Transmission enhancement by deployment of interferometric wavelength converters within all-optical cross connects

Wavelength-division multiplexing (WDM) networks are expected to utilize all-optical cross connects (OXCN) for signal routing. Because a signal path is likely to contain a number of OXCNs, their cascadability is essential. Furthermore, because wavelength converters in the OXCNs improve traffic performance and ease network management, their cascadability, in particular, is important. Using interferometric wavelength converters (IWCs) we have previously demonstrated experimentally a cascade of 10 converters at 10 Gbit/s with <2-dB penalty. In this paper we analyze the cascadability limitations of OXCNs deploying IWCs. The wavelength converters used in the experiments and in this analysis are interferometric wavelength converters, where semiconductor optical amplifiers are used as optically controlled phase shifters in a Michelson configuration.