Two-bounce optical arbitrary permutation network.

The two-bounce free-space arbitrary interconnection architecture is presented. It results from a series of three-dimensional topological transformations to the Benes network, the minimum rearrangeable nonblocking network. Although functionally equivalent to the Benes network, it requires only two stages of global (spanning multiple chips) optical interconnections. The remaining stages of the modified Benes interconnection network are local and are implemented electronically (on individual chips). The two-bounce network is optimal in the sense that it retains the Benes minimum number of electronic switching resources yet also minimizes the number of optical links needed for global interconnection. Despite the use of higher-order k-shuffle (k > 2) global optical interconnects, the number of 2 x 2 switching elements is identical to the two-shuffle Benes network: there is no need for k x k crossbar switches for local interconnection at each stage. An experimental validation of the two-bounce architecture is presented.