根据纳米计量分辨力的要求,设计一套共焦法布里-珀罗(F-P)干涉显微测头。系统光源采用保偏光纤直接导入,从F-P腔外入射。光路设计成便于减小光学共模噪音的差动形式。通过建立模型分析系统光学特性,得出反射平板的最佳反射率以及共焦结构对干涉条纹的影响。实验验证表明反射平板反射率为40%时可以使系统得到对比度高,信噪比好的干涉条纹;针孔光阑可以方便寻找测量透镜的焦点和减小杂散光的噪音;系统轴向分辨力达到0.2nm。 According to the requirement of nanometer resolution, a confocal Fabry-Perot interference microscope probe was designed. The system light source adopts the polarization maintaining fiber to be directly introduced and enters from the F-P cavity. The optical path is designed as a differential form that reduces the optical common-mode noise. By modeling the optical properties of the system, the optimal reflectance of the reflector and the effect of the confocal structure on the interference fringes are obtained. Experimental results show that the reflectivity of reflective plate is 40%, the system can get high contrast and good signal-to-noise ratio interference fringes. The pinhole diaphragm can easily find the focus of the measuring lens and reduce the noise of stray light. The axial resolving power Reaches 0.2 nm.