Abstract: An object of the invention is to provide an optical waveguide device which is able to efficiently absorb or remove leaked light propagating in a substrate. An optical waveguide device in which an optical waveguide is formed on a substrate, in which the optical waveguide includes a main waveguide through which signal light propagates, and a metal layer (a bonding layer or an electrode) is formed, through a high refractive index layer having a refractive index higher than the refractive index of the substrate, in at least a part of a region on which the main waveguide is not formed.

Abstract: An optical waveguide device includes a substrate with an electro-optic effect on which an optical waveguide and an electrode for controlling optical waves propagating through the optical waveguide are formed and at least one light source for irradiating ultraviolet light on the substrate.

Abstract: A thin-plate LN optical control device includes: a thin-plate LN optical waveguide element which includes an optical waveguide formed by thermal diffusion of Ti in a substrate made of lithium niobate, and a control electrode that is formed on the substrate and is configured to control a light wave propagating through the optical waveguide, and in which at least a part of the substrate is thinned; and a housing that accommodates the thin-plate LN optical waveguide element in an air-tight sealing manner. Oxygen is contained in a filler gas inside the housing.

Abstract: In a waveguide-type optical element, broaderband operation becomes possible. The waveguide-type optical element includes optical waveguides (110 and 112) formed on a substrate (100) having an electro-optic effect and a control electrode for controlling an optical wave that is transmitted through the optical waveguide, the control electrode comprises a central electrode (104) and ground electrodes (106 and 108), the central electrode being formed along the optical waveguide, and the ground electrodes being formed so as to put the central electrode therebetween in a surface direction of the substrate at a predetermined distance from the central electrode, and the central electrode or the ground electrodes have multiple pairs of facets, each comprising two facets facing each other, along a transmission direction of high-frequency signals that are transmitted through the central electrode and the ground electrodes.

Abstract: A thin-plate LN optical control device includes: a thin-plate LN optical waveguide element which includes an optical waveguide formed by thermal diffusion of Ti in a substrate made of lithium niobate, and a control electrode that is formed on the substrate and is configured to control a light wave propagating through the optical waveguide, and in which at least a part of the substrate is thinned; and a housing that accommodates the thin-plate LN optical waveguide element in an air-tight sealing manner. Oxygen is contained in a filler gas inside the housing.

Abstract: In a waveguide-type optical element, broaderband operation becomes possible. The waveguide-type optical element includes optical waveguides (110 and 112) formed on a substrate (100) having an electro-optic effect and a control electrode for controlling an optical wave that is transmitted through the optical waveguide, the control electrode comprises a central electrode (104) and ground electrodes (106 and 108), the central electrode being formed along the optical waveguide, and the ground electrodes being formed so as to put the central electrode therebetween in a surface direction of the substrate at a predetermined distance from the central electrode, and the central electrode or the ground electrodes have multiple pairs of facets, each comprising two facets facing each other, along a transmission direction of high-frequency signals that are transmitted through the central electrode and the ground electrodes.

Abstract: To effectively prevent the acceleration of the drift phenomenon generated by the application of a high electric field to a substrate through a bias electrode in a waveguide type optical element. A waveguide type optical element includes a substrate (100) having an electro-optic effect, two optical waveguides (104 and 106) disposed on a surface of the substrate, a non-conductive layer (120) which is disposed on the substrate and is made of a material having a lower dielectric constant than the substrate, and a control electrode (150) which is disposed on the non-conductive layer and is intended to generate a refractive index difference between the two optical waveguides by respectively applying electric fields to the two optical waveguides, and the non-conductive layer is constituted of a material which includes silicon oxide, an oxide of indium, and an oxide of titanium and has a ratio between a molar concentration of the titanium oxide and a molar concentration of indium oxide of 1.

Abstract: To effectively prevent the acceleration of the drift phenomenon generated by the application of a high electric field to a substrate through a bias electrode in a waveguide type optical element. A waveguide type optical element includes a substrate (100) having an electro-optic effect, two optical waveguides (104 and 106) disposed on a surface of the substrate, a non-conductive layer (120) which is disposed on the substrate and is made of a material having a lower dielectric constant than the substrate, and a control electrode (150) which is disposed on the non-conductive layer and is intended to generate a refractive index difference between the two optical waveguides by respectively applying electric fields to the two optical waveguides, and the non-conductive layer is constituted of a material which includes silicon oxide, an oxide of indium, and an oxide of titanium and has a ratio between a molar concentration of the titanium oxide and a molar concentration of indium oxide of 1.

Abstract: An aspect of the present invention is an optical modulator including a substrate, a plurality of optical waveguides, and a plurality of modulation electrodes provided on the substrate in order to modulate light propagating through the optical waveguides. The modulation electrodes include signal electrodes, to which modulation signals are supplied, and ground electrodes. The signal electrodes include first and second signal electrodes. The ground electrodes include a first ground electrode provided between the first and second signal electrodes, a second ground electrode provided on the opposite side of the first signal electrode from the first ground electrode adjacent to the first signal electrode, and a third ground electrode provided on the opposite side of the second signal electrode from the first ground electrode adjacent to the second signal electrode. A concave groove is formed in each of the first to third ground electrodes.

