Multi-10kW diode laser systems with wall-plug efficiency greater than 50%

We report on different approaches to increase the wall-plug efficiency of our high-power diode laser systems in the near infrared. At output-powers in the range from 10kW to 30kW we demonstrate a wall-plug efficiency from 49% to 51% at the operating point for fiber coupled industrial grade laser systems. Furthermore, we demonstrate a novel approach of a free space direct diode laser for drying applications with an output power of 12kW and a wall plug efficiency of 56%. The laser power is scalable to several tens of kW optical output power for intensities up to 200W/cm².