Conducting single-transverse-mode operation with a wide tuning range in commercial multimode VCSELs by beam-profile-adapted optical feedback.

This research investigated the feasibility of employing beam-profile-adapted optical feedback to conduct commercial multi-transverse-mode vertical-cavity surface-emitting lasers (VCSELs) to emit a single transverse mode with a wide tuning range. Experimentally, for a VCSEL with its solitary spectrum consisting of almost no fundamental transverse mode, the fundamental transverse mode could be conducted to lase with a tuning range of about 1285 GHz and side-mode suppression ratio of around 20 dB. These results can greatly enhance the performance of VCSELs in many applications.