Abstract: An optical modulator includes a substrate having a main surface including a first area and a second area, an optical modulation portion disposed on the first area, and an optical waveguide portion disposed on the second area. The optical modulation portion includes a first mesa waveguide and an electrode connected to the first mesa waveguide. The first mesa waveguide includes a p-type semiconductor layer, a first core layer, and an n-type semiconductor layer. The optical waveguide portion includes a second mesa waveguide. The second mesa waveguide includes a first cladding layer, a second core layer, and a second cladding layer. The second core layer is optically coupled to the first core layer. The first cladding layer contains a p-type dopant and protons. The second cladding layer contains an n-type dopant.

Abstract: A photonic-crystal surface emitting laser includes a first semiconductor layer, a photonic crystal layer having a refractive index higher than a refractive index of the first semiconductor layer and provided on the first semiconductor layer, and an active layer provided opposite to the first semiconductor layer with respect to the photonic crystal layer. The photonic crystal layer has a first region and a plurality of second regions each having a refractive index different from a refractive index of the first region and periodically disposed in the first region in a plane of the photonic crystal layer. The second regions extend from the photonic crystal layer to the first semiconductor layer.

Abstract: A method for manufacturing an optical modulator is disclosed. The method includes a step of preparing a Mach-Zehnder modulator, a step of acquiring, based on a light transmittance in an arm waveguide, a relationship between a voltage applied to an electrode and a phase change amount of light propagating through the arm waveguide, a step of acquiring, based on the relationship, a voltage in which the phase change amount of the light propagating through the arm waveguide has a predetermined when the light is modulated, and a step of storing the voltage in a storage unit.

Abstract: A semiconductor optical device includes a substrate formed of silicon and having a first optical waveguide and a semiconductor element formed of a III-V compound semiconductor and having a second optical waveguide, the semiconductor element being bonded to an upper surface of the substrate. The first optical waveguide and the second optical waveguide form a directional coupler.

Abstract: The light modulator includes a substrate having a main surface including a first area, a second area, and a third area, a first III-V compound semiconductor layer of a first conductivity-type provided on the first area, a second III-V compound semiconductor layer of a first conductivity-type or a second conductivity-type provided on the second area, a core provided on the third area and including a group III-V compound semiconductor, and an electrode connected to the first III-V compound semiconductor layer. The first III-V compound semiconductor layer includes a first portion having a thickness smaller than a thickness of the core in a second direction orthogonal to the main surface and a second portion having a thickness larger than the thickness of the first portion in the second direction. The second portion is disposed between the first portion and the core.

Abstract: An optical filter includes a first loop mirror, a second loop mirror, a first waveguide optically coupled to the first loop mirror and the second loop mirror, and a first access waveguide. The first loop mirror includes a first loop waveguide and a first multiplexer/demultiplexer. The second loop mirror includes a second loop waveguide and a second multiplexer/demultiplexer. The first loop waveguide is optically coupled to the first multiplexer/demultiplexer. The second loop waveguide is optically coupled to the second multiplexer/demultiplexer. The first waveguide is optically coupled to the first multiplexer/demultiplexer and the second multiplexer/demultiplexer. The first access waveguide is optically coupled to the first waveguide.

Abstract: An optical modulator includes a first mesa waveguide extending in a first direction, and a second mesa waveguide. The first mesa waveguide includes a p-type first semiconductor layer disposed over a substrate, a core layer disposed over the first semiconductor layer, a p-type second semiconductor layer disposed over the core layer, and an n-type third semiconductor layer disposed over the core layer. The second semiconductor layer and the third semiconductor layer are arranged adjacent to each other in the first direction. An electrode is disposed over the third semiconductor layer. A joining surface between the second semiconductor layer and the third semiconductor layer is inclined with respect to a surface orthogonal to the first direction.

Abstract: An optical modulator includes a substrate having a main surface including a first area and a second area, an optical modulation portion disposed on the first area, and an optical waveguide portion disposed on the second area. The optical modulation portion includes a first mesa waveguide and an electrode connected to the first mesa waveguide. The first mesa waveguide includes a p-type semiconductor layer, a first core layer, and an n-type semiconductor layer. The optical waveguide portion includes a second mesa waveguide. The second mesa waveguide includes a first cladding layer, a second core layer, and a second cladding layer. The second core layer is optically coupled to the first core layer. The first cladding layer contains a p-type dopant and protons. The second cladding layer contains an n-type dopant.

Abstract: A method for manufacturing an optical modulator is disclosed. The method includes a step of preparing a Mach-Zehnder modulator, a step of acquiring, based on a light transmittance in an arm waveguide, a relationship between a voltage applied to an electrode and a phase change amount of light propagating through the arm waveguide, a step of acquiring, based on the relationship, a voltage in which the phase change amount of the light propagating through the arm waveguide has a predetermined when the light is modulated, and a step of storing the voltage in a storage unit.

Abstract: A method for manufacturing an optical modulator is disclosed. The optical modulator includes a Mach-Zehnder modulator, the Mach-Zehnder modulator including an electrode and an arm waveguide, the electrode being provided on the arm waveguide. The method includes a step of preparing the Mach-Zehnder modulator, a step of acquiring a relationship between a voltage applied to the electrode and a phase change amount of light propagating through the arm waveguide based on a light transmittance in the arm waveguide, a step of acquiring a voltage in which a range of a phase change amount of light in the Mach-Zehnder modulator has a predetermined range based on the relationship, and a step of storing the voltage in a storage unit.

