An electro-optic fibre sensor with double pass configuration for measuring high ac voltage

A new fibre optic sensor suitable for high voltage measurements is introduced. The sensor is based on a double pass configuration of light through a Bi12TiO20 (BTO) photorefractive crystal. To obtain the double pass configuration, a back-reflecting prism with high stability to temperature variations is incorporated in the sensor head. The prism enhances the performance of the sensor allowing the BTO to work in a wide linear region of its transfer function. To prove the feasibility of our fibre optic sensor, one ac periodic wave and transient event of high voltage were measured and reported. The sensor is proved to be robust, linear, and shows high resolution in the detection of voltage impulses.