中文摘要：

文章在中国计量科学研究院研制的差拍法布里-珀罗（F-P）干涉仪基础上，提出用密封干涉光路的真空系统方法，来消除空气折射率变化对测量结果的影响。研究了空气折射率变化对测量精度的影响关系，给出真空系统所需的真空度的估计式。并设计制作了适用于该系统的密封干涉光路的真空系统。

英文摘要：

In this paper, a novel way based on NIM＇s heterodyne Fabry-Perot interferometer was put forward to avoid the effect of the change of air refractive index by airproofing the interference light path in vacuum. The influence of the change of air refractive index to the measured precision was studied, and the approximate formula of vacuum degree that vacuum system required was concluded. The vacuum system that adjusts the interference light path was designed and built.