Modeling and analysis of the coupling effect for large-scale multi-band optical networks.

The stimulated Raman scattering (SRS) effect is non-negligible in multi-band transmission and causes signal power transfer between channels, which is the primary bottleneck in optical networks. The current literature investigates the SRS effect in the physical layer. Investigating the impact of the SRS effect in the network layer is challenging because of the high dynamics in routing, frequency, and launch power assignment. We develop a novel perspective, the coupling effect, to analyze the influence of the SRS effect in the network layer. We construct a directed weighted network called the Flow Coupling Network (FCN) to investigate the coupling effect and propose the flow coupling strength and network coupling strength. Based on the flow coupling strength, we examine the rationality of FCN and optimize the launch power of each flow. We find that the optimization through the flow coupling strength exceeds the optimization through frequency in network capacity. Based on the network coupling strength, we investigate the influence of the coupling effect and find that greater network capacity gain can be achieved through power optimization under stronger network coupling strength. Furthermore, we examined the network coupling strength in WS small-world networks, BA scale-free networks, and ER random networks. We discovered that the network coupling strength increases as the network scale increases in WS small-world networks.