Müller, M.M.MüllerKlenke, A.A.KlenkeSteinkopff, A.A.SteinkopffShestaev, E.E.ShestaevTünnermann, A.A.TünnermannLimpert, J.J.Limpert2022-03-142022-03-142019https://publica.fraunhofer.de/handle/publica/40640210.1109/CLEOE-EQEC.2019.8871494Power scaling of ultrafast fiber lasers has been accelerated by coherent beam combination [1]. Persisting challenges regarding the average power, i.e. mode instabilities, or regarding the peak power, i.e. high nonlinear phase, can be easily overcome by using several parallel amplifiers in a stabilized interferometer configuration. In this contribution, we present a new record average power for ultrafast laser systems enabled by coherent beam combination and the use of partially-reflective dielectric mirrors as high-power compatible combining element.en620conference paper