Electronic dispersion compensation for PMD in 40-GB/s optical links

In 40-Gb/s optical systems, it is impossible to neglect the electronic dispersion of polarization-mode dispersion (PMD). As the data rate is increased, the maximum useful length of the fiber decreases according to the square of the increase. With the development of VLSI and DSP technologies, the electronic dispersion compensation for optical network has aroused greater world attention. In this paper, the performance of decision feedback equalizer (DFE) in PMD-limited 40-GB/s optical links is analyzed by using Matlab/Simulink. A simple equalizer circuit, in fold-cascade traveling-wave filter topology, is presented and the results based on S-parameter simulations show that a DFE equalizer consisting of a 3-tap feed forward equalizer (FFE) and a 2-tap feed back equalizer (FBE) can mitigate PMD effectively.