Magnetic field measurement using Fabry-Perot fiber-optic sensor with 3D microstructures

Weak magnetic field measurement technology is valuable in geophysics, medical imaging, space exploration, and material science. Fiber-optic sensors, with their resistance to electromagnetic interference, compact size, high sensitivity, rapid response, and remote sensing potential, are widely used in magnetic field sensing. This experiment uses fiber-optic sensors to measure weak magnetic fields. The principle is based on Fabry-Perot (F-P) interference, and a 3D elastic micro-rhombus structure is printed on a single-mode fiber (SMF) end facet using femtosecond laser two-photon polymerization (TPP) lithography. An iron microsphere is added to make it magnetically sensitive. By monitoring the reflection spectrum of this sensor, a sensitivity of approximately -39.05 pm/mT is obtained in the 0-5.25 mT range.