Patent ID: 7444085

Claim:
A DQPSK optical receiver circuit for receiving an optical signal which is DQPSK modulated, comprising: a splitting unit for splitting a received optical signal; a first photoelectric conversion unit for converting one phase modulated component of one of the optical signals which is split by the splitting unit into an intensity modulated electric signal; a second photoelectric conversion unit for converting a phase modulated component which is orthogonal to the one phase modulated component of the other optical signal split by the splitting unit into an intensity modulated electric signal; a first data reproduction unit for reproducing a data signal and a clock signal from an output of the first photoelectric conversion unit; a second data reproduction unit for reproducing a data signal from an output of the second photoelectric conversion unit; and a phase synchronization unit for synchronizing phases of an output data signal of the first data reproduction unit and an output data signal of the second data reproduction unit.