Hitachi Cable, Inc.

Fujitsu Corporation

Yokogawa Electric Corporation

Satoshi Takasugi

Takeshi Hoshida

Yasuyuki Suzuki

Hiroshi Onaka

Takafumi Terahara

George Ishikawa

Kentaro Nakamura

Akira Miura

Hiroyuki Matsuura

Hisato Uetsuka

Jens Rasmussen

Morio Wada

Akihiko Isomura

Hideaki Arai

Takafumi Chiba

Tetsu Hasegawa

An interferometer for demodulating a differential M-phase shift keying signal includes a PLC type interferometer main body, a heating portion that heats the PLC type interferometer main body, and an intermediate member having a higher stiffness than that of the PLC type interferometer main body, for bonding the PLC type interferometer main body and the heating portion with each other while being sandwiched therebetween. A linear expansion coefficient difference between the PLC type interferometer main body and the intermediate member is equal to or smaller than 4.5&#xd7;10/&#xb0; C., and a thermal conductivity difference between the PLC type interferometer main body and the intermediate member is equal to or larger than 10 W/mK. A phase of an optical signal flowing through the interferometer is adjusted by using the heating portion and a second heating portion.

Interferometer for demodulating differential M-phase shift keying signal

A waveguide type variable optical attenuator has: a substrate; two optical circuits that are in parallel formed on the substrate, each of the optical circuits including two couplers that conduct the branching and coupling of light and are connected to the input port and output port of light and two waveguides through which the two couplers are connected; a polarization maintaining fiber one end of which is connected to the output port of one of the two optical circuits and the other end of which is connected to the input port of the other of the two optical circuits while being twisted 90&#xb0;; and a heater that is provided around neighboring waveguides of the two optical circuits such that the neighboring waveguides share heat to be generated by the heater.

Waveguide type variable optical attenuator

Growing community of inventors

Hitachi, Japan

Satoshi Takasugi