Implementation Efficiency of a Two-Stage EDFA Amplifier with an Inverted Trapezoidal Filter on Gain Flattening

In this paper, A mathematical model was developed to study via simulation the performance of a two-stage erbium doped fiber amplifier (EDFA) model in order to investigate their efficiency when it implemented in optical chain, to obtain a flat gain for 8 WDM channels. The EDFA model contains two identical erbium-doped fibers (EDF1, EDF2) separated by an inverted trapezoidal optical filter (ITOF), some others components are used to enhance the signal amplification quality such an isolator and ASE filter. A simplified dynamic numerical model of EDFA based on a homogeneously broadened two-level approximation of an erbium ion which include the signal, pump and both forward and backward ASE powers propagation is used. A uniform spectral shape of gain is obtained for both used configurations, the single EDFA simulation and EDFA cascades simulation. The results show the possibility to obtain an equalized output power in good agreement with results in literatures.