ИСТИНА

We study two-color soliton-like propagation of laser radiation in a quadratic nonlinear medium under both second- and thirdorder dispersion (TOD) actions. The main feature of this soliton-like propagation is an asymmetric pulse shape and the presence of nonlinear chirp. We propose approximate formulas for the pulses shapes and their chirps. We clarify the limits of applicability of these formulas on basis of numerical simulation and show that the propagation dynamics matches analytical formulas at a rather long propagation distance. It is remarkable that the pulse amplitude evolution demonstrates an explicit dependence on the TOD coefficient.