Novel viewpoint for explaining thermal degradation mechanism of fiber Bragg gratings

摘要

In this paper, the thermal degradation mechanism of ultraviolet-induced fiber Bragg gratings (FBGs) written in silica fiber doped with germanium has been developed. The thermal degradation up to 840 °C has been repeatedly examined, and their reflectivity and Bragg wavelength change have been carefully observed. In addition, the temperature characteristic of the FBG is tested by putting it into a silica tube furnace heated from room temperature to 600 °C. The experiment results obtained has shown that the FBGs' thermal behavior is similar to a spring's. Therefore, a novel viewpoint, atomic elastic model applied to explain the thermal degradation mechanism of FBGs, is firstly present. The work is closely related to the use of FBGs for application in temperature sensor field, and the work is also related to form mechanism of FBGs.