Abstract: One aspect is a heat reflective member, a laminated structure in which quartz glass layers are formed on an upper surface and a lower surface of a siliceous sintered powder layer. The heat reflective member has an impermeable layer formed at a portion of the siliceous sintered powder layer at a cut-out end portion of the heat reflective member. The impermeable layer has a thickness at least larger than half of a thickness of the siliceous sintered powder layer and through which a gas or a liquid is prevented from penetrating. A buffer layer is formed between the impermeable layer and the siliceous sintered powder layer next to the impermeable layer and spaced apart from the cut-out end portion. The buffer layer changes in density from the impermeable layer toward the siliceous sintered powder layer.

Abstract: The optical device includes a semiconductor layer formed on a cladding layer and composed of a III-V compound semiconductor, and a light-receiving element for monitoring a semiconductor laser formed on the semiconductor layer and oscillation light of the semiconductor laser. A first p-contact layer and a first n-contact layer of the semiconductor laser, a second p-contact layer and a second n-contact layer, and a light absorption layer of the light-receiving element are composed of the same III-V compound semiconductor (InGaAsP).

Abstract: One aspect is a reflective member, which has a laminated structure in which transparent quartz glass members are formed on an upper surface and a lower surface of an opaque siliceous sintered powder layer. The opaque siliceous sintered powder layer has a thickness of 0.1 mm or more and a thickness distribution of ±0.05 mm or less. When a load is applied to each of the transparent quartz glass members on an upper surface and a lower surface of the laminated structure in a direction parallel to the laminated structure, the reflective member is fractured at a load of 5 N or more per square centimeter. The laminated structure includes a semi-transparent portion having a width of 0.01 mm or less, which has an intermediate opacity between an opacity of the opaque siliceous sintered powder layer and an opacity of each of the transparent quartz glass members.

Abstract: A light-emitting device includes a waveguide-type light-emitting element formed on a cladding layer, a core formed on the cladding layer and constituting a port opposite to an output port of the light-emitting element, and a light absorption layer formed on the core in contact therewith. The core may be composed of a III-V compound semiconductor such as InP. The core is composed of a III-V compound semiconductor capable of guiding (transmitting) light (laser light) output from the light-emitting element. The light absorption layer is composed of a III-V compound semiconductor having a refractive index higher than that of the core, such as InGaAs. The III-V compound semiconductor having a higher refractive index has an absorption coefficient for light (light output from the light-emitting element) transmitted through the core.

Abstract: A semiconductor laser of the present invention includes: a waveguide structure including, in order, a first semiconductor layer, an active layer, and a second semiconductor layer; a p-type semiconductor layer disposed in contact with one side surface of the active layer; an n-type semiconductor layer disposed in contact with the other side surface of the active layer; a reflector optically coupled to one end of the active layer in a waveguide direction; a waveguide layer optically coupled to the other end of the active layer in the waveguide direction; a diffraction grating disposed on either one of a lower surface and an upper surface of the waveguide layer; and a refractive index control unit for changing a refractive index of the waveguide layer. Thus, the semiconductor laser of the present invention can provide a good high-temperature operation with a simple configuration.

Abstract: A semiconductor laser includes: a waveguide structure including, in order, a first semiconductor layer, an active layer, and a second semiconductor layer; a p-type semiconductor layer disposed in contact with one side surface of the active layer; an n-type semiconductor layer disposed in contact with the other side surface of the active layer; a waveguide layer optically coupled to the active layer in a waveguide direction; a first diffraction grating disposed on either one of a lower surface of the first semiconductor layer, an upper surface of the second semiconductor layer, and a side surface of the active layer; a second diffraction grating disposed on either one of a lower surface and an upper surface of the waveguide layer; and a refractive index control unit for changing a refractive index of the waveguide layer. The semiconductor laser can achieve a good high-temperature operation with a simple configuration.

