Patent ID: 7903983

Claim:
An optical receiver comprising: an optical front end receiving an optical signal modulated by differential phase shift keying and converting the received optical signal to electrical first and second data signals corresponding to differential phase shift keying signals including an in-phase and a quadrature phase; a clock regenerator regenerating a clock signal from the first data signal; a first demultiplexer demultiplexing the first data signal into two signals; a first decision circuit outputting the two signals demultiplexed by the first demultiplexer using the clock signal; a delay member outputting a delayed clock signal produced by delaying the clock signal; a second decision circuit outputting the two signals demultiplexed by the first demultiplexer using the delayed clock signal; a second demultiplexer demultiplexing the second data signal into two signals; an inverter generating an inverted clock signal by inverting the clock signal and outputting either the inverted clock signal or the clock signal; a third decision circuit outputting the two signals demultiplexed by the second demultiplexer using the inverted clock signal or the clock signal, respectively; and a fourth decision circuit respectively outputting the two signals output by the third decision circuit using the delayed clock signal.