790 W incoherent beam combination of a Tm-doped fiber laser at 1941 nm using a 3 × 1 signal combiner.

ABSTRACT

In this paper, we report on a high-power incoherent beam combination of three Tm-doped fiber amplifiers at 1941 nm based on a 3×1 signal combiner. An output power of 790 W is achieved from the signal combiner with a slope efficiency of 52.2% with respect to the launched pump power and a beam quality factor M2 of 2.7. The beam quality factor is close to the theoretical limit of the 3×1 fiber combiner. The parameters of the amplifier are optimized to increase the laser efficiency. Our analyses show that this structure is sufficient to support kilowatt-level output power while maintaining the high beam quality.