Abstract: A semiconductor optical device in which a light emitting region that emits light and a reflecting region that reflects the light to the light emitting region side are integrated includes a core layer that is provided in the light emitting region, and a waveguide layer that is provided in the reflecting region, that is optically coupled to the core layer, and that has a band gap that is larger than energy of the light. The reflecting region has a first thyristor that overlaps the waveguide layer in a direction that intersects a propagation direction of the light.

Abstract: An optical modulator includes a first mesa waveguide and a second mesa waveguide. Each of the first mesa waveguide and the second mesa waveguide includes a first semiconductor layer that has a p-type conductivity and is provided on a substrate, a second semiconductor layer that has a p-type conductivity and is provided on the first semiconductor layer, a core layer provided on the second semiconductor layer, and a third semiconductor layer that has an n-type conductivity and is provided on the core layer. The first semiconductor layer has a dopant concentration greater than a dopant concentration in the second semiconductor layer.

Abstract: A semiconductor device includes: a semiconductor layer formed on a substrate; a first resin layer formed on the semiconductor layer; a second resin layer formed on the first resin layer; a first wiring layer that is formed on the semiconductor layer and is buried in the second resin layer; a second wiring layer that is formed on the second resin layer and the first wiring layer, and is electrically connected to the first wiring layer; and a first inorganic insulating film covering the second resin layer and the second wiring layer, wherein an area of the first wiring layer is larger than an area of the second wiring layer.

Abstract: An optical modulator includes an input waveguide having a first width enabling a propagation of a light-beam in a single-mode, a tapered waveguide having an input end connected to the input waveguide and an output end having a second width larger than the first width, an optical demultiplexer having an input port connected to the output end, a first output port connected to a first arm waveguide, and a second output port connected to a second arm waveguide connected to the second output port, a first electrode disposed on the first arm waveguide, and a second electrode disposed on the second arm waveguide. The first arm waveguide has a third width larger than the first width. The first arm waveguide is located within a first strip region. The first strip region having a fourth width twice as large as the third width.

Abstract: An optical modulator includes an input waveguide having a first width enabling a propagation of a light-beam in a single-mode, a tapered waveguide having an input end connected to the input waveguide and an output end having a second width larger than the first width, an optical demultiplexer having an input port connected to the output end, a first output port connected to a first arm waveguide, and a second output port connected to a second arm waveguide connected to the second output port, a first electrode disposed on the first arm waveguide, and a second electrode disposed on the second arm waveguide. The first arm waveguide has a third width larger than the first width. The first arm waveguide is located within a first strip region. The first strip region having a fourth width twice as large as the third width.

Abstract: A Mach-Zehnder modulator includes: first and second resistive elements each having first and second contact areas, the first and second contact areas of the first resistive element being arranged in a direction of a first axis, the first and second contact areas of the second resistive element being arranged in a direction of a second axis; a common conductor connecting the first contact areas of the first and second resistive elements with each other; first and second waveguide structures each including a waveguide portion extending in a direction of a third axis intersecting the first and second axes; a first signal conductor connected to the waveguide portion of the first waveguide structure and the second contact area of the first resistive element; and a second signal conductor connected to the waveguide portion of the second waveguide structure and the second contact area of the second resistive element.

Abstract: A Mach-Zehnder modulator includes a first arm waveguide; a second arm waveguide; a conductive region for connecting the first arm waveguide and the second arm waveguide to each other; a differential transmission path including a first metal body and a second metal body connected to the first arm waveguide and the second arm waveguide, respectively, and a third metal body for a reference potential; and a capacitor connected between the conductive region and the third metal body.

Abstract: A spot-size converter includes: a support body that includes a main surface including a first to a fifth areas; a mesa structure that includes a first part on the first area and includes a second part on the second to the fourth areas; and an embedding structure that includes a first region and a second region in which a first and a second side-surfaces of the second part of the mesa structure are respectively embedded. The second part of the mesa structure includes a portion that has a width gradually decreasing in a direction from the third area toward the fifth area. The first region of the embedding structure extends along the first side-surface and terminates at one of the third and the fourth areas. The second region of the embedding structure extends along the second side-surface of the second part and is disposed on the fifth area.

Abstract: A semiconductor device includes: a semiconductor layer formed on a substrate; a first resin layer formed on the semiconductor layer; a second resin layer formed on the first resin layer; a first wiring layer that is formed on the semiconductor layer and is buried in the second resin layer; a second wiring layer that is formed on the second resin layer and the first wiring layer, and is electrically connected to the first wiring layer; and a first inorganic insulating film covering the second resin layer and the second wiring layer, wherein an area of the first wiring layer is larger than an area of the second wiring layer.

Abstract: A Mach-Zehnder modulator includes: a first semiconductor arm including a lower semiconductor region, an upper semiconductor layer, and a core layer disposed between the lower semiconductor region and the upper semiconductor layer; a second semiconductor arm including a lower semiconductor region, an upper semiconductor layer, and a core layer disposed between the lower semiconductor region and the upper semiconductor layer; a conductive semiconductor region connecting the lower semiconductor regions of the first and second semiconductor arms with each other; and a differential transmission line including a first signal transmitting conductor, a second signal transmitting conductor, and a reference potential conductor. The first and second signal transmitting conductors are coupled to the first and second semiconductor arms, respectively.