Comparisons on PMD-compensation feedback methods for bandwidth-rich transmission formats

We compare the performance of polarization-mode dispersion (PMD) compensators under different feedback methods, as a function of the signal spectrum bandwidth. The return-to-zero (RZ), carrier-suppressed RZ, and chirped RZ transmission signals with various spectral bandwidths have been tested with different degree of polarization (DOP) or radio-frequency (RF) spectrum monitoring methods in the feedback circuitry of the compensator. Results show possible limitations of the DOP monitoring method in the PMD compensator particularly for the bandwidth-rich transmission formats, when compared to the conventional RF spectrum feedback method.