Mode-Group Division Multiplexing: Transmission, Node Architecture, and Provisioning

Few Mode Fibers (FMF) and Space DivisionMultiplexing (SDM) are an attractive solution to offer high capacity in optical networks. Although transmission along FMF presents several issues mainly due to the cross-talk among modes, the use of Multiple Input Multiple Output (MIMO) coherent receivers permits to limit the impact of such physical impairment. However, the complexity of MIMO is not negligible (especially with a large number of modes) and the spatial modes must cover the same path, thus limiting network flexibility, e.g., routing modes along different paths is not admitted. In this paper we exploit the concept of Mode-Group Division Multiplexing (MGDM) and we investigate the network architecture and provisioning supporting MGDM. Modes are divided in groups: the modes within a group are co-routed and received with a reduced-complexity MIMO receiver, while the different groups can be routed along different paths. Different node architectures supporting MGDM are presented taking in account state-of-the-art components and devices, even commercially available on the market. A quality of transmission (QoT) model is also presented accounting to the inter mode group crosstalk, that cannot be neglected in the reach evaluation. QoT is exploited by a proposed connection provisioning scheme for MGDM. Simulations are carried out in metro/rural network scenarios with different link span lengths. Simulations show high throughput increase while limiting the complexity of receivers.