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: 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: In an embodiment, an optical inspection circuit includes: an optical modulator comprising an optical waveguide on a substrate, the optical waveguide having a core comprising a semiconductor; a first input waveguide optically connected to the optical modulator, the first input waveguide having a core comprising the semiconductor; an output waveguide optically connected to the optical modulator, the output waveguide having a core comprising the semiconductor; a photodiode on the substrate in a vicinity of the optical modulator; a wire electrically connecting the optical modulator and the photodiode; and a second input waveguide optically connected to the photodiode, the second input waveguide having a core comprising the semiconductor.

Abstract: A light receiving device includes, on a substrate, a Si waveguide core provided in a dielectric layer, a first i-type waveguide clad, an i-type core layer, a second i-type waveguide clad, p-type layers disposed on one side of a side surface of a layered structure in a light waveguide direction, the layered structure including the first i-type waveguide clad, the i-type core layer, and the second i-type waveguide clad, n-type layers disposed on the other side, and an electrode on a surface of each of the n-type layers. A width of the Si waveguide core is set to be able to suppress absorption of light in a vicinity of an input edge of the i-type core layer.

Abstract: An optical connection structure includes a first optical waveguide and a second optical waveguide. The first optical waveguide is a rib-type optical waveguide including a core and a slab by a rib. Also, the first optical waveguide is formed in an optical connection region on a substrate. The second optical waveguide is formed on the substrate. The second optical waveguide includes an Si core made of Si. The second optical waveguide is disposed on the substrate in the optical connection region to overlap the first optical waveguide in a height direction.

Abstract: There is provided an optical waveguide constituted by a core made of a semiconductor and formed on a substrate. A grating coupler is provided at one end of the optical waveguide. Further, a reflecting portion formed on the optical waveguide by being optically coupled to the optical waveguide is provided at the other end of the optical waveguide. The optical waveguide constituted by the core includes a light intensity modulation unit that modulates an intensity of guided light in the optical waveguide. The light intensity modulation unit is constituted by a variable optical attenuator.

Abstract: An alignment optical circuit includes: a plurality of grating couplers that are formed on a substrate and arranged on a line; a plurality of optical waveguides that are connected to the plurality of grating couplers, respectively. Further, the alignment optical circuit includes an optical sensor that is formed on the substrate and measures optical intensity at a first light-receiving spot and a second light-receiving spot on a line along an arrangement direction of the plurality of grating couplers.

Abstract: A stage, electric probes, an optical probe, an electric measurement device, an optical measurement device, and a first positioning mechanism are provided. The stage includes a second positioning mechanism that changes relative positional relationship between the electric probes and an electric connection portion of each of the optical elements. The electric probes electrically connect the electric measurement device and each of the optical elements. The optical probe optically connects the optical measurement device and each of the optical elements. The first positioning mechanism changes relative positional relationship between the optical probe and an optical connection portion of each of the optical elements.

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: Provided is a photodetector which can be manufactured in a standard process of a mass-produced CMOS foundry. The photodetector includes a silicon (Si) substrate; a lower clad layer; a core layer including a waveguide layer configured to guide signal light, and including a first Si slab doped with first conductive impurity ions and a second Si slab doped with second conductive impurity ions; a germanium (Ge) layer configured to absorb light and including a Ge region doped with the first conductive impurity ions; an upper clad layer; and electrodes respectively connected to the first and second Si slabs and the Ge region. A region of the core layer sandwiched between the first Si slab and the second Si slab operates as an amplification layer.

Abstract: An optical characteristic inspection circuit includes, in order, an optical input element, an optical splitter circuit including a resistor, a first optical circuit to be inspected connected to one output of the optical splitter circuit, a second optical circuit to be inspected connected to another output of the optical splitter circuit, and a photodetector that detects an intensity of light transmitted through the first optical circuit to be inspected and an intensity of light transmitted through the second optical circuit to be inspected. Therefore, the present invention can provide an optical characteristic inspection circuit capable of reducing man-hours required for optical characteristic inspection.

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: Plural grating couplers having grating conditions different from each other and plural optical waveguides respectively connected with the plural grating couplers are included. The plural grating couplers have the same arraying directions of gratings. Further, each of the plural grating couplers has a different grating interval as a grating condition. Further, plural reflection units respectively provided to the plural optical waveguides are included.

Abstract: An embodiment optical test circuit includes a first optical circuit and a second optical circuit formed on a substrate, an input optical waveguide optically connected to the first optical circuit and the second optical circuit, and an output optical waveguide optically connected to the first optical circuit and the second optical circuit. The optical test circuit also includes a light emitting diode optically connected to the input optical waveguide, and a photodiode optically connected to the output optical waveguide.

Abstract: The misalignment between light reception lenses and light reception elements in a lens integrated light reception element for converting a plurality of optical signals with different wavelengths into electric signals is easily inspected. The lens integrated light reception element includes one or more light reception lenses that receive the optical signals, one or more light reception elements each disposed on a main axis of the light reception lens and converting the optical signal into the electric signal, one or more inspection pinholes through which illumination light passes, and one or more inspection lenses each including a main axis parallel to the main axis of the light reception lens and converging the illumination light having passed through the inspection pinhole.

Abstract: A light receiving device includes, on a substrate, a Si waveguide core provided in a dielectric layer, a first i-type waveguide clad, an i-type core layer, a second i-type waveguide clad, p-type layers disposed on one side of a side surface of a layered structure in a light waveguide direction, the layered structure including the first i-type waveguide clad, the i-type core layer, and the second i-type waveguide clad, n-type layers disposed on the other side, and an electrode on a surface of each of the n-type layers. A width of the Si waveguide core is set to be able to suppress absorption of light in a vicinity of an input edge of the i-type core layer.

Abstract: A light reception device of the present invention includes a first i-type cladding region, an n-type waveguide core having a predetermined width, and a second i-type cladding region in contact with a side surface of the n-type waveguide core on a substrate, includes a p-type absorption layer, a p-type diffusion barrier layer, a p-type contact layer, and a p-type electrode formed in an upper part above a region including a part of the n-type waveguide core, with an i-type insertion layer interposed between the upper part and the region, and includes an n-type electrode on an upper surface of another part of the n-type waveguide core.

Abstract: An embodiment optical circuit wafer includes a plurality of unit sections formed on a wafer. The plurality of unit sections are formed in each of first dies, second dies, and third dies. Further, each of the plurality of unit sections includes electrical pads formed in a common layout. Further, each of the plurality of unit sections includes optical input/output ports formed in a common layout. The input/output ports are, for example, grating couplers. Further, each of the plurality of unit sections includes optical circuits. The optical circuits have different circuit structures from one another.