Design of wideband hybrid amplifiers for local area networks

Optimisation of design parameters of hybrid fibre amplifiers for multi-wavelength operation in local area networks is presented. The authors consider hybrid amplifiers consisting of a distributed Raman fibre amplifier (RFA) and a remotely pumped discrete erbium-doped fibre amplifier (EDFA). The design is based on a numerical model that includes pump-to-pump and signal-to-signal interactions and generation of amplified spontaneous emission (ASE) in the RFA, and solves the standard rate equations and propagation equations for pump, signal and ASE spectral components within the EDFA. An efficient average power analysis algorithm has been used to solve the equations. To achieve a 40 nm bandwidth with gain ripple less than 10% and net gain higher than 10 dB, three pump laser diodes (LDs) must be used when wavelength-division-multiplexed (WDM) signals are transmitted in the C-band but only one pump LD is sufficient for 50 WDM channels with 0.8 nm spacing placed in the L-band