Enhanced soliton spectral tunneling effect of self-compressing nonautonomous colored femtosecond solitons

Abstract

The discovery of stimulated Raman self-scattering (SRSS) effect of femtosecond optical solitons is acknowledged to be among the most notable achievements of nonlinear fiber optics. This effect is also often called intrapulse stimulated Raman scattering (ISRS), or soliton self-frequency shift (SSFS), thereby emphasizing the unusual regime of stimulated Raman scattering, when the spectrum of a high-power ultrashort laser pulse proves to be so broad that it covers the band of Raman resonances of the medium. The soliton-like wave packets with continuously shifted spectrum traveling not only in the ordinary space and time, but also in the spectral space, are known as colored femtosecond solitons. Colored solitons play an important role in the soliton supercontinuum generation. The most interesting features of colored optical solitons are connected with the possibility of their tunneling in the spectral domain through a potential barrier-like spectral inhomogeneity of group velocity dispersion (GVD), including the forbidden band of positive GVD. This effect is known as soliton spectral tunneling effect (SST). In this Report, we consider the influence of the soliton binding energy on dynamics of the SST effect assuming that the amplitude and duration of the tunneling soliton vary in time when the soliton spectrum approaches a forbidden GVD barrier. We show that soliton self-compressing effect has dramatic impact on the SST through forbidden spectral region of positive GVD.