Abstract: An optical device includes an electro-optic crystal layer, a first optical waveguide formed in the electro-optic crystal layer, and an electrode that applies an electric signal to the first optical waveguide. Further, the optical device includes a second optical waveguide in an amorphous state formed in the electro-optic crystal layer and connected to the first optical waveguide.

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 device includes a substrate, a first cladding layer that is laminated on one surface of the substrate, and a first optical waveguide that is formed in the first cladding layer at a side opposite to the substrate in the first cladding layer. The optical device further includes an electro-optic crystal layer that is laminated on a surface of the first cladding layer at a side opposite to the substrate, and a second optical waveguide that is formed of the electro-optic crystal layer on a surface of the electro-optic crystal layer at a side opposite to the first cladding layer. The optical device further includes a second cladding layer that is laminated on a surface of the electro-optic crystal layer at a side opposite to the first cladding layer.

Abstract: An optical device includes an electro-optic crystal layer, a first optical waveguide formed in the electro-optic crystal layer, and an electrode that applies an electric signal to the first optical waveguide. Further, the optical device includes a second optical waveguide in an amorphous state formed in the electro-optic crystal layer and connected to the first optical waveguide.

Abstract: An optical waveguide device includes an intermediate layer, a thin-film LN layer including X-cut lithium niobate, and a buffer layer stacked on a substrate; an optical waveguide formed in the thin-film LN layer; and an electrode for driving. The intermediate layer is formed by an upper first intermediate layer and a lower second intermediate layer, the second intermediate layer having a permittivity that is smaller than a permittivity of the first intermediate layer.

Abstract: An optical device includes a thin film Lithium Niobate (LN) layer, a first optical waveguide, and a second optical waveguide. The thin film LN layer is an X-cut or a Y-cut LN layer. The first optical waveguide is an optical waveguide that is formed on the thin film LN layer along a direction that is substantially perpendicular to a Z direction of a crystal axis of the thin film LN layer. The second optical waveguide is an optical waveguide that is routed and connected to the first optical waveguide. At least a part of a core of the first optical waveguide is made thicker than a core of the second optical waveguide.

Abstract: An optical device includes an X-cut substrate, and a first waveguide and a second waveguide each being formed on the substrate and having a folding structure. The optical device includes a first signal electrode to generate a first electric field, and a second signal electrode to generate a second electric field with a reverse phase as compared to the first field. The first waveguide includes a first waveguide on an outward side to which the first field is applied from the first signal electrode, and a first waveguide on a return side to which the second field is applied from the second signal electrode. The second waveguide includes a second waveguide on the outward side to which the first field is applied from the first signal electrode, and a second waveguide on the return side to which the second field is applied from the second signal electrode.

Abstract: An optical device includes a silicon substrate, a waveguide formed of a thin film that is laminated on the silicon substrate and that is made of a perovskite oxide with a large electro-optic effect as compared to lithium niobate, and a cladding layer that covers the waveguide. Further, the optical device includes ground electrode that has a ground potential and a signal electrode that is arranged at a position facing the ground electrode and that applies driving voltage to the waveguide.

Abstract: An optical waveguide device includes an intermediate layer, a thin-film LN layer including X-cut lithium niobate, and a buffer layer stacked on a substrate; an optical waveguide formed in the thin-film LN layer; and an electrode for driving. The intermediate layer is formed by an upper first intermediate layer and a lower second intermediate layer, the second intermediate layer having a permittivity that is smaller than a permittivity of the first intermediate layer.

Abstract: An integrated photonic device having an array of two or more semiconductor optical amplifiers includes a first semiconductor optical amplifier, which has a first gain region and a second gain region connected by a first connecting waveguide, and a second semiconductor optical amplifier, which is provided in parallel with the first semiconductor optical amplifier and has a third gain region and a fourth gain region connected by a second connecting waveguide. The first gain region and the second gain region are provided on an outer side of the third gain region and the fourth gain region. The first connecting waveguide is configured to connect the first gain region and the second gain region on the outer side of the second connecting waveguide.

Abstract: An optical modulator in which an optical signal is input from one side of a package, includes in the package, a chip that optically modulates the optical signal and in which an input waveguide and an output waveguide of the optical signal are led to mutually different destinations each being one end of the chip facing the one side of the package and a side surface of the chip orthogonal to the one end of the chip; an input optical system coupled to the input waveguide of the chip; and an output optical system coupled to the output waveguide of the chip.

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 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 transceiver device includes: an optical circuit that includes an optical modulator to generate a modulated optical signal and an optical reception circuit to convert a received optical signal into an electric signal and implemented in a rectangular optical circuit area; a driver circuit that drives the optical modulator and arranged along a first side of the optical circuit area; an amplifier circuit that converts an output signal of the optical reception circuit into a voltage signal and arranged along a second side of the optical circuit area, the second side being orthogonal to the first side; a first electrical component that is electrically coupled to the driver circuit and arranged in an area adjacent to the driver circuit; and a second electrical component that is electrically coupled to the amplifier circuit and arranged in an area adjacent to the amplifier circuit.

Abstract: An optical device includes an optical coupler that performs branching of the input light and outputs a first-type branched light and a second-type branched light; a polarization converter that changes the direction of polarization of the second-type branched light output from the optical coupler; and a polarization synthesizer that outputs a polarization multiplexed light by synthesizing the first-type branched light, which is output from the optical coupler, and the second-type branched light, which has the direction of polarization changed by the polarization converter. The optical coupler has the wavelength characteristic that cancels out the wavelength characteristic of the polarization synthesizer regarding the second-type branched light included in the polarization multiplexed light.

Abstract: An optical device includes an optical coupler that performs branching of the input light and outputs a first-type branched light and a second-type branched light; a polarization converter that changes the direction of polarization of the second-type branched light output from the optical coupler; and a polarization synthesizer that outputs a polarization multiplexed light by synthesizing the first-type branched light, which is output from the optical coupler, and the second-type branched light, which has the direction of polarization changed by the polarization converter. The optical coupler has the wavelength characteristic that cancels out the wavelength characteristic of the polarization synthesizer regarding the second-type branched light included in the polarization multiplexed light.

Abstract: An optical transceiver device includes: an optical circuit that includes an optical modulator to generate a modulated optical signal and an optical reception circuit to convert a received optical signal into an electric signal and implemented in a rectangular optical circuit area; a driver circuit that drives the optical modulator and arranged along a first side of the optical circuit area; an amplifier circuit that converts an output signal of the optical reception circuit into a voltage signal and arranged along a second side of the optical circuit area, the second side being orthogonal to the first side; a first electrical component that is electrically coupled to the driver circuit and arranged in an area adjacent to the driver circuit; and a second electrical component that is electrically coupled to the amplifier circuit and arranged in an area adjacent to the amplifier circuit.