Statistical properties of low-frequency fluctuations during single-mode operation in distributed-feedback lasers:: experiments and modeling

Extensive experimental and numerical investigations of feedback-induced instabilities in single-mode distributed-feedback lasers are presented that confirm the basic assumptions of the Lang-Kobayashi model. We give experimental evidence of the occurrence of low-frequency fluctuation (LFF), alternation between LFF and stable emission, and coherence collapse during single-mode operation of the laser. We have obtained quantitative agreement between modeling and experiment in long-time statistical investigations of the time intervals between subsequent LFF dropouts. In particular, we show that even the dependence of the dynamics on the injection current, which results in a scaling law, is quantitatively identical in modeling and experiment. (C) 1999 Optical Society of America. OCIS codes: 140.5960, 140.1540.