An apparatus comprising: at least one analog-to-digital converter, ADC, (120,122, 124, 126) configured to convert a first and second polarization components of an optical signal in form of electrical signals into first and second digital polarization signals; and at least one frequency-domain equalizer, FDEQ, (128, 130) coupled to the at least one ADC (120,122, 124, 126), wherein the at least one FDEQ (128, 130) is configured to compensate for distortion in the first and second digital polarization signals; wherein the at least one FDEQ comprises a first FDEQ and a second FDEQ; at least one interpolator (134, 136) configured to interpolate the compensated first digital and second digital polarization signals; wherein the at least one interpolator (134, 136) comprises a first digital interpolator, DI, coupled to the first FDEQ and a second DI coupled to the second FDEQ, and wherein the first and second FDEQs are disposed between the at least one ADC (120,122, 124, 126) and the first and second DIs; an equalizing module coupled to the at least one interpolator (134, 136) and configured to generate a first equalized polarization signal and a second equalized polarization signal based on the first and second interpolated digital polarization signals; and a timing error detector, TED, coupled to the equalizing module and configured to detect timing error in the optical signal based on one of the first and second equalized polarization signals; wherein the at least one interpolator (134, 136) is coupled to the TED and is configured to resample the first and second equalized polarization signals based on the detected timing error. at least one analog-to-digital converter, ADC, (120,122, 124, 126) configured to convert a first and second polarization components of an optical signal in form of electrical signals into first and second digital polarization signals; and at least one frequency-domain equalizer, FDEQ, (128, 130) coupled to the at least one ADC (120,122, 124, 126), wherein the at least one FDEQ (128, 130) is configured to compensate for distortion in the first and second digital polarization signals; wherein the at least one FDEQ comprises a first FDEQ and a second FDEQ; at least one interpolator (134, 136) configured to interpolate the compensated first digital and second digital polarization signals; wherein the at least one interpolator (134, 136) comprises a first digital interpolator, DI, coupled to the first FDEQ and a second DI coupled to the second FDEQ, and wherein the first and second FDEQs are disposed between the at least one ADC (120,122, 124, 126) and the first and second DIs; an equalizing module coupled to the at least one interpolator (134, 136) and configured to generate a first equalized polarization signal and a second equalized polarization signal based on the first and second interpolated digital polarization signals; and a timing error detector, TED, coupled to the equalizing module and configured to detect timing error in the optical signal based on one of the first and second equalized polarization signals; wherein the at least one interpolator (134, 136) is coupled to the TED and is configured to resample the first and second equalized polarization signals based on the detected timing error.