3-D optical networks of directional couplers and Mach-Zehnder

Principles of the proper design of intersection graphs (IGs) of 3-D networks of directional couplers (DCs) and Mach-Zehnder interferometers (MZIs) and their classification are presented. The IGs are described in graph theoretical terms as well as by the number of DCs and MZIs, respectively. Routing within the IGs (and in turn within the spatial switch) and future work is also discussed.