Abstract: An optical transmission device includes a substrate, a waveguide, a signal wire, a ground wire, and a first stub wire. The waveguide is provided on the substrate and transmits an optical signal. The signal wire and the ground wire are disposed on the substrate along the waveguide and include, at end portions, bonding portions electrically connected to an external substrate by wires. The first stub wires are connected to the end portions of the ground wires. The distance between the signal wire and the first stub wire is shorter than the distance between the signal wire and the ground wire.

Abstract: An optical device includes an optical modulator formed on a substrate. The optical device includes: a signal electrode for the optical modulator that is formed on the substrate; a ground electrode for the optical modulator that is formed on the substrate; an optical waveguide that is provided in a region between the signal electrode and the ground electrode; a first buffer region that is formed between the optical waveguide and the substrate; and second buffer regions that are formed between the optical waveguide and the signal electrode and between the optical waveguide and the ground electrode. A permittivity of the second buffer regions is higher than a permittivity of the first buffer region.

Abstract: An optical device includes: a ground electrode having a ground potential; a thin film optical waveguide formed by a thin film substrate stacked on the ground electrode; a signal electrode that is arranged at a position facing the ground electrode across the thin film optical waveguide and that transmits a high frequency signal; and a dielectric that covers at least a part of an exposed surface of the signal electrode.

Abstract: An optical device includes an optical waveguide formed of a crystal thin film having an electro-optic effect, an RF electrode configured to apply a high-frequency voltage to the optical waveguide, and a DC electrode configured to apply a DC voltage to the optical waveguide, wherein the RF electrode has a coplanar electrode configuration, and the DC electrode has a microstrip electrode configuration.

Abstract: An optical device includes an optical modulator on an optical IC chip. The optical modulator includes an optical waveguide, first and second wiring patterns that are formed along the optical waveguide and a polymer pattern. A portion of the polymer pattern is formed on the optical waveguide and located in a region between the first and second wiring patterns. Each of the first and second wiring patterns includes a modulation portion that is formed parallel to the optical waveguide, a pad portion, and a transition portion that connects the modulation portion and the pad portion. A shape of a region between the transition portion of the first wiring pattern and the transition portion of the second wiring pattern is a curve. The polymer pattern has a curved portion in the region between the transition portion of the first wiring pattern and the transition portion of the second wiring pattern.

Abstract: An optical device has an optical transmitter circuit formed in a substrate, a first port configured to output an optical signal generated by the optical transmitter circuit from an edge of the substrate during services and to input a test light from the edge of the substrate during a test, and a photodetector configured to detect the test light input from the first port.

Abstract: An optical transmission device includes: a substrate; a waveguide that is provided in the substrate and transmits an optical signal; a signal wiring that is provided in the substrate and transmits an electric signal; and a silicon wiring that is provided in the substrate and is silicon added with an impurity. The signal wiring is placed in an area of the substrate, the area being away from an end of the substrate by a predetermined distance or more. One end of the silicon substrate is connected to the signal wiring, and the other end of the silicon wiring extends to the end of the substrate.

Abstract: An optical device includes: a substrate; an optical waveguide that forms a Mach-Zehnder interferometer; a signal electrode; and a ground electrode. The optical waveguide is placed between the signal electrode and the ground electrode. An electric field is generated in a direction along a surface of the substrate when a voltage is applied between the signal electrode and the ground electrode. The optical waveguide includes a first waveguide through which input light propagates, a curved waveguide which is optically coupled to the first waveguide, and a second waveguide which is optically coupled to the curved waveguide. The signal electrode includes first and second electrodes that are respectively placed near the first and second waveguides. An electric signal is supplied to the first electrode, and an inverted electric signal is supplied to the second electrode.

Abstract: An optical transmission device has a modulator, a first terminal groove, and relay groove. The modulator has a groove on a waveguide formed on a substrate. EO polymer is placed in the groove in the modulator. The modulator modulates light propagated through the waveguide by changing the phase of the light propagated through the waveguide through change of the refractive index of the EO polymer placed in the groove in the modulator by means of an electric signal. The first terminal groove is formed on the substrate and has a width larger than a width of the groove in the modulator. The relay groove is formed on the substrate and communicates with the groove in the modulator and the first terminal groove. Furthermore, the EO polymer is placed in the relay groove and the first terminal groove.

Abstract: An optical device cut from a wafer into a chip by dicing, on the wafer, the optical device includes a plurality of optical waveguides; an optical circuit connected to the optical waveguide; and of the plurality of optical waveguides, a testing optical waveguide that guides test light to the optical circuit to be tested, by bypassing a non-connected optical waveguide portion at a terrace for mounting an optical chip component.

Abstract: An optical device includes an optical circuit and a test circuit optically connected to the optical circuit. The test circuit includes a first grating coupler configured to receive test light, a second grating coupler configured to output, as reference light, the test light passed through the first grating coupler, and a first branch coupler connected to an output of the first grating coupler. The first branch coupler includes first output connected to an input of the optical circuit and configured to branch and output the test light from the first grating coupler to the optical circuit. Further, the first branch coupler includes a second output connected to an input of the second grating coupler and configured to branch and output the test light from the first grating coupler to the second grating coupler.

