Generalised attenuation coefficients and a novel simulation model for Raman fibre amplifiers

With the introduction of a pair of generalised attenuation coefficients, a novel simulation model for a fibre Raman amplifier is proposed. Unequal signal and pump attenuation coefficients, multiple-pump interaction and double Rayleigh scattering are taken into account. The evolution of powers within each step can be calculated by a semi-analytical method so that the iteration step size can be enlarged by more than an order of magnitude under saturated amplification, to save computing time without loss of precision. Comparison with experimental results on net gain and noise figures shows good agreement