Fuji Electric Co., Ltd.

Naoki Kaiho

Nobuhiko Tsuji

Yasukazu Sano

Tomio Shimizu

Tetsuya Saito

A bidirectional optically powered signal transmission apparatus includes a control station and a field station which are optically linked by an optical fiber for signal transmission and for power transmission. The control station sends a first light beam to a light receiver in the field station. The field station sends a second light beam to the control station. The first and second light beams are at different wavelengths so that simultaneous bidirectional transmission is enabled. The field station further converts a portion of the first light beam to electric power for powering the field station. The field station demodulates an AC component superimposed on the light it receives to produce an AC electric signal for control of the field station. The control and field stations include respective optical transceiver circuits, each including a light source, light receiver and light splitter-coupler. The light receiver in the control station further includes a light receiver array for converting a portion of the first light beam to electric power.

Bidirectional optically powered signal transmission apparatus

A bidirectional optically powered signal transmission apparatus includes a control station and a field station which are optically linked by an optical fiber. The control station sends a first light beam to a light receiver in the field station. The field station sends a second light beam to the control station. The first and second light beams are at different wavelengths so that simultaneous bidirectional transmission is enabled. The field station further converts a portion of the first light beam to electric power for powering the field station. The field station demodulates an AC component superimposed on the light it receives to produce an AC electric signal for control of the field station. Optical transmitting and receiving functions in the field station are preferably combined into an integrated opto-electric and electro-optic converter (O-E and E-O converter). The O-E and E-O converter is preferably an integrated circuit.

A rotatable polygon mirror comprising a transparent regular polygonal cylinder having the sides of a regular polygon. The sides are rotationally symmetrical with one another relative to a rotating axis of the transparent regular polygonal cylinder. The transparent regular polygonal cylinder has inner surfaces in the body of the transparent regular polygonal cylinder which correspond to the respective sides of the regular polygon, where the inner surfaces consist of total internal reflection surfaces.

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Tokyo, Japan

Naoki Kaiho