Crosstalk-preventing scheduling in AWG-based cell switches

AWG-based optical switching fabrics are affected by coherent crosstalk, that can significantly impair system operation when the same wavelength is used simultaneously on several input ports to forward data to output ports. To permit large port counts in a NxN AWG, the scheduling of transmissions across the AWG must therefore prevent switch configurations that generate large crosstalk. We study the properties and the existence conditions of switch configurations able to control coherent crosstalk. Our results show that it is possible to keep an AWG-based switch with large port counts in the feasible operational region without significant performance degradation, provided that a proper scheduling algorithm is used.