed different oscillating wavelength. This optical semiconductor device is provided by maintaining the coupling coefficient of each of said semiconductor lasers at a constant value by adjusting the composition of an optical guide layer or the mask width for the MOVPE growth.

Abstract: A set of semiconductor laser elements and manufacturing method. The set of semiconductor laser elements have mutually different oscillation wavelengths, and perform single longitudinal mode oscillation by having periodically varying refractive index within the elements. The set of semiconductor laser elements are formed together from one semiconductor substrate. Duty cycle of a diffraction grating in each element differs from each other corresponding to the oscillation wavelength to realize equal coupling coefficient. Alternatively, a product of coupling coefficient and the length of area in which the diffraction grating is formed or a product of coupling coefficient and the length of the element is made substantially constant.

Abstract: In an optical semiconductor device fabrication method for simultaneously forming elements having different operation wavelengths on a circular semiconductor substrate, the number of elements for each operation wavelength is made constant efficiently and the operation characteristics of the elements are made highly uniform, by parabolically changing the operation wavelength of the optical semiconductor device from a center portion of the circular semiconductor substrate toward an outer periphery thereof.

Abstract: An integrated semiconductor laser produced by forming waveguide layers each having a particular band gap and a particular layer thickness collectively and then forming an InP current blocking layer. After an InGaAsP layer has been formed on an InP substrate, a waveguide including a multiple quantum well active layer is formed by selective MOVPE. Then, the waveguide is buried in an InP current blocking layer. In this configuration, the current blocking layer exhibits its expected function without regard to the width of SiO2 stripes used for selective metalorganic vapor phase epitaxial growth (MOVPE). The laser is feasible for high output operation and can be produced at a high yield.

Abstract: There is provided an optical semiconductor device including an optical waveguide structure having a quantum well layer and an optical confinement layer as a core layer, wherein the core layer has a thickness varying in a lengthwise direction of the optical waveguide to thereby have a function of spot-size conversion, and the quantum well layer is designed to have a band-gap energy which is constant within ±30 meV in the direction. The above-mentioned optical semiconductor device makes it possible to an optical gain to laser oscillation wavelength over all ranges of a resonator, and hence makes it no longer necessary to form a region only for spot-size conversion (SSC). This ensures that a device length can be as small as that of a conventional laser diode. In addition, lower threshold value characteristic and high temperature operation performance could be achieved, and a yield in devices per a wafer can be significantly enhanced.

Abstract: In an optical semiconductor device including a semiconductor substrate, an active layer formed on the semiconductor substrate, a pnpn-type current blocking layer formed on a side of the active layer, and a carrier recombination layer on the semiconductor substrate on the side of the active layer, a structure of the active layer is different from a structure of the carrier recomibination layer.

Abstract: In an optical semiconductor device including a semiconductor substrate, an active layer formed on the semiconductor substrate, a pnpn-type current blocking layer formed on a side of the active layer, and a carrier recombination layer on the semiconductor substrate on the side of the active layer, a structure of the active layer is different from a structure of the carrier recombination layer.

Abstract: An optical semiconductor device is constituted from a group III-V compound semiconductor of which a crystal is grown by a selective metal-organic vapor phase epitaxy. At least two kinds of the group V elements are included and the compound semiconductor is formed under a group V element supplying condition different from that of a non-selective metal-organic vapor phase epitaxy so that the compound semiconductor includes the desired proportions of the group V elements.

Abstract: In an optical semiconductor device fabrication method for simultaneously forming elements having different operation wavelengths on a circular semiconductor substrate, the number of elements for each operation wavelength is made constant efficiently and the operation characteristics of the elements are made highly uniform, by parabolically changing the operation wavelength of the optical semiconductor device from a center portion of the circular semiconductor substrate toward an outer periphery thereof.

Abstract: An optical semiconductor device comprising a plurality of semiconductor lasers formed on a single substrate is provided, in which each of said semiconductor lasers emits a laser lights having designed different oscillating wavelength. This optical semiconductor device is provided by maintaining the coupling coefficient of each of said semiconductor lasers at a constant value by adjusting the composition of an optical guide layer or the mask width for the MOVPE growth.