Study on Optical Fiber Bragg Grating Temperature Sensors for Human Body Temperature Monitoring

It is usually that the sensitivity of fiber Bragg grating(FBG) temperature sensor is low, that is 0.010nm/°C, Which is not efficient for the accurate measurement of human body temperature. This paper develop two methods of FBG encapsulation to increasing the sensitivity of FBG temperature sensor. First, we used epoxy resin to encapsulate the FBG in Teflon pipe. Although temperature sensitivity was significantly improved about 12 times higher than naked FBG temperature sensor, its linearity was inferior than naked FBG sensor. In order to not destroy the linearity of the temperature sensor, we let the FBG in a free state in the capillary tube, only fix the two endpoint. The temperature sensitivity is 23.4pm/°C, and the linearity is good.