Abstract: An optical device includes a first layer, a second layer, two first waveguides arranged in a side by side manner in the first layer; two second waveguides arranged in a side by side manner in the second layer, and a third waveguide arranged between the first waveguides and between the second waveguides. The first waveguide includes a first tapered waveguide and a second tapered waveguide. The third waveguide includes a third tapered waveguide that is disposed side by side with the second tapered waveguides. The first tapered waveguide has a width that is gradually narrower as the first tapered waveguide is away from a joining point with the second tapered waveguide. The second tapered waveguide has a width that is gradually narrower as the second tapered waveguide is away from a joining point with the first tapered waveguide. The third tapered waveguide has a width that is gradually wider.

Abstract: A magnet fixing method includes heating a rotor core. The magnet fixing method also includes inserting one or more of magnets, to which fixing sheets are bonded, into the uppermost one or more of slots with the rotor core being rotatably supported by a rotating jig such that openings of the slots face sideways. The magnet fixing method also includes fixing each magnet to the corresponding slot by heating a foam layer to foam the foam layer. The inserting one or more of magnets includes inserting the magnets into all the slots by repeating insertion of one or more of the magnets into the corresponding one or more of the slots with the associated one or more of the fixing sheets facing upward, and rotation of the rotor core.

Abstract: An optical chip includes a chip area located on a wafer, and an optical circuit arranged in the chip area. The optical chip includes a first waveguide that is connected to a first operational fiber, a second waveguide, and a first coupler that includes a first port that is connected to the first waveguide and the second waveguide and a second port that is connected to the optical circuit. Furthermore, the optical chip includes a first trench that is formed on a surface of the chip area, that is connected to the second waveguide, and in which a first test purpose fiber is inserted.

Abstract: An optical device includes a plurality of first Si waveguides that split and output an optical signal received from an input unit, plurality of LN waveguides that are included in a LN modulator and that transmit the optical signals that are split and output by the first Si waveguides, and a plurality of second Si waveguides that multiplex and output the associated optical signals that are output from the plurality of respective LN waveguides. The device includes an output unit that outputs the optical signal multiplexed by the second Si waveguides, and a plurality of Mach-Zehnder interferometers disposed on each of waveguides connected by the first Si waveguides, the LN waveguides, and the second Si waveguides, respectively. When there are differences among waveguide lengths of the LN waveguides, the device is configured such that the optical path lengths of the waveguides for the respective Mach-Zehnder interferometers are equalized.

Abstract: An optical device includes an optical waveguide, a buffer layer that is layered on the optical waveguide, and an opening that is formed at least in the buffer layer above a part near a side surface of the optical waveguide. The optical device further includes an electrode that is layered in the opening and that is configured to apply a signal to the optical waveguide and a silicon layer that is layered on the buffer layer excluding the opening.

Abstract: An optical device includes a substrate, a layered structure provided on the substrate and including an intermediate layer, an optical waveguide formed of a thin crystal film having an electro-optic effect, and a buffer layer stacked in this order, and an electrode provided on or above the buffer layer and configured to apply a direct current voltage to the optical waveguide. The resistivity of the intermediate layer is higher than the resistivity of the buffer layer.

Abstract: An optical device includes two first waveguides arranged side by side, and a single second waveguide arranged so as to be side by side with and away from the first waveguides. The first waveguide includes first tapered waveguide and second tapered waveguide. The second waveguide includes a third tapered waveguide and a third waveguide. The first tapered waveguide is constituted such that width is wider as the first tapered waveguide is closer to the second tapered waveguide. The second tapered waveguide is constituted such that width is narrower as the second tapered waveguide is farther away from the first tapered waveguide. The third tapered waveguide is constituted such that width is wider as the third tapered waveguide is closer to the third waveguide. The first waveguide has a structure constituted such that first gap between the two first waveguides is made wider than second gap between the two first waveguides.

Abstract: An optical device includes a modulator and a tap coupler. The modulator includes an optical waveguide that is formed of a thin-film lithium niobate (LN) substrate and through which light passes, and an electrode that applies voltage to the optical waveguide, and modulates a phase of light that passes through the optical waveguide in accordance with an electric field in the optical waveguide, where the electric field corresponds to the voltage. The tap coupler includes at least a part formed of the thin-film LN substrate, and splits a part of the light that passes through an inside of the optical waveguide. The tap coupler includes a delayed interferometer that splits a part of the light that passes through the optical waveguide, at a split ratio corresponding to a phase difference of light that passes through an inside of the tap coupler from the optical waveguide.

