An EDFA (Erbium-Doped Fiber Amplifier) is a type of optical amplifier used in fiber-optic communication systems to amplify optical signals. The core component of an EDFA is a segment of optical fiber that is doped with erbium ions. Erbium is chosen for its ability to amplify signals in the wavelength range around 1550 nanometers, which corresponds to the low-loss window of optical fibers.

The operation of an EDFA involves the process of stimulated emission, where the erbium ions, when excited by pumping laser light, release photons that are coherent with the incoming signal. This amplifies the optical signal passing through the doped fiber without the need for converting it into an electrical signal and then back into an optical signal.


Data-driven Modelling of EDFAs by Neural Networks

Dependence of EDFA gain shape on input power and input spectrum shape is modelled using a simple neural network-based architecture for amplifiers with different gains and output powers. The model can predict the gain within ±0.1 dB. Even though the model has good success predicting the performance of the particular EDFA it is trained with, it is not as successful when used to predict a different EDFA, or even the same EDFA with a different pump power. However, retraining the model with a small amount of supplementary data from a second EDFA makes the model able to predict the performance of the second EDFA with little loss in performance.