Oscillatory waveform caused by piezoelectric vibration of pockels crystal and its effective suppression

In measurements of impulse voltages by Pockels sensors, oscillatory components have been observed in the tail parts of the optical signals. In this paper, oscillatory components of Bi4Ge3O12 (BGO) Pockels crystals of various shapes are investigated. The tested BGO crystals are rectangular solids, a cylindrical solid, and a tapered quadratic solid. The oscillatory components are derived from the light outputs and the frequency analysis is performed. The oscillation frequency of the rectangular crystals is lower than the theoretical value and that of a cylinder is the same as that of circumscribed rectangular solid. In the case of the tapered BGO crystal, it is possible to reduce the oscillatory components by distributing piezoelectric vibration over a broad frequency bandwidth. © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.