A fiber laser including doped-core fiber having inner and outer cladding is optically pumped by plurality of diode-lasers. Light emitted by the diode-lasers is coupled into a single multimode optical fiber. Light from the multimode optical fiber is directed to a wavelength selective reflecting device that is partially reflective in a narrow reflection band about a peak reflection wavelength. A portion of the light having the peak reflection wavelength is reflected from the wavelength selective reflecting device back along the multimode optical fiber and back into the plurality of diode-lasers. This locks the emitting wavelength of the light emitted from each of the diode-lasers to the peak reflection wavelength. Light at the emitting wavelength that is not reflected from the wavelength selective reflective device is coupled into the inner cladding of the doped-core fiber for optically pumping the fiber laser.