A general construction for nonblocking crosstalk-free photonic switching networks

The graph representation G(M) of a multistage network M is well-known. C.T. Lea (1990) 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 none-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 the commonly used type. In this paper we use the same principle to establish the crosstalk-free property for the popular Log₂(N,k,p) network