Single-mode operation and transverse-mode control in VCSELs induced by frequency-selective feedback

An experimental study of a vertical-cavity surface-emitting laser with frequencyselective feedback is reported. We show that we can force the laser to emit in its fundamental transverse mode or in a higher order transverse mode and that we can also control the polarization emitted in the fundamental one. We obtain single fundamental-mode operation within a large range of injection current values (almost ~2.5 I/sub th/) and a maximum optical power of 2.7 mW. In this current range, the output is found to be stable.