Abstract: Optical output character of one-layer and two-layer nonlinear optical film andayased by numeric method is given to indicate that:the material nonlinearity has a great influence upon optical ouput character; the lower bistability threshold value light intensity and character of amplifing light intensity are chained by chosen suitable two-layer strcuture; otherwise, adjusting the distance between two nonlinear optical films and collimation of input light can improve the optical bistability output character.

Key words: nonlinear optical film, optical bistability, threshod value light intensity