Single 1-cm diode-laser bar emits 267 W

Scientists from the Fraunhofer-Institut (Munich, Germany) have built a monolithic diode-laser array that produces a record continuous-wave 980-nm output power of 267 W at a current of 333 A from a single 1-cm bar.

According to the group, whose results were announced at Photonics West 2000 (San Jose, CA) last January, wall-plug efficiency is 40%, and the average power density in the active area at the facet is 9.5 MW/cm². The bar--which has a fill factor of 50% and comprises 25 broad-area lasers with 200-?m aperture and 2-mm resonator length--is mounted on a microchannel copper heat sink having a thermal resistance of less than 0.29 K/W.

At 150-W optical output power, wall-plug efficiency increases to 50%, with a corresponding slope efficiency of 0.9 W/A. Although reliability data are not yet available, such arrays will be used eventually for pumping solid-state lasers and for materials processing. Because fewer diode-laser bars are needed to achieve a desired output power level, significant cost reductions for mounting, optics, and complete laser systems are expected. Contact Jürgen Braunstein at [email protected].