976nm high brightness fiber-coupled laser modules for ytterbium fiber laser pumping

Multi-kilowatt, continuous-wave fiber lasers continue to drive the need for higher power, higher brightness, and more efficient diode laser pump modules. It is well documented that increases in pump module power either enable higher power CW fiber lasers or minimize complexity of the multi-stage fiber combiners for a given power. Additionally, increasing pump module brightness positively impacts the SRS threshold of a given multi-kilowatt CW fiber lasers architecture. We report on the continued progress by nLIGHT to develop and deliver the highest brightness diode-laser pumps using single-emitter technology at 976 nm for Ytterbium fiber laser pumping. Building upon our prior developments that have enabled higher emitter counts in the element® packages, nLIGHT is releasing two new 976 nm module configurations: a 2×7 module with 155 W into 105 μm – 0.15 beam NA, and a 375 W 2×12 into 200 μm – 0.16 beam NA. Additionally, we have demonstrated high efficiency designs utilizing a new chip on submount (COS) architecture: with a 430 W 2×12 into 200 μm – 0.16 beam NA and 57% electro-optical efficiency, and an alternative 2×15 design resulting in 600 W at 57 % electro-optical efficiency at 23 A when coupled into 200 μm – 0.18 beam NA.