Impairment-aware routing, modulation, spectrum, and core allocation with bit loading in spectrally–spatially flexible optical networks

This work proposes a physical layer impairment-aware routing, modulation, spectrum, and core allocation optimization framework in elastic optical networks with multi-core fibers. The inter- and intra-core impairments considered are crosstalk between adjacent cores, in-band crosstalk, non-linear interference, and amplified spontaneous emission noise. Further, bit loading is used in the proposed framework, independently modulating each demand’s frequency slots, depending on each frequency slot’s interference level. An optimization framework is initially developed for benchmarking purposes, followed by a heuristic algorithm and demand ordering technique for larger-sized networks. For both optimization and heuristic approaches, an end-to-end acceptable bit error rate is ensured for each provisioned demand. The benefits of the proposed approach are illustrated through simulations, demonstrating that they achieve lower fragmentation and less spectrum usage as compared to other state-of-the-art techniques.