Temperature and vibration insensitive fiber optic vector magnetic field sensor

Abstract

We propose and demonstrate a fiber optic vector magnetic field sensor based on the magneto-optical Faraday effect. The sensor has excellent environmental adaptability. Due to the polarization dependence of Faraday effect in polarization-maintaining fiber coil, the sensor uses two orthogonal polarization states to detect the direction and intensity of magnetic field. By establishing the magnetic sensitivity model of the sensor through the Jones matrix, we analyze the magnetic field-induced phase difference in the two orthogonal polarization states theoretically. Then the influence of environmental temperature and vibration on the output of the two polarization states of the sensor is analyzed, and the sensor can theoretically achieve complete suppression of environmental temperature and vibration errors. The experimental results show that the sensor sensitivity is 0.507 mV/mT. The directivity of the vector magnetic field sensor reaches 21 dB with the orientation error of ±0.4°. The sensor also has excellent robustness. It is insensitive to environmental temperature changes between 30 °C and 50 °C and environmental vibrations within 1 g. The suppression effect of environmental errors can reach 9.8 times with high anti-interference capability in experiments. The proposed sensor has potential applications in navigation, vehicle detection, and current sensing.