Thermal sensitivity increase of RFBG in the visible range

Abstract

Thermal sensitivity increase of regenerated fiber Bragg gratings (RFBG) in the visible range is reported. The FBGs are produced by direct illumination under the phase mask using UV light from two different laser sources at 248 nm. After regeneration the thermal sensitivity is obtained at 500°C to avoid spectra vanishing for temperatures near that of regeneration. At 500°C, the determined thermal sensitivities are 5.74pmK-1 before and 7.65pmK-1 after regeneration (single mode fiber in the visible, femtosecond laser), and a similar pattern is presented for all regenerated FBGs.