Magnetic field sensing through magnetic force using Erbium-doped fiber laser

Erbium demonstrates significant paramagnetism, which can be attracted by magnetic force in an externally applied magnetic field. For an Erbium-doped fiber, such attraction generates strain inside the fiber, resulting in birefringence. In this paper, we detect this birefringence change by using an Erbium-doped dual-polarization fiber laser to study the magnetic force experienced by the Erbium-doped fiber. It shows the birefringence change is significant, which suggests a potential new method to measure magnetic field directly without using transducers.