Abstract: An optical waveguide device includes a first substrate including a first optical waveguide and a low refractive index layer covering the first optical waveguide and being formed of a material having a lower refractive index than a refractive index of the first optical waveguide, and a second substrate joined to the first substrate and including a rib type optical waveguide which is a second optical waveguide and is formed of a material having an electro-optic effect, in which the first optical waveguide and the second optical waveguide have parts optically coupled to each other, and in plan view of the optical waveguide device, a protruding portion is formed in the second substrate in a boundary portion where the first optical waveguide overlaps with the second substrate, and a thickness of the second substrate in the protruding portion is set to be thinner than a thickness of the second substrate in the second optical waveguide.

Abstract: An optical waveguide element includes a substrate, an optical waveguide disposed inside the substrate or on the substrate, and an electrode provided along the optical waveguide, working on the optical waveguide to generate a phase change in a light wave propagating through the optical waveguide. The electrode is a traveling-wave electrode. In a modulation section where the light wave is controlled by the electrode, the electrode and the optical waveguide are configured so that the phase change generated in a first modulation section located within a predetermined distance range from a downstream side end portion along a propagation direction of a traveling wave of an electrical signal propagating through the electrode has a sign opposite to a sign of the phase change generated in a second modulation section located within a predetermined distance range from an input end of the electrical signal on an upstream side along the propagation direction.

Abstract: To provide an optical element in which an electrode is directly formed on an LN substrate, and a drift phenomenon is suppressed. In an optical element including: a substrate made of lithium niobate crystals; and an electrode disposed on the substrate, the substrate and the electrode are in direct contact with each other, and as a contact metal disposed on a surface of the electrode where the electrode is in contact with the substrate, a metal material whose standard enthalpy of formation per coordinate bond upon oxidation is greater than a standard enthalpy of formation per coordinate bond of niobium pentoxide is used.

Abstract: To provide an optical element in which an electrode is directly formed on an LN substrate, and a drift phenomenon is suppressed. In an optical element including: a substrate made of lithium niobate crystals; and an electrode disposed on the substrate, the substrate and the electrode are in direct contact with each other, and as a contact metal disposed on a surface of the electrode where the electrode is in contact with the substrate, a metal material whose standard enthalpy of formation per coordinate bond upon oxidation is greater than a standard enthalpy of formation per coordinate bond of niobium pentoxide is used.

Abstract: Provided is an optical modulator module in which an occurrence of an error burst or an increase of an optical loss caused by a vapor phase transportation material can be effectively suppressed. The optical modulator module includes a substrate 1 that has a pyroelectric effect, an optical waveguide 2 that is formed on a principal surface of the substrate 1, a conductive film (not illustrated) that is formed on the substrate 1, and control electrodes (31 to 33) that control a light wave propagated through the optical waveguide 2. In the optical modulator module, the light wave is input to an end portion 21 of the optical waveguide (or is output from the end portion 21 of the optical waveguide) by a space optical system (not illustrated). Adsorption means 4 for adsorbing a vapor phase transportation material is disposed in the vicinity of the end portion 21 of the optical waveguide.

Abstract: An optical modulator including an optical modulation element mounted inside a housing, in which at least a portion of an electric line is connected to an external circuit board through a flexible printed circuit, and which is disposed on the external circuit board. A recess portion that mounts the flexible printed circuit is formed on an outer bottom surface of the housing and at a part where the flexible printed circuit is connected, and a device for preventing a resonance mode is provided such that a resonance mode of a microwave and a millimeter wave or a parallel plate mode is prevented from being generated among a surface A of the recess portion facing the flexible printed circuit, an electric wiring part B provided on the flexible printed circuit overlapping the surface A when seen in a plan view, an electric wiring part C provided on the external circuit board overlapping the surface A when seen in a plan view.

Abstract: It is possible to suppress carrier light with a simple configuration when modulating the carrier light to generate optical sideband components. An optical carrier-suppressed signal generator includes first splitting means used to split input carrier light into two light beams, an optical modulator which modulates one split carrier light beam and outputs light including optical sideband components, a phase modulator which phase-modulates another split carrier light beam, and second or third splitting means used to split the output light of the optical modulator into two light beams. The output light split by the second or third splitting means and the output light of the phase modulator are multiplexed to obtain the amplitude of the signal waveform of optical power, and the optical modulator is controlled such that the obtained value is minimized.

Abstract: Provided is an optical waveguide device in which destabilization of a DC bias which is applied to an optical waveguide, due to a bias electrode picking up electric noise, is reduced and an operating characteristic is stable. An optical waveguide device includes: a substrate having an electro-optic effect; an optical waveguide formed on the substrate; a modulation electrode for applying an electric field corresponding to a modulation signal to the optical waveguide; and a bias electrode for applying an electric field corresponding to a DC bias to the optical waveguide, in which in order to reduce capture of electric noise by the bias electrode, with respect to at least a part of the bias electrode, a plurality of electrode portions (b11, b12) are formed in at least one (B1) of the pair of electrodes by folding back one electric line.

