High-power erbium-doped-fiber amplifiers operating in the saturated regime

Abstract
It is shown that highly saturated, erbium-doped fiber amplifiers (EDFAs) can be employed as efficient power amplifiers. Differential pump-to-signal conversion efficiencies of 59% (quantum efficiency of 93%) can be obtained, resulting in 54 mW (+17.3 dBm) of amplified signal for only 100 mW of pump power at 978 nm. In addition, these amplifiers are shown to have virtually flat spectral-gain characteristics with a 1-dB bandwidth in excess of 38 nm. Operating in this mode, EDFAs are attractive for application as power amplifiers to ease power budget restrictions in point-to-point digital links, video distribution networks, and LANs.