Anritsu Corporation

Masaya Nanami

Kenji Kawano

Toru Nakahira

Seiji Uchida

Yuji Sato

Nobuhiro Igarashi

Hiroaki Senda

Satoshi Matsumoto

Takeshi Tsukamoto

Eiji Kawazura

Makoto Saito

Takeshi Hondo

Toshiyuki Suzuki

Herein disclosed is an optical modulation device, comprising: a substratehaving a polarization non-reversal regionand a polarization reversal region; an optical waveguideincluding first and second branched optical waveguide portions; and a traveling waveguide including a center electrodeand a ground electrodeto have an electric signal applied thereto, said traveling waveguide and said first and second branched optical waveguide portions collectively forming an interaction portion to have said incident light interacted with said electric signal, said interaction portion being constituted by a first interaction sub-portionand a second interaction sub-portion, said first and second interaction sub-portions being respectively positioned in regions of said substrate having opposite polarization orientations with each other, in which said center electrode is positioned in face to face relationship with one of said first and second branched optical waveguide portions at said first and second interaction sub-portion to ensure that said incident light in said first and second branched optical waveguide portions are phase modulated, and in which said interaction portion includes an optical waveguide shift sub-portion sandwiched between said first and second interaction sub-portions to have positions of said first and second branched optical waveguide portions shifted therein in a transverse direction, ensuring that positions of said first and second optical waveguides relative to said center and ground electrodes are interchanged between said first and second interaction sub-portions.

Optical modulation device

Herein disclosed is an optical modulator, having: a substrate (); and a center and ground electrodes (to), in which the substrate has ridge portions (to), the center and ground electrodes are respectively formed above the ridge portions, the ridge portions below the center and ground electrodes respectively have top parts () having a respective first and second end points () separated with a distance of 'W', the substrate has a bottom surface () between the ridge portions having center and midway points () positioned with a respective distance of W/2 and W/N (3&#x2266;N&#x2266;25) from the first end point, the ridge portion below the center electrode has a normal line (), and the center point and the midway point define a straight line () crossed with the normal line at an angle larger or equal to 90.1&#xb0;.

Optical modulator

In an optical modulator comprising substratehaving electro-optical effect, two optical waveguidesformed in the substrate, buffer layerformed on the substrate, traveling-wave electrodehaving center conductorand ground conductorsabove the buffer layer, and ridge sections formed with recessed sectionstoby carving at least a part of the substrate where an electrical field strength of high-frequency electrical signal propagating the traveling-wave electrode is strong, in which the ridge sections include center conductor ridge sectionhaving the center conductor formed above and ground conductor ridge sectionhaving the ground conductor formed above, and the center conductor ridge section has one of the two optical waveguides formed therein, the recessed sections are practically symmetrical to the center line between the two optical waveguides and the traveling-wave electrode is practically symmetrical to the center line of the center conductor.

An optical modulator, including: a substrate; an optical waveguide embedded in the substrate; a traveling wave electrode mounted on the substrate and having a traveling wave applied thereon so that a light wave is modulated by the traveling wave with an electro-optic effect. The traveling wave electrode includes a center electrode and ground electrodes; in which the optical waveguide has a plurality of interaction optical waveguides that form a Mach-Zehnder optical waveguide that modulates the light wave in a phase modulation manner when the traveling wave is applied to the traveling wave electrode, the interaction optical waveguides form a region where respective widths of the interaction optical waveguides are different from each other, and the center electrode and the ground electrodes are positioned such that interaction efficiencies between the high frequency electric signal and the light wave guided in the respective interaction optical waveguides are substantially equal to each other.

Herein disclosed is an optical modulator, comprising: a substrate () having an electro-optic effect; an optical waveguide () formed in the substrate; a traveling wave electrode () including a center electrode () and ground electrodes () to have a high frequency electric signal applied thereto, the traveling wave electrode and the optical waveguide collectively forming a high frequency interaction portion () to have the incident light phase modulated under the condition that the high frequency electric signal is applied to the traveling wave electrode; and bias electrodes each including a center electrode () and ground electrodes () to have a bias voltage applied thereto, each of the bias electrodes and the optical waveguide collectively forming a bias voltage interaction portion () to have the incident light phase modulated under the condition that the bias voltage is applied to the bias electrode, in which the traveling wave electrode and the bias electrodes are extended in a propagation direction of the incident light with the traveling wave electrode () positioned between the bias electrodes ().

