Patent ID: 8923460

Claim:
A method for processing a pair of random polarization electrical signals derived from coherent dual polarization optical signals received over an optical link, the method comprising: receiving a first input signal having a first polarization and a second input signal having a second polarization; filtering the first input signal by a first complex SISO FIR filter and the second input signal by a second complex SISO FIR filter to generate a first filtered input signal and a second filtered input signal; filtering the first and second filtered input signals by a first two-by-two matrix filter having four branches, wherein first and second branches receive the first filtered input signal, third and fourth branches receive the second filtered input signal, outputs of the first and third branches are summed to generate a first equalized filtered signal and outputs of the second and fourth branches are summed to generate a second equalized filtered signal; filtering the first and second input signals by a second two-by-two matrix filter having four branches, wherein first and second branches receive the first input signal, third and fourth branches receive the second input signal, outputs of the first and third branches are summed to generate a first equalized signal and outputs of the second and fourth branches are summed to generate a second equalized signal; and, adapting the first and second complex SISO FIR filters based on the first and second equalized signals and the first and second equalized filtered signals.