Measurement technique for pump and signal background absorption of erbium doped fibres

Modelling erbium doped fibre (EDF) amplifiers requires an accurate characterisation of the doped fibre. Zech (1995) claims to present absorption measurements of an EDF with new variables (absorbed pump power and fibre transmission), leading to the absorption constant, the saturation power (P_sat) and the background absorption constant. No other process has been considered in order to explain the excess absorption. The same method has already been presented by Georges et al. (1992), and another process, pair induced quenching (PIQ) was shown to be predominant in all the fibres under study. We compare both processes in the particular case presented by Zech