Design of a magnetic field and temperature fiber sensor based on Fabry–Pérot interferometer and OAM interrogation

We have designed a Fabry–Pérot interferometric fiber sensor based on the principal component analysis (PCA) assisted orbital angular momentum (OAM) interrogation for simultaneous measurement of magnetic field intensity and temperature. A hollow core fiber sandwiched between two segments of single mode fiber serving as the sensing probe, is introduced to the Gaussian interference arm. Encapsulated with magnetic fluid, the intensity and phase of Gaussian beam are highly sensitive to the variations of magnetic field and temperature, exerting a modulation on the intensity and rotation angle of OAM interferograms. A dual-parameter sensing matrix to discrimination the cross-sensitivity could be established via the PCA-assisted OAM interrogation. The minimum sensing resolutions of magnetic field and temperature are calculated as 0.06 G and 0.0079 °C, respectively.