灵敏稳定的光纤弱磁场传感器

A Sensitive and Stable Optical Fiber Sensor for Weak Magnetic Field

为了使光纤马赫 -陈德尔 (Mach- Zehnder)干涉仪在弱磁场传感器中能够稳定地工作 ,作者采用了等长的短干涉臂的措施 ,这样虽然导致使用的磁致伸缩材料 (MT)长度很短 ,引起传感器灵敏度降低 ,但提高了传感器的稳定性 .为了提高传感器的灵敏度 ,把传感器的调制频率设定在由 MT和光纤传感臂组成的系统的固有频率上 ,并且采用不同长度的 MT的组合来加宽此谐振频率的带宽 ,使得系统的固有频率在随温度变化时 ,传感器仍有较好的稳定性 .作者研制成功的光纤弱磁场传感器既有较高的灵敏度 (8× 10 - 3A/ m) 。

We have succeeded in fabricating a stable optical fiber sensor for weak magnetic field which has a sensitivity as high as 8×10 -3 A/m. Its stable operation is brought about by two short fiber arms in equal length. And the high sensitivity is attained by adjusting the AC modulation frequency to the intrinsic resonant frequency of the system which consists of the magnetostrictive material and the fiber arms, and by employing a combination formed by magnetostrictive materials in different lengths to broaden the bandwidth of the resonant curve.