Scalable network architectures using the Optical Transpose Interconnection System (OTIS)

The Optical Transpose Interconnection System (OTIS) proposed by Marsden ct al. (Opt. Lett. 18, 13 (July 1993), 1083-1085) makes use of free-space optical interconnects to augment an electronic system by adding nonlocal interconnections. In this paper, we show how these connections can be used to implement a large-scale system with a given network topology using small copies of a similar topology. In particular, we show that, using OTIS, an N-2 node 4-D mesh can be constructed from N copies of the N-node 2-D mesh, an N-2 node hypercube can be constructed from N copies of the N-node hypercube, and an (N-2, alpha(2), c/2) expander can be constructed from N copies of an (N, alpha, c) expanders, all with small slowdown. Finally, we show how this expander construction can be used to build multibutterfly networks in a scalable fashion. (C) 2000 Academic Press.