Electro-absorption characteristics of InAs/InP quantum-dash lasers: A step towards monolithic integrated laser-modulator for next generation passive optical networks

The exponential increase in the bandwidth requirements due to various broadband triple-play services viz. voice, video and data, at the finger tips, over few years, is pushing the backhaul as well as last mile access networks towards their capacity limits. Hence, various standardizations to meet the next generation access network requirements has set forward, for instance, 100G Ethernet and 400G, which is under consideration. This requires to explore new and alternate networks and photonic device technologies that will enable sustainability with the exploding data traffic needs and meets the requirements of the future access networks. 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. In this research work, we aim to investigate the electro-absorption characteristics of a new class of InAs/InP quantum-dash based material. Quantum-dash nanostructures has already show tremendous potential as an active medium in light sources from high bit rate wavelength division multiplexed systems and passive optical networks. The inherent wide gain profile offered by these nanostructures, which covers CLU communication bands, has been exploited to demonstrate broadband lasers and optical amplifiers, employing simple device configurations, for easy in integration with the existing optical networks. Hence, this study would further reinforce employment of an integrated InAs/InP quantum-dash laser-modulator, enabling tens of Giga-bits-per-second transmission at the end user, which is currently struggling with the limit data rate offered by the direct modulation scheme. Moreover, other advantages of low-cost, small-foot print, and possibility of mass deployment of this device would qualify as a next generation access network transmitter device. Performance characteristics of an integrated laser-amplifier will also investigated, thus allowing to amplify the signal seamlessly and improve the signal to noise ratio, which would enable achieving higher data rates. The InAs/InP Qdash active region is a chirped barrier layer thickness structure. The two-section method will be employed to investigate the electoabsorption and amplification characteristics. In particular, device variables such as cavity length, section length, current injection into the laser section, reverse bias voltage of the modulator section, etc. would be investigated, along with the literature, to shed light into the device physics. Through this work would like to set a platform for the researchers to understand the fundamental physics of quantum-dashes 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.