On the second-order approximation of PMD

A second-order polarization mode dispersion (PMD) approximation based upon the pulse-width distortion has been studied, It shows that a complete secon d-order approximation should include the second derivative of the PMD vecto r as well as the first derivative of the PMD vector. Second-order pulse dis tortions are explicitly expressed including a 'first-order' term involving principal states of polarization (PSP) of the pulse and a second-order term involving the beating between fiber chromatic dispersion and effective PMD ) chromatic dispersion. An analytical result is derived for the probability of second-order PMD power penalty; It shoes that the mean PMD of the fiber should be restricted to 26 ps and 18 ps, respectively for an optical link with zero and 850 ps/nm chromatic dispersion, in order to maintain a one dB second-order PMD power penalty with a probability below 10(-6) at a data r ate of TO Gb/s, The analysis also indicates that a second-order PMD compens ator can be used as a dynamic chromatic dispersion compensator.