Influence of Polarization Direction on Polarization States Distribution of Polarization Encoder

Principle of polarization encoding based on electro-optic effect of LiNbO3 crystal is analyzed, influence on polarization encoding optical field effects is studied when the incident light polarization direction changes. Theoretical calculations show that, with the angle between the polarization of incident laser beam and the main axis of LiNbO3 crystal increases, rotation angle of polarization ellipse deviated from the vertical direction increases, but ellipticity decreases, at any other position except in the center of the encoder, the change is non-linear, and rotation angle change is different at different position. Experiment measurement results are in accord with ones of the calculation.