Normalized temperature sensitivity of fiber Bragg gratings inscribed under different conditions

In this paper we present results on the normalized temperature sensitivity of UV- and fs-induced fiber Bragg gratings in a singlemode fiber with ~4.7 mol% GeO₂ and having an Ormocer coating. In the 1500-1600 nm wavelength range, the former shows an almost constant value of 6.165×10^-6 K^-1, whilst the fs-induced present some variation not related with the strength of the grating but probably due to induced birefringence. The average value obtained was 6.191×10^-6 K^-1 which is higher than the former. For the UV-induced gratings in the Corning SMF-28 fiber (3.67 mol% GeO₂) the value obtained was 6.143×10^-6 K^-1. The achieved values are compatible with the use of Corning 7980 silica-based cladding fiber. Preliminary results also show no measurable impact of the hydrogenation process or the strength of the grating on the normalized temperature sensitivity.