Development of a laser synthetic wavelength interferometer for large displacement measurement with nanometer accuracy.

A laser synthetic wavelength interferometer that is capable of achieving large displacement measurement with nanometer accuracy is developed. The principle and the signal processing method of the interferometer are introduced. The displacement measurement experiments and the comparisons with a commercial interferometer both in small and large ranges are performed in order to verify the performance of the interferometer. Experimental results show that the average errors and standard deviations of the interferometer are in accordance with those obtained from the commercial interferometer. The resolution and the nonlinearity of the interferometer are also discussed in detail. These results show that the development of the interferometer is reasonable and feasible.