Optical Amplifiers for Modern Networks

Recent trends in optical networks, such as reconfigurable optical add drop multiplexing (ROADM) and optical cross connects, require advanced optical amplifiers based on both erbium doped fibre amplifiers (EDFAs) and Raman technology. To address the dynamic nature of modern networks, EDFAs should provide broadband variable gain operation, flexible mid-stage access, fast transient response to dynamic events, and advanced spectral monitoring and control to adjust to changing spectral conditions in the network. An important supplement to EDFA technology is the use of distributed Raman amplification (DRA) to achieve transmission over multi-span ultra long haul (ULH) links in all optical networks, as well as very high loss repeaterless links