A new design for WDM packet switching networks with wavelength conversion and recirculating buffering

In this paper we study switching fabric design in WDM optical switching networks with recirculating buffers. The switching network we consider may have arbitrary wavelength conversion capabilities. We focus on limited range wavelength conversion while considering full range wavelength conversion as a special case. We show that by adopting the idea of concentrators the cost of the switching fabric can be substantially reduced. For example, for a typical switching network with 16 input/output fibers, 16 wavelength channels per fiber, 12 delay lines and wavelength conversion degree 7, the new design can yield about 20% savings in network cost. We also give an efficient algorithm to assign the outputs to the inputs in the switching network.