Strategies for Optimized Raman Amplification Deployment in DWDM Mesh Networks

Abstract

Raman amplification can be critical for the feasibility of the most performance-demanding optical channels in regional and long-haul networks, minimizing the need to deploy expensive 3R regenerators and/or allowing to use more spectral efficient channel formats. Hybrid Raman/Erbium-doped fibre amplifiers (EDFAs) enable to cost-effectively exploit the benefits of Raman amplification. However, these amplifiers are costlier than simple EDFAs. Therefore, their deployment should be optimized such that the resulting capacity increase and cost reduction (due to saving 3R regenerators) outweighs the additional cost of introducing these amplifiers. Achieving this goal can be a complex task in dense wavelength division multiplexing (DWDM) mesh networks, in view of the different optical channels that overlap at each fibre span. This paper overviews and extends a framework to place hybrid Raman/EDFA amplifiers in DWDM networks with the objective of minimizing the overall network capital expenditures. The performance of the framework is evaluated using reference long-haul networks. Results show that an optimized placement enables to maximize the benefit of deploying hybrid amplifiers while still keeping their number to a minimum.