Loss tailoring of high-power broad-area diode lasers

Broad-area diode lasers (BALs) with high power are highly desirable for a variety of applications. However, such lasers suffer from strongly deteriorated beam quality due to multimode behavior in the lateral direction. In this Letter, we present an approach to flexibly tailor the optical loss of different-order lateral modes by etching micro-holes on the laser mesa with controlled position and numbers. Through arranging the micro-holes at the peak positions of high-order lateral modes with an increasing number from the mesa center to both edges, high-order modes are suppressed due to a larger propagation loss than the fundamental mode. As a result of enhanced mode discrimination, we demonstrate that this technique provides a greatly improved beam quality and about two times higher brightness for 100 μm wide BAL, while maintaining high power and slope efficiency output.