Coupling effects for grey separate spatial solitons in a biased series photorefractive crystal circuit with both the linear and quadratic electro-optic effects

The existence and coupling of grey-grey separate spatial solitons in a biased series photorefractive crystal circuit with both the linear and quadratic non-linearity is investigated in this paper. The numerical solution of the grey-grey separate spatial solitons is presented. The effect of coupling between the two separate spatial solitons and the influence on each soliton due to the input intensity and crystal's temperature is analysed. Changing the intensity of the soliton in one crystal affects the soliton in both crystals due to flow of the light induced current through the circuit. Also, the effect of changing the temperature of one crystal affects the soliton in both crystals due to the coupling effect. The soliton width dependence on the temperature is different for each crystal.