Effect of Ramam gain on the characteristic of soliton propagation

Using the nonlinear Schrödinger equation (NLSE) including Raman gain effect but ignoring fiber loss situation, the linear operator and nonlinear operator specific expression are obtained based on MATLAB fractional Fourier numerical algorithm. They are applied to the NLSE including Raman gain, and the evolutions of soliton pulse are simulated in optical fiber through changing parameters. The result shows that soliton propagation stability is destroyed compared with the case considering no Raman gain, leading to the rapid attenuation of optical soliton. The influence degree depends on input soliton pulse peak power. The effects of Raman gain on ground state soliton and high order soliton are not the same.