Cancellation of SRS crosstalk in WDM optical communication systems by series or parallel techniques

We have shown that SRS crosstalk in WDM systems can be reduced in the presence of dispersion by a factor of the order of the Raman gain G, by either a series or parallel arrangement. In the absence of dispersion, perfect cancellation can be obtained in the series arrangement, but not in the parallel one. The parallel arrangement may be more practical as it does not require the use of spectral inversion. These methods can in principle provide substantial reductions in SRS crosstalk, and may thus provide means for enhancing the performance of future WDM systems