Promotional effects of cerium in ytterbium doped fibers on proton irradiation damage

This paper investigated the defect generation mechanism of two self-made ytterbium-doped fibers (a Yb-doped fiber and a Yb/Ce-doped fiber) under proton irradiation and the influence of Ce-doping on proton radiation defects. The macroscopic damage of different optical fibers caused by proton irradiation energy and irradiation doses was further studied. Fluorescence spectroscopy, EPR electron paramagnetic resonance and SEM experiments were used to characterize the micro defects and macro damage of the fibers. The following conclusions are drawn: the damage on the surface of optical fibers increases continuously with the increase of irradiation dose, and does not change significantly with the increase of proton energy. The main defect in the irradiated fibers is proved to be the Al-OHC defect which leads to energy loss in the visible light region and a photon darkening effect. After Ce doping, the change trend of the amount of Al-OHC defect is greatly suppressed, while it shows little effect on the oxygen defect (intrinsic), and basically does not change this trend. On the other hand, Ce doping can also effectively reduce the generation of Si-E' defects in the irradiated fibers according to the EPR electron paramagnetic resonance experiment. In conclusion, due to the presence of two valence states of Ce ions, Ce doping prominently improves the performance of high-power Yb-doped fibers under proton irradiation.