Observation of spatial nonlinear self-cleaning in a few-mode step-index fiber for special distributions of initial excited modes
Z. Mohammadzahery, Maryam Jandaghi, Ebrahim Aghayari, Hasan Nabavi
Abstract
Abstract In this paper, we experimentally demonstrate that a nonlinear Kerr effect in suitable coupling conditions can introduce a spatially self-cleaned output beam for a few-mode step-index fiber. The impact of the distribution of the initial excited modes on spatial beam self-cleaning has been demonstrated. It is also shown experimentally that for specific initial conditions, the output spatial pattern of the pulsed laser can be reshaped into the LP 11 mode due to nonlinear coupling among the propagating modes. Self-cleaning into LP 11 mode required higher input powers with respect to the power threshold for LP 01 mode self-cleaning. Our experimental results are in agreement with the results of numerical calculations.