Monitoring of radiation effects in phospho-silicate optical fibers: applications in various domains of nuclear industry

Macroscopic properties of optical fibers are affected by irradiation through 3 main processes: radiation-induced attenuation (RIA), radiation-induced emission and compaction. RIA that corresponds to an increase of the optical loss per unit length of the fiber is the prominent process. Phospho-silicate optical fibers are very sensitive to radiation which can be explained by the properties of defects concerning phosphorous atoms that strongly absorb light in the ultraviolet to infrared range. Studies have shown that the RIA increases in a linear way with the value of the deposited dose and that the dose conversion factor is neither dependant on the dose itself, nor on temperature. These specific features allow phospho-silicate fibers to be used as dosimeters. For fibers used as optical amplifiers in spatial industry, a radiation hardening can be obtained by adding cerium to ytterbium-erbium co-doping that counters the effects of defects linked to phosphorous atoms. (A.C.)