ARC-induced long period gratings in fluorine-doped optical fibers

Here we present our results in the fabrication of Long Period Gratings (LPGs), through the Electric Arc Discharge technique, in standard communication optical fibers and two different optical fibers made of pure-silica core and Fluorinedoped cladding. In last years, F-doped fibers have been studied, since they represent a suitable solution in highenergy applications, due to their radiation hard properties. First, we present the accomplishments of our Electric Arc Discharge based technique, for the fabrication in SMF28 fiber. The optimization of the parameters lead us to the inscription of short LPGs with deep attenuation bands (more than to 30 dB), narrow bandwidths and with a wide choice of spatial periods. Afterwards, we report the results obtained in the fabrication of LPGs in F-doped fibers: gratings were achieved with maximum attenuation band depths in range 25-30 dB and low power losses. The analysis of the sensitivity to temperature and surrounding refractive index (SRI) changes was also carried out, and the results have been compared to those in standard fiber. We found out that gratings in F-doped fibers exhibit a slightly lower temperature response, whereas the SRI sensitivity is higher than in standard fiber, providing in our opinion the opportunity of novel applications.