Pump block combines diodes for 350 W output

Designed and built with laser-diode chips from Bookham’s High Power Laser facility (Zurich, Switzerland), a pump block launched by Visotek (Livonia, MI) delivers 350 W at 976 nm from a single fiber with a 200 μm core diameter and 0.2 numerical aperture. The block combines the output from two modules, each with 44 single 7.5 W laser-diode chips that are polarization multiplexed. The proprietary design—developed using technology from the Fraunhofer USA Center for Laser Technology (Plymouth, MI)—results in a two-dimensional array with 88 total single-emitter diodes that eliminates all beam-shaping optics and uses only collimation lenses for both axes and a single focusing lens. Because the individual laser diodes are operated at 7.5 W, well below the more than 10 W that can be achieved for these diodes, the pump block is specified for a long operational lifetime. Such high-power output from a single fiber can be applied to materials processing applications, and offers a fast track to researchers developing new fiber and solid-state laser designs by providing a compact “off-the-shelf” pump source. Contact Andy Held at [email protected].