Effect of polarization dependent loss on the DOP feedback signal in PMD compensation

The impact of polarization dependence loss (PDL) on the degree of polarization (DOP) feedback signal in polarization mode dispersion (PMD) compensation is discussed in this paper. PDL affects DOP only in the presence of PMD. And in the presence of PMD and PDL, DOP relates not only to both the PMD and the PDL vectors, but also to the signal's polarization states. The PDL minimum endangering PMD compensation is determined by the step size of the practical PMD compensating algorithm, and the DGD value in optical fiber systems. DOP could no longer act as the feedback signal in PMD compensation unless PDL in the fiber system has been effectively eliminated before PMD compensation.