Thin-Diameter Photonic Crystal Fiber Magnetic Field Sensor Based on Controlled Hole Collapse and Infiltration

A thin-diameter photonic crystal fiber (TDPCF) magnetic field sensor based on hole collapse and infiltration is proposed and demonstrated. Due to the controlled hole collapse in TDPCF, the interaction between the mode field distribution and the magnetic fluid (MF) is effectively strengthened, causing the direct absorption and scattering of magnetic nanoparticles to transmit light. Consequently, the proposed sensor exhibits a magnetic field sensitivity of up to 0.099 dB/Oe within the range of 0 to 60 Oe. The TDPCF-based magnetic field sensor has several desirable merits such as high sensitivity, convenient integration, and good stability, which provides a promising candidate in environmental and industrial-related magnetic field monitoring applications.