A Linear Optical Current Transducer Based on Crystal Wedge Imaging Detection

This paper proposes a linear optical current transducer based on a crystal wedge imaging detection. It converts the Faraday magneto-optical rotation to the horizontal displacement of the light and dark interference fringes by using the crystal wedge, and then uses a dual-quadrant detector to locate the fringes to achieve a real-time measurement of current. Compared with the usual light intensity detection method it has the outstanding advantages of no optical power dependency, very low temperature drift, and simple algorithm and linear measurement. In addition, a magneto-optical film is employed to replace the magneto-optical crystal to cut down the optical path and the linear birefringence. The dual-quadrant detector is employed to achieve low cost, high resolution, and high precision. The experimental results show that the transducer meets the accuracy class 0.2 S.