The Mathematical Analysis on the Nonlinearity under Different Subdivision Numbers with Ellipticity Polarization Laser Source

The nonlinear error is the main error source of the laser interferometer which is widely used in the precision engineering. This paper studies the relations between the nonlinear error and the heterodyne interferometer with the ellipticity polarization laser source under the different optical subdivision numbers. The simulation shows that if the two beams source are elliptical polarization with the same ellipse angle, the nonlinearity in four-pass-subdivision is bigger than two-pass-subdivision. However, if only one laser beam exists ellipticity polarization or both laser beams are ellipticity polarizations with different ellipse angles, the nonlinearity in four-pass-subdivision is smaller than two-pass-subdivision. This study is useful to design the heterodyne interferometer.