This invention discloses an optical receiver (14) provided with: a phase modulation unit (15) that generates local oscillation light and modulates a phase of the local oscillation light; a coherent detection unit (10) that causes a received optical signal and the local oscillation light phase-modulated by the phase modulation unit (15) to interfere and converts the optical signal to an electrical signal; a polarization separation/adaptive equalization unit (11) that performs polarization separation and adaptive equalization on the electrical signal after coherent detection; and decoding units (12, 13) that decode the polarization-separated electrical signals output from the polarization separation/adaptive equalization unit (11).