Abstract: A brazing paste contain a brazing material in an amount of 80% by mass or more and 95% by mass or less; and a binder in an amount of 5% by mass or more and 20% by mass or less. The brazing material contains a flux in an amount of 2% by mass or more and 5% by mass or less. The binder contains a solid solvent containing two or more hydroxyl groups and having 8 to 10 carbon atoms, and a liquid solvent. When the binder does not contain a thixotropic agent, the liquid solvent is contained in an amount of 68% by mass or more with respect to a total of the binder, and when the binder contains a thixotropic agent, the thixotropic agent is contained in an amount of 11% by mass or less with respect to a total of the binder.

Abstract: A brazing paste contain 80% by mass or more and 95% by mass or less of a brazing material; and 5% by mass or more and 20% by mass or less of a binder. The binder contains a solid solvent containing two or more hydroxyl groups and having 5 to 7 carbon atoms, and a liquid solvent.

Abstract: An optical modulator includes a first shifter and a second shifter. The first shifter includes a first waveguide through which first light passes, and a first electrode that causes power according to a drive voltage to act on the first waveguide. The first shifter shifts a phase of the first light passing through the first waveguide in accordance with the drive voltage applied to the first electrode. The second shifter includes a second waveguide through which second light passes, and a second electrode that causes power according to a drive voltage to act on the second waveguide. The second shifter shifts a phase of the second light passing through the second waveguide in accordance with the drive voltage applied to the second electrode. The second shifter is constituted to have a smaller amount of phase shift according to a predetermined amount of drive voltage than the first shifter.

Abstract: A device includes a waveguide, an electrode that has a coplanar structure, and an interaction unit that is constituted such that the interaction unit is inserted into a slot of the waveguide, that is formed using an electro-optical polymer, and that acts on light passing through the waveguide according to a voltage received from the electrode. The device includes an excessive length unit that extends to an input side and an output side of the interaction unit and that is formed using the electro-optical polymer, and an other waveguide that is not connected to the waveguide and that is formed by inserting the excessive length unit into the slot located between a first doped layer that is connected to a ground electrode disposed parallel to the excessive length unit and a second doped layer that is connected to a signal electrode disposed parallel to the excessive length unit.

Abstract: An optical device includes a slot waveguide, and an electrode that has a coplanar structure including a signal electrode and a ground electrode disposed parallel to the slot waveguide. Furthermore, the optical device includes a plurality of electro-optical polymers each of which is inserted into a slot provided in the slot waveguide in a split state, and a bridge that is disposed in a boundary region located between the split electro-optical polymers and that electrically connects the ground electrode and another ground electrode.

Abstract: 1An optical device includes a substrate, a dielectric substance that is laminated on the substrate, an optical waveguide that is surrounded by the dielectric substance, and a heater electrode that is disposed on the optical waveguide and that is surrounded by the dielectric substance. The optical waveguide is a rib type optical waveguide that includes a slab and a rib on the slab, that is located below the heater electrode, and that has a structure in which a width of the slab is less than or equal to 11 times a width of the rib.

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: 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 coupler that inputs an optical signal received from a light source, a semiconductor optical amplifier that amplifies the optical signal received from the optical coupler, and a light receiving element that receives spontaneous emission light received from the semiconductor optical amplifier. The optical coupler includes a first input port to which the optical signal received from the light source is input, a second input port that is connected to an input stage of the light receiving element and that is different from the first input, and an output port that is connected to an input stage of the semiconductor optical amplifier, and that outputs optical signal received from the first input port to the semiconductor optical amplifier. The light receiving element receives, via the output port and the second input port, spontaneous emission light received from the semiconductor optical amplifier.

Abstract: An optical device is formed on an optical integrated circuit (IC) chip. The optical device includes: an optical circuit, a first grating coupler, a second grating coupler, a first 1×2 coupler, and a second 1×2 coupler. The first 1×2 coupler is equipped with a first optical port provided at a single-port end and a second optical port and a third optical port provided at a two-port end. The second 1×2 coupler is equipped with a fourth optical port provided at a single-port end and a fifth optical port and a sixth optical port provided at a two-port end. The first grating coupler is coupled to the first optical port. The second optical port is coupled to the optical circuit. The third optical port is coupled to the fourth optical port. The fifth optical port is coupled to the second grating coupler.