Coherence collapse and redshifting in vertical-cavity surface-emitting lasers exposed to strong optical feedback

The response of a commercial-grade, single-mode vertical-cavity surface-emi tting laser to very strong optical feedback is investigated. With increasin g feedback magnitude, the lasing spectrum broadens dramatically, eventually resulting in coherence collapse, and the lasing peak shifts to longer wave lengths. These effects became less severe with the onset of higher-order mo des. A theoretical model is provided to explain the redshifting of the lasi ng spectrum with feedback. (C) 2001 American Institute of Physics.