采用动态技术测试静态场的光纤测磁传感仪

在根据Mach－Zehnder干涉仅原理制作的各种光纤测磁传感仪中，由于传感臂一般都由磁致伸缩材料与光纤粘合在一起而构成，所以磁性材料所特有的磁致现象将导致重复测量的结果出现不确定的模糊。为了消除这种磁致误差，本文所设计的系统采用磁场扫描技术，除了在传感臂上施加一个频率为ω0的载波场以提高其灵敏度之外，同时还施加了一个频率为ω0的慢速扫描场以使各次重复测量保持相对的动态平衡，这样当被测场与交变的们置场共同作用于传感头时，利用相位检测装置即可得出被测场的大小。本系统可探测的最小静态场为10E－7（Oe／m）。

Fiber Optic DC Magnetometer by a Sweeping Technique

According to the Mach-Zender interferometer, a fiber optic magnetometer for detectiong DC magnetic fields includes a first optical fiber having a magnetostrictive jacket thereon which defines a sensing arm, and a second fiber defining a reference arm. A first AC magnetic field of frequency op and a second AC field of frequency eq and DC magnetic fields are imposed on the magnetostrictive jacket so as to cause optical path length chang. This induces a corresponding phase shift in light transmitted through the sensing arm fiber. The phase detection device and the lock in amplifier will produce a signal proportional to t he DC magnetic field.The minimum detectable field is 10$-07(Oe/m).