Müller, M.M.MüllerAleshire, C.C.AleshireKlenke, A.A.KlenkeHaddad, E.E.HaddadLegare, F.F.LegareTünnermann, A.A.TünnermannLimpert, J.J.Limpert2022-03-062022-03-062020https://publica.fraunhofer.de/handle/publica/26343210.1364/OL.392843An ultrafast laser delivering 10.4 kW average output power based on a coherent combination of 12 step-index fiber amplifiers is presented. The system emits close-to-transform-limited 254 fs pulses at an 80 MHz repetition rate, and has a high beam quality (M2<1.2) and a low relative intensity noise of 0.56% in the frequency range of 1 Hz to 1 MHz. Automated spatiotemporal alignment allows for hands-off operation.en620535journal article