Fabrication of nanoporous silica rods from curable nanocomposites and their application in Yb-doped fiber lasers

Abstract Rare-earth (RE) doped silica glass is essential for constructing high-power fiber lasers. However, the achievement of high doping concentrations with a uniform RE ion dispersion in the SiO2 glass matrix is hindered by clustering and inhomogeneous distribution. Herein, a novel technique—UV-curable nanocomposite technology (UV-CNCT)—is demonstrated for fabricating a nanoporous silica rod with a high doping concentration and uniform dispersion of RE ions in a SiO2 glass matrix. A preform with an Yb-doped P2O5-Al2O3-SiO2 core and pure SiO2 cladding, and a single cladding fiber with a doping concentration of 2.1 wt% (for Yb2O3) are fabricated. A linear all-fiber resonant cavity is constructed to analyze the laser performance. Experimental results reveal the highly uniform dispersion of dopants at a relatively high concentration for both the preform and fiber without aggregation, center dip. The proposed technology is expected to be an effective approach for the fabrication of high-quality RE-doped silica glass for advanced fiber lasers.