TRANSVERSE-MODE SELECTION IN EXTERNAL-CAVITY VERTICAL-CAVITY SURFACE-EMITTING LASER-DIODES

A theoretical study is performed of the multimode dynamics and steady- state transverse-mode selection in vertical-cavity surface-emitting la sers subject to weak optical feedback in an external-cavity configurat ion. Attention is focused on the competition between the two lowest-or der modes (LP(01) and LP(11) degenerate modes) appropriate to the chos en circularly symmetric vertical-cavity surface-emitting laser structu re. It is shown that preferential excitation of either mode can be eff ected by appropriate choice of optical feedback delay. Opportunities f or enhancing modal discrimination by adjusting the strength of optical feedback are also presented. (C) 1996 Optical Society of America.