Inter-Band GSNR Degradations and Leading Impairments in C+L Band 400G Transmission

Wideband optical transmission presents an appealing solution to network throughput and capacity requirements, improving existing network architectures with minimally invasive upgrades. This framework provides new perspectives into quality of transmission (QoT) management as a result of inter-band effects; the QoT is commonly given by the generalized signal-to-noise ratio (GSNR). In this study we address the leading impairments in multi-band nonlinear transmission in a C+L scenario from an operational point of view, supported by mathematical models and simulations. From this approach we identify that stimulated Raman scattering (SRS) is the main contributor to inter-band effects and causes the main variation in the GSNR degradation; correspondingly, we show that the inter-band nonlinear interference (NLI) can be neglected in a C+L scenario.