以衍射理论为基础，用箝位输出功率表征限幅器的限幅效果，推导了折射型光限幅器出射功率的表达式.数值计算了连续激光照射下，限幅器出射功率、限幅能力和最佳限幅位置的变化规律.结果表明：限幅器的出射功率随入射功率的增加衰减振荡，其振荡周期取决于介质相对于光束焦点的位置；限幅器的限幅能力随入射光束腰半径和光阑孔径的变大而减弱；入射功率范围固定，入射光束腰半径和光阑孔径增大时，介质的最佳限幅位置向入射光束的焦点靠近，但是在某些入射功率范围内会存在多个最佳限幅位置；光限幅器的箝位输出功率随光阑线性透过率的增加存在线性增加和非线性增加两个不同区域，实际应用中应在线性增加区域确定光阑孔径的大小.

Taking the diffraction theory as the foundation,with the maximum output power representing the effect of optical limiter,expression of output power in optical limiter based on nonlinear-refraction was derived.Rules of output power,limiting ability and the best position of medium to limit were analyzed in numerical method when the limiter was irradiated by continuous Gaussian beam.The result indicates that the output power oscillates and weakens along with increasing input power,and its oscillation period depends on the distance between the medium and beam focal point.Limiter′s limiting ability will decrease if waist size of the incident Gaussian beam and the aperture size increase.With a fixed input power scope,medium′s best limiting position will move towards the focal point if waist size of Gaussian beam and the aperture size increase,but the best limiting position will change a lot with different input power scopes.There will be linear and nonlinear scopes when the maximum output power varies along with the transmittance of aperture.