Quantum dot semiconductor lasers with optical feedback

We analyse the sensitivity of quantum dot semiconductor lasers to optical feedback. While bulk and quantum well semiconductor lasers are usually extremely unstable when submitted to back reflection, quantum dot semiconductor lasers exhibit a reduced sensitivity. Using a rate equation approach, we show that this behaviour is the result of a relatively low but nonzero line-width enhancement factor and strongly damped relaxation oscillations. # 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1 Introduction The performance of quantum dot devices is presently the subject of great interest [1]. In particular, several studies have concentrated on the sensitivity of quantum dot semiconductor lasers to the influence of optical feedback [2, 3]. Unlike bulk or quantum well semiconductor lasers, these devices have symmetric gain curves [1] and experiments [4] have demonstrated very small phase-amplitude coupling (a-parameter). As the extra sensitivity of semiconductor lasers to feedback i