Watt-level Yb-doped silica glass fiber laser with a core made by sol-gel method

A Yb-doped silica glass fiber laser with a core made by sol-gel method is reported. The maximum power of 1.14 W is obtained with a pump power of 5.46 W at a wavelength of 976 nm. The slope efficiency is 34%. The refractive index fluctuation across the core is below 5x10(-4) at a doping level of Yb 0.15 mol%, A(2)O(3) 4.0 mol%, and P2O5 2.0 mol%. High background attenuation of 6 dB/m at 1 053 nm limites the slope efficiency and maximum output power