RFBG Thermal Aging Evaluation Above Regeneration Temperature

Regenerated fiber Bragg grating (RFBG) sensors for thermal aging at high temperatures from 600 °C to 1000 °C are produced and analyzed in this work. Seed FBGs are regenerated at 850 °C–900 °C and thermal characterized at the increasing steps of 50 °C–100 °C. Signal decay is measured from the reflected spectra until imminent erasure. The objective is to analyze the RFBG sensors lifetime above the regeneration temperature for long periods after annealing cycles with increasing thermal levels. Lifetime results from RFBG were reported to be a few hours above their regeneration temperature. Our results are significantly better. The sensors resisted for the time intervals of one to eight days up to 100 °C above the regeneration temperature. In addition, some sensors remained stable in terms of the spectral amplitude for more than four days in that thermal condition.