Pf. Wysocki et al., MODELING, MEASUREMENT, AND A SIMPLE ANALYTIC APPROXIMATION FOR THE RETURN LOSS OF ERBIUM-DOPED FIBER AMPLIFIERS, IEEE photonics technology letters, 7(12), 1995, pp. 1409-1411
When fiber-optic systems contain erbium-doped fiber amplifiers (EDFA),
reflections are enhanced by the gain of the amplifiers and can degrad
e system performance, We present a simple approximate analytic express
ion for the return loss of pumped EDFA's, with and without discrete re
flections that applies at both the signal and pump wavelengths, A nove
l return loss measurement test set is used to verify the validity of t
his expression for a particular EDFA design, Using a computer simulati
on, the return loss is computed as a function of EDFA design to assess
the range of validity of the approximate expression. The expression s
erves as an easy way to chain amplifiers and accurately predict the ef
fects of reflections in long systems.