The characteristics of fiber Bragg gratings(FBG) at local temperature are investigated based on the transfer matrix method.The reflective spectrum model of the FBG at local temperature is analyzed by theoretics and simulations.The results show that when a small section of the FBG is affected by the temperature variation,the reflective spectrum splits into two main peaks.The wavelength of the splitting point shifts linearly and periodically with the local temperature on the FBG.An experiment is also presented,and its results are agreement with the simulations.
