补偿光纤Michelson弱磁传感器相位漂移的新方法

New Method to Compensate the Phase Shift of Fiber Optic Michelson Interferometric Weak Magnetic Sensor

提出了基于谐波分析的相位补偿法,用以解决光纤Michelson弱磁传感器中由于环境因素如温度变化等引起相位漂移带来的输出信号衰落问题。该方法对正交工作点附近相位变化非常敏感,利用干涉仪参考臂压电陶瓷(PZT)的反馈电压可有效地控制相位漂移。实验表明:干涉仪相位变化小于1°;将高频调制磁场Hmcosωmt加于干涉仪信号臂换能器上探测直流弱磁信号,传感器输出信号稳定性好,线性度优于1%,灵敏度达3.5×10-6rad/nT(Hm=4 000 nT)。

A new method to compensate the phase shift in fiber optic Michelson interferometric weak magnetic sensor based on harmonic analysis is proposed to solve the signal fading problem of the sensor that arises from environmental effects such as ambient tem- perature fluctuations. The method is sensitive to the phase variation around the quadrature, and it can effectively control the phase shift by using a correction signal to piezoelectric ceramic in reference arm of the interferometer. Experimental results show that the phase variation of the interferometer is less than 1°. Applying a magnetic dither Hmcosωm t to the magnet transducer in signal arm of the interferometer for detecting direct-current weak magnetic signals, the stable magnet field sensing signals are obtained, the magnetic sensibility of the sensor is 3.5 × 10^-6 rad/nT （Hm =4 000 nT） and the linearity is better than 1%.