A high-power narrow-bandwidth all-fiber thulium-doped silica fiber master oscillator power amplifier (MOPA) system that consists of a low power thulium-doped continuous wave fiber laser seed and two-stage thulium-doped double-clad fiber amplifiers pumped by fiber-pigtailed multimode diodes at 790 nm is reported. The center wavelength of the fiber laser is 1963 nm and the 3 dB bandwidth is 0.24 nm. The maximum output power is 22 W at a slope efficiency of 44% with respect to the launched pump power.