Multi-modes interferometer for magnetic field and temperature measurement using Photonic crystal fiber filled with magnetic fluid

An in-line modal Mach-Zehnder interferometer (MZI) based on a magnetic fluid-filled photonic crystal fiber (PCF) was proposed in this paper. The Mach-Zehnder interference was induced by the single mode fiber (SMF)photonic crystal fiber (PCF)-single mode fiber (SMF) structure. And the photonic crystal fiber was filled with magnetic fluid to measure the magnetic field and temperature. There are multiple cladding modes are involved into the interference. Hence simultaneous measurement of temperature and refractive index can be achieved by simultaneously monitoring the two different modes interference spectra. The sensitivities of magnetic field and temperature can reach up to 0.072 nm/Gs and -0.080 nm/degrees C, respectively.