A novel method for Raman amplifier propagation equations

A novel numerical method for the standard propagation equations of Raman amplifiers with multiple pumps is presented and derived based on the four-step Adams-Bashforth method. Our proposed multistep method can increase the accuracy and stability in designing Raman amplifiers compared with the one-step method. Output signal, pump, and backscattering pump powers have been numerically simulated and compared by utilizing our multistep method and one-step method. The results show that our method can reduce the computing time over three orders of magnitude with excellent accuracy by comparison with the direct integration method for the Raman amplifier propagation equations.