Discrete solitons in nonlinear zigzag optical waveguide arrays with tailored diffraction properties.

Abstract

We show that the discrete diffraction properties of a nonlinear optical zigzag waveguide array can be significantly modified, by exploiting the topological arrangement of the lattice itself. This introduces extended interactions (beyond nearest neighbors), which, in turn, affect the lattice dispersion relation within the Brillouin zone. As a result of this band alteration, we demonstrate that altogether different families of discrete soliton solutions are possible, which are stable over a wide range of parameters. In the regime where instabilities occur, all scenarios are considered in detail. By appropriately engineering the geometrical configuration of the array we find both standing and traveling diffraction-free beams. Our method opens opportunities for diffraction management that can be employed to generate low-power spatial discrete optical solitons.