Photobleaching Effects Caused by Ambient Light on the Radiation‐Induced Attenuation of Germanosilicate Optical Fibers

We demonstrate the influence of the ambient lightning on the X‐ray radiation‐induced attenuation (RIA) in the visible to infrared domains of germanosilicate optical fibers (OFs). RIA spectra and kinetics are then discussed depending on the illumination conditions in terms of point defects and also from a practical point of view. In the presence of an external illumination, the RIA levels can change and therefore lead to misinterpretations during irradiation campaigns. This study highlights the role of the GeY defect in infrared Ge‐doped OF RIA and its significant sensitivity to photobleaching.