Adaptive TLS approach for nonlinearity compensation in laser interferometer

Abstract

The heterodyne laser interferometer has been widely used in linear displacement and precise measurement field. However the periodic nonlinearity that arises from incomplete laser sources and non-ideal optical components restricts the precise measurement at the nanometer level. In this paper, the total least squares (TLS) algorithm which can obtain optimal compensation parameters of nonlinearity is introduced. Using the TLS algorithm, the nonlinearity error is reduced and the measurement data can be more stabilized. The effectiveness of TLS approach is verified through the comparison of the experimental results with those obtained by a capacitance displacement sensor.