Optimization of WDM optical packet switches with sparse wavelength converters and nondegenerate fiber delay lines

Abstract

In this paper, we investigate the somewhat untraditional approach of contention resolution in WDM optical packet switches. The most striking characteristics of the developed switch architecture are that (1) contention resolution is achieved by a combined sharing of fiber delay-lines (FDLs) and tunable optical wavelength converters (TOWCs); (2) FDLs used for contention resolution is in non-degenerate form, i.e., buffers are achieved by non-uniform distribution of the delay lines; (3) TOWCs just can achieve wavelength conversion in partial continuous wavelength channels, i.e., sparse wavelength conversion. We describe and analyze the concrete configuration of FDLs and TOWCs under non-bursty and bursty traffic scenarios. Simulation results demonstrate that for a prefixed packet loss probability constraint, e.g., 10 -6 , the developed architecture provides a different point of view in the optical packet switching (OPS) design. That is, combined sharing of FDLs and TOWCs can, effectively, obtain a good tradeoff between the switch size and the cost, and TOWCs which are achieved in sparse form can also decrease the implementing complexity.