REDUCTION OF 4-WAVE-MIXING CROSSTALK IN WDM SYSTEMS USING UNEQUALLY SPACED CHANNELS

Crosstalk due to four-wave mixing (FWM) is the dominant nonlinear effe ct in long-haul multichannel optical communication systems employing d ispersion-shifted fiber. A technique to design the channel frequency a llocation in order to minimize the crosstalk due to FWM is presented. It is shown that suitable unequal channel separations can be found for which no four-wave mixing product term is superimposed on any of the transmitted channels. This is obtained at the expense of some expansio n of the system bandwidth. Simulations are presented to show the effec tiveness of this technique in a 10-channel, 10-Gb/s per channel, syste m.