Annealing treatment and wavelength shifting characteristics of regenerated fiber Bragg gratings

A novel fabrication method for thermal regenerated fiber Bragg grating (RFBG) with intensity larger than 43% (reflective to the original FBG) was developed. Conventional seed fiber Bragg grating (SFBG) was erased at 800 °C. The sample was continuously heated to 900 °C, during which RFBG occurred. The as-prepared RFBG was taken for thermal annealing cycles (18 °C–1000 °C) to study its wavelength shift characteristics. At the beginning of the test, the wavelength was unstable and inclined to increase 148 pm. After four cycles, the wavelength reached a stable value. Temperature sensing experiment at 18 °C–1000 °C was carried out for RFBG and a sensitivity of (11.07 + 0.00781T) pm/°C with a satisfactory stability was obtained. The developed RFBG could be applied to high temperature detection in aerospace industries.