Nippon Telegraph and Telephone Corporation

Masaki Koutoku

Masahiro Yanagisawa

Masaru Kobayashi

Toshikazu Hashimoto

Hiroshi Takahashi

Takayuki Mizuno

Yasuyuki Inoue

Manabu Oguma

Tsutomu Kitoh

Yoshiteru Abe

Ikuo Ogawa

Tomohiro Shibata

Shuichiro Asakawa

Yoshinori Hibino

Senichi Suzuki

Takeshi Kitagawa

Ryou Nagase

Takaharu Ohyama

Tsutomu Kitou

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

It is an object of the present invention to reduce the size of a circuit and the adverse effects of fabrication errors, while increasing yield. Signal light incident on a circuit through input waveguides propagates from the exterior to interior of the circuit while rotating counterclockwise. The signal light passes through a point of inflection in the center of the circuit, subsequently propagate clockwise from the interior to exterior of the circuit, and then exit output waveguides. Two arms constituting a delay circuit and optical couplers can be integrated together at such an interval that they are not coupled together. Therefore, the size of the circuit can be reduced compared to the prior art.

Waveguide-type optical signal processing circuit

Growing community of inventors

Isehara, Japan

Masaki Koutoku