Optical voltage sensor based on electrooptic crystal multiplier

A novel optical voltage sensor based on the electrooptic crystal multiplier is proposed and experimentally investigated. Different from the conventional bulk-type optical voltage sensor, the optical sensing unit is simply composed of an electrooptic crystal and two polarizers and does not need quarter wave-plate. By using different modulation approaches, both ac and dc voltages can be measured with controllable sensitivity and measurement range. The effective value of ac voltage can also be measured with nonmodulation approach. The dc voltage from 0.1 to 120 V and 50 Hz ac voltage from 0.05 to 100 V have been measured with good linearity. The potential applications of the proposed voltage sensor include the low voltage measurement in the field of electromagnetic compatibility and the high voltage measurement in electric power industry.