Wavelength-tuned phase-shifting calibration based on the fourier transform in time domain

The phase-shifting interferometer using a wavelength tunable laser is applied to test large optical components. A method based on the one-dimensional Fourier transform in time domain to calibrate the phase in wavelength-tuned phase-shifting interferometer is presented. It solves the problem that how to control the phase-shifting step to a certain value at different interferometric cavity lengths when testing. The calibration software is written and the wavelength-tuned phase-shifting interferometer using a tunable laser with the central wavelength 632.8 nm is established. In the experiments, the results are compared with the results obtained by the ZYGO interferometer. It shows that when the cavity length is less than 2 m, the testing precision is lambda/50.