Abstract

Polarization mode dispersion (PMD) has emerged as a key limitation in: (i) 10-Gb/s systems that use older legacy fiber, and (ii) 40-Gb/s systems that use even the newest types of fiber due to the non-zero PMD that appears in most in-line components. For such systems, PMD compensators would be needed to reduce the probability of network outage. Typically, PMD compensators attempt to correct a single WDM channel and are composed of a polarization controller, a differential-group-delay element, and a monitoring feedback loop.^1,2 The feedback loop is necessary to rotate the state-of-polarization (SOP) of the incoming signal for optimal alignment to the DGD element. Almost all PMD com-pensators have assumed that the system is linear and that the effects of PMD do not change much faster than on a millisecond time scale.

© 2002 Optical Society of America