Nippon Telegraph and Telephone Corporation

Nippon Telegraph and Telephone Public Corporation

Hiroshi Kanbe

Tatsuya Kimura

Yoshihiko Mizushima

Kenji Kajiyama

Elmer H Hara

In an optoelectronic switch, a photodiode is used as an optical-to-electrical converter in which a first semiconductor including a p-n junction is combined with a second semiconductor having a narrower energy band gap than the first semiconductor to form a heterojunction. When supplied with a light signal modulated by an electrical signal, the photodiode becomes ON or OFF depending upon the magnitude of a reverse bias voltage applied to said photodiode. A source for applying the bias voltage to the photodiode comprises two voltage sources of the same polarity or a single voltage source. The optoelectronic switch, has a high isolation ratio and broad transmission bandwidth, consumes little electrical power and produces low cross-talk levels when used in switching arrays.

Optoelectronic switches

The impurity concentration distribution of the layers of a multilayer junction diode is varied such that the concentration in a first region contiguous to the junction is low, in a second region is high, in a third region is low and in a last region gradually increases in the direction away from the junction.

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Tanashi, Japan

Hiroshi Kanbe