A bilateral optocirculation circuit with three ports

A bilateral circulation circuit using LED-photodiode optoisolators is proposed. It is revealed theoretically and experimentally that bilateral and circular transmission is achieved by the enhancement of the current transfer ratio through optoelectronic positive feedback loops. Since the feedback loops are dispersed among three ports, it is possible to get circular signals in and out of optional ports. This circuit has stable positive gain and stable coupling efficiency because of optoelectronic feed-forwards. The bilateral frequency responses of gain extend over several hundred kilohertz.