1. An optical receiver comprising: an optical to electrical converter (OEC) to produce an electrical signal vector representing at least one of amplitude, phase, and polarization information of a modulated optical carrier transmitted through an optical channel with impairments; and a signal processor coupled to the OEC to process the electrical signal vector to compensate the impairments of the optical channel, the signal processor comprising: an adaptive equalizer having an adaptation to generate an equalized output using a rotated error from an error, a rotator coupled to the adaptive equalizer to rotate the equalized output to generate a rotated vector using a phase and polarization matrix, a slicer coupled to the rotator to generate a decision from the rotated vector, and an error calculator coupled to the slicer to generate the error, the error being difference between the rotated vector and the decision.