Nitride VCSEL design for continuous-wave operation of higher-order optical modes

Abstract

Anticipated performance of possible designs of nitride vertical-cavity surface-emitting lasers (VCSELs) has been analyzed and compared with the aid of an advanced 3D optical–thermal–electrical self-consistent simulation. It has been revealed in the simulation that, to achieve room-temperature (RT) continuous-wave (CW) VCSEL threshold operation, uniformity of both carrier-concentration and temperature-increase distributions within VCSEL active regions are equally important. Besides, mostly because of problems with an effective confinement of an optical field in a radial direction, RT CW lasing in standard nitride VCSELs is usually easier to achieve on higher-order transverse modes than on lower-order ones. Therefore, a novel design of nitride VCSELs with double (annular and central dot) p-side contacts has been intentionally constructed to enhance an excitation of low-threshold high-order transverse optical modes. Anticipated RT CW performance characteristics of the novel design have been proved to be definitely more promising than those of other possible configurations of nitride VCSELs. In particular, our calculations have confirmed that RT CW lasing is possible in this new nitride VCSEL. Besides, this device has been found to be less sensitive (than other nitride VCSELs) to possible crystal imperfections created around an active region while high-resistive areas are formed.