Abstract: An optical device includes a substrate that includes a substrate-side electrode, and a chip that includes N active layers and a chip-side electrode that is mounted on the substrate-side electrode. From among bumps that are disposed side by side with an Nth layer on both sides of a surface that is located opposite the Nth layer and that is included in the substrate-side electrode, bumps located at a position farther away from the center of gravity of all of the bumps are defined as first bumps, and bumps located at a position closer to the center of gravity are defined as second bumps. In at least one combination of the first bump and the second bump, the first bump and the second bump are arranged on the substrate-side electrode such that a distance between the first bump and the surface is longer than a distance between the second bump and the surface.

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: An optical device includes an optical amplifier that optically amplifies incident light, a first isolator that is arranged on an input stage of the optical amplifier and inputs the incident light to the optical amplifier, and a second isolator that is arranged on an output stage of the optical amplifier and receives input of incident light that has been optically amplified by the optical amplifier. The first isolator inputs, to the optical amplifier, first linearly-polarized incident light that is converted from randomly-polarized incident light and that has been transmitted. The second isolator, when reflected light of the first linearly-polarized incident light that has been optically amplified by the optical amplifier is input from a reverse direction, converts reflected light of the first linearly-polarized incident light to reflected light of second linearly-polarized light that is orthogonal to the reflected light of the first linearly-polarized incident light.

Abstract: An optical device includes an input waveguide and an output waveguide. The optical device includes an interference region that includes an input unit optically coupled with the input waveguide, that includes an output unit optically coupled with the output waveguide, and that has a larger waveguide width than a waveguide width of the input waveguide and a waveguide width of the output waveguide. Further, the optical device includes an unnecessary light waveguide that is included in the output unit in the interference region and that is arranged parallel to the output waveguide. The unnecessary light waveguide is a single-mode waveguide that includes a rib portion and a slab portion with a smaller thickness than a thickness of the rib portion, and that guides only a fundamental mode of light.

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 circuit element formed on a substrate, the optical circuit element includes a first waveguide and a second waveguide, the second waveguide having a shape in a width direction, the shape being asymmetrical to the first waveguide. The first waveguide includes a first segment and a second segment, the first segment having a width that changes along a light propagation direction, the second segment continuous with the first segment. The second waveguide includes a coupled waveguide adjacent to the second segment of the first waveguide. At least one of the second segment and the coupled waveguide has a shape with a width that changes along the light propagation direction.

Abstract: An optical transmission module includes a photonic integrated circuit, a processor that controls the power state of the photonic integrated circuit, and a current source circuit that supplies electric current to a light source used for the photonic integrated circuit. The photonic integrated circuit has an optical multiplexer block including a plurality of multiplexers connected in a n-level tree structure (n is an integer greater than 1), 2{circumflex over (?)}n optical modulators connected to inputs of the optical multiplexer block, and a photodetector connected to an input or an output of each of the plurality of the multiplexers. The light source emits a light beam to be incident onto a corresponding one of the 2{circumflex over (?)}n optical multiplexers. The processor controls the current source circuit for each of the plurality of the multiplexers, based on the monitored value acquired from the photodetector provided to each of the plurality of the multiplexers.

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 a transition unit in which a first waveguide and a second waveguide are disposed in an overlapped manner such that a magnitude relationship of an effective refractive index between the vertical modes propagating the first waveguide and the vertical modes propagating the second waveguide is inverted at the positions of input and output. The transition unit allows, at the input, the second waveguide to be a single mode waveguide and allows, at the output, the second waveguide to be a multi-mode waveguide through which TM0 light in the maximum vertical mode and light in a higher-order mode propagate. The optical device includes a removing unit that allows the second waveguide to be a single mode waveguide through which the TM0 light propagates by removing the light in the higher-order mode from the light received from the transition unit.

Abstract: An optical waveguide device includes a pair of waveguides. One of the waveguides includes a first core formed in a conversion region and a third core formed in an exit region. The other of waveguides includes a second core formed in the conversion region and a fourth core formed in the exit region. Cross-sectional areas of the first and second cores are different from each other at an input end. Distributions of a refractive index of the first and second cores are respectively asymmetric in a perpendicular direction. A quantitative relation provided at the input end between an effective refractive index of an odd mode of TE0 and an effective refractive index of an even mode of TM0 is opposite to the quantitative relation provided at the output end. Cross-sectional areas of the third and fourth cores are different from each other at an output end.

Abstract: A wavelength tunable laser device includes: a first mirror; a second mirror; an optical amplifier provided between the first mirror and the second mirror; a wavelength tunable filter provided between the first mirror and the second mirror; and an optical waveguide coupling the optical amplifier and the wavelength tunable filter. The optical waveguide includes a first waveguide formed with a first width and a second waveguide formed with a second width wider than the first width.

Abstract: An optical module includes: a first board having an optical component bonded thereto with an adhesive; a connection structure part rising from the first board and made of a material having lower thermal conductivity than thermal conductivity of a material of the first board; and a second board joined to the connection structure part.

Abstract: A multilayer film includes a single-crystal silicon layer, a first layer containing Zr, a second layer containing ZrO2, and a third layer containing a perovskite oxide having an electrooptic effect. The first layer, the second layer, and the third layer are provided in this order above the single-crystal silicon layer, and the multilayer film is transparent to a wavelength to be used.

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 waveguide device has a substrate, an intermediate layer, a thin-film LN layer containing an X-cut lithium niobate, and a buffer layer stacked on the substrate, and an optical waveguide having a ridge shape formed in the thin-film LN layer. The optical waveguide device includes a plurality of electrodes provided, respectively, at a first side and a second side of the optical waveguide. The electrodes are disposed so that respective bottom surfaces thereof are at positions lower than a position of a surface of the buffer layer.

Abstract: An optical waveguide device includes a substrate on which an intermediate layer, a thin-film LN layer of lithium niobate, and a buffer layer are stacked; an optical waveguide formed in the thin-film LN layer; and a plurality of electrodes near the optical waveguide. The intermediate layer and the buffer layer contain a same material of a metal element of any one of group 3 of group 18 of a periodic table of elements.

Abstract: An optical 90-degree hybrid includes two splitters, two combiners and four arm waveguides that connect output ports of the splitters and input ports of the combiners. Each of the splitters, the arm waveguides, and the combiners is a part of an optical waveguide. The optical waveguide is configured so that the phase error generated in the splitters due to wavelength change is suppressed by the phase error generated in the arm waveguides due to the wavelength change. The optical waveguide is further configured so that the phase error generated in the splitters due to deviation of a structure parameter from a certain value (e.g., design value) is suppressed by the phase error generated in the arm waveguides due to the deviation.