Optical receiver, polarization separation device and polarization separation method

Provided is a polarization separation device which converges filter coefficients used in polarization separation processing more quickly. This polarization separation device comprises: a first filter unit (11) which applies a filtering process on each of a first and second input signal, which are detected from a received signal, with elements of a characteristic matrix representing the inverse characteristics of an optical transmission line as filter coefficients, and uses each of the filtered signals to output a first output signal; a second filter unit (12) which applies a filtering process on each of the first and second input signals with the other elements of the characteristic matrix as filter coefficients, and uses each of the filtered signals to output a second output signal; a filter coefficient update unit (13) which uses the relation between the elements of the characteristic matrix to update the first filter coefficients so as to further reduce both error signals for each of the first and second output signals; and a filter coefficient update unit (14) which uses the relation between the elements of the characteristic matrix to update the second filter coefficients so as to further reduce both error signals for each of the first and second output signals.