Sumitomo Osaka Cement Co., Ltd.

National Institute of Information and Communications Technology, Incorporated

Youichi Hosokawa

Norikazu Miyazaki

Toshio Kataoka

Kei Katou

Satoshi Oikawa

Tetsuya Kawanishi

Tokutaka Hara

Kaoru Higuma

Masayuki Motoya

Motohiro Takemura

Atsushi Kanno

Yoshizumi Ishikawa

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 waveguideformed on the substrate, and a control electrode having a signal electrodeand ground electrodesandfor controlling light waves that propagate through the optical waveguide, in which the signal electrodehas, in an intersection portion in which the signal electrodeis disposed on the optical waveguide, a narrow portion at which a width of the signal electrodeis narrower than those of portions before and after the intersection portion.

Optical waveguide device

Provided is an optical modulator in which low-voltage drive and a stable modulation characteristic are secured over a wide bandwidth. An optical modulator includes: a substratean optical waveguide (not shown) formed in the substratea modulation electrode (a signal electrodeand a ground electrode) for modulating light waves propagating through the optical waveguide; and an external signal line (not shown, only a connection connectoris shown) which is provided outside the substrate and supplies a modulation signal to the modulation electrode, in which an impedance value of the modulation electrode in an active region S in which an electric field formed by the modulation electrode is applied to the optical waveguide is set to be lower than an impedance value of the external signal line, and an impedance adjustment parthaving an impedance adjustment function with respect to mainly a modulation signal in a low-frequency area and configured of a lumped-constant circuit, and an impedance matching line L having an impedance adjustment function with respect to mainly a modulation signal in a high-frequency area are disposed between the external signal line and the active region of the modulation electrode.

Optical modulator

Provided is an optical modulator in which even in a case where an optical waveguide and a control electrode are highly integrated, a distortion due to stress acting on the optical waveguide from lead-out wiring of a signal electrode is mitigated and occurrence of a temperature drift or the like is suppressed. An optical modulator includes: a substratehaving an electro-optic effect; optical waveguides (Lto L), each of which is formed on the substrate and provided with at least one Mach-Zehnder type optical waveguide; and a control electrode which controls light waves propagating through the optical waveguides, in which the control electrode is configured of signal electrodes (Sand S) and ground electrodes (Gto G), each of the signal electrodes being provided with a pad part (SP or SP) for input or output, which is electrically connected to an electric circuit which is provided outside the substrate, an interaction part (indicated by arrow R) which applies an electric field to the optical waveguide, and a lead-out wiring part which connects the pad part and the interaction part to each other, a portion of the lead-out wiring part is disposed parallel to an extended direction (a lateral direction in) of the Mach-Zehnder type optical waveguide within a range (indicated by arrow R) in which two branching waveguides configuring the Mach-Zehnder type optical waveguide are present in the extended direction, and any one of a portion of the interaction part, another portion of the lead-out wiring part, and a stress relaxation structure of the ground electrode is formed at a position which is axially symmetrical to the portion of the lead-out wiring part with respect to a centrosymmetric axis in the extended direction of the Mach-Zehnder type optical waveguide.

An optical waveguide element module decreases discontinuity of electrical connection between an optical waveguide element and a relay substrate, without wire-bonding using long wires. An edge shape L of the signal electrode side of the ground electrode is surrounded by two shapes (L, L). Shape Lis obtained by connecting an input end of the control electrode to a location where a space between the ground electrodes becomes W. Shape Lis such that an impedance change of the control electrode from the input end to the location at which the space between the ground electrodes becomes Wis constant or continuously changes. A space between grounding wires connecting the ground electrodes of the element and ground lines of the relay substrate is larger than a space between the ground electrodes. In an embodiment, a terminal substrate and an output end of the control electrode are connected.

Optical waveguide element module

An optical device is provided, which includes: an optical waveguide provided in a substrate having an electro-optic effect; a signal electrode provided on the substrate and above the optical waveguide; and a peeling prevention film which is provided on at least a part of an outer peripheral portion of the substrate and at a position spaced apart from the signal electrode, and also serves as a ground electrode.

Optical device

Provided is an optical waveguide element including a first interactive part, a first EO substrate line, a second interactive part, and a second EO substrate line. A relay substrate unit includes a first relay substrate line, a second relay substrate line, and a loss adjusting part. The loss adjusting part is provided to the relay substrate line in a combination in which an electrical loss is low so that an electrical loss in a combination of the first EO substrate line and the first relay substrate line, and an electrical loss in a combination of the second EO substrate line and the second relay substrate line become approximately the same as each other.

Optical modulation device

Provided is an optical pulse-generator and an optical pulse-generating method which are capable of generating an optical pulse train with an arbitrary pattern. An optical pulse-generatorincludes a first optical modulatorconfigured to modulate input light using a first modulation signal SIGto generate optical pulses, a second optical modulatorconfigured to perform a modulation operation using a second modulation signal SIGsynchronizing with the first modulation signal SIGand having a signal pattern that is set to output only specific part of the optical pulses, and a dispersion compensatorconfigured to compensate a chirp of the optical pulse output from the first optical modulator

Optical pulse-generator and optical pulse-generating method

[Task] Reduction in crosstalk between signal electrodes. [Means for Resolution] An optical modulatorincludes a relay substrateincluding a substrate portion, and signal electrodesand, and a ground electrodewhich are provided on the substrate portion, and an optical waveguide substrateincluding an electrode-optical substrate, signal electrodesand, and an optical waveguidewhich are provided on the electro-optical substrate. Modulation signals are input from endsandon one side of the signal electrodesand, the other endof the signal electrodeis electrically connected to the signal electrode, the other endof the signal electrodeis electrically connected to the signal electrode, an optical wave, which propagates through the optical waveguide, is modulated by the modulation signals which propagate through the signal electrodesand, the ground electrodeis provided between the signal electrodesand, and the relay substrateincludes a first adjacent portionat which the signal electrodesandare adjacent to each other, and a through-holethat is provided in the ground electrodeat the first adjacent portion

The optical modulator includes optical modulation units. The plurality of optical modulation units is disposed in parallel on the same substrate. One input waveguide branches off to be connected to the Mach-Zehnder type optical waveguide of each optical modulation unit, and an entire optical waveguide is formed such that outputs from the Mach-Zehnder type optical waveguides are combined and output through one output waveguide. A modulation signal with the same intensity is applied to a modulation electrode of each optical modulation unit. In at least some of the optical modulation units, mechanical structures including the modulation electrodes of the optical modulation units are configured such that an amplitude value of an optical output modulated by the modulation signal of the optical modulation unit is &#xbd;(n is a natural number) of a maximum amplitude value in other optical modulation units.

An optical modulator comprises a substratehaving a thickness of 20 &#x3bc;m or less and an electro-optic effect, a reinforcing substrateholding the substratethereon and a resin layerdisposed between the substrate and the reinforcing substrate, in which the substrateincludes optical waveguidesandand control electrodesandwhich control light waves propagating through the optical waveguide, in which the optical waveguides include at least two optical waveguidesseparated from each other, and in which the control electrodesdisposed between the two optical waveguides are configured to include two electrodesdisposed along each optical waveguide, and a thin lineconducting the two electrodesat a same potential.

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Tokyo, Japan

Youichi Hosokawa