Magnetic-Ionic-Liquid-Functionalized Photonic Crystal Fiber for Magnetic Field Detection

A compact optical fiber magnetic field sensor based on a magnetic-ionic-liquid-functionalized photonic crystal fiber (PCF) has been proposed and experimentally demonstrated. The magnetic field sensor was fabricated by splicing an index-guiding PCF having one magnetic-ionic-liquid-infiltrated (MIL-infiltrated) air hole in the innermost layer infiltrated with conventional single-mode fibers. The transmission spectral magnetic response of the proposed sensor have been measured and theoretically analyzed. Owing to the effective interaction between the MIL and transmission light as well as the controllable attenuation property of MIL, the magnetic field sensitivity reaches up to -0.01991 dB/Oe for a relatively linear magnetic intensity range of 0 to 440 Oe.