Nippon Telegraph and Telephone Corporation

Ntt Electronics Corporation

Takaharu Ohyama

Yoshiyuki Doi

Ikuo Ogawa

Yoshifumi Muramoto

Masahiro Yanagisawa

Masaru Kobayashi

Toshikazu Hashimoto

Hiroshi Takahashi

Yuichi Suzuki

Tsutomu Kitoh

Yoshiteru Abe

Akimasa Kaneko

Tomohiro Shibata

Senichi Suzuki

Shuichiro Asakawa

Yasuaki Tamura

Takeshi Kitagawa

Ryou Nagase

Masaki Koutoku

The present invention is intended to provide a compact and simple optical semiconductor device that reduces crosstalk (leakage current) between light receiving elements. According to the present invention, since a back surface electrode is a mirror-like thin film, crosstalk to an adjacent light receiving element can be suppressed, thereby reducing a detection error of a light intensity. By disposing a patterned back surface electrode or by disposing an ohmic electrode at the bottom of an insulating film over the whole back surface, contact resistance on the back surface can be reduced. By using the optical semiconductor elements with a two-dimensional arrangement and by using a mirror-like thin film as the back surface electrode, crosstalk can be reduced. By accommodating the optical semiconductor elements in the housing in a highly hermetic condition, the optical semiconductor elements can be protected from an external environment.

Optical semiconductor device

An optical module has a structure for reducing the stress applied to a package. The optical module is structured so that an end face of a waveguide () of a planar lightwave circuit () is joined to a plurality of packages () storing therein optical elements so that the waveguide is optically coupled to the optical elements. The optical module includes a housing () storing therein a planar lightwave circuit and a plurality of packages in which an upper face of a protrusion () formed in the bottom section is fixed to the planar lightwave circuit (). Each of the plurality of packages () is electrically connected to an electric part () provided in the housing () via flexible printed circuits ().

Optical module

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

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Yokohama, Japan

Takaharu Ohyama