Radiation-induced absorption in optical fibers in the near-infrared region: the effect of H/sub 2/- and D/sub 2/-loading

Loss spectra are compared in H/sub 2/- and D/sub 2/-loaded and gas-free N-doped fiber samples after /spl gamma/-irradiation. It is found that D/sub 2/-loading allows reduction of induced absorption at the wavelengths of 1.30 and 1.55 /spl mu/m by a factor of /spl sim/5 at a total dose of /spl sim/1 MGy. H/sub 2/-loading is shown to be less efficient, owing to H/sub 2/ and OH-group absorption bands increasing the total loss in the telecom spectral windows. Pretreatment of fibers via D/sub 2/-loading and pre-irradiation appears to be a promising radiation-hardening technique.