Reduced parametric wavelength-interchanging cross-connect architectures with scalability and modularity

Summary form only given. Wavelength conversion in wavelength-division multiplexing (WDM) networks offers distributed network management and reduction in blocking rising from wavelength contentions. While it is generally accepted that the benefit of wavelength conversion rises with increased traffic load, the main argument against wavelength conversion has been the cost and the complexity associated with realizing it in the network. Such a realization requires deployment of wavelength-interchanging cross-connects (WIXCs), which is far more sophisticated than wavelength-selective cross-connects (WSXCs), which provide only space switching based on wavelengths. Hence, it is preferred that WSXCs are deployed first and, if the blocking rate rises, they are upgraded to WIXCs in a modular manner. Another consideration for future upgrades is scalability both in the number of space ports and in the number of wavelength channels. Rising traffic demand in the network may continue to drive the need for an increased number of wavelength channels. Unfortunately, the existing WIXC architectures based on variable-input-to-fixed-output wavelength converters do not offer such scalability or modularity for upgrades. This paper examines and demonstrates the case for scalable upgrades of WIXCs based on parametric wavelength converters. We discuss the capability of upgrading a WSXC to a partially blocking WIXC, and eventually to a rearrangeably nonblocking WIXC by incrementally adding appropriate modules.