Modal dynamics in semiconductor lasers: Bulk vs Quantum Well devices

In this work we analyze experimentally the modal dynamics of
multi-longitudinal mode semiconductor lasers for both bulk and
Quantum-Well devices. Modal switching is the dominant feature in both
cases. In bulk lasers, the dynamics is noise-driven and involves only
two main modes. On the contrary, in quantum-well lasers the dynamics
involves a periodic switching among several longitudinal modes
progressing in a well determined sequence from the bluest to the reddest
mode in the optical spectrum. We analyze the differences in modal
dynamics for these two kinds of laser by comparing the modal switching
statistics and studying the effects of noise and modulation in the
pumping current and the influence of weak optical feedback. A model for
the dynamics will be discussed.