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 elds is presented. The technique is based on the recently introduced distributed magnetic- eld ber optic sensor, which exploits Faraday rotation of polarization in standard single-mode bers. In the present case, the ber is arranged in several concatenated short coils, and the component of the magnetic eld parallel to the ber 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 eld parallel to the coil plane can be calculated. By arranging two close coils on orthogonal planes, a 3D reconstruction of the magnetic eld 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 ber loops.