Investigation of photo-darkening effect in ytterbium-doped microstructure optical fiber through the laser sintering fabrication method

Abstract Here we investigated photo-darkening (PD) effect and its influence on laser performance in Yb3+-doped microstructure optical fiber made through the laser sintering technique (LST). Through measuring the temporal evolution of PD excess loss at 633 nm and fiber lasing characteristics, it was found that the home-made fiber has relatively low PD and high slope efficiency. The obtained PD equilibrium loss αeq at 633 nm is 1.07 dB/m. After 30 h 976 nm laser irradiation, the fiber presents a quite small power degradation of 0.45 %. Moreover, the laser slope efficiency shows a small decline of 0.26 %, from 81.03 % to 80.77 %. The investigation of optical performance demonstrates that Yb3+-doped fiber fabricated by LST has uniform elements distribution, reasonable absorption, low background loss and a relatively low PD behavior, making it a potential application for effective high-power fiber lasers.