ANALYSIS OF ULTRA-BROAD STIMULATED EMISSION FROM SEMICONDUCTOR LASER COVERING L AND U BANDS

III-V compound semiconductors are of particular relevance due to their superior optoelectronic properties compared to the II-VI counterpart, mainly in light sources, covering a broad wavelength range from visible to mid-infrared range. This feature have attracted the scientific community and semiconductor lasers utilizing hetero-junction which is considered an important breakthrough, has been realized with bulk and later on the quantum confined active region, showing unprecedented improvement in the performance characteristics. Thanks to the progress in the crystal growth technology which made high quality ultra-thin layers (in nanometer range) growth possible, a requirement of quantum confinement behavior to materialize. Further improvements to the optoelectronic properties of laser devices such as low threshold, high temperature and high power operation by incorporating quantum confinements in two (quantum wires) and three dimensions [quantum dots (Qdot)] have also been demonstrated compared to the one dimensional confining quantum well (Qwell) counterpart. Recently, broadband lasing emission resulting from interband optical transitions via InAs/GaAs Qdot and InAs/InP quantum dash (quasi Qdots) active region based laser devices around O band and C L U bands (~ 1.3 m and ~ 1.6 m, respectively) have been demonstrated from a simple p-i-n heterostructure device. This new class of laser diodes displayed stimulated emission -3dB bandwidth of ~ 20 to 75 nm with output power 150 to 1000 mWs. This approach is shown to be compact and simple in device design by proper engineering of quantized energy states as well as utilizing the high inhomogeneity of the dot/dash nanostructures, which is inherent from self-assembled growth technology. The proposed research work focus on understanding the origin of broadband lasing from InAs/InP Qdash laser device qualitatively. For this, the broadband laser diodes will be characterized by identifying and varying different device variables such as operating temperature, ridge-width and device length comparison at elevated temperature, etc., to shed light on the carrier distribution and emission process. This will set a platform for the researchers to understand the device physics of broad emission laser diodes and optimize the active region device for eventual achievement of enhanced lasing bandwidth (~ 100 nm) and high performance (> 50% wall plug efficiency) devices. Highlighting the importance of such devices to the scientific community, they will find applications not only in optical communications (optical interconnects, next generation terra-bit applications) but also in in cross disciplinary field of spectroscopy, sensing, bio-imaging, metrology, etc. (as efficient and high power broadband light sources, thus improving the sensitivity and resolution of respective optical systems). 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 Photonics in Saudi Arabia.