Abstract
Crosstalk in optical switching elements (SEs) is one of the major shortcomings in optical switching networks, and avoiding crosstalk is an important issue for making optical network work properly. We propose a new class of optical multistage interconnection networks (MINs) -vertically stacked Benes network VSB(N, K) that has N inputs (outputs) and consists of K vertically stacked Benes network. The VSB(N, K) network can support any permutation of N-element set {0,1, ...,N-1} rearrangeably nonblocking and also free of first-order crosstalk in SEs with a higher flexibility and much lower hardware cost than that of available optical MINs built on a combination of horizontal expansion and vertical stacking of Banyan networks. The complete algorithms to realize permutation crosstalk-free in a VSB(N, K) network are also the main contributions of this paper.