Relaxation Dynamics of QDLs Subjected to External Effect (Optical Feedback)رسالة ماجستير

Abstract

In this study, we examine quantum dot lasers (QDLs) that utilize quantum dots as the active medium. QDLs work on the principle of tight confinement of charge carriers in quantum dots, and find a wide range of applications in medical imaging, sensing, quantum information processing and optical communications. Due to their vital role in optical communication and optical tomography in addition to the ability of high rates of data processing, new approaches are employed to enhance their performance. Our work focuses on the theoretical treatment of the optical feedback effects on the dynamics of QDLs using a rate equation approach. Analytical expressions for both relaxation oscillation (RO) frequency and damping rate are derived. In addition, the simulation method is used to compare our results with that for solitary lasers. It is found that optical feedback strengthens RO frequency and reduces the damping rate and factor as the injection rate increases, which indicates the decrease in system stabilities. Furthermore, a region of instabilities implies by positive damping rate is observed. Moreover, for negative detuning frequency, there is a region of bistability which makes the laser capable to use as optical switch and in optical data storing.