A fiber laser with a fiber for laser light generation having an entrance end and an exit end comprises a pump light source for generating pump light to be coupled via the entrance side into the fiber. At the exit end of the fiber a first resonator mirror is provided which is highly reflecting for the laser light to be generated in the wavelength range with the smallest light amplification and to the light of the pump light source. Spaced from the first resonator mirror a second resonator mirror is provided via which light of further wavelength ranges can be fed back into the fiber with the aid of a collimating lens.