Abstract

We present an experimental study of the spatial coherence properties of Broad-Area Vertical-Cavity Surface-Emitting Lasers (BA-VCSELs). In particular we demonstrate that the spatially incoherent emission regime [1] that can be invoked in pulsed operation stems from two different thermal effects: thermal lens and thermal chirp. We have separately measured the influence of these effects on the appearance of the spatially incoherent emission by pre-installing a thermal lens through a current bias and subsequently modulating a pulse onto the bias. By means of a differential method we are able to analyze the emission character during the additional current pulse alone.

© 2009 IEEE