Abstract: An optical modulator with FPC and optical transmission device using the same are provided. This optical modulator includes a flexible printed circuit which electrically connects the optical modulator to a circuit board. The flexible printed circuit has a substantially quadrilateral shape. A pad is formed on the flexible printed circuit along one side of the substantially quadrilateral shape so as to be electrically connected to the circuit board. In order to release the mechanical stress applied onto the side or the end portion of the flexible printed circuit and/or to prevent propagation of distortion generated in the side or the end portion, the flexible printed circuit has: a cutout or a notch provided in a direction from a part of at least one side toward the inside of the flexible printed circuit; and/or a curved portion connecting at least two adjacent sides.

Abstract: An optical modulator includes: an optical modulation element which includes signal electrodes; lead pins; and a relay substrate in which a conductor pattern which electrically connects each of the lead pins and each of the signal electrodes to each other are formed, and the optical modulator is configured such that the amount of radiation of a high frequency at a connection portion between the conductor pattern and the signal electrode is increased compared to a portion other than the connection portion.

Abstract: An optical modulator having a substrate having an electro-optic effect, an optical waveguide formed in the substrate, and a signal electrode and ground electrodes formed on the substrate so as to interpose the optical waveguide, in which the signal electrode and the ground electrodes respectively have a plurality of electrode layers, and an interval between the signal electrode and the ground electrode is larger than a mode field diameter of the optical waveguide in a first layer of the electrode layers closest to the substrate and is smaller than the interval in the first layer of the electrode layers in at least any one of second and upper layers of the electrode layers.

Abstract: In an optical waveguide element, an optical waveguide is formed on a substrate, the optical waveguide has a main waveguide that propagates signal light, a waveguide for unnecessary light that guides unnecessary light released from the main waveguide, and a waveguide for collecting unnecessary light to which the unnecessary light emitted from the waveguide for unnecessary light is introduced, the waveguide for unnecessary light is connected to the waveguide for collecting unnecessary light via a waveguide for connection, and a width of the waveguide for connection, which is a width in a direction that perpendicularly intersects a propagation direction of the unnecessary light, at a portion connected to the waveguide for collecting unnecessary light is set to be wider than a width at a portion connected to the waveguide for unnecessary light with the waveguide for connection.

Abstract: An optical waveguide device includes a substrate in which an optical waveguide is formed. The optical waveguide has a Y-branched structure in which light beams propagating through a main waveguide are branched into two parts, and a three-branched structure in which the optical waveguide is branched into three waveguides including the main waveguide and two sub-waveguides on both sides of the main waveguide at a front stage of the Y-branched structure. The main waveguide includes a linear waveguide portion in which a waveguide width is constant and a tapered waveguide portion in which the waveguide width gradually increases between the three-branched structure and the Y-branched structure.

Abstract: Provided is an optical modulator in which degradation of an extinction ratio is suppressed and a temperature drift phenomenon is suppressed. An optical modulator includes: a substrate having an electro-optic effect; an optical waveguide formed on the substrate; and a control electrode for controlling light waves propagating through the optical waveguide, in which the optical waveguide has one or more Mach-Zehnder type optical waveguides (A1 to A3 and B1 to B3), the control electrode has DC electrodes (C1 to C4) which apply DC bias, a feeder electrode which feeds DC bias to the DC electrode crosses one of two branched waveguides of the Mach-Zehnder type optical waveguide, and a first dummy electrode (a dotted line E5 or E6) is provided at a specific position on the other one of the two branched waveguides, which is a specific position symmetrical in relation to a position at which the feeder electrode crosses the one of the two branched waveguides.

Abstract: An optical modulator capable of curbing deterioration of transmission properties due to deformation of a housing is provided. Provided is an optical modulator including a substrate (10) on which an optical waveguide (20) is formed and a housing (30) that accommodates the substrate, in which the optical waveguide includes mode conversion branching portions (21, 22) which convert a mode of light waves propagating through the optical waveguide and branch the light waves, a mounting portion (32) protruding from a surface (31) inside the housing and holding the substrate is formed, and the substrate is fixed to the mounting portion in an arrangement in which a fixed end (33) between the substrate and the mounting portion is positioned outside a region including the mode conversion branching portions when the substrate is seen in a plan view.