An optical modulator has, on a substrate having electro-optic effect, an optical waveguide including an input optical waveguide, two branching optical waveguides which branch a light beam incident to the input optical waveguide into two beams, two interaction optical waveguides which modulate a light beam phase by applying a voltage between a center electrode and ground electrodes, a multiplexing optical waveguide which multiplexes the light beams which propagate through the two interaction optical waveguides, and an output optical waveguide which is connected to the multiplexing optical waveguide through a multiplexing point. In the optical modulator, a high-order mode light beam which is generated by multiplexing the phase-modulated light beam and which is radiated from the multiplexing point to an inside of the substrate as two radiant light beams while the high-order mode light beam hardly propagates through the output optical waveguide, and at least one of the two radiant light beams is detected by a monitor photodetector. The output optical waveguide is formed while deformed in order to secure a space for mounting the monitor photodetector such that at least one of optical axes of the radiant light beams in a substrate end portion located on the output optical waveguide and an end of the output optical waveguide are separated from each other by a predetermined distance.

Monitor photodetector equipped optical modulator

A waveguide type optical device has an optical waveguide formed on a substrate, functional optical waveguide an optical input end face and an optical output end face which are provided to respective substrate end faces an input optical waveguide connecting the optical input end face and the functional optical waveguides, an output optical waveguide connecting the optical output end face and the functional optical waveguides, and a signal light monomode optical fiber. The input optical waveguide and the output optical waveguide is formed so as to form angles other than 0&#xb0; with the functional optical waveguides at the optical input end face and the optical output end face respectively, such that an angle between each of the input optical waveguide and the output optical waveguide with respect to a corresponding one of the substrate end faces is other than 90&#xb0;.

Waveguide type optical device

An optical waveguide for guided an incident light is formed on a substrate having an electro-optic effect. A first buffer layer is formed to cover an upper surface of the substrate. A conductive film is formed above the first buffer layer. A center electrode and a ground electrode are formed for applying a voltage in order to induce an electric field in the optical waveguide. A second buffer layer is formed between the conductive film and at least one of the center electrode and the ground electrode. The conductive film is formed to be present on at least a part below the ground electrode. A light guided through the optical waveguide is modulated by changing a phase by a voltage applied to the optical waveguide. Thereby, a thermal drift can be effectively restricted so that an optical modulation device having excellent electric characteristics can be realized.

Optical modulation device having excellent electric characteristics by effectively restricting heat drift

A laser absorption spectroscopy type gas detection device is provided in which a light source device emits a laser beam containing a light component having a wavelength corresponding to an absorption spectrum of gas to be detected. A concave mirror has a reflecting surface to reflect and condense the laser beam reflected by material body existing in an advancing direction of the laser beam. A light receiver is disposed at the condensing position by the concave mirror and outputs an electric signal for detecting whether the gas to be detected is present in a vicinity of the material body. An adjustment mechanism freely moves and adjusts a relative position of the concave mirror and the light receiver in accordance with a distance to the material body such that the light receiver is positioned at the condensing position.

Laser absorption spectral diffraction type gas detector and method for gas detection using laser absorption spectral diffraction

A gas detecting apparatus includes a gas cell, a laser source, a light diffuser and a photodetector. The gas cell has a gas inlet hole for letting the target gas come inside and a gas discharge hole for discharging the target gas, and retains a target gas to be detected. The laser source emits coherent light into the gas cell in order to detect a concentration of the target gas. The light diffuser is disposed in the optical path of the coherent light output from the laser source to diffuse the coherent light, thereby eliminating coherence of the coherent light. The photodetector receives light diffused by the light diffuser.

Growing community of inventors

Zama, Japan

Masaya Nanami