Nd3+-doped silica glass and fiber prepared by modified sol-gel method

Large-size Al/Ndco-doped silica glass with 5000 ppm Ndand 50,000 ppm Aldoping concentrations was prepared by the modified sol-gel method combined with high-temperature melting and molding technology. Electron probe microanalyzer tests indicated that high doping homogeneity was achieved with this sample preparation method. The spectral properties of the Ndions were evaluated. Nd-doped silica fiber(NDF) with a core-to-clad ratio of 20/125 μm was drawn from the preform with the Al/Ndco-doped silica glass as the core. In the laser oscillation experiment, a maximum output power of 14.6 W at 1.06 μm with a slope efficiency of 39.6% was obtained from the NDF pumped by a commercial808 nm laser diode. To the best of our knowledge, this is the highest laser power reported for an NDF operated at 1060 nm and prepared by a non-chemical vapor deposition method. In the master oscillator power amplifier experiment, a maximum power of 16.6 W corresponding to a slope efficiency of 30.5% at 1061 nm was also demonstrated. The laser performance of the NDF exhibited the great advantages and potential of the modified sol-gel method in fabricating Nd-doped silica glass for a new type of NDFs like large mode area fibers and fibers with large diameter ratio of core/cladding.