Gain Profile Characterization and Modeling for Dual-Stage EDFA Abstraction and Control

Relying on a two-measurement characterization, in this work a simple and effective gain profile model for dual-stage optical erbium-doped fiber amplifiers (EDFAs) working under full spectral load conditions is presented and validated. Starting from the model of an ideal EDFA, the gain ripple profile is determined as the target parameters of the amplifier vary using a linear combination of two contributions. Being a consequence of the absorption/emission curves of erbium in the two stages, the first represents a characteristic of the specific device and reflects also the residual impact due to the gain flattening filter (GFF), while the second parameter accounts for a feature of the considered amplifier model, scaling according to the set tilt target. The proposed model faithfully reproduces the dynamics of EDFA by varying the total input power and the target gain and tilt parameters, as shown experimentally on a set of 14 devices divided into 4 different models from 2 vendors, of which 10 in C-band and 4 in L-band. The obtained error distributions present an unbiased peak shape with variability between the 25 and 75 percentiles below 0.2 dB for the worst case in C-band and 0.1 dB in L-band, respectively.