Optical feedback sustained self-pulsations in semiconductor lasers

In this work we study the dynamics of a single-cavity semiconductor laser device, able to work in self-pulsating regime as a consequence of a nonlinearity distributed in the whole active region and driven by the electromagnetic-field intensity in the laser cavity. Numerical values of the nonlinearity degree necessary to establish the self-pulsating regime are given which can be used for a comparison with experimental measurements of semiconductor materials properties. The optical feedback influence on the self-pulsating device is also studied showing how pulsation characteristics are affected by the presence of a reflected signal and pointing out the feedback ability to cause their generation or quenching. The possibility of using current and optical feedback for the pulsation characteristics control and for the switch of the laser output is discussed. © Società Italiana di Fisica.