1. A method, comprising: receiving a carrier wave comprising a first polarization state and a second polarization state, wherein a correlation exists between the first polarization state and the second polarization state; generating a first constellation corresponding to the first polarization state and a second constellation corresponding to the second polarization state; calculating a first expected value based on the first constellation and a second expected value based on the second constellation; equalizing, by an adaptive equalizer, a first output based on a first signal associated with the first polarization state and a second output based on a second signal associated with the second polarization state; calculating a first error based on a difference between the first expected value and the first output, the first expected value being constrained based on the first output and the second output; calculating a second error based on a difference between the second expected value and the second output, the second expected value being constrained based on the first output and the second output; generating a feedback signal based on the first error, the second error and the correlation; and determining coefficients for filters of the adaptive equalizer using the feedback signal.