Influence of nonlinearity on measuring precision of dual-frequency laser interferometer with two longitudinal modesYang Chun-sheng, Zhang Tao, Cheng Jun-kang, Liu Guo-dong 1. School of Manufacturing Science and Engineering, Sichuan University, Chengdu 610065, China; 2. National Institute of Measurement and Testing Technology, Chengdu 610021, ChinaAbstract:The nonlinearity error of the dual-frequency laser interferometer with two longitudinal modes and special subsequent electrical signal processing system was studied. The expressions for the output signal pair were desired based on the theoretical analysis when the nonlinearity exised. From the above it was given that the nonlinearity makes the frequency-mixing output signals shift and undulate, and its main factors are the perfection degree of the optical system adjustment and the polarization splitting degree of the polanzation beam splitter. The maximum signal shift amplitude was close to that observed on oscillograph and it could be used to estimate the perfection degree of the optical system adjustment and determine the maximum interpolation number in the subsequent signal processing stage.[著者文摘]
Key words:technology of instrument and meter;longitudinal mode; dual-frequency laser interferometer; nonlinearity; shift; polarization splitting degree