Influence of two-photon absorption on soliton self-frequency shift

Abstract

Abstract:The creation of mid-infrared supercontinua necessitates the use of soft-glass fibers. However, some materials, like chalcogenide, have a substantial two photon absorption. We introduce a model for soliton self-frequency shift that successfully includes this effect.

Efficient method of calculation of Raman soliton self-frequency shift in nonlinear optical media

“…Thus, one obtains a new description of the dynamics of collective coordinates able to give a good reconstruction of the dynamics of the exact field. For example a good evaluation of the stimulated Raman scattering effects and in certain cases a contribution for a good calculation of soliton self-frequency shift, taken as an addition method comparing to that observed in [20][21][22]. These additional collective coordinates act on variational equations inn order to give a complete characterization of the light pulse.…”

“…Hence, a well estimation of the frequency and temporal shifts depends on the level of precision given by the modified conventional ansatz function. Following this analysis, as previously investigated [17][18][19]21], we will present the variational equations obtained when we use successively a conventional ansatz and the modified conventional ansatz function.…”

“…To the best of our knowledge, the so-called "method of moment for nonlinear Schrödinger equation" [20], with its possibilities to reduce the problem to a system of coupled ordinary nonlinear differential equations is one of the best candidate for this approach. Furthermore, the method provides approximations which receive different names depending on the specific field of application: time-dependent variational method, collective coordinates method, the averaged Lagrangian [21,22] and the so-called quadratic phase approximation [20]. The results shown for the evolution of the field solution using the moments method are exact and in some sense rigorous.…”

“…Unfortunately, it clearly appears that the choice of these ansatze function, having a standard quadratic phase, is not sufficient to give a correct description of intra-pulse Raman scattering where high-and low-frequency components of an optical pulse pump transfer energy to the red side through stimulated Raman scattering. This deficiency was already perceived by some authors who suggested to use the moment method [20][21][22] in order to study the effect of frequency chirp on the Raman-induced frequency shift in the cases of both normal and anomalous dispersion. Then, the method was used by many authors to investigate the behavior of optical pulses when several physical phenomena should occur during the propagation.…”

“…However, if the efficient practical method to calculate the soliton self-frequency shift uses the method of moment [20][21][22], it is also observed that some physical specific pulse parameters able to give a qualitative detailed picture of the role and mode of singular or simultaneous action of some selected higher-order terms (such as third-order dispersion, self-phase modulation, quintic nonlinearity, self-steepening, or stimulated Raman scattering) require an important amount of calculation with these method using the exact pulse field throughout the pulse propagation. The use of the variational analysis presents two major advantages.…”