Fiber cantilever deflection magnetometer in Fabry-Perot multi-mirror host for detection of ˜mT field: Experimental demonstration and modeling

Abstract We devise a tunable cavity fiber Fabry-Perot magnetometer circuit hosting cantilever-deflection using cobalt-doped nickel ferrite coated optical fiber as cantilever. The magnetic field induced modulation of cavity length of Fabry-Perot due to bending of the fiber-cantilever in the transverse direction as observed experimentally is modeled using the fiber-to-fiber coupling signature in the platform of Fabry-Perot multiple-reflection-transmission analysis. By introducing in-house fabricated silver-coated fiber-mirror in this configuration, sensitivity is improved by optimizing the coating-process through real-time monitoring towards achieving a maximum reflectivity of 95%. We demonstrate a high-performance and tunable sensitivity three-mirror Fabry-Perot assembly of fiber-cantilever-deflection magnetometer capable of detecting ˜mT or even lower in the dynamic range of 0–100 m T.