Abstract

We study a multimode semiconductor laser subject to a moderate optical feedback with a time delay comparable to the relaxation oscillation periods. The laser total output exhibits low frequency fluctuations (LFF). This phenomenon is characterized by intensity dropouts with an average time between the dropouts much longer than the relaxation oscillation periods and mode beating characteristic times. Recent experiments demonstrate that the laser output can be multimode and display antiphase [1] . In that regime, the fast oscillation frequency is still controlled by the extra-cavity round-trip time, but the oscillation phases can vary from mode to mode. A phenomenological multimode description has recently been reported [2], leading to in-phase solutions for short external cavity.

© 2000 IEEE