| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical hybrid circuit, an optical receiver and a light receiving method, having a low wavelength dependency, a low phase deviation characteristic and a low insertion loss and being suitable for compaction in configuration and monolithic integration. <P>SOLUTION: The optical hybrid circuit 1 includes a multi-mode interference (MMI) coupler 2 including a pair of input channels provided at positions symmetrical with respect to a center position in a widthwise direction thereof, a pair of first output channels neighboring with each other outputting a pair of first optical signals having an in-phase relationship, and a pair of second output channels neighboring with each other outputting a pair of second optical signals having an in-phase relationship. The MMI coupler converts QPSK signal light or DQPSK signal light into the pair of first optical signals and the pair of second optical signals having an in-phase relationship. The optical hybrid circuit includes a 2:2 optical coupler 3 connected to the first or the second output channels, including two channels at an input side and including two channels at an output side. The 2:2 optical coupler converts the pair of first optical signals or the pair of second optical signals into a pair of third optical signals having a quadrature phase relationship. <P>COPYRIGHT: (C)2010,JPO&INPIT |
