Nippon Telegraph and Telephone Corporation

Takeshi Kitagawa

Motohaya Ishii

Shinji Mino

Takashi Goh

Takashi Yamada

Akira Himeno

Masayuki Okuno

Shunichi Souma

Masahiro Yanagisawa

Masaru Kobayashi

Toshikazu Hashimoto

Hiroshi Takahashi

Shin Kamei

Tsutomu Kitoh

Yoshiteru Abe

Ikuo Ogawa

Tomohiro Shibata

Shuichiro Asakawa

Senichi Suzuki

Takao Kimura

Shuichi Shibata

Ryou Nagase

Takaharu Ohyama

Akihiro Takagi

Masaki Koutoku

Hisaaki Okazaki

Masaharu Horiguchi

An optical module controls its output characteristics electrically and an optical switch constitutes the optical module. An optical waveguide circuit (PLC) and an electronic circuit (IC) for driving the PLC are mounted on the same substrate. The IC is composed of a bare chip to be molded afterward. Wiring of the IC is grouped and integrated on the PLC substrate to achieve higher density and miniaturization of the optical module.

Optical module and optical switch

A wave transmission medium includes an input port-and an output port-. A field distributionand a field distributionare obtained by numerical calculations. The field distributionis a field distribution of the propagation light (forward propagation light) launched into the input port-. The field distributionis a field distribution of the phase conjugate light (reverse propagation light) resulting from reversely transmitting from the output port side an output field that is expected to be output from the output port-when an optical signal is launched into the input port-. According to the field distributionsand, a spatial refractive index distribution is calculated such that the phase difference between the propagation light and reverse propagation light is eliminated at individual points (x, z) in the medium.

Wave transmission medium and waveguide circuit

Optical module and optical switch constituting the same

An optical module controls its output characteristics electrically and an optical switch constitutes an optical module. An optical waveguide circuit (PLC) and an electronic circuit (IC) for driving the PLC are mounted on the same substrate. The IC is composed of a bare chip to be molded afterward. Wiring of the IC is grouped and integrated on the PLC substrate to achieve higher density and miniaturization of the optical module.

A practical optical waveguide circuit is provided which includes many intersections but is low loss. The width of a waveguide core is wat input and output terminal sections and wat an intersecting section, where w&#x3e;w. The core width of the intersecting section is made different from that of the input and output terminal sections, or the core height of the intersecting section is made different from that of the input and output terminal sections. The core width is smoothly varied between the intersecting section and the input and output terminal sections by a tapered section. When the number of the waveguides intersecting with the intersecting section is 100, the intersection loss is 5.8 dB for the conventional device where w=w=5 &#x3bc;m, but is 1.8 dB when w=12 &#x3bc;m, thereby being able to reduce the intersection loss sharply.

Optical waveguide circuit

Processes for preparing oxide powders and superconducting oxides

Growing community of inventors

Yokohama, Japan

Takeshi Kitagawa