Abstract

Very high capacity optical communication systems can be designed by using wavelength division multiplexing (WDM) and dispersion-shifted fiber. In these systems four-wave mixing (FWM) is the dominant nonlinear effect [1], [2]. If the channels are equally spaced, all the product terms generated by FWM in the bandwidth of the system fall at the channel frequencies, giving rise to channel crosstalk. Moreover, the distortion is enhanced by the parametric gain provided by the channel power to the FWM waves at the detector [3]. With proper unequal channel spacing it is possible to prevent FWM waves from being generated at the channel frequencies [4].

© 1994 Optical Society of America