A Polarimetric Fiber Sensor for Detecting Current and Vibration Simultaneously

A polarimetric fiber sensor based on the Faraday effect and elastic-optic effect is proposed and experimentally demonstrated for simultaneous electric current sensing and real-time vibration monitoring. Both the current and vibration information can be demodulated by lock-in amplifier (LIA) and separated through frequency domain filter due to the difference in frequency. The principle of the polarimetric sensor is theoretically analyzed and numerical simulation is performed to verify the actual effectiveness of separating current and vibration signals. Furthermore, the independent demodulation of current and vibration at different vibration frequencies and current is experimentally demonstrated, respectively. Moreover, the cross-talk between current and vibration sensing units is low and can be ignored.