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Reconfigurable multi-carrier transmitters and their application in next generation optical networks

Lakshmijayasimha, Prajwal Doddaballapura orcid logoORCID: 0000-0002-3381-3337 (2022) Reconfigurable multi-carrier transmitters and their application in next generation optical networks. PhD thesis, Dublin City University.

With the advent of new series of Internet services and applications, future networks will have to go beyond basic Internet connectivity and encompass diverse services including connected sensors, smart devices, vehicles, and homes. Today’s telecommunication systems are static, with pre-provisioned links requiring an expensive and time-consuming reconfiguration process. Hence, future networks need to be flexible and programmable, allowing for resources to be directed, where the demand exists, thus improving network efficiency. A cost-effective solution is to utilise the legacy fibre infrastructure more efficiently, by reducing the size of the guard bands and allowing closer optical carrier spacing, thereby increasing the overall spectral efficiency. However, such a scheme imposes stringent transmitter requirements such as frequency stability, which would not be met with the incumbent laser-array based transmitters. An attractive alternative would be to employ an optical frequency comb (OFC), which generates multiple phase correlated carriers with precise frequency separation. The reconfigurability of such a multi-carrier transmitter would enable tuning of channel spacing, number of carriers and emission wavelengths, according to the dynamic network demands. This research thesis presents the work carried out, in the physical layer, towards realising reconfigurability of an optical multi-carrier transmitter system. The work focuses on an externally injected gain-switched laser-based OFC (EI-GSL), which is a particular type of multi-carrier source. Apart from the detailed characterisation of GSL OFCs, advances to the state of the art are achieved via comb expansion, investigating new demultiplexing methods and system implementations. Firstly, two novel broadband GS-OFC generation techniques are proposed and experimentally demonstrated. Subsequently, two flexible and compact demultiplexing solutions, based on micro-ring resonators and laser based active