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Negative refraction and spatial echo in optical waveguide arrays.

The special symmetry properties of the discrete nonlinear Schrödinger equation allow a complete revival of the initial wave function employed in the context of stationary propagation of light in a waveguide array. As an inverting system, we propose a short array of almost isolated waveguides, which cause a relative π phase shift in the neighboring waveguides. By means of numerical simulations of the model equations, we demonstrate what we believe is a novel mechanism for the negative refraction of spatial solitons.