A coherent optical receiver for an optical communication network, said coherent optical receiver being configured to receive a polarization multiplexed optical signal (s(t)) and to process it for generating a first received component (X Hk) and a second received component (X Vk), each of said first received component (X Hk) and said second received component (X Vk) comprising a mixing of a first polarization component (Y Hk; Y HOk) and a second polarization component (Y Vk; Y VOk) of said polarization multiplexed optical signal (s(t)) as originally transmitted, said coherent optical receiver further comprising a polarization demultiplexer (PD; PD') in turn comprising: - a first circuit (PMi H, PMi V; PMi HE, PMi HO, PMi VE, PMivo) configured to calculate a first Fourier transform (FX Hq; FX HEq) of said first received component (X Hk) and a second Fourier transform (FX Vq; FX VEq) of said second received component (X Vk); - a second circuit (M1, M2, A1, PMo H; M1 E, M1 O, M2 E, M2 O A1, PMo H) configured to multiply said first Fourier transform (FX Hq; FX HEq) by a first transfer function (FH11 q; FH11 Oq), multiply said second Fourier transform (FX Vq; FX VEq) by a second transfer function (FH12 q; FH12 Oq) and add said multiplied first Fourier transform (P1 q) and said multiplied second Fourier transform (P2 q) thereby providing a demultiplexed Fourier transform (FY Hq; FY HOq), and retrieve said first polarization component (Y Hk; Y HOk) by applying an inverse Fourier transform operation to said demultiplexed Fourier transform (FY Hq; FY HOq); and - a third circuit (S1, PMf11, PMf12; S2, PMf11 O, PMf11 E, PMf12 O, PMf12 E) configured to retroactively update said first transfer function (FH11q; FH11 Oq) and said second transfer function (FH12 q; FH12 Oq), according to said retrieved first polarization component (Y Hk; Y HOk), said first received component (X Hk) and said second received component (X Vk). - a first circuit (PMi H, PMi V; PMi HE, PMi HO, PMi VE, PMivo) configured to calculate a first Fourier transform (FX Hq; FX HEq) of said first received component (X Hk) and a second Fourier transform (FX Vq; FX VEq) of said second received component (X Vk); - a second circuit (M1, M2, A1, PMo H; M1 E, M1 O, M2 E, M2 O A1, PMo H) configured to multiply said first Fourier transform (FX Hq; FX HEq) by a first transfer function (FH11 q; FH11 Oq), multiply said second Fourier transform (FX Vq; FX VEq) by a second transfer function (FH12 q; FH12 Oq) and add said multiplied first Fourier transform (P1 q) and said multiplied second Fourier transform (P2 q) thereby providing a demultiplexed Fourier transform (FY Hq; FY HOq), and retrieve said first polarization component (Y Hk; Y HOk) by applying an inverse Fourier transform operation to said demultiplexed Fourier transform (FY Hq; FY HOq); and - a third circuit (S1, PMf11, PMf12; S2, PMf11 O, PMf11 E, PMf12 O, PMf12 E) configured to retroactively update said first transfer function (FH11q; FH11 Oq) and said second transfer function (FH12 q; FH12 Oq), according to said retrieved first polarization component (Y Hk; Y HOk), said first received component (X Hk) and said second received component (X Vk).