Simple Method for Polarization Dispersion Measurements in Long Single-Mode Fibres

The study of polarization dispersion in standard single-mode fibres takes on a growing importance, because the delay between polarization modes causes pulse broadening and may become predominant in multigigabit long-span optical links. The combined effects of weak birefringence and fluctuating mode coupling result in a stochastic behaviour of the polarization dispersion and of the output polarization state. The so-called principal states, a particular set of orthogonal polarization states, experience the greatest difference in propagation time and are therefore very convenient for the description of polarization dispersion [1]. Recent contributions use the properties of these states to demonstrate that the evolution of polarization is quite similar to a random walk and the probability density function of the fluctuating polarization dispersion can therefore be described by a Gaussianlike distribution [2,3].