Nonblocking photonic switch networks

A practical algorithm is described, with examples, for deciding whether or not a given network of 2×2 photonic switches is truly unblocking. Nonblocking photonic networks with specific additional properties, e.g. planarity, short path length, are also discussed, and specific networks, which have advantages over the square networks so far fabricated, are described. It is also shown that a correspondence can be set up between classical switch networks and networks of 2×2 switches, so that the classical results on blocking can be carried over to these networks