Analysis of factors affecting extinction ratio about double-crystal electro-optic switch

In order to analyze the factors affecting the contrast-ratio of a electro-optic switch with double crystals,the index-ellipsoid method is adopted.The experiments show that there are close dependence of the difference of light direction of double crystals and the polarization direction of the polarizers on contrast-ratio.A good Q-swtiching effect could be obtained if the above two factors are more precisely adjusted.