Numerical modelling and experimental investigation of double-cladding erbium-ytterbium-doped fibre amplifiers

A comprehensive model for characterising double-cladding erbium-ytterbium-d oped fibre amplifiers (EYDFAs) is proposed and experimentally verified for the first time to our knowledge. The model is based on rate and propagation equations in a homogeneous two-level active medium and takes into account the modified pump absorption arising from the double-cladding structure and the presence of ytterbium ions, The influence of the cladding pumping sche me on the multimode pump absorption. radial population inversion and the am plified spontaneous emission are also modelled. The numerical mode is capab le to predict amplifier gain, output spectra, gain saturation and amplifier noise. The model has been fully validated in a large number of operating c onditions and a fairly good agreement is obtained between the experimental data and the numerical simulations over a wide range of input parameters.