Abstract

High performance single-mode Vertical-Cavity Surface-Emitting Lasers (VCSELs) are of great interest for high speed, low-noise and low-cost optical interconnections However, the growth of these multilayer devices is complex. Indeed, they are composed of an optical cavity containing quantum wells (QWs) embedded between two high-reflectivity Distributed Bragg Mirrors (DBRs), respectively n and p-type doped for electrical injection. To obtain low resistivity mirrors, heterojunction band discontinuity effects must be minimized by for instance inserting a thin gradual composition layer at each heterointerface. Furthermore, p-type doped DBRs have to be grown at a much lower temperature than the one used for the QWs’region, in order to prevent any Beryllium diffusion. Finally, in these structures, the spectral alignment between the gain of the QWs and the single longitudinal Fabry-Perot resonance, which is very sensitive to errors on layer thicknesses, strongly influences the performance of the VCSEL. Thus, it is difficult to obtain high efficiency VCSELs without a high precision control on layer thicknesses. The control technique to be used must be real-time performed and versatile because of the varying growth conditions involved.

© 2000 IEEE