Spectral Repeatability of Regenerated Fiber Gratings Prepared by High Temperature Annealing

Two groups of fiber Bragg gratings were fabricated by using UV laser, and group one was annealed at 850 degrees C in the high temperature furnace. Grating regeneration occurred after the initial grating vanished. For the regenerated gratings from group one, the variation in Bragg wavelength is 0. 22 nm and the average transmissions strength is 2. 57 dB, while the variation of transmission among ten gratings is 0. 52 dB. Group two underwent post-annealing at 1 100 degrees C after the process of grating regeneration at 850 degrees C. For the regenerated gratings from group two, the variation in Bragg wavelength is 0. 41 nm and the average transmissions strength is 0. 69 dB, while the variation of transmission among ten gratings is 0. 16 dB. The variation in Bragg wavelength of grating with post-annealing is notably larger than that of the regenerated gratings in group one, which is caused by the small difference in fixed tension among the ten gratings. The process of grating regeneration has good reproducibility. The mass production of the regenerated gratings by high temperature annealing is feasible.