Patent ID: 8837957

Claim:
An apparatus comprising: a processor configured to compute a transfer function based at least in part on an amplitude response of a wavelength selective switch (WSS); and a frequency-domain equalizer (FDEQ) configured to filter, using the transfer function and in a frequency domain, a plurality of digital samples of a polarization multiplexed phase-shift-keying signal that has been transported over an optical channel, wherein filtering the plurality of digital samples compensates for filtering effects of at least one WSS located in the optical channel, wherein computing the transfer function comprises: generating an error signal power; computing an initial transfer function based on the amplitude response of the WSS; and iteratively generating an updated transfer function as a product of a previous transfer function and the inverse of the amplitude response of the WSS until the error signal power is minimized, wherein the previous transfer function in a first iteration is the initial transfer function, wherein the updated transfer function generated by one iteration is used as the previous transfer function in a next iteration, and wherein a transfer function that minimizes error signal power is designated as the transfer function of the FDEQ.