S+C+L High-Capacity Transmission Systems: Challenges and Opportunities

More than two decades after the first terabit transmission using the C+L band, and recent advancements in ultra-wideband (UWB) technology have demonstrated remarkably high-throughput achievements in S+C+L demonstrations. The development of fast and reliable closed-form propagation models accounting for wavelength-dependent impairments has paved the way for effective equalization techniques that contribute to this capacity boost. In this work, we compare the capacity of S+C+L systems to C+L and C systems, highlighting the importance of model-based power control strategies. Additionally, we explore different power pre-emphasis to either maximize capacity or achieve a uniform signal-to-noise ratio (SNR), the latter being of interest for actual networks in which the bit rate options of a transceiver are typically limited. Furthermore, we use the model-based performance prediction to analyze the impact of the amplifier's failure, highlighting the complex challenges this process leads to in terms of inter-channel stimulated Raman scattering (ISRS) power variations and transmission performance. Overall, this work aims to study through model-based simulations, the benefits and challenges of UWB systems while considering the feasibility of its deployment.