It is disclosed a coherent optical receiver for an optical communication network configured to receive a polarization multiplexed optical signal and to process it for generating a first and second received components thereof. Each of the first and second received components comprises a mixing of a first and second polarization components of the originally transmitted signal. The coherent optical receiver comprises a polarization demultiplexer comprising a first, second and third circuit. The first circuit calculates first and second Fourier transforms of the first and second received components. The second circuit multiplies the first and second Fourier transforms by a first and second transfer functions, respectively, adds them thereby providing a demultiplexed Fourier transform and retrieves the first polarization component applying thereto an inverse Fourier transform. The third circuit retroactively updates the first and second transfer functions, according to the retrieved first polarization component and the first and second received components.