A novel quasi-distributed fiber optic sensor for 3D vector measurement of static magnetic fields

A novel method to perform 3D vector measurement of intense and static magnetic fields is presented. The technique is based on the recently introduced distributed magnetic-field fiber optic sensor, which exploits Faraday rotation of polarization in standard single-mode fibers. In the present case, the fiber is arranged in several concatenated short coils, and the component of the magnetic field parallel to the fiber axis is measured by the distributed sensor. We show that by analyzing amplitude and spatial phase of the Faraday rotation measured along a coil, the 2D vector component of the magnetic field parallel to the coil plane can be calculated. By arranging two close coils on orthogonal planes, a 3D reconstruction of the magnetic field is achieved. Measurement uncertainty of few percents has been experimentally demonstrated over coils of just two loops; better accuracy can be obtained by increasing the number of fiber loops.