Abstract: An optical device includes a cladding layer and a core formed on the cladding layer and including a crystal of a III-V compound semiconductor crystal. The core has a plurality of first regions and second regions periodically connected in series. In addition, adjacent first regions and second regions have reversals of polarization. In the plurality of first regions and second regions included in the core, the adjacent first region and second region have reversals of polarization in a direction perpendicular to a waveguide direction.

Abstract: Provided is a heat reflective member, which is prevented from braking even in a high-temperature environment. It generates no dust in use, and can be washed with a chemical liquid. The heat reflective member has a laminated structure in which quartz glass layers are formed on an upper surface and a lower surface of a siliceous sintered powder layer. The heat reflective member includes: an impermeable layer which is formed at a portion of the siliceous sintered powder layer at an end portion of the heat reflective member, which has a thickness at least larger than half of a thickness of the siliceous sintered powder layer, and through which a gas or a liquid is prevented from penetrating; and a buffer layer which is formed between the impermeable layer and the siliceous sintered powder layer, and which changes in density from the impermeable layer toward the sintered powder layer.

Abstract: A semiconductor layer is formed on a substrate, and is formed with a semiconductor. The semiconductor can be, for example, a group III-V compound semiconductor. Further, in the semiconductor layer, a p-type p-region, an i-type i-region, and an n-type n-region, which form a pin junction in a planar direction of the substrate, are formed. A light absorbing layer is formed on the p-region of the semiconductor layer, and is formed with a p-type semiconductor. A contact layer is formed on the light absorbing layer, and is formed with a p-type semiconductor.

Abstract: A wavelength-tunable laser a circling waveguide having a circling structure; a first coupled waveguide coupled to the circling waveguide in one region; and a second coupled waveguide coupled to the circling waveguide in another region, wherein a first reflection region is connected in the light guiding direction of the first coupled waveguide, an active region and a second reflection region are sequentially connected in the light guiding direction of the second coupled waveguide, and the refractive index of at least part of the circling waveguide is modulated.

Abstract: A photoelectric conversion device includes a plurality of optical waveguides that are formed on a substrate and have the same waveguide direction, and a plurality of waveguide-type photoelectric conversion elements that are connected to the respective optical waveguides. The plurality of photoelectric conversion elements is arranged in the waveguide direction of the plurality of optical waveguides. In a planar view, the line segment connecting the photoelectric conversion elements adjacent to one another in the waveguide direction of the plurality of photoelectric conversion elements is inclined with respect to the waveguide direction.

Abstract: There is provided a technique that includes a first annealing step of annealing the reaction tube; a first cleaning step of cleaning an inner surface of the reaction tube, after the first annealing step, with a liquid including a fluorine compound having a first concentration; a first rinsing step of washing away the fluorine compound used in the first cleaning step with pure water; a second annealing step of annealing the reaction tube; a second cleaning step of cleaning the inner surface of the reaction tube, after the second annealing step, with a liquid including a fluorine compound having a second concentration higher than the first concentration; and a second rinsing step of washing away the fluorine compound used in the second cleaning step with pure water.

Abstract: A torque transmission joint to suppress occurrence of noise when reversing the direction of rotation of a drive shaft. A first transmission member fixed to an output shaft (the drive shaft) is engaged with a first elastic member such that a first gap in a circumferential direction is interposed, as well as with an intermediate transmission member such that a larger gap in the circumferential direction is interposed. A second transmission member fixed to an end portion of a worm is engaged with a second elastic member such that a second gap in the circumferential direction is interposed, as well as with the intermediate transmission member such that a larger gap in the circumferential direction is interposed. First and second annular convex portions are fitted to, respectively, first and second concave portions to prevent separation of the first and second elastic members with respect to the intermediate transmission member.

Abstract: A torque transmission joint includes a first elastic body having a plurality of first elastic pieces pinched in a circumferential direction between respective first convex portions and a coupling, and a second elastic body having a plurality of second elastic pieces pinched in the circumferential direction between respective second convex portions and the coupling.

