High-resolution optical fiber ring magnetic field sensor

The high-resolution measurement of magnetic field is of great significance in scientific research and production. Here we propose a high-resolution fiber ring magnetometer based on laser frequency stabilization technology. By connecting one output port to an input port of a fiber coupler with a splitting ratio of 1:99, the fiber ring resonator (FRR) generates a series of highly narrow transmission resonances. Through clever structural design, the response of the magnetostrictive material (TbDyFe cake) to the magnetic field changes is efficiently transmitted to the FRR, and the response is amplified by multiloop wrapping. By tracking the high-Q resonant peak of the FRR based on the laser frequency stabilization technique, we realize the high magnetic field resolution of 433 pT/√Hz over 1 Hz.