The continued rise of high-average power femtosecond lasers is enabling new possibilities in precision manufacturing but also introducing critical challenges. At power levels reaching hundreds of watts and pulse energies of several hundred microjoules, issues such as local fluence control, beam uniformity degradation, and thermal lensing inducing phase distortions have become major obstacles to high-quality processing. In addition, thermal load management on the workpiece (Heat affected zone) - previously negligible at moderate power - is now crucial to ensure stable and reliable operation.

This paper discuss how to overcome these challenges with appropriate beam-shaping. We explore the performance limits of a combined system, integrating a beam shaping (square top-hat) module including mode-cleaning (passive beam stabilization) and a beam splitting (9x3 pattern with different pitch in w=x and y to optimize the process speed and quality) module together. Together, they enable the simultaneous shaping and multi-channel distribution of high-energy ultrafast pulses, driven by a Tangor 300 W, 300 µJ laser. Through this approach, we demonstrate that beam quality can be preserved, fluence profiles optimized, and parallel processing capabilities unlocked—contributing to the removal of key technological bottlenecks in high-power femtosecond micromachining. We will discuss the shape criteria, and how stable they are at higher power, and discuss the challenges to overcome through the whole optical chain.