A general construction for nonblocking crosstalk-free photonic switching networks

Abstract

The graph representation G(M) of a multistage switching network M is well known. Lea [IEEE Trans Commun 38 (1990), 529-538] observed that link-disjoint paths in M correspond to node-disjoint paths in G(M). He proposed G(M) as a network by treating nodes as crossbars to transfer the node-disjoint property to the crosstalk-free property essential for photonic networks using directional couplers as components. However, such a network has its peculiarities and is not commonly used. In this paper, we will show how to take advantage of this correspondence to construct nonblocking crosstalk-free networks using the vertical stacking method. Our construction simplifies the proofs of many existing results, as well as establishing some new results. (C) 2003 Wiley Periodicals, Inc.