Abstract

The recent rapid advances in performance of vertical cavity surface emitting lasers (VCSELs) have permitted consideration to be given to novel applications of such devices in, for example, optical data links and two-dimensional optical switching. In such applications consideration must be given to the effects of optical feedback on device operating characteristics. The transverse mode structure of stand-alone . VCSELs has been studied quite extensively but modifications of that mode structure due to optical feedback have received rather less attention. This contribution reports a theoretical study which has been performed of the multimode dynamics and steady state transverse mode selection in Vertical Cavity Surface Emitting Lasers (VCSELs) subject to weak optical feedback in an external cavity configuration. Attention is focussed on the competition between the two lowest order modes (LP₀₁ and LP₁₁) appropriate to the chosen circularly symmetric VCSEL structure. It is shown that preferential excitation of either mode can be effected by appropriate choice of optical feedback delay. Opportunities for enhancing modal discrimination by adjusting the strength of optical feedback are also

© 1996 Optical Society of America