In-field comparison among polarization-mode-dispersion measurement techniques

We report polarization mode dispersion measurements on a 168 km long undersea optical cable, performed with two techniques. From experimental results, statistical behavior of polarization parameters and their time fluctuations have been extracted. An average differential group delay of about 13 ps shows that dispersion-shifted fibers can be affected by a polarization dispersion significantly larger than standard step-index fibers. The correlation length of the polarization-coupling perturbation in the tested fibers is not negligible with respect to the link length.