Fiber Bragg grating temperature sensor and calibration scheme in high magnetic field environment : An application for aluminium electrolysis cell in potline

In recent years, Fiber Bragg Grating (FBG) has attracted increasing interest for sensing applications, due to its unique fiber structure which offers many advantages such as immunity towards Electro-Magnetic Interference (EMI), rugged structure, high sensitivity, and accuracy. Moreover, the FBG temperature sensor has greater sensitivity and inexpensive price, therefore it is increasingly used in several industrial applications. In this article, the design, construction, calibration, and testing of an FBG temperature sensor probe are presented with detailed experimental analysis. Due to passive characteristics, these sensors do not influence EMI during sensing. Therefore, it will be the best possible choice for high magnetics field areas like Aluminum electrolysis cells in potlines. The static characteristics of the FBG temperature sensor such as precision, sensitivity, accuracy, linearity, etc. are presented. A rod-type temperature sensor with a high resolution of 0.2051°C and higher sensitivity of 13 pm$/^{\circ}$C has been discussed. In a broad frequency range, the proposed sensor demonstrates outstanding temperature sensitivity with enhanced characteristics. In the Fial section, the difficulties and potential of FBG sensors for sensing applications are discussed.