Magnetic Field and Temperature Sensing Based on a Macro-Bending Fiber Structure and an FBG

In this paper, an optical fiber sensor for simultaneous measurement of magnetic field and temperature is proposed and demonstrated. The sensor consists of a macro-bending single-mode-fiber structure (MSS) and a closely concatenated fiber Bragg grating (FBG), both of which are coated with magnetic fluid. The MSS and FBG induce two types of dips in the transmission spectrum of the sensor, and they have the different sensitivities to magnetic field and temperature. Consequently, the simultaneous measurement for the dual-parameter can be realized by monitoring the wavelength shifts of the two types of dips. A sensor was fabricated and experimentally characterized. The results show that the proposed sensor is simple and effective in the simultaneous measurement of temperature and magnetic field.