Spatiotemporal dynamics of self-similar parabolic pulse evolution in multimode fibers

In this paper, we have investigated for the first time, the spatiotemporal dynamics of self-similar parabolic pulse evolution in multimode fibers. Two types of fiber are considered, graded-index and step-index MMFs. For the quality of the generated parabolic pulse, the mismatch parameter is used. A thorough study of the evolution of the pulse parameters as a function of the initial parameters has been carried out. As a result, the initial pulse evolved into a linearly chirped pulse with a parabolic intensity shape in both fibers, under the predominantly excitation of the fundamental mode. It has been shown, in particular, that the pulse can be compressed to a temporal duration of about 40 fs. Moreover, a spatiotemporal nonlinear dynamic, beam auto-selection, of one specific mode, is investigated through graded-index MMF, under the different initial modes excitation. The parabolic pulse formation process plays a critical role in this nonlinear dynamic. This approach provides another framework to understand the complex nonlinear dynamics in MMFs.