Performance evaluation of metal-coated fiber Bragg grating sensors for sensing cryogenic temperature

A metal recoated fiber Bragg grating sensor has been designed, fabricated and tested to study its temperature response at cryogenic temperature around 15 K. Metals like aluminium (Al), copper (Cu), lead (Pb) and indium (In) are considered for recoating the FBG sensors. Indium recoated FBG (IRCFBG) sensors showed a higher sensitivity at around 15 K compared to Al, Cu and Pb coated FBG sensors. In addition, the IRCFBG sensor was tested for its repeatability, stability and performance in the high magnetic field (8 T). The experimental results of the IRCFBG sensor test revealed a satisfactory performance. They will be reported in this paper.