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 t he top surface of the laser into a dome shape by chemical etching. Thi s reduces the reflectance of the top mirror over an approximately annu lar region, thereby reducing the lasing area compared to the contact a rea in a controlled manner. A sevenfold reduction in threshold current over equivalent conventional VCSELs is demonstrated for a nonoptimize d device that maintains a similar threshold current density. (C) 1995 John Wiley & Sons, Inc.