Fiber Fabry-Perot interferometer sensor for dynamic magnetic field detection based on microwave photonic filter

A novel fiber Fabry-Perot interferometer (FPI)-based sensing system for dynamic magnetic field detection is proposed and experimentally demonstrated. The FPI is composed of a reflector and a cleaved end face of a single mode fiber, and is fixed on a giant magnetostrictive rod. The significant length change of the FPI cavity caused by external dynamic magnetic field is interrogated by a microwave photonic filter (MPF) system, in which the phase shift of a single-frequency electrical signal within the passband of the MPF is utilized and recorded. Experimental results show that the magnetic field sensitivity and minimum detectable magnetic field reach up to 4.13 × 10^-4 rad/μT and 1.36 μT/Hz^1/2 respectively.