Wafer-Scale Method of Controlling Impurity-Induced Disordering for Optical Mode Engineering in High-Performance VCSELs

Abstract

Impurity-induced disordering (IID) provides a wafer-scale method of enhancing the performance of vertical-cavity surface-emitting lasers (VCSELs) for applications requiring higher output power in a specific optical mode. IID has been demonstrated to achieve higher optical power, faster modulation, and single-mode operation in oxide-confined VCSELs. Through the formation of an IID aperture, spatial control of mirror reflectivity can be selectively used to increase the threshold modal gain of only selected optical modes. However, these IID apertures have been limited by the lack of a method to control the shape of the diffusion front. For maximum laser mirror loss, IID apertures employed for mode-control require deep disordering. Consequently, significant lateral diffusion can be present that undesirably increases the lasing threshold for the fundamental mode. A manufacturable method is presented for controlling the shape of the IID aperture diffusion front by tailoring the strain of the diffusion mask. Experimental analysis to determine an optimal IID aperture size for single-mode high-power operation is next discussed. Numerical analysis of the mirror losses induced and consequent reduction in supported higher order modes as a result of the IID aperture is then presented.