Design and Research on Light Sources in a White Light Interferometer

In a white light interferometer, the parameters of white light sources determine the distribution of interference fringes, and exert a direct impact on the identification accuracy of central fringes. For the white light interferometer which uses synthesized sources constituted by multiple broadband sources, its interference signals are a superposition of signals interfered by a single source, so as to cause the redistribution of the interference signal intensity. In order to more accurately determine the location of zero-order central fringes, improve the systemic resolution, and reduce the requirements of the signal-to-noise ratio of the system, the optimal wavelength combination needs to be determined. This article proposed a method to optimize the parameters of light sources. Through the theoretical analysis, it obtained simple formulas of the optimal wavelength combination, and put forward the examples of the related numerical simulations. The computer simulation results show that, in the interferogram generated after the light sources are optimized, the visibility of its zero-order fringes increases, which is more conducive to improving the measuring accuracy of the system.