The emission of broad-area(BA)lasers always contains several lateral modes(along the junction plane)even at low drive levels, which lead to inferior beam quality. To increase the discrimination against high-order lateral modes, we developed a simple technique for depositing a profiled thin layer of SiO2 on the output facet of a broad-area laser that has a 100-μm-wide injection current stripe. The profiled coating provided a nearly Gaussian reflectivity in the lateral direction (parallel to the junction plane).The detailed fabrication processes are provided, measuring results and the beam quality of uncoated and coated lasers have been compared. The slope efficiency was achieved to 1.00W/A from0.84W/A. The angle of the farfield pattern narrowed so did the M2.A theoretical analysis on BA devices with the profiled reflectivity facet has been given, and the precision of the thin layer has been discussed . |