Abstract

A key requirement in most ≥10-Gbit/s/channel WDM transmission systems is periodic compensation of chromatic dispersion. Such compen-sators generally produce a negative dispersion value to compensate for the positive accumulated dispersion due to the transmission fiber. There are two critical issues that severely hamper the performance of longer-distance dispersion-compensated WDM systems: (i) the transmission fiber itself has a spectral dependency of chromatic dispersion, i.e., 0.07 ps/nm^2,1 and (ii) the most common type of dispersion compensator, dispersion compensating fiber (DCF), has a dispersion spectral dependency that is mismatched to the transmission fiber. These issues guarantee that only one WDM channel will have exact compensation, with shorter wavelength channels typically accumulating negative dispersion and longer wavelength channels accumulating positive dispersion.^2,3 Compounding these problems is the fact that dispersion slope changes with fiber length, fiber nonlinearities, signal power fluctuations, fiber type, and temperature. Hence, dispersion slope compensators are of significant value to optical systems designers.

© 2002 Optical Society of America