An electro-optic modulator for high voltage applications exhibits reduced corona and arcing by utilizing dielectric-coated electrodes in conjunction with a non-centrosymmetric crystal. The inclusion of an insulative coating (i.e., a dielectric material) on at least a portion of the electrodes reduces the possibility of arcing or corona, without requiring the application of any type of coating material directly on the crystal itself. Thus, the birefringent response of the crystal is not impacted by this coated electrode configuration of the present invention. In one configuration, the exposed surfaces of the electrodes are coated with an insulative material, while maintaining a direct contact between the electrodes and the surface of the crystal.