Abstract

We investigated the origin of phase-locking efficiency degradation often observed in passively phase-locked laser arrays operating far from threshold. The experimental study was based on an elementary array of two Ytterbium-doped fiber lasers. The two amplifiers were implemented in parallel and the exiting beams were combined in free space through a beam splitter in a common unidirectional ring resonator. The coherent combining efficiency and the spectral behaviours were characterized at different pumping levels and for short or long cavity length mismatches between the two lasers.

© 2015 IEEE