NONLINEAR PHASE-SHIFT AND DETUNING BY 2ND-ORDER AND 3RD-ORDER NONLINEARITIES

We have analyzed the nonlinear phase shift and the wave-number detunin g induced by the second-and third-order nonlinearities. Analytical exp ressions were obtained under the fixed intensity approximation. With a strong pump intensity, the conversion efficiency curve plotted agains t the phase-mismatch narrows. Due to the detuning effect, the conversi on efficiency at perfect phase-matching saturates with the increase of the pump intensity. The experimental result confirms our theory and s hows an asymmetric effect caused by the third-order nonlinearity at hi gher intensity.