An apparatus comprises a polarization-diversity optical hybrid that converts an optical signal into a plurality of optical signals comprising a first polarization component and a second polarization component orthogonal to the first polarization component, one or more detectors that convert the plurality of optical signals into a plurality of first analog electrical signals, DC blocking elements that remove DC signal components to output a plurality of second analog electrical signals, analog to digital converters (ADCs) coupled to the DC blocking elements that convert the plurality of second analog electrical signals into a plurality of digital signals, and a digital signal processing (DSP) unit coupled to the ADCs. The DSP is configured to perform a fiber dispersion compensation on the plurality of digital signals and add DC offsets to output a plurality of DC-restored compensated digital signals.