Femtosecond soliton propagation in optical fibers with slowly decreasing dispersion

Abstract

Currently, solitons with a minimum duration of approximately 50 fs are obtained in optical fibers. Adiabatic compression of solitons in fibers with slowly decreasing dispersion (FSDD) is promising for the generation of high-quality pulses with a shorter duration in the near IR.1 New effects arise at the femtosecond pulse propagation in fibers. For the theoretical description of such a propagation, the traditional nonlinear Schrödinger equation needs to be modified. In recent papers2-4 nonlinear equations were considered, and the real part as well as the imaginary part of the third-order nonlinear susceptibility χ(3) was taken into account. In Refs. 3 and 4 the real spectral dependence χ(3) (ω) is discussed. In this paper we discuss the model that, in addition to the effects mentioned above, takes into account the Stokes losses associated with the material excitation during the Raman self-scattering effect and the dependence of the third-order nonlinear effects on the radiation frequency.