Ultrahigh-Temperature Chirped Fiber Bragg Grating Through Thermal Activation

The feasibility of thermal regeneration of chirped fiber Bragg gratings inscribed in commercial single-mode fibers using a 248-nm excimer laser has been experimentally demonstrated. Regenerated chirped gratings (RCGs) with a strong and symmetrical reflection profile can be achieved by 80 min of thermal treatment at a temperature of 800°C. The thermal cycling test results show that the RCGs provide a stable and reproducible spectral response (both in bandwidth and in reflective intensity) over the temperature range from 25°C to 1000°C, indicating their good potentials for fiber laser and sensing applications under high-temperature conditions.