A novel single-wavelength fiber ring laser with 250 mW output power is reported. A double-clad polarization-maintaining erbium-ytterbium co-doped fiber was used in a unidirectional ring cavity as an active medium to eliminate spatial hole-burning effect in the cavity. The output of the laser was single-longitudinal mode. A fiber Fabry-Perot filter was used in the cavity to increase the longitudinal-mode spacing which eliminated the mode hopping. The maximum output power produced by the laser without mode hopping was 250 mW. The optical signal to noise ratio (OSNR) of the laser was more than 40 dB.