Role of Inherent Radiation-Induced Self-Trapped Holes in Pulsed-Radiation Effect on Pure-Silica-Core Optical Fibers

Radiation-induced attenuation (RIA) is investigated in pure-silica-core optical fibers (PSFs) upon their pulsed-X-ray irradiation. RIA at small post-pulse times (t ≤ 0.001–0.1 s) is argued to be mainly due to inherent self-trapped holes (STHs), whereas at large times, due to strain-assisted STHs, as shown by Girard
et al
. Significant suppression of inherent STHs is found to occur in PSFs upon pulsed pre-irradiation with a dose of just ∼100–200 Gy. Thus, a radiation-hardening effect is revealed for the first time, which is of practical value for PSFs to be exposed to pulsed irradiation. Fiber drawing temperature T
_d
is found to have an essential effect on RIA upon pulsed irradiation. The optimal T
_d
-values are estimated for PSF applications at small (t < 0.01 s) and large (t > 0.01 s) post-pulse times.