Measurement Method of Verdet Constant Based on Refractive Index Dispersion of Optical Fiber Current Sensing Materials

With the rapid development of ubiquitous power internet of things, people put forward higher and higher requirements for the informationization level of power equipment. Optical fiber current sensor has a very high level of information technology, so it attracts the attention of scholars. However, the existence of linear birefringence in optical materials and its low sensitivity to current and magnetic fields have always been the main reasons that restrict optical current sensors. The Feldt constant of optical fiber current sensor material characterizes the responsiveness of optical material to Faraday effect, which is closely related to the measurement sensitivity of all-optical fiber current sensor. The traditional method of measuring the Feldt constant is to calculate the Feldt constant by measuring the Faraday magneto-optical deflection angle. This method will be affected by linear birefringence and other factors, so that the measurement results are lower than the actual values. Based on the principle of frequency dispersion in refractive index light, a spectrophotometric method is proposed to measure the Verdet constant of optical materials. Compared with the traditional methods, the results show that the proposed method can avoid the influence of linear birefringence and other factors, and has guiding significance for improving the measurement sensitivity of optical fiber current sensor.