Quasi-distributed temperature sensor system based on various-packaged FBG

Different package of fiber Bragg grating (FBG) temperature sensors were introduced. The temperature sensitive factors of the sensors were derived analytically and verified by experiments. A quasi distributed temperature sensor system consisted of different-packaged FBG, wideband light source, and FBG interrogator was set up successfully. The experiment results of the different FBG temperature sensors were compared by analyzing the variety properties of center wavelength in identical conditions. From the experimental results, it is shown that the central wavelength of FBG temperature sensor with different package shifts diversely; while good linearity and preferable repeatability are present among the various FBG sensors, and there is almost no hysteresis effect. The temperature sensing ability of the packaged FBG sensor is improved and the temperature sensitivity coefficient is about 3 or more times as much as that of the bare FBG. The temperature resolution of the packaged FBG sensor can reach up to 0.03 degrees C. It is indicated that all the packaged FBG sensors are suitable to measure temperature according to specific application environment.