介绍了一种新型的纳米级精度位移测量激光干涉仪。提出了耦合差动干涉的新方法。通过对光程差进行倍增，提高了干涉仪的分辨率和稳定性。该干涉仪结构简洁紧凑，光路布局对称性好，不存在死光程，容易装调，符合阿贝原则和结构变形最小原则，在10 mm(可以扩展至50 mm)测量范围内，获得了λ/1600的分辨率和纳米级的测量精度。

A new laser displacement measurement interferometer with nanometric accuracy has been developed. A new method called Coupled Differential Interferometry is proposed. The resolution and the stability of the interferometer are improved by multiplicating the optical path difference (OPD). The new interferometer is simple in concept, symmetric in optical paths, without optical deadpath, easy to set up and align. A λ/1600 resolution and a few nanometer accuracy are achieved within the range of 10 mm.