Beier, FranzFranzBeierOtto, Hans-JürgenHans-JürgenOttoJauregui, CesarCesarJaureguiVries, Oliver deOliver deVriesSchreiber, ThomasThomasSchreiberLimpert, JensJensLimpertEberhardt, RamonaRamonaEberhardtTünnermann, AndreasAndreasTünnermann2022-03-042022-03-042014https://publica.fraunhofer.de/handle/publica/23609810.1364/OL.39.003725In this Letter, we demonstrate a single-mode continuous-wave fiber laser amplifier emitting 146 W of average output power at a wavelength of 1009 nm. The wavelength and bandwidth of the seed oscillator are defined by a pair of fiber Bragg gratings. The seed is amplified in a two-stage ytterbium-doped rod-type amplifier to 146 W with a high slope efficiency of 64%, showing excellent beam quality and stability throughout the experiment. The ASE suppression is as high as 63 dB.en535journal article