Schmidt, O.O.SchmidtWirth, C.C.WirthTsybin, I.I.TsybinSchreiber, T.T.SchreiberEberhardt, R.R.EberhardtLimpert, J.J.LimpertTünnermann, A.A.Tünnermann2022-03-042022-03-042009https://publica.fraunhofer.de/handle/publica/21878310.1364/OL.34.001567We report on spectral combination of four high repetition rate 5 ns pulsed Yb-doped fiber amplifiers at 1 mu m wavelength. The output beam is spatially and temporally superposed by use of an all-reflective diffraction grating. 1.1 kW average power and 220 mu J pulse energy were extracted with a combining efficiency of 99%.enphotonic crystal fiberdoped fiberlaserarea620535journal article