High power self-organized coherent beam combination of 1018 nm Yb-doped fiber lasers

A pair of fiber lasers with high output power and low quantum-defect at 1018 nm was demonstrated. These two 1018 nm fiber lasers were used as the source of Michelson cavity to show experimentally that a coherent beam combination of two Yb-doped double-cladding fiber lasers using all-fiber Michelson cavity technique was achieved. We obtained an output power of 55 W with a coherent combination efficiency of 90.2%, which is the highest output power that single-mode 1018 nm fiber lasers have obtained so far. Moreover, we proved that coherent beam combination by using Michelson cavity can achieve high power single-mode output of fiber laser.