Incoherently coupled spatial soliton pairs due to both the linear and quadratic electro-optic effects

Abstract

A number of new photorefractive materials, where refractive index changes in materials are simultaneously governed by both the linear and quadratic electro-optic effects, have been found in recent decades. Here we first present a comprehensively theoretical study of incoherently coupled spatial soliton pairs due to both the linear and quadratic electro-optic effects in all four possible realizations: dark-dark, bright-bright, gray-gray, and dark-bright. These soliton pairs owe their existence to the co-effects of both the linear and quadratic electro-optic effects where PR effect may be enhanced, weakened, or even counteracted because of the interaction of these two electro-optic effects. It is shown that these incoherently coupled spatial soliton pairs can be established provided that the incident beams have the same polarization, wavelength, and are mutually incoherent. At last, we give a simple elucidation on the stabilities of these incoherent coupled soliton pairs. Relevant examples are also provided.