Dynamics of a semiconductor laser with optical feedback

We investigate both experimentally and theoretically the dynamics of a semi conductor laser with optical feedback in the low-frequency fluctuation regi me. First we demonstrate that low-frequency fluctuations can be observed fo r both single and multimode operation of a semiconductor laser with optical feedback. The analysis of the fast dynamics associated with this low-frequ ency instability is well described by single-mode rate equations. In the mu ltimode regime, fast pulsation is observed in every laser mode. In this cas e the fluctuations in total intensity are much smaller than those in the in tensity of each individual mode, This indicates the presence of anticorrela tions dynamics at high frequency between the different laser modes. [S1050- 2947(99)08307-9].