Analysis of PMD-Induced System Penalty Using Pulse Spreading

This paper presents a technique that predicts the polarization-mode-dispersion (PMD)-induced system penalty based on rms pulse spreading. Amplifled-spontaneous-emission noise limited and thermal noise limited cases are investigated for the nonreturn to zero (NRZ) and return to zero modulation formats. A comparison is made with similar approaches that use three alternative metrics: the string length up to first order, the conventional string length, and the weighted string length. It is shown that the technique based on pulse spreading extends the applicable range of the system-penalty prediction in terms of both the mean link PMD and the modulated-signal bandwidth.