Aleshire, C.C.AleshireSteinkopff, A.A.SteinkopffKarst, M.M.KarstKlenke, A.A.KlenkeJauregui, C.C.JaureguiKuhn, S.S.KuhnNold, J.J.NoldHaarlammert, N.N.HaarlammertSchreiber, T.T.SchreiberLimpert, J.J.Limpert2022-05-062022-05-062021https://publica.fraunhofer.de/handle/publica/41703110.1109/CLEO/Europe-EQEC52157.2021.95416582-s2.0-851204392092-s2.0-851176084362-s2.0-85117608436Multicore fibres (MCFs) with active doped cores are a promising technology to increase effective mode area and therefore available power and energy of fibre amplifiers and lasers, most recently demonstrated in coherently combined systems [1]. With ns-class pulses, energies of up to 26 mJ have been extracted from advanced fibre designs in multi-stage amplifiers [2]. Self-focusing at peak powers of around 5 MW limits the maximum pulse energy extracted from a single fused silica core, but MCF lasers potentially enable continued scaling beyond these limitations by distributing energy over many cores. Modelling of rod-type MCFs show potential to achieve multi-kW average power and Joule-class combined pulses from a 1 m long fibre [3]. In this submission, a Q-switched 16-core rod-type Yb-doped MCF is demonstrated, which can directly seed further MCF amplification stages without the need for fibre arrays or beam-splitting optics.en620conference paper