针对传统差分平面镜干涉仪结构复杂、需要光学部件多从而导致系统调试困难、测量信噪比低等缺点，提出了一种结构简单需要光学部件少的新型差分平面镜干涉仪系统。此干涉仪能够产生对称的空间四光路，对环境因素（湿度、温度及大气压）的变化有很好的抗干扰能力，测量分辨率高。如果附加其他光学元件，可轻易实现对偏摆角、微滚转角、直线度等几何量的测量。静态状态下，其位移漂移小于1 nm，而同等条件下传统迈克耳孙干涉仪漂移大于10 nm。基于此系统的精密角度测量干涉仪，使用电子细分为2π/516的相位计，可以得到0.024 μrad的测量分辨率。

Because the tradition differential plane mirror interferometer (DPMI) has the disadvantages of complicated structure, many optical components and difficulty for adjusting, a novel differential plane mirror interferometer is proposed. Due to its diagonal symmetry of the two frequencies beams, this system has a good stability with environmental variation and a high resolution. With this special arrangement and the use of some additional optical components, the measurements of yaw angle, small rotation, straightness become easy to implement. Experimental result shows that the displacement drift of this system is under 1 nm in the static measurement, while the Michelson interferometer system is more than 10 nm under the same condition. The angular interferometer based on this new structure, with electronic interpolation of 2π/516, has a measurement resolution of 0.024 μrad.