In this study, we compare the pulsed X‐ray radiation responses of standard, radiation‐tolerant optical fibers with those of super‐hard, radiation‐resistant multimode (MM‐SRH) and single‐mode (SM‐SRH) fluorine‐doped optical fibers. Real‐time measurements of radiation‐induced attenuation (RIA) spectra were conducted in the spectral range of 0.6 to 3.0 eV (400–2000 nm), both at room temperature and at liquid nitrogen temperature, to characterize the nature of metastable defects, quickly recombining after the short (a few tens of ns) irradiation pulse. Additionally, we monitored the RIA kinetics at the two telecommunication wavelengths, 1550 and 1310 nm, from the microsecond timescale to several hundreds of seconds. MM‐SRH fibers exhibit superior light transmission efficiency following the X‐ray irradiation pulse, better than the other fiber compositions and the one expected from current literature on transient responses of silica‐based optical fibers. Possible explanation of this radiation hardness could be the very high level F‐doping distribution in this graded‐index optical fiber, demonstrating how the RIA in optical fibers strongly depends on fiber composition and manufacturing parameters.
Michele et al. (Thu,) studied this question.