Abstract: To perform a stable bias control by improving detection accuracy of intensity of an dither signal component, which is detected by a photo detector, in an optical modulator including a bias electrode to which a dither signal is applied, and a photo detector that monitors an optical signal propagating through the inside of an optical waveguide in the same substrate. The optical modulator includes: a substrate having a piezoelectric effect (102); an optical waveguide (116a or the like) that is formed on the substrate; a bias electrode (158a or the like) that controls an optical wave that propagates through the optical waveguide; and a photo detector (168a or the like) that is formed on the substrate, and monitors an optical signal that propagates along the optical waveguide.

Abstract: A transmission line has a signal electrode formed on one surface of a flexible printed circuit, and a ground electrode formed on the other surface of the flexible printed circuit. A connection terminal has signal terminals formed on both the surfaces of the flexible printed circuit and electrically connected to each other through a via hole, and ground terminals formed on both the surfaces of the flexible printed circuit and electrically connected to each other through the via hole. The signal terminal on the surface, on which the ground electrode is formed, is formed such that at least a width in an end portion on the transmission line side is narrower than a width of a part of the signal terminal on the surface, on which the signal electrode is formed, to be at the same position when the flexible printed circuit is seen in a plan view.

Abstract: An optical modulator and an optical transmission device using the same are provided. The optical modulator includes an optical waveguide substrate where an optical waveguide is formed; a light modulation element, provided in the optical waveguide substrate and including a modulation electrode applying an electric field corresponding to a modulation signal to the optical waveguide; a terminal substrate, disposed near the light modulation element and including terminal resistors that terminate the modulation signal, wherein the optical waveguide substrate, the light modulation element and the terminal substrate are accommodated in a housing; and a heat dissipation auxiliary element, provided between the terminal resistors and the housing. A distance b between the terminal resistors and the heat dissipation element is set to be shorter than a distance a from the terminal resistors to an end on the side of the optical waveguide substrate of the terminal substrate.

Abstract: A small and inexpensive optical modulator having suppressed temperature drift and high reliability and an optical transmission device using the same are provided. The optical modulator includes an optical waveguide substrate where an optical waveguide is formed; a control electrode that is provided on the optical waveguide substrate and applies an electric field to the optical waveguide; and a relay substrate that is disposed in the vicinity of the optical waveguide substrate and includes electrical wirings that relay electrical signals from the outside to the control electrode. The control electrode includes a signal electrode. The optical modulator comprises terminating units that include terminal resistors that terminate the signal electrode. At least a part of the terminating units are provided on the relay substrate.

Abstract: An optical modulator is provided and includes a substrate that has an electro-optic effect, an optical waveguide that is formed on the substrate, a plurality of control electrodes that control a light wave propagated through the optical waveguide, and a plurality of light receiving elements that detect a light wave propagated through the optical waveguide. The optical modulator has two or more independent optical waveguide modulation portions. The light receiving elements are respectively provided in an upper part of the substrate with respect to the independent optical waveguide modulation portions. A wiring substrate is located above the substrate. A plurality of electric wirings are located on the wiring substrate. The plurality of electric wirings are disposed to extend in the vicinity of one side of the wiring substrate, are electrically connected to the light receiving elements, and output a signal detected by the light receiving elements to the outside.

Abstract: Provided is an optical modulator module in which a modulation substrate having a plurality of optical modulation units is stored inside a package case. The optical modulator module includes a plurality of signal supply lines configured to supply a modulation signal to the optical modulation unit through a connector terminal which is introduced into the package case. At least two or more of the plurality of signal supply lines are set such that the signal supply lines have overall electrical lengths which are different from each other.

