Fujitsu Corporation

Takashi Yokota

Tatsuro Kunikane

Hideki Isono

Mitsuru Yumoto

Kiyoshi Terai

Hirosuke Furuta

Kazushi Asanuma

Eiji Kikuchi

Masayuki Shiga

Shoichi Miura

Substrate for mounting optical components and electric circuit

Method of fixing cylindrical optical part and electric part

A wavelength-division multiplexing optical transmission system is disclosed which transmits light of wavelengths .lambda..sub.1, .lambda..sub.2 and .lambda..sub.3 (.lambda..sub.1 &lt;.lambda..sub.2 &lt;.lambda..sub.3) by way of a single optical fiber. An optical multiplexer/demultiplexer of the filter type is used which includes a parallelogram prism, a first filter formed on a side face of the parallelogram prism, and second and third filters formed on the opposite side face of the parallelogram. Bidirectional optical fiber communications between the central telephone exchange side and a subscriber side can be achieved using such optical multiplexer/demultiplexer of the filter type. With the arrangement of the invention, an optical multiplexer/demultiplexer of the filter type can be produced at a low cost without the necessity of using a filter having a wide stopping band as a filter to be formed on a parallelogram prism.

Wavelength-division multiplexing optical transmission system

An optical branching filter branches or mixes lights of n-kind of wavelengths. An input/output port for the light mixed n-kind of wavelengths is provided to one of two surfaces of the transparent block and second input/output parts for forming optical filters allowing only the lights having the predetermined wavelengths to pass therethrough, respectively among the lights in n-kind of wavelengths, but reflecting the lights having other wavelengths, respectively is provided to any one of two surfaces. A first input/output port and n second input/output ports, respectively is formed by an optical waveguide and a lens which optically connects the optical waveguide and first input/output part or a second input/output part. Positions of each second input/output port are selected so that the length of optical paths formed between the lenses of the first input/output port in the second input/output port are in the reverse proportion to the lengths of wavelengths corresponding to the second input/output portions.

Optical branching filter

Growing community of inventors

Yamato, Japan

Takashi Yokota