| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical receiving circuit which has a balanced receiver and a direct detecting receiver with common constitution, and easily alternates both the receivers according to use styles. <P>SOLUTION: The optical receiving circuit includes an optical filter receiving an optical signal modulated by differential phase shift keying, a delay interferometer, dual optical detectors, and a discriminating circuit. The circuit is made to function as the balanced receiver. Further, the circuit is equipped with an optical switch means for turning on and off an optical signal of a D component output from the delay interferometer, so as to make the optical receiving circuit function as the balanced receiver by making the dual optical detectors photodetect optical signals of a C component and the D component when the optical signal of the D component is turned off, and as the direct detecting receiver by making the dual optical detectors photodetect only the optical signal of the C component when turned off. <P>COPYRIGHT: (C)2007,JPO&INPIT |