Abstract: An optical modulator with FPC and optical transmission device using the same are provided. This optical modulator includes a flexible printed circuit which electrically connects the optical modulator to a circuit board. The flexible printed circuit has a substantially quadrilateral shape. A pad is formed on the flexible printed circuit along one side of the substantially quadrilateral shape so as to be electrically connected to the circuit board. In order to release the mechanical stress applied onto the side or the end portion of the flexible printed circuit and/or to prevent propagation of distortion generated in the side or the end portion, the flexible printed circuit has: a cutout or a notch provided in a direction from a part of at least one side toward the inside of the flexible printed circuit; and/or a curved portion connecting at least two adjacent sides.

Abstract: A waveguide optical element which includes a plurality of optical waveguides provided on a substrate having an electro-optic effect includes: a plurality of signal electrodes controlling light waves propagating through the optical waveguides; and a plurality of ground electrodes provided so as to interpose each of the signal electrodes therebetween, in which at least one of the ground electrodes includes a first layer and a second layer formed on the first layer, the second layer is formed such that a distance between the second layer and the signal electrode adjacent to the second layer is larger than a distance between the first layer and said signal electrode adjacent to said second layer, and a thickness of the ground electrode which includes the first layer and the second layer is 25 ?m or more.

Abstract: In an optical modulator including an FPC for performing electrical connection with an external circuit substrate, to maintain high light transmission quality by appropriately driving the optical modulator even when the reflection of a radio frequency signal occurs in a connection portion between the FPC and the main body of the optical modulator. Provided is an optical modulator including a flexible printed circuit for performing electrical connection with a circuit substrate, in which the flexible printed circuit includes at least one wire pattern for propagating a radio frequency signal, and the wire pattern includes at least one radio frequency attenuation portion for attenuating power of the radio frequency signal by a predetermined amount.

Abstract: To perform a stable bias control by improving detection accuracy of intensity of an dither signal component, which is detected by a photo detector, in an optical modulator including a bias electrode to which a dither signal is applied, and a photo detector that monitors an optical signal propagating through the inside of an optical waveguide in the same substrate. The optical modulator includes: a substrate having a piezoelectric effect (102); an optical waveguide (116a or the like) that is formed on the substrate; a bias electrode (158a or the like) that controls an optical wave that propagates through the optical waveguide; and a photo detector (168a or the like) that is formed on the substrate, and monitors an optical signal that propagates along the optical waveguide.

Abstract: Object To provide an optical waveguide device capable of suppressing an excess optical loss at a low level. Means An optical waveguide device including a substrate having an electro-optic effect, an optical waveguide 1 formed on the substrate, and a control electrode having a signal electrode 2 and ground electrodes 3 and 4 for controlling light waves that propagate through the optical waveguide, in which the signal electrode 2 has, in an intersection portion in which the signal electrode 2 is disposed on the optical waveguide 1, a narrow portion at which a width of the signal electrode 2 is narrower than those of portions before and after the intersection portion.

Abstract: To suppress peeling-off or cracks of a solder-fixing portion, which are caused by vibration during transportation or operation, in an optical modulator with FPC, thereby suppressing deterioration of radio-frequency characteristics of a signal path in an effective manner at low cost. An optical modulator 100 includes a flexible printed circuit (106) that performs electrical connection with a circuit substrate. The flexible printed circuit has a substantially quadrilateral shape. In the flexible printed circuit, a pad (210 and the like), which is electrically connected to the circuit substrate, is provided along one side of the substantial quadrilateral. In addition, in the flexible printed circuit, signal patterns (220 and the like), which are connected to signal lead pins (120 and the like) for signal transmission which is provided in the optical modulator, are provided in another side opposite to the one side.

Abstract: An optical modulation element configured by forming an optical waveguide on an optical element substrate and a polarization-combining part that combines light waves modulated in the optical modulation element are disposed in a housing. A plurality of lead pins are fixed to a side wall of the housing. Each of the plurality of lead pins has a protrusion portion protruding into an internal space of the housing and is electrically connected to the optical modulation element by bonding a wire to the protrusion portion. A loop shape of a wire that is bonded and connected to at least part of the lead pins among the plurality of lead pins is different from a loop shape of a wire that is bonded and connected to other lead pins.