Low frequency fluctuations and locked states in a multi-mode semiconductor laser with external cavity

The low frequency fluctuations (LFF) in a multi-mode semiconductor laser in an external cavity is investigated experimentally and theoretically. The results of the dynamical behaviors not only of the total intensity but also of a few frequency resolved dominant modes of the solitary laser are presented. We demonstrate experimentally and numerically that the so-called locked state (synchronous Sisyphus effect) we reported previously in which the dropout events occur with a high degree of periodicity persists even when the laser operates on a large number of solitary cavity modes. We show that slow energy transfer between solitary modes is a common effect when the laser undergoes LFFs or is in the locked state and that this effect is predicted by the multi-mode Lang-Kobayashi equations to be noise driven. (C) 2001 Elsevier Science B.V. All rights reserved.