Influence of GeO(2) Content on the Spectral and Radiation-Resistant Properties of Yb/Al/Ge Co-Doped Silica Fiber Core Glasses

In this study, Yb/Al/Ge co-doped silica fiber core glasses with different GeO(2) contents (0–6.03 mol%) were prepared using the sol–gel method combined with high-temperature sintering. The absorption, fluorescence, radiation-induced absorption, continuous-wave electron paramagnetic resonance spectra, and fluorescence decay curves were recorded and analyzed systematically before and after X-ray irradiation. The effects of GeO(2) content on the valence variations of Yb(3+)/Yb(2+) ions, spectral properties of Yb(3+) ions, and radiation resistance of Yb/Al/Ge co-doped silica glasses were systematically studied. The results show that even if the GeO(2) content of the sample is relatively low (0.62 mol%), it can inhibit the generation of Yb(2+) ions with slight improvement in the spectral properties of Yb(3+) ions in the pristine samples and effectively improve its radiation resistance. Direct evidence confirms that the generation of trapped-electron centers (Yb(2+)/Si-E’/Al-E’) and trapped-hole centers (Al-OHC) was effectively inhibited by Ge co-doping. This study provides a theoretical reference for the development of high-performance, radiation-r esistant Yb-doped silica fibers.