The technology for manufacturing active elements for high-power (more than 1 kW) Yb3+:YAG disk lasers has been developed. A series of disk active elements with a thickness of 200...400 μm, a diameter of 8...15 mm, and a Yb3+concentration of 8...15 at. % has been created. A model of a CW disk laser with an output power of 45 W, an optical efficiency more than 45%, and a pump power density more than 2.5 kW/cm2 has been made.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.