A class of scalable optical interconnection networks through discrete broadcast-select multi-domain WDM

Passive star-coupled optical interconnects with wavelength-division multiplexing hold a strong potential for realizing flexible large-scale multicomputer networks. Virtual point-to-point regular connectivities can be defined and modified in a network with broadcast-select routing via distributed wavelength assignment to the nodes. The system size in this approach is bound by the number of separable wavelength channels. The paper proposes a network class that achieves scalability by grouping the nodes into clusters and employing a separate pair of broadcast and select couplers with each cluster. Interconnecting the clusters according to a regular topology results in a modular architecture with reconfigurable partitions and significantly reduced fiber link density. This approach efficiently combines wavelength-division with direct space interconnection, taking advantage of the properties of each. For the topologies of most significance to parallel computing, the paper studies conflict-free wavelength assignment that maximizes spatial reuse, identifies the valid network partitions, and evaluates the fiber link density and both space and wavelength channel throughput improvement. The results show that cube and shuffle networks take most advantage of the proposed approach in terms of maximizing wavelength reuse