High-Dynamic and High-Precise Optical Current Measurement System Based on the Faraday Effect

In this paper, a high-dynamic and high-precise optical current measurement system based on the Faraday effect is presented. First, the sensor concept is presented and different sensor constructions are analyzed. Then, a measurement system based on a rare-earth iron garnet film is investigated. The measurement system uses multiple signal processing channels to increase the signal-to-noise ratio. Furthermore, the measurement range exceeds a rotation of 180° and therefore requires a counting mechanism to count the number of rotations. Finally, the precision of the presented system is analyzed. The precision is determined to be 4.9 ppm at a rotation range of 3300°.