Hollow-core photonic crystal fiber Fabry–Perot sensor for magnetic field measurement based on magnetic fluid

Based on the characteristic of magnetic-controlling refractive index, the magnetic fluid filled in hollow-core photonic crystal fiber (HC-PCF) can be used as the sensitive medium in the cavity of a fiber Fabry–Perot (F–P) magnetic field sensor. The structure and the sensor principle are introduced. The theoretical simulations of the mode distribution of the HC-PCF filled with the magnetic fluid and the sensor output spectra are discussed in detail. The sensor multiplexing capability is indicated as well. Magnetic field measurement sensitivity is about 33 pm/Oe based on the proposed sensor.

► A magnetic sensor is proposed based on an HC-PCF filled with magnetic fluid (MF).
► The principle is the characteristic of magnetic-controlling refractive index of the MF.
► Magnetic field measurement sensitivity is about 33 pm/Oe.