Incoherently coupled Gaussian soliton pairs in biased photorefractive crystal having both the linear and quadratic electro-optic effect

Abstract

Propagation characteristics of incoherently coupled Gaussian soliton pairs are studied in photorefractive media having both the linear and electro-optic effect. Applying paraxial ray approximation, a very large family of bright–bright Gaussian soliton pairs in photorefractive crystals having both the linear and quadratic electro-optic effect has been identified. These composite solitons can exist only when the carrier beams have the same polarization, wavelength and are mutually incoherent. It is shown that the incoherently coupled soliton pair cannot propagate as a stationary entity if its components have different spatial widths. A wide parameter space of spatial width of the soliton pair and its power has been found where it can exist as a stationary entity. The paraxial theory shows that the identified family of soliton pairs is stable. An interesting finding is that of bistable states in this system for the degenerate case of the power being same for both components of the soliton pair. A relevant example has been taken for illustration of our results where the crystal is PMN-0.33PT.