Dual Mode Interference Magnetic-Field Sensor Based on Hollow Suspended-Core Fiber

A novel magnetic field sensor based on hollow suspended-core fiber (HSCF) has been proposed and fabricated. The magnetic fluid is filled into the microfluidic channel of the HSCF. The core-core mode (LP ₀₁ and LP ₁₁ modes) interference is excited in the core of the HSCF. The refractive index sensitivity of the interferometer is 331 nm/RIU. The magnetic response of the proposed sensor has been investigated and the results show that a high magnetic field sensitivity of 115.7 pm/Oe is achieved in the magnetic field strength range from 20 to 80 Oe. With the advantages of robustness, high sensitivity, simple interference spectrum and integrated online microfluidic channel, the HSCF interferometer-based magnetic field sensor has promising applications in the fields of aerospace, geological hazards, and navigation.