光楔是实现光纤法布里珀罗(F-P)传感器互相关解调的重要光学元件。根据互相关解调的原理分析了造成光楔和光纤F-P传感器F-P腔的反射光相位不同的因素，进而建立了光楔的干涉光强的数学模型，在此基础上对具有不同反射率的光楔的干涉光强进行了数值仿真，和相同反射率的光纤F-P传感器F-P腔的干涉光强对比之后建立了光楔的简化数学模型。对光楔的简化数学模型进行的误差分析表明：当光楔的楔角小于0.1°且两端面反射率乘积不大于9%时，光楔的简化数学模型引入的误差小于0.6%。光楔的数学模型为建立基于互相关解调的光纤F-P传感系统以及进一步提高系统的解调精度奠定了理论基础。

The optical wedge plays a vital role in the cross-correlation demodulation system of optical fiber Fabry-Pérot(F-P) sensors. A mathematical model for the light intensity reflected from the optical wedge is established based on analyzing results of the factors that cause the interference optical phase differences between the optical wedge and the F-P cavity of optical fiber F-P sensors according to the cross-correlation demodulation principle. The light intensity reflected from the optical wedges with different reflectivity combinations are numerically simulated and a simplified mathematical model for the light intensity reflected from the optical wedge is established by comparing the light intensity reflected from the optical wedge with those from the F-P cavity with the same reflectivity combinations. The analysis results of errors between the simplified mathematical model and the mathematical model indicate that the error of the simplified mathematical model for optical wedges is less than 0.6% when the optical wedge angle is less than 0.1° and the product of two surfaces′ reflectivity is not more than 9%. The simplified theoretical model of the optical wedges lays a theoretical foundation for establishing optical fiber F-P sensor systems based on the cross-correlation demodulation principle and further improving the accuracy of the demodulation system.