Passive Temperature-compensated Fiber Fabry-Perot Magnetic Field Sensor

A passive temperature-compensated magnetic field sensor based on the material thermal-optics effect has been proposed. The proposed structure is easy to fabricate, consisting of only two single-mode optical fibers adhered to a magnetostrictive rod and the Fabry-Perot (FP) cavity filled with polydimethylsiloxane (PDMS). Benefitting from the negative thermal-optics coefficient of PDMS, the temperature cross-sensitivity of the sensor decreased from 351.02 pm/°C to 12.59 pm/°C, while exhibiting a high magnetic field sensitivity of 160.66 pm/mT@38.47-61.52 mT. The proposed sensor avoids complex control systems, composite structures, and bulky packaging. This feature effectively compensates for temperature influences during magnetic field detection, making it an ideal candidate for stable magnetic field sensors in practical applications.