Observation of soliton ridge states for the self-imprinting of fiber-slab couplers

We investigate experimentally the energy exchange patterns and consequent propagation dynamics of an extended hybrid-dimensional interaction between a one-dimensional and a two-dimensional spatial soliton in a biased photorefractive crystal. Results show that conditions can be found in which the coupling manifests propagation invariant features. The mechanism hinges on mutual distortion through spatially nonlocal components of response, as opposed to standard wave overlap, which would lead to a diffusion of the needle into the slab mode. These nonlocal-nonlinearity-driven ridge modes represent the instrument for writing fiber-slab couplers, the key to attaining soliton-based wavelength selectivity with electroactivated features.