An ultrafast ytterbium-doped fiber laser system based on coherent beam combination of 16 amplifier channels is presented. The system delivers 1.83 kW average power at 2.3 mJ pulse energy and 240 fs pulse duration. The combining efficiency of 82% and the beam M2-value of 1.8 currently is limited by thermal lensing in some optical components, which were identified and are to be replaced.
