Scaling up the average power and pulse energy of ultra-short-pulse lasers is one of the main topics in laser physics. At Helmholtz Institute Jena, we are interested in fiber-based laser sources. A variety of approaches are investigated, which can and are being combined in a single system to provide ultra-short high-energy pulses at high repetition rates and average powers. This makes these systems suitable for applications like high harmonic generation (HHG) that require high peak powers to work, while the high repetition rates compensate for the low conversion efficiency.