LAUSR

The optical voltage sensor (OVS) based on the Pockels effect and its light intensity detection mode has a limitation of half-wave voltage and optical power correlation. In this paper, a new type of OVS which can achieve linear measurements of a wide range electrooptic (EO) phase delay was proposed. It uses a crystal wedge to convert EO phase delay to a displacement image of light stripes, and an image acquisition system that captures the spot and calculates the displacement. Mathematical derivation regarding the linear relationship between the stripes displacement and phase delay is given; a suitable image sensor and a stripe location algorithm are selected. Experimental verification is carried out, and several key issues are discussed. Compared with light intensity detection mode, the experimental results show that this measuring mode is independent of light source. An imaging mode also offers a large dynamic range and a good linear measurement of EO phase delay in the range of 291° with a measurement error of less than 0.5%. This mode is not limited by the half-wave voltage of crystal. Temperature drift errors on measurement results are also reduced.