Reduced-threshold-current vertical cavity surface-emitting laser

A simple method for reducing the threshold current of vertical cavity surface-emitting lasers (VCSELs) is described. The approach modifies the top surface of the laser into a dome shape by chemical etching. This reduces the reflectance of the top mirror over an approximately annular region, thereby reducing the lasing area compared to the contact area in a controlled manner. A sevenfold reduction in threshold current over equivalent conventional VCSELs is demonstrated for a nonoptimized device that maintains a similar threshold current density. © 1995 John Wiley & Sons, Inc.