A system and method for improving the transmission quality of a WDM
optical communications system begins by determining the bit-error rate
for an optical channel before forward error correction is performed at a
receiver. The pre-corrective bit-error rate is fed back through a feed
back circuit that includes a parameter adjustment module which adjusts an
optical signal parameter based on the bit-error rate. As examples, the
signal parameter may be a channel power, dispersion, signal wavelength,
the chirp or eye shape of an optical signal. The feedback circuit may
also adjust various parameters within the WDM system, including amplifier
gain, attenuation, and power for one or more channels in the system. By
adjusting these parameters based on a pre-corrective bit-error rate,
transmission quality is improved and costs are lowered through a
reduction in hardware.