Full suppression of radiation-induced darkening in ytterbium-doped fiber lasers by synergistic deuterium doping and D 2 loading

Fiber lasers are increasingly employed in radiative applications, where maintaining laser performance under irradiation is of great importance. Deuterium (D 2 ) loading has been proven efficient in enhancing the radiation resistance of fibers. Nevertheless, such treatment commonly suffers from gas out-diffusion, and the full suppression of radiation-induced darkening has not yet been achieved. In this work, we introduced a pretreatment–deuterium solution doping technique, which stabilized deuterium within the fiber preform. Combined with D 2 loading, the laser output power under irradiation remained at its initial level. The solution doping process locked OD groups within the fiber core, suppressing color center formation at the source. Coupled with the dynamic repair function of D 2 loading, this approach achieved complete suppression of radiation-induced darkening under 200 Gy (Si) gamma-ray irradiation, providing a promising strategy for the development of high-performance radiation-resistant fiber lasers.