A High Resolution Three-Axis Fiber Magnetometer

A vector magnetometer is typically configured as a three-axis device to measure the field along three orthogonal directions. Magnetostrictive fiber optic magnetometers [1] operate as a vector device, sensing the component of magnetic field along a particular direction. Previously we demonstrated a low resolution (10-2 Gauss/√Hz) three-axis magnetometer for heading sensor applications [2]. In this work, we designed and tested a three- axis fiber-optic magnetic sensor with a resolution of 10-5 GaussWHz below 1 Hz. An important application of this device is the remote sensing of ambient low-frequency magnetic noise. We present the low-frequency resolution and demonstrate the low crosstalk and high directionality of such a device, as well as its temperature stability between 0° and 55° C.