Soliton propagation in the presence of intrapulse Raman scattering and nonlinear gain

The propagation of ultrashort solitons in fiber-optic systems in the presence of intrapulse Raman scattering is investigated. Narrowband filtering and nonlinear gain are used to control the self-frequency shift and the background instability. The soliton perturbation theory is used to obtain the steady-state solutions as well as their existence conditions. Linear stability analysis is employed to study the steady-state solutions and the results are verified by numerically solving the propagation equation. We show that, using narrowband filtering and nonlinear gain, stable soliton propagation over long distances can be realized in fiber-optic systems in the presence of intrapulse Raman scattering.