Dependence of fiber Bragg grating thermal stability on grating fabrication process

Summary form only given. Fiber gratings thermal stability was investigated at 600°C during 600 hours. These results point out the strong dependence of gratings thermal stability on their fabrication process, different defects may be created and different mechanisms involved, as well as the complexity of their long-term evolution law, which will have to be fully understood before deriving grating lifetime under operating conditions.