Multicomponent photorefractive cnoidal waves: stability, localisation, and soliton asymptotes

The authors consider the problem of propagation of nonlinear waves through photorefractive crystals in which a nonlinear response is induced by a drift mechanism. This problem is used as an example to formulate an algorithm for constructing a new class of stable self-consistent periodic solutions, which are multicomponent photorefractive cnoidal waves. Explicit exact analytic expressions are derived for the distributions of the optical field in terms of parts of such solutions containing up to three mutually incoherent components of the optical field. It is shown that, in a fairly wide range of the spatial period, such cnoidal waves are stable and that their spatial structure is conserved in collisions of the waves with one another and in the presence of stochastic perturbations of the distributions of the field intensities of the components.