Performance improvements by dynamic amplifier reconfigurations for C + L-band optical networks in the presence of stimulated Raman scattering

Abstract

C+L-band optical networks suffer from transmission impairments including amplified spontaneous emission noise and Kerr-induced and stimulated-Raman-scattering-induced nonlinear interference. The generalized signal-to-noise ratio (GSNR) profiles across different links of the network play a crucial role in determining the overall network traffic load and operating margins, but the GSNR is highly dependent on the signal power profiles along the link and time-varying channel-loading conditions, particularly for future dynamic mesh networks. As the network is dynamically loaded, we monitor the GSNR across the active channels of each link and investigate the benefits of regularly reconfiguring the erbium-doped fiber amplifier (EDFA) gain and tilts to optimize either (1) the mean GSNR minus the GSNR standard deviation (i.e., to achieve a high and flat GSNR across channels) or (2) the minimum GSNR to improve the traffic load and/or GSNR margins. Different lightpath provisioning strategies are studied, and simulation results for COST 239, a German network, and a sample Alibaba production network show that, compared with static EDFA configurations assuming fully loaded conditions, the GSNR margin and hence network robustness with dynamic EDFA reconfigurations can be improved by at least 0.45, 0.57, and 0.72 dB, respectively, with similar or better network blocking probability. Alternatively, the improved GSNR profiles can enable an average network capacity improvement of at least 9%, 8%, and 16%, respectively, in principle when operating at the same GSNR margin at 30% spectral occupancy.