Researcher Haneen Noman Jaradat, a student in the Master’s Program in Physics, has defended her thesis titled "Relaxation Dynamics in Quantum-dot Laser Subjected to External Effect (Optical Feedback)".
This research explores quantum-dot lasers that use quantum dots as active materials. Quantum-dot lasers operate based on tight confinement of charge carriers in quantum-dots, where a wide range of applications in medical imaging, sensing, quantum information processing and optical communications are found. Due to its vital role in disease treatment and optical imaging, in addition to its high capacity in data processing, new approaches are being used to improve its performance.
The researcher concentrates on the theoretical treatment of the dynamic effects of optical feedback using the rate equation approach. A mathematical formula was derived for both the relaxation oscillation and the damping rate. In addition, a simulation method was used to compare the results of this study with the result of a single laser. It was revealed that optical feedback enhances the relaxation oscillations and reduces the rate and damping factor by increasing the injection rate, resulting in decreased stability of the system. Moreover, it was found that there is an unstable region in the system indicated by a positive damping rate, and there is also a bi-stable region that allows the laser to be used as an optical switch and to store optical information.
The thesis was supervised by Dr. Muayad Abusaa and co-supervised by Dr. Adli Saleh. The committee of examiners included Dr. Mohammad Khalil and Dr. Suleiman Rabaa.