Abstract

Semiconductor laser diodes with external optical feedback (EOFSL) have found considerable interest within the last 10 years.^[1-5] This is due to the practical importance of this system as well as the EOFSL can serve as a model system for the investigation of the dynamics of nonlinear systems with infinite dimensions. EOFSL exhibit dramatical changes in the output behavior for specific values of the operation parameters.¹'¹ Several different regimes can be cathegorized according to the feedback level. For a low level of feedback the linewidth of the laser is reduced. At higher feedback levels the linewidth redution saturates and finally, there is an abrupt increase in the linewidth form some MHz up to several GHz, which is generally refered to as the coherence collapse. Experiments and numerical simulations have shown a quasi-periodic route^[2] as well as an intermittency route^[3] to chaos for the variation of the feedback level and the injection current, respectively, both serving as controlparameter.

© 1992 IQEC