Abstract: An oscillation wavelength adjustment type TLD for adjusting a control amount of a resonator length L, independently from physical property values of a waveguide material when a waveguide is used in the phase adjustment, without an external resonator structure in accordance with a MEMS technology employs a reflective phase adjuster including a multi-mode interference waveguide, which is optically coupled to an optical gain waveguide and has a configuration including one input port and five output ports, and a reflective delay line array connected to an output waveguide on a side of the five output ports of the multi-mode interference waveguide. Five reflective delay lines provided in the reflective delay line array are capable of adjusting the intensity of reciprocating light in accordance with a wavelength change of transmitted light.

Abstract: A heat exchange plate having flow paths through which a heat medium flows and an elongated rectangular plate shape including: an upper and lower walls covering the flow paths from both sides of the heat exchange plate in a plate thickness direction; and partition walls connecting the upper and lower walls in the plate thickness direction to partition the flow paths. The heat medium flows through the flow paths is a longitudinal direction of the heat exchange plate. At least one end portion of the heat exchange plate in the longitudinal direction closes the plurality of flow paths. The upper and lower walls, and partition walls constituting the closing portion are compressed in the plate thickness direction. The heat exchange plate further includes: a brazing portion filling a gap present between the upper wall and lower walls, and the partition walls constituting the closing portion.

Abstract: An optical semiconductor chip of the present disclosure includes a high frequency line between an electrode pad receiving a modulation signal and a modulation electrode on the optical waveguide constituting a laser. The depletion layer capacitance generated in an active layer of the optical waveguide is cancelled by an inductance component of the high frequency line. When a portion directly below the high frequency line is embedded with a low-dielectric-constant material or is made hollow, the parasitic capacitance is further reduced. The high frequency line may have a zigzag shape as well as a linear shape. The electrode pad on the optical semiconductor chip can be connected to other substrates including RF lines for modulation signal input by bumps or wire bonding.

Abstract: A wavelength-tunable laser includes a substrate, a waveguide layer over the substrate, and a cladding over the waveguide layer. The wavelength-tunable laser further includes an active layer in a part of the waveguide layer, and a tunable wavelength filter in at least one end region of the waveguide layer in a direction along which light is to be guided.

Abstract: An optical semiconductor chip of the present disclosure includes a high frequency line between an electrode pad receiving a modulation signal and a modulation electrode on the optical waveguide having a light absorption layer. The depletion layer capacitance generated in the light absorption layer is canceled by an inductor component of the high frequency line. When a portion directly below the high frequency line is embedded with a low-dielectric-constant material or is made hollow, the parasitic capacitance is further reduced. The high frequency line may have a zigzag shape as well as a linear shape. The electrode pad on the optical semiconductor chip can be connected to other substrates including RF lines for modulation signal input by bumps or wire bonding.

Abstract: An optical waveguide is an optical waveguide including a semiconductor quantum well structure, the optical waveguide including a first region in which the semiconductor quantum well structure is not disordered and a second region in which the semiconductor quantum well structure is disordered. The first region has a first bandgap wavelength, the second region has a second bandgap wavelength, and a region in which the semiconductor quantum well structure is disordered in such a manner that a bandgap wavelength continuously decreases from the first bandgap wavelength to the second bandgap wavelength is provided between the first region and the second region.

Abstract: Provided are an optical transmitter that improve a signal path between the optical modulation module and a substrate, prevent deterioration of a modulated signal, and can obtain a signal in a wide frequency band. An optical transmitter of the present disclosure includes an optical modulation light source chip, an RF wiring substrate connected to the optical modulation light source chip, and an RF connection substrate having a metal bump connecting the optical modulation light source chip and the RF wiring substrate. The optical modulation light source chip is configured to include a semiconductor substrate, a semiconductor layer, a wiring layer connected to the semiconductor substrate and in contact with the metal bump, and a wiring layer connected to the semiconductor layer and in contact with the metal bump.

Abstract: In the wavelength variable light source and its control method of the present disclosure, intensity of oscillation light in a plurality of non-operating ports of MMI is utilized in consideration of filter characteristics between an operating port and a non-operating port that does not directly contribute to oscillation operation. By controlling the RTF laser so that the light intensity of the wavelength of the oscillation light in the monitored non-operation port is in a desired relationship, a wavelength variable light source reflecting SMSR characteristics is realized. The SMSR can be effectively controlled only by adding a photodetector to a non-operation port which has not been considered by the RTF laser of the prior art. In the wavelength variable light source, the inspection of the SMSR and the SMSR monitor during actual operation can be realized by a simple mechanism.

Abstract: An photonic integrated circuit for which a mounting process in free space optics is not performed, formation and airtight sealing of an optical device are precisely performed, and cost reduction can be effectively achieved has a configuration including a lid portion connected to an upper surface of a semiconductor substrate to cover an optical waveguide and a mirror provided on the upper surface of the semiconductor substrate and a lens in the lid portion for concentrating light reflected by the mirror and emitting the light outward. A bonding material on an upper surface of a dielectric film formed above the upper surface of the semiconductor substrate and a bonding material formed in a peripheral edge portion of the lid portion are disposed so as to overlap witheach other to be bonded.