Abstract: Provided is an optical modulator including: a relay substrate; a first transmission line that is provided on a flat surface of the relay substrate, and transmits an electrical signal along the flat surface; a second transmission line that is provided separately from the relay substrate, is electrically connected to the first transmission line, and transmits, to the first transmission line, the electrical signal that has been input from an outer side in a direction that is not included in the flat surface; a modulation unit that modulates an optical signal by using the electrical signal that is transmitted by the first transmission line and the second transmission line; and a shield that shields a radiation component of the electrical signal that is radiated from the second transmission line.

Abstract: An optical modulator including an optical modulation element mounted inside a housing, in which at least a portion of an electric line is connected to an external circuit board through a flexible printed circuit, and which is disposed on the external circuit board. A recess portion that mounts the flexible printed circuit is formed on an outer bottom surface of the housing and at a part where the flexible printed circuit is connected, and a device for preventing a resonance mode is provided such that a resonance mode of a microwave and a millimeter wave or a parallel plate mode is prevented from being generated among a surface A of the recess portion facing the flexible printed circuit, an electric wiring part B provided on the flexible printed circuit overlapping the surface A when seen in a plan view, an electric wiring part C provided on the external circuit board overlapping the surface A when seen in a plan view.

Abstract: Provided is an optical modulator in which a phenomenon of a resonance mode or the like is prevented from being generated in a recess portion of a housing that mounts a flexible printed circuit and of which broadband characteristics are improved. There is provided an optical modulator in which an optical modulation element is mounted inside a housing, in which at least a portion of an electric line is connected to an external circuit board 7 through a flexible printed circuit 6, and which is disposed on the external circuit board.

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: Provided is an optical modulator module including a waveguide substrate in which an optical waveguide and control electrodes (signal electrode, DC bias electrodes, and the like) for controlling a light wave propagating through the optical waveguide are formed, a relay substrate which is disposed in the vicinity of the waveguide substrate and in which a DC bias wiring for supplying a DC bias voltage to the control electrodes (DC bias electrodes) is formed, and a package case which stores the waveguide substrate and the relay substrate. A loop of wire standing from the relay substrate to a position higher than a top surface of the waveguide substrate is provided in a part of the DC bias wiring. The loop of wire is disposed inside the package case at a position within 10 mm from any one of locations where a solder is used.

Abstract: Provided is an optical modulator module in which an occurrence of an error burst or an increase of an optical loss caused by a vapor phase transportation material can be effectively suppressed. The optical modulator module includes a substrate 1 that has a pyroelectric effect, an optical waveguide 2 that is formed on a principal surface of the substrate 1, a conductive film (not illustrated) that is formed on the substrate 1, and control electrodes (31 to 33) that control a light wave propagated through the optical waveguide 2. In the optical modulator module, the light wave is input to an end portion 21 of the optical waveguide (or is output from the end portion 21 of the optical waveguide) by a space optical system (not illustrated). Adsorption means 4 for adsorbing a vapor phase transportation material is disposed in the vicinity of the end portion 21 of the optical waveguide.

Abstract: Provided is an optical modulator in which a phenomenon of a resonance mode or the like is prevented from being generated in a recess portion of a housing that mounts a flexible printed circuit and of which broadband characteristics are improved. There is provided an optical modulator in which an optical modulation element is mounted inside a housing, in which at least a portion of an electric line is connected to an external circuit board 7 through a flexible printed circuit 6, and which is disposed on the external circuit board.

Abstract: Provided is an optical waveguide device in which destabilization of a DC bias which is applied to an optical waveguide, due to a bias electrode picking up electric noise, is reduced and an operating characteristic is stable. An optical waveguide device includes: a substrate having an electro-optic effect; an optical waveguide formed on the substrate; a modulation electrode for applying an electric field corresponding to a modulation signal to the optical waveguide; and a bias electrode for applying an electric field corresponding to a DC bias to the optical waveguide, in which in order to reduce capture of electric noise by the bias electrode, with respect to at least a part of the bias electrode, a plurality of electrode portions (b11, b12) are formed in at least one (B1) of the pair of electrodes by folding back one electric line.

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: Provided is an optical modulator including: a relay substrate; a first transmission line that is provided on a flat surface of the relay substrate, and transmits, along the flat surface of the relay substrate, an electrical signal that has been input from an outer side; a second transmission line that is provided in the relay substrate, and transmits the electrical signal in a direction that is not included in the flat surface; a modulation unit that modulates an optical signal by using the electrical signal that is transmitted by the first transmission line and the second transmission line; and a shield that shields a radiation component of the electrical signal that is radiated from a contact of the first transmission line and the second transmission line.

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.