Magnetic-Fluid-Coated Photonic Crystal Fiber and FBG for Magnetic Field and Temperature Sensing

A novel optical fiber sensor for simultaneous measurement of magnetic field and temperature is proposed and demonstrated. The sensor consists of a cascaded photonic crystal fiber (PCF) interferometer and fiber Bragg grating (FBG). The interferometer and the FBG are sealed in a capillary tube filled with magnetic fluid. The transmission spectrum of the sensor contains both the information of the interferometer and the FBG. The FBG is only sensitive to the temperature but the PCF interferometer is also sensitive to the magnetic field, which in turn can be used for the simultaneous measurement of magnetic field and temperature. A sensor was fabricated and investigated experimentally.