Design of and Resiliency Enhancement in Coarse/Fine Hybrid Granular Routing Optical Networks Based on Iterative Path-Pair-Loop Inflation

A spectral-resource-utilization-efficient and highly resilient coarse granular routing optical network architecture is proposed. The improvement in network resiliency is realized by a novel concept named loop inflation that aims to enhance the geographical diversity of a working path and its redundant path. The trade-off between the inflation and the growth in circumference length of loops is controlled by the Simulated Annealing technique. Coarse granular routing is combined with resilient path design to realize higher spectral resource utilization. The routing scheme defines virtual direct links (VDLs) bridging distant nodes to alleviate the spectrum narrowing effect at the nodes traversed, allowing optical channels to be more densely accommodated by the fibers installed. Numerical experiments elucidate that the proposed networks successfully achieve a 30+0/0 route diversity improvement and a 12% fiber number reduction over conventional networks.