Multi-band Elastic Optical Networks: Overview and Recent Contributions from the IoTalentum Project.

Space division multiplexing (SDM) technology and band division multiplexing (BDM) are potential candidates for the bandwidth extension of the existing optical transport networks. Contrary to the SDM technology, whose activation requires a huge CAPEX cost, BDM is viewed as a practical solution in the short or middle term. However, the complete upgrade of a network to a multi-band elastic optical network (MB-EON) would incur significant expenses due to the costly components like erbium doped fiber amplifiers (EDFAs). Therefore, an efficient solution may come from performing a partial upgrade of the EON, lighting up the L-band of only some of the fibers, as an intermediate or a set of intermediate steps towards the final full upgrade. On the other hand, capacity extension by using other spectral bands in BDM also requires survivability provisioning. As providing connections with protection leads to additional spectrum consumption, by benefitting from service level agreement (SLA) differentiated protection, resources for connection protection can be more efficiently utilized. In this paper, we provide an overview of multi-band elastic optical networks and a summary of our previous works in the framework of the EU MSCA IoTalentum project, with the main focus on the partial migration of a C-band only network to C + L band system, and on SLA-differentiated survivability in MB-EONs.