Research on Improving the Measurement Accuracy of Laser Interferometer System

In the laser interferometer system based on the four quadrants photoelectric, phase difference between two quadrants photoelectric is the way of identifying the fringe width and rotating angle, in order to achieving the measurement of two-dimensional small angle. Due to the temperature instability of the laser itself, the system installation error, the electronic device noise, and wave-front error etc, interference fringes prone to bending, and the received optical signal contains unequal amplitude and DC offset error, which will have a serious impact on measurement. Therefore, this paper analysis these impact of the wave-front error on the interferometer system and propose improvement measures. New hardware circuit is designed to eliminate the DC offset and the new algorithm based on multiple linear regression models is proposed to achieve the high-precision extraction of phase difference. The experiment results show that the methods reach the angle accuracy 0.1 arc second.