Abstract

Amplified spontaneous emission (ASE) significantly degrades the efficiency of small-signal erbium-doped fiber amplifiers (EDFAs) when they are operated at high gains or at wavelengths away from the peak of the gain spectrum. We provide experimental and theoretical evidence that under these conditions it is possible to increase the efficiency for a 1550-nm signal by pumping away from the peak of the 980-nm absorption band. A small noise figure penalty is present, but this technique is useful for increasing the loss budget or lowering the pump power requirements for links that require small number of in-line amplifiers. More generally, we find that in most practical situations there is a minimal gain penalty for pump wavelengths over the range from 960 to 1000 nm.

© 1992 Optical Society of America