Radiation hardening of pure silica optical fibres by high pressure hydrogen treatment

It was proved that hydrogen (H₂) treatment, consisting of loading with H₂ under high pressure and immediate preirradiation up to dose values of 10⁴ Gy, considerably increases the radiation hardness of optical fibres with a pure SiO₂ core, especially of those with a low OH content. These fibres even show a reduction of their initial attenuation at wavelengths < 700 nm in contrast to a significant increase between 1200 nm an 1600 nm (growth of OH absorption bands). Therefore, H₂ treatment should be restricted to fibre applications in the visible wavelength range, up to about 850 nm. A treatment with highly enriched deuterium should extend the usefulness to wavelengths around 1300 nm.