Polarization-Dependent Loss in Polarization Modulated Photonic Links: Model and Experiment

We investigate the effect of a discrete source of polarization-dependent loss in polarization-modulated optical links, using a Jones- and Stokes-vector description. We derive an expression for the output photocurrent in terms of the launch state and the link characteristics. We verify the theoretical description with an experimental investigation of a photonic link into which controlled polarization-dependent losses are introduced. The experimental results confirm a surprising theoretical conclusion: the distortion caused by polarization-dependent loss is equivalent to a simple system phase shift.