Collisions between spatiotemporal solitons of different dimensionality in a planar waveguide

A (2+1)-dimensional nonlinear Schrodinger equation including third-order dispersion is a natural model of a waveguide, in which strong temporal dispersion is induced by a grating in order to make the existence of two-dimensional spatiotemporal solitons possible. By means of analytical and numerical methods, we demonstrate that this model may support, simultaneously, stable dark quasi-one-dimensional (stripe) solitons and two-dimensional elevation solitons ("antidark solitons") in the form of weakly localized "lumps." The spatial position of lumps can be controlled by passing stripe dark solitons through them in an arbitrary direction. To substantiate this mechanism, we analytically calculate a position shift generated by a headon collision between the stripe and lump. The obtained results are in good agreement with direct numerical simulations.