Defects and Improvements of Pockels Transducer Voltage Segmentation

The sensing range and sensitivity of optical voltage transducer are badly limited by the inherent half-wave voltage of the electro-optic crystals and a nonlinear polarization demodulation based on Malus' law. A multi-segmented structure can meet the requirement of the half-wave voltage but is only suitable for 500 kV and above voltage levels with incident wavelength of 632.8 nm, but it is not suitable for all voltage levels if the incident wavelength is greater than 1330 nm. By the way in the multi-segmented structure its optical path and devices are deviated easily by vibrations and thermal expansion and contraction. In this paper, the multi-segmented structure is improved to be suitable for various high-voltage levels with the wavelength of 632.8 nm or greater, and moreover, a new approach is presented to use MgTiO3 ceramics to enwrap around BGO (Bi4Ge3O12) crystal to reduce the integral voltage errors from 0.260% to 0.012%.