Structured mirrors supporting phase-locking and beam-shaping of a multicore fiber laser

Summary form only given. Summary for only given. Multicorefiber lasers (MCF) present an interesting approach to design short-length, high-power fiber-lasers. In this concept not one but many active waveguiding microcores are placed on a ring inside a large pump core. The microcores form a circular laser array. The geometry is optimized for diode pumping Nd-doped MCFs with a length of just 50 cm, absorbing more than 95% of pump radiation, emitting 26 W output power at a slope efficiency of 37% have already been realized. We report on a new mirror design combining the features of increasing intermodal discrimination and beam shaping in one element.