Quantum-dash nanostructure based monolithic tunable semiconductor lasers and ultra-broadband lasers for green optical communications

The remarkable increase in the use of wireless services such as video streaming, gaming, and social media services, to name only few, over few years, to fulfill the demand of subscribers, is rapidly pushing the existing optical networks to work at their capacity limits. This trend has put forth the standardization of 100G Ethernet recently, and hence urgently need novel network architectures and photonic device technologies that will enable sustainability with the exploding data traffic needs. Moreover, achieving higher data rate with minimum cost upgrade and mass deployment in the communication systems, are the key requirements, that necessitates considering novel transmitters and receivers which forms the backbone of the optical networks. The proposed research work focus on investigating two such novel light sources, namely, monolithic tunable lasers and multi-segment broadband lasers. These devices exploits the inherent wide gain spectrum of quantum-dash (Qdash) nanostructure based active region covering CLU communication bands, while retaining simple device configurations, to be able to integrate effortlessly in the next generation optical networks. Two different active region designs are considered, first, a fixed barrier thickness multi-stack Qdash-in-well structure, and second, a chirped structure (i.e. the barrier thickness is varied across the multi-stack Qdash-in-well structure to intentionally disperse the optical transitions). The multi-section lasers are fabricated and characterized to extract their performances. Later, monolithic tunable lasers and multi-segment broadband lasers are studied thoroughly by varying different device variables such as cavity length, section length, current injection, etc. and compared across the two active region designs, along with the literature, to shed light into the device physics particularly concentrating on the carrier distribution and emission process. Through this work we not only aim to demonstrate novel devices but also to set a platform for the researchers to understand the fundamental physics of broad emission and enable them to design efficient devices. Apart from the research contents, the project also aims at strengthening Photonics research, particularly in the field of optoelectronic devices, in the department of Electrical Engineering (EE), King Fahd University of Petroleum and Minerals (KFUPM). This will facilitates the undergraduate/graduate students to appreciate the field of Photonics and also reinforce the department and KFUPM research competency in both, accommodating other research projects, and training students for fast growing job market of the important technological field of Photonics in Saudi Arabia.