Photobleaching Effect on Infrared Radiation-Induced Attenuation of Germanosilicate Optical Fibers at MGy dose levels

We investigated the radiation-induced attenuation (RIA) at 1550 nm under X-rays in two single-mode germanosilicate optical fibers (OFs): the Corning SMF-28e+ and a homemade fiber manufactured by the Universite Cote d’Azur in the framework of the CERTYF project. The RIA dependence on the injected power level of the probing signal is studied in order to analyze the photobleaching phenomenon at high doses [>100 kGy(SiO2)]. The Corning SMF-28e+ revealed no RIA variation with the signal power (microwatts–milliwatts range), proving to be a good candidate for distributed OF sensor (DOFS) applications, while the CERTYF OF showed a clear photobleaching effect. A fitting routine based on the second-order growth kinetics model of Griscom has been performed, which has shown good consistency with the experimental results and offered a quantitative evaluation of the photobleaching effect on the CERTYF OF.