Spatiotemporal behavior of periodic arrays of spatial solitons in a planar waveguide with relaxing Kerr nonlinearity

Abstract

We report picosecond pulsed experiments and numerical simulations of spatially induced modulational instability, which we used to form stable periodic arrays of bright soliton beams in a planar Kerr-like CS2 waveguide. We have found that the generation stage of these arrays is accurately described by the usual nonlinear Schrödinger wave equation, whereas the temporal dynamics of the nonlinearity is beneficial for subsequent stable propagation of the soliton arrays. In the picosecond regime the finite molecular relaxation time of the reorientational nonlinear index inhibits the Fermi–Pasta–Ulam recurrence predicted for an instantaneous Kerr nonlinearity. Moreover, the inhibition is associated with a novel spatiotemporal dynamics confirmed by numeric and streak-camera recordings.