Investigation on low-temperature characteristics of FBG sensors and the technology to enhance sensitivity

The mode of FBG´s temperature-sensing is analyzed to and the low temperature performance of FBG is experimental study. Three package technologies can be used for enhancing the sensitivity of FBG under low temperature; the technologies include capillary steel tube package, metallized package and organic polymer package. The results show that the temperature sensitivity of bare FBG under low temperature is 0.00998 nm /°C, the temperature sensitivity of FBG with capillary steel tube package, metallized package and organic polymer package are 0.0213 nm /°C, 0.0283 nm /°C and 0.1376 nm /°C separately, which are 2.02, 3.30, 10.23 times compared with the bare fiber. The temperature sensitivity of FBG sensor under low temperature could be increased effectively by using package technology.