in this paper, we present what we believe is the first demonstration of a new rectangular kd*p crystal as an electro-optic switch and calculations of the stress-induced birefringence and depolarization loss in the crystal. we simulated and experimentally demonstrate the thermal depolarization loss of crystal in both cylindrical and rectangular shape. the results show that by using a rectangular kd*p crystal, the effects of the thermally induced birefringence and depolarization can be lessened. (c) 2017 optical society of america