Abstract: The torque transmission joint includes an intermediate transmission member, and a first transmission member and a second transmission member that are arranged with one each on both side sections in the axial direction of the intermediate transmission member, with the outer side sections in the radial direction of each engaging with the inside section in the radial direction of the intermediate transmission member. The first transmission member and the second transmission member have a first preliminary engagement section and a second preliminary engagement section at the end sections in the axial direction on sides close to each other. The first preliminary engagement section and the second preliminary engagement section engage with each other with a circumferential gap interposed therebetween that does not disappear when torque transmission is performed between the first transmission member and the second transmission member via the intermediate transmission member.

Abstract: Provided is a heat reflective member, which is prevented from braking even in a high-temperature environment. It generates no dust in use, and can be washed with a chemical liquid. The heat reflective member has a laminated structure in which quartz glass layers are formed on an upper surface and a lower surface of a siliceous sintered powder layer. The heat reflective member includes: an impermeable layer which is formed at a portion of the siliceous sintered powder layer at an end portion of the heat reflective member, which has a thickness at least larger than half of a thickness of the siliceous sintered powder layer, and through which a gas or a liquid is prevented from penetrating; and a buffer layer which is formed between the impermeable layer and the siliceous sintered powder layer, and which changes in density from the impermeable layer toward the sintered powder layer.

Abstract: One aspect is a reflective member, which has a laminated structure in which transparent quartz glass members are formed on an upper surface and a lower surface of an opaque siliceous sintered powder layer. The opaque siliceous sintered powder layer has a thickness of 0.1 mm or more and a thickness distribution of ±0.05 mm or less. When a load is applied to each of the transparent quartz glass members on an upper surface and a lower surface of the laminated structure in a direction parallel to the laminated structure, the reflective member is fractured at a load of 5 N or more per square centimeter. The laminated structure includes a semi-transparent portion having a width of 0.01 mm or less, which has an intermediate opacity between an opacity of the opaque siliceous sintered powder layer and an opacity of each of the transparent quartz glass members.

Abstract: A worm reducer includes: a housing including a wheel accommodating portion, and a worm accommodating portion; a worm wheel including wheel teeth disposed on an outer circumferential surface and rotatably supported inside the wheel accommodating portion; and a worm including worm teeth disposed on an outer circumferential surface to mesh with the wheel teeth and rotatably supported inside the worm accommodating portion, wherein a proximal end portion of the worm is connected to a drive shaft such that torque can be transmitted. An inner circumferential surface of the worm accommodating portion includes a housing side step surface which faces a proximal end side in an axial direction of the worm. An outer circumferential surface of the worm includes a worm side step surface which closely faces the housing side step surface in the axial direction at a portion axially deviated from a portion where the worm teeth are disposed.

Abstract: A worm reduction gear, including: an inner diameter side holder in which a bearing is internally fitted and held; an outer diameter side holder which includes a holder holding part in which the inner diameter side holder is internally fitted and held so as to be able to be relatively rotated and moved and to be displaced in a direction orthogonal to a center axis of a worm wheel and a center axis of a worm, and which is internally fitted and held in a holding recessed part of a housing; and an elastic urging member in a circumferential direction which elastically urges the inner diameter side holder against the outer diameter side holder in a direction of rotating in the circumferential direction.

Abstract: There is provided a technique that includes a first annealing step of annealing the reaction tube; a first cleaning step of cleaning an inner surface of the reaction tube, after the first annealing step, with a liquid including a fluorine compound having a first concentration; a first rinsing step of washing away the fluorine compound used in the first cleaning step with pure water; a second annealing step of annealing the reaction tube; a second cleaning step of cleaning the inner surface of the reaction tube, after the second annealing step, with a liquid including a fluorine compound having a second concentration higher than the first concentration; and a second rinsing step of washing away the fluorine compound used in the second cleaning step with pure water.