Elimination of radiation damage in Tm-doped silica fibers based on the radical bleaching of deuterium loading

We present the deuterium-loading induced radical recovery of 2µm laser fiber and absorption efficiency in thulium (Tm)-doped silica fibers under gamma irradiation in the range of 185Gy-1000Gy. The optical-optical efficiency and fiber cladding absorption spectra of the Tm-doped silica fibers with multi-dose irradiation and deuterium treatment have been measured. It was found that the reduction of the optical-optical efficiency and the additional absorption, both induced by irradiation, were positively associated with the dose. Under the deuterium loading, the efficiencies of the multi-irradiated TDFs could be restored to above 91.9% of the pristine, and the radiation induced absorptions were almost completely vanished. The results indicate that deuterium-loading has an extensive prospect for the radiation hardness of Tm-doped silica fiber.