SHUFFLE-EQUIVALENT INTERCONNECTION TOPOLOGIES BASED ON COMPUTER-GENERATED BINARY-PHASE GRATINGS

Several different shuffle-equivalent interconnection topologies that c an be used within the optical link stages of photonic-switching networ ks are studied. These schemes include the two shuffle, the two banyan, and the segmented two shuffle, which can be used to interconnect two- input, two-output switching nodes. The schemes also include the four s huffle and the four banyan, which can be used to interconnect four-inp ut, four-output switching nodes. (Note: The segmented two shuffle and the four banyan are novel interconnection topologies that were develop ed to satisfy some of the constraints of free-space digital optics). I t is shown that each of these interconnection topologies can be implem ented by the use of relatively simple imaging optics that contain spac e-invariant computer-generated binary-phase gratings. The effects of n ode type and interconnection topology on the laser power requirements and the optical component complexity within the resulting systems are also studied. The general class of networks known as extended generali zed shuffle networks is used as a baseline for the analysis. It is sho wn that (2, 1, 1) nodes and (2, 2, 2) nodes connected by two-banyan in terconnections can produce power-efficient and cost-effective systems. The results should help identify the architectural trade-offs that ex ist when a node type and an interconnection topology are selected for implementation within a switching system based on free-space digital o ptics.