Interaction between polarization mode dispersion and polarization-dependent losses in optical communication links

Abstract

The interplay between polarization mode dispersion (PMD) and polarization-dependent losses (PDLs) is systematically analyzed by a model that assumes the concatenation of independent birefringent and PDL elements in a distributed way. It is shown that PDL enhances the differential group delay for the optical link and also induces a faster frequency decorrelation that increases the magnitude of higher-order PMD. In addition, PDL converts the real-valued PMD vector into a complex vector, giving rise to a loss of orthogonality between the principal states of polarization that scales with the link PDL. The dynamic equation for the global PDL vector that characterizes the polarization states with maximum and minimum attenuation is also solved. The frequency dependence of this vector is found to be a function of the total link PMD. Finally, the probability density functions for both the PMD and the PDL vectors will be discussed.