Abstract: A gas meter includes a meter body having a meter inlet into which a fluid-to-be-measured is to flow and a meter outlet from which the fluid-to-be-measured is to flow out, and an extended section extending from the meter inlet to an interior of the meter body. The gas meter further includes a flow rate measurement unit inside the meter body, the flow rate measurement unit having a measurement flow passage having a straight tubular shape, a lead-in port and a lead-out port for the fluid-to-be-measured, and a shutoff valve in an internal passage of the extended section. The lead-in port is airtightly connected to the extended section so as to communicate with the internal passage.

Abstract: An optical device is formed on an optical IC chip. The optical device includes: an optical device circuit; a first optical waveguide that is coupled to the a first grating coupler; a second grating coupler; a polarization rotator that is coupled to the first grating coupler; a polarization beam combiner or a polarization beam splitter that is coupled to the polarization rotator and to the second grating coupler; and a second optical waveguide that is coupled to the polarization beam combiner or to the polarization beam splitter. The first optical waveguide and the second optical waveguide respectively extend to an edge of the optical IC chip.

Abstract: An optical modulator has an optical input port and an optical output port provided on a same end of a substrate; an optical waveguide pair formed in the substrate and configured to form a Mach-Zehnder interferometer, one end of the optical waveguide pair being connected to the optical input port and the other end of the optical waveguide pair being connected to the optical output port, the optical waveguide pair having a bending part; a groove provided along the optical waveguide pair in the bending part; and a signal electrode that applies a high-frequency electrical signal to the optical waveguide pair, wherein the signal electrode has an expanded section having an increased cross sectional area at a section intersecting the groove.

Abstract: An optical waveguide includes: a plurality of linear portions arranged in parallel to each other; a plurality of arcuate portions, in the folded portion of the optical waveguide, concentrically arranged about a predetermined center position as a center on the substrate at intervals narrower than intervals between the plurality of linear portions, each of the arcuate portions having a central angle that increases as each of the arcuate portions is closer to the center position; and a plurality of connecting portions respectively connecting the plurality of linear portions and the plurality of arcuate portions, at least one group of the connecting portions bending in a direction opposite to a direction where each of the arcuate portions bends.

Abstract: An optical transmission device has a modulator, a first terminal groove, and relay groove. The modulator has a groove on a waveguide formed on a substrate. EO polymer is placed in the groove in the modulator. The modulator modulates light propagated through the waveguide by changing the phase of the light propagated through the waveguide through change of the refractive index of the EO polymer placed in the groove in the modulator by means of an electric signal. The first terminal groove is formed on the substrate and has a width larger than a width of the groove in the modulator. The relay groove is formed on the substrate and communicates with the groove in the modulator and the first terminal groove. Furthermore, the EO polymer is placed in the relay groove and the first terminal groove.

Abstract: An optical transceiver has a first optical waveguide connected to an input/output port for signal light, a second optical waveguide configured to input and output test light, an optical circuit configured to perform optical-to-electrical conversion or electrical-to-optical conversion, and an optical switch provided between the optical circuit and the first and the second optical waveguides and configured to switch between a first path connecting the optical circuit to the first optical waveguide and a second path connecting the optical circuit to the second optical waveguide, wherein the optical switch is configured to select the second path in an ON state with an electrical voltage being applied to the optical switch, and select the first path in an OFF state without the electrical voltage being applied to the optical switch.

Abstract: An optical device includes an optical modulator on an optical IC chip. The optical modulator includes an optical waveguide, first and second wiring patterns that are formed along the optical waveguide and a polymer pattern. A portion of the polymer pattern is formed on the optical waveguide and located in a region between the first and second wiring patterns. Each of the first and second wiring patterns includes a modulation portion that is formed parallel to the optical waveguide, a pad portion, and a transition portion that connects the modulation portion and the pad portion. A shape of a region between the transition portion of the first wiring pattern and the transition portion of the second wiring pattern is a curve. The polymer pattern has a curved portion in the region between the transition portion of the first wiring pattern and the transition portion of the second wiring pattern.

Abstract: An optical transmission device includes a substrate, a waveguide, a signal wire, a ground wire, and a first stub wire. The waveguide is provided on the substrate and transmits an optical signal. The signal wire and the ground wire are disposed on the substrate along the waveguide and include, at end portions, bonding portions electrically connected to an external substrate by wires. The first stub wires are connected to the end portions of the ground wires. The distance between the signal wire and the first stub wire is shorter than the distance between the signal wire and the ground wire.

Abstract: An optical device includes an optical modulator formed on an optical IC chip. A shape of the IC chip is a rectangle or a parallelogram. The optical modulator includes an interferometer, wiring patterns, a first polymer pattern, and a second polymer pattern. The interferometer includes an optical waveguide that is formed in a direction from a first edge to a second edge of the optical IC chip. The wiring patterns are formed parallel to the optical waveguide. The first polymer pattern is formed along the first edge or the second edge. The second polymer pattern is connected to the first polymer pattern and formed on the optical waveguide without overlapping the wiring patterns.