Analysis of the nonlinearity in Mach-Zehnder heterodyne interferometric polarimeter

Mach-Zehnder heterodyne interferometric polarimeter can precisely measure the polarization state of light in real time.In order to improve the measurement precision and reduce the nonlinear error,which arises from the elliptical polarization of the laser,polarization leakage of the polarized beam splitter(PBS) and misalignment of the PBS were analyzed.The error formula was deduced.The simulation results showed that different amplitude ratio and phase difference of the measured beam had different nonlinear error output.The error was quite similar to the nonlinear error calculated in the Michelson heterodyne interferometer.