Patent ID: 8886057

Claim:
An optical receiver comprising: a splitter that splits a local oscillator lightwave into a first local oscillator lightwave and a second local oscillator lightwave; a measurement unit that measures phase variation of the first local oscillator lightwave and outputs a phase variation signal indicating the measured phase variation; a receiving unit that receives a signal lightwave and the second local oscillator lightwave and mixes these lightwaves and converts the mixed lightwaves into a digital signal; a dispersion compensator that reduces chromatic dispersion of the digital signal by giving a predetermined dispersion property to the digital signal, and outputs a dispersion compensation parameter indicating the predetermined dispersion property; a compensation calculator that calculates a phase compensation value by compensating for dispersion of the phase variation signal according to the dispersion compensation parameter, and inverting the dispersion-compensated phase variation signal; a phase processing unit that rotates phase of the dispersion-reduced digital signal based on the phase compensation value, thereby rotating the phase based on the phase variation to which the predetermined dispersion property is given; and a discriminating unit that discriminates the phase-rotated signal.