Abstract: Herein disclosed is an optical modulation device, comprising: a substrate 1 having a polarization non-reversal region 17a and a polarization reversal region 17b; an optical waveguide 18 including first and second branched optical waveguide portions 18a, 18b; and a traveling waveguide including a center electrode 19a and a ground electrode 19b, 19c to 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-portion 20a and a second interaction sub-portion 20b, 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

Abstract: Herein disclosed is an optical modulator, having: a substrate (1); and a center and ground electrodes (4a to 4c), in which the substrate has ridge portions (8a to 8c), 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 (10a, 10b) having a respective first and second end points (18, 19) separated with a distance of “WR”, the substrate has a bottom surface (21b) between the ridge portions having center and midway points (23, 24) positioned with a respective distance of WR/2 and WR/N (3?N?25) from the first end point, the ridge portion below the center electrode has a normal line (13), and the center point and the midway point define a straight line (25) crossed with the normal line at an angle larger or equal to 90.1°.

Abstract: In an optical modulator comprising substrate 1 having electro-optical effect, two optical waveguides 3a, 3b formed in the substrate, buffer layer 2 formed on the substrate, traveling-wave electrode 4 having center conductor 4a and ground conductors 4b, 4c above the buffer layer, and ridge sections formed with recessed sections 9a to 9c by 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 section 8a having the center conductor formed above and ground conductor ridge section 8b having 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.

Abstract: 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.

Abstract: A technical problem related to a traveling wave electrode type of optical modulator comprising a substrate having the electro-optical effect, optical waveguides formed in the substrate, and a traveling wave electrode formed above the substrate includes improvement of the characteristics such as optical modulation bandwidth, driving voltage, and characteristic impedance of the traveling wave electrode type of optical modulator. To solve the problem, the structure of ridge portions is optimized which is formed in such a manner that a part of the substrate at regions where electric field generated by a high frequency electric signal traveling through the traveling wave electrode is strong is reduced in thickness by digging. Further, a buffer layer is formed over the substrate where the ridge portions are formed and a conducting layer is formed over the buffer layer.

Abstract: In an optical modulator comprising substrate 1 having electro-optical effect, two optical waveguides 3a, 3b formed in the substrate, buffer layer 2 formed on the substrate, traveling-wave electrode 4 having center conductor 4a and ground conductors 4b, 4c above the buffer layer, and ridge sections formed with recessed sections 9a to 9c by 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 section 8a having the center conductor formed above and ground conductor ridge section 8b having 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.

Abstract: Herein disclosed is an optical modulator, comprising: an optical waveguide (3); and a traveling wave electrode (4) including an interaction portion (9) for modulating a phase of incident light and an input feed-through portion (7), in which the optical modulator further comprises at least one impedance transformation portion for reducing an impedance mismatching between a characteristic impedance of the interaction portion and at least one of characteristic impedances of the input feed-through portion, a connector electrically connected to the input feed-through portion, and an external circuit, at least one of the impedance transformation portions has a characteristic impedance which is different from a geometric mean of the characteristic impedances of said interaction portion and said input feed-through portion, a geometric mean of the characteristic impedances of the interaction portion and the connector, or a geometric mean of the characteristic impedances of the interaction portion and the external circ

Abstract: Herein disclosed is an optical modulation device, comprising: a substrate 1 having a polarization non-reversal region 17a and a polarization reversal region 17b; an optical waveguide 18 including first and second branched optical waveguide portions 18a, 18b; and a traveling waveguide including a center electrode 19a and a ground electrode 19b, 19c to 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-portion 20a and a second interaction sub-portion 20b, 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

Abstract: Herein disclosed is an optical modulator, comprising: a substrate (1) having an electro-optic effect; an optical waveguide (3) formed in the substrate; a traveling wave electrode (4) including a center electrode (4a) and ground electrodes (4b, 4c) to have a high frequency electric signal applied thereto, the traveling wave electrode and the optical waveguide collectively forming a high frequency interaction portion (20) 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 (22a, 23a) and ground electrodes (22b, 22c, 23b, 23c) to have a bias voltage applied thereto, each of the bias electrodes and the optical waveguide collectively forming a bias voltage interaction portion (19, 21) 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 e

Abstract: Herein disclosed is an optical modulator, having: a substrate (1); and a center and ground electrodes (4a to 4c), in which the substrate has ridge portions (8a to 8c), 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 (10a, 10b) having a respective first and second end points (18, 19) separated with a distance of “WR”, the substrate has a bottom surface (21b) between the ridge portions having center and midway points (23, 24) positioned with a respective distance of WR/2 and WR/N ( 3 ?N?25 ) from the first end point, the ridge portion below the center electrode has a normal line (13), and the center point and the midway point define a straight line (25) crossed with the normal line at an angle larger or equal to 90.1°.

Abstract: Herein disclosed is an optical modulator, comprising: a substrate (1) having an electro-optic effect; an optical waveguide (3) formed in the substrate; a traveling wave electrode (4) including a center electrode (4a) and ground electrodes (4b, 4c) to have a high frequency electric signal applied thereto, the traveling wave electrode and the optical waveguide collectively forming a high frequency interaction portion (20) 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 (22a, 23a) and ground electrodes (22b, 22c, 23b, 23c) to have a bias voltage applied thereto, each of the bias electrodes and the optical waveguide collectively forming a bias voltage interaction portion (19, 21) 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 e

Abstract: Herein disclosed is an optical modulator, comprising: a substrate 1 having an electro-optic effect; an optical waveguide 12 embedded in the substrate 1 to have a light wave guided therein; a traveling wave electrode 4 mounted on the substrate 1 to have a traveling wave applied thereon so that the light wave is modulated by the traveling wave with the electro-optic effect, the traveling wave electrode being constituted by a center electrode 4a and ground electrodes 4b, 4c; in which the optical waveguide has a plurality of interaction optical waveguides 12a, 12b to collectively form a Mach-Zehnder optical waveguide operative to modulate the light wave in a phase modulation manner under the condition that the traveling wave is applied to the traveling wave electrode, the interaction optical waveguides 12a, 12b collectively form a region where respective widths of said interaction optical waveguides are different from each other, and the center electrode 4a and the ground electrodes 4b, 4c are positioned such tha

Abstract: 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.

Abstract: 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.

Abstract: 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° 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°.

Abstract: A waveguide type optical device has an optical waveguide formed on a substrate, functional optical waveguides provided to the optical waveguide, at least one of an optical input end face and an optical output end face for the optical waveguide which are provided to substrate end faces which are ends at longitudinal direction sides of the substrate, and at least one of an input optical waveguide connecting the optical input end face and the functional optical waveguides, and an output optical waveguide connecting the optical output end face and the functional optical waveguides. At least one of the input optical waveguide and the output optical waveguide is formed so as to form angles other than 0 with the functional optical waveguides at the at least one of the optical input end face and the optical output end face, and so as to make angles formed to the substrate end faces at the respective sides different from 90°.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.