Abstract: An aspect of the present invention is an optical modulator including an electro-optic substrate, an optical waveguide, and a signal electrode for applying an electric field corresponding to a modulation signal to the optical waveguide. The electro-optic substrate includes a trench portion, which is formed by digging a surface of the electro-optic substrate, and a ridge portion, which is formed in a ridge shape by the trench portion so that an optical waveguide is provided. The trench portion includes a first trench portion, which is a trench portion between a pair of branched optical waveguides, and a second trench portion, which is a trench portion other than the first trench portion. Digging depths of the first and second trench portions are different.

Abstract: An optical waveguide device includes a substrate with an electro-optic effect on which an optical waveguide and an electrode for controlling optical waves propagating through the optical waveguide are formed and at least one light source for irradiating ultraviolet light on the substrate.

Abstract: To provide an optical device sealing structure capable of simply sealing an optical fiber inserting portion. Provided is a structure that seals an optical device including a metallic case having an optical element disposed therein and an optical fiber inserted through a through hole of the case, wherein a Zn-containing surface is formed on a surface of a bare fiber portion that is formed by partly removing a coating of the optical fiber so as to expose a bare fiber, and wherein an Sn-containing sealing material is charged between the Zn-containing surface and an inner wall of the through hole.

Abstract: An optical modulator has a ridge optical waveguide and a modulation electrode. The modulation electrode is composed of a signal electrode to which a modulation signal is supplied, a first ground electrode, and a second ground electrode, the signal electrode has a wide portion having a width wider than the width of the uppermost portion of the ridge optical waveguide, the first ground electrode has a central portion ground electrode component provided on a first surface so as to extend along a first direction, and the second ground electrode has a central portion ground electrode component provided on a second surface so as to extend along the first direction. The central portion ground electrode components respectively have a first and a second through-holes, and these through-holes overlap the wide portion of the signal electrode as seen in a planar view.

Abstract: To provide an optical device sealing structure capable of simply sealing an optical fiber inserting portion. Provided is a structure that seals an optical device including a metallic case having an optical element disposed therein and an optical fiber inserted through a through hole of the case, wherein a Zn-containing surface is formed on a surface of a bare fiber portion that is formed by partly removing a coating of the optical fiber so as to expose a bare fiber, and wherein an Sn-containing sealing material is charged between the Zn-containing surface and an inner wall of the through hole.

Abstract: An object is to provide a light modulator capable of highly accurate bias control by maintaining main output characteristics and monitor characteristics in an appropriate relationship and matching a bias point determined using monitor output and an optimal bias point of main output. The light modulator includes an optical waveguide formed in a substrate having a thickness of 20 ?m or less, in which the optical waveguide includes a Mach-Zehnder waveguide and an output waveguide for guiding signal light from a multiplexing portion of the Mach-Zehnder waveguide and outputting the signal light outside the substrate and monitoring means that monitors signal light or radiated light. Leaked light-removing means for removing some of the radiated light propagating through the output waveguide from the output waveguide and emitting the radiated light outside the substrate is provided in the light modulator.

Abstract: A method according to an aspect of the present invention, is a method for manufacturing an optical waveguide element, including: an optical waveguide forming step of forming an optical waveguide extending in a first direction in a substrate by doping the substrate with an impurity for reducing a coercive electric field of the substrate, a ridge forming step of forming a first ridge part including the optical waveguide and a second ridge part intersecting the first ridge part, and a poling step of reversing a polarization direction of a region of the substrate divided by the second ridge part by applying voltage to the region.

Abstract: In order to provide an optical modulator capable of suppressing generation of mode mismatching light in the Y-multiplexer in the MZ-type waveguide or mixing of the mode mismatching light with the radiation-mode light or the output light, and separately extracting output light and radiation-mode light, there is provided an optical modulator having a Mach-Zehnder type waveguide on a surface of a dielectric substrate, wherein a waveguide after multiplexing in a Y-multiplexer in an output side of the Mach-Zehnder type waveguide is a multiple mode waveguide 2, a subsidiary output waveguide as a high-order mode waveguide 2 is connected to a portion where the multiple mode waveguide is changed to a main output waveguide 3 as a single mode waveguide, and the multiple mode waveguide 2 has a length equal to or longer than 150 ?m.

Abstract: An optical waveguide device in which optical characteristics are less degraded even when a branch angle in a Y branch portion of an optical waveguide is great is provided.

Abstract: An optical modulator has a ridge optical waveguide and a modulation electrode. The modulation electrode is composed of a signal electrode to which a modulation signal is supplied, a first ground electrode, and a second ground electrode, the signal electrode has a wide portion having a width wider than the width of the uppermost portion of the ridge optical waveguide, the first ground electrode has a central portion ground electrode component provided on a first surface so as to extend along a first direction, and the second ground electrode has a central portion ground electrode component provided on a second surface so as to extend along the first direction. The central portion ground electrode components respectively have a first and a second through-holes, and these through-holes overlap the wide portion of the signal electrode as seen in a planar view.

Abstract: An aspect of the present invention is an optical modulator including a substrate, a plurality of optical waveguides, and a plurality of modulation electrodes provided on the substrate in order to modulate light propagating through the optical waveguides. The modulation electrodes include signal electrodes, to which modulation signals are supplied, and ground electrodes. The signal electrodes include first and second signal electrodes. The ground electrodes include a first ground electrode provided between the first and second signal electrodes, a second ground electrode provided on the opposite side of the first signal electrode from the first ground electrode adjacent to the first signal electrode, and a third ground electrode provided on the opposite side of the second signal electrode from the first ground electrode adjacent to the second signal electrode. A concave groove is formed in each of the first to third ground electrodes.