Abstract: An oscillation wavelength adjustment type TLD for adjusting a control amount of a resonator length L, independently from physical property values of a waveguide material when a waveguide is used in the phase adjustment, without an external resonator structure in accordance with a MEMS technology employs a reflective phase adjuster (20) including a multi-mode interference waveguide (21), which is optically coupled to an optical gain waveguide and has a configuration including one input port and five output ports, and a reflective delay line array (25) connected to an output waveguide on a side of the five output ports of the multi-mode interference waveguide (21). Five reflective delay lines (24-0 to 24-4) provided in the reflective delay line array (25) are capable of adjusting the intensity of reciprocating light in accordance with a wavelength change of transmitted light. The intensity of the reciprocating light can also be adjusted by an electric signal applied from the outside.

Abstract: An optical semiconductor chip of the present disclosure includes a high frequency line between an electrode pad receiving a modulation signal and a modulation electrode on the optical waveguide having a light absorption layer. The depletion layer capacitance generated in the light absorption layer is canceled by an inductor component of the high frequency line. When a portion directly below the high frequency line is embedded with a low-dielectric-constant material or is made hollow, the parasitic capacitance is further reduced. The high frequency line may have a zigzag shape as well as a linear shape. The electrode pad on the optical semiconductor chip can be connected to other substrates including RF lines for modulation signal input by bumps or wire bonding.

Abstract: An optical waveguide is an optical waveguide including a semiconductor quantum well structure, the optical waveguide including a first region in which the semiconductor quantum well structure is not disordered and a second region in which the semiconductor quantum well structure is disordered. The first region has a first bandgap wavelength, the second region has a second bandgap wavelength, and a region in which the semiconductor quantum well structure is disordered in such a manner that a bandgap wavelength continuously decreases from the first bandgap wavelength to the second bandgap wavelength is provided between the first region and the second region.

Abstract: After a step of etching a core layer, a lower cladding layer, and a substrate so that a recessed opening including one end of an optical waveguide is formed relative to a multilayer board and a step of forming mask layers on a top surface of the substrate including the opening, in a step, crystal is grown with respect to the mask layers in the opening, and a tilt surface to be used as the monolithic mirror is formed. An upper cladding layer is formed covering the core layer at the same time. Then, formation of an optical waveguide pattern, formation of the optical waveguide and an end surface of the optical waveguide, formation of a dielectric film for preventing reflection, and formation of a metal film on a surface of the tilt surface are executed.

Abstract: An optical circuit is provided in which electric circuit parts and optical circuit parts are integrated in a stack on a printed substrate. The optical circuit is provided with a lid having a temperature regulation function that uses a temperature control element and an optical fiber block capable of optical input and output. Temperature control of optical circuit elements can be efficiently performed by mounting electric circuit parts and optical circuit parts on a printed substrate in advance by a reflow step using OBO technology and subsequently attaching a lid that includes a temperature control element.

Abstract: A semiconductor device includes an electrode which is arranged on an organic material with an insulation film interposed therebetween and which does not easily peel away from the organic material along with the insulation film. An insulation film in a region including pad portions of a phase shift electrode and a modulation electrode has openings at the centers of the pad portions of the phase shift electrode and the modulation electrode, the edge portions of which are formed on the phase shift electrode and the modulation electrode. In this way, the adjoining edges of the phase shift electrode and modulation electrode and the insulation film are all covered by the insulation film so as not to be exposed to the atmosphere.

Abstract: A tunable laser that is characterized by including a gain waveguide ACT made of an optically active semiconductor material, and a tunable wavelength filter TWF that selects light of a specific wavelength using current injection, which are integrated on a compound semiconductor substrate S, in which at least one or more of the tunable wavelength filters TWF are formed to select a specific wavelength of light from the light from the waveguide ACT and return the selected specific wavelength of light back to the waveguide ACT, and a semiconductor mixed crystal material constituting the tunable wavelength filter TWF has a strained multiple quantum well structure MQW in which a mixed crystal material ratio changes periodically.

Abstract: An optical module includes: a substrate; one or more light sources that produce light that is an optical signal; one or more light reflection units that change the direction of travel of the light to a direction substantially perpendicular to the substrate; one or more optical waveguides that optically connect the one or more light sources and the one or more light reflection units to each other; and a lid that is attached to the substrate to cover the one or more light sources, the one or more light reflection units and the one or more optical waveguides. The lid has one or more lenses that collimate light directed by the one or more light reflection units and transmit the light to the outside of the lid.

Abstract: There is provided an optical element mounted on a substrate and an optical coupling element mounted on the substrate. The optical coupling element includes a guide unit extending in a direction parallel to a plane of the substrate so as to fix an optical fiber. There is provided a mold resin layer formed on the substrate so as to cover the optical element and expose a side surface of the optical coupling element at one end of the guide unit. The optical element includes a light incidence/emission unit on a side surface perpendicular to the plane of the substrate, and the other end of the guide unit and the light incidence/emission unit are disposed to face each other.

Abstract: To provide an optical module, an optical wiring board, and a method for manufacturing an optical module that provide the two-dimensional freedom degree of the joint portion between the optical module and the optical fiber even through the OBO method is applied to an optical module mounted via WLP.

Abstract: An optical integrated circuit of the present disclosure is a monolithic optical integrated circuit formed on a substrate and includes a semiconductor laser, a 1×N optical demultiplexer, array waveguides including N waveguides, each of the N waveguides having a semiconductor optical amplifier (SOA) configured to amplify a corresponding split light beam from the semiconductor laser, and an N×1 optical multiplexer. A phase of light beams output from the SOA at input ports of the N×1 optical multiplexer is set so that the output light beams are multiplexed at an output port of the N×1 optical multiplexer in the same phase. A phase can be set by setting a length of the N waveguides and providing a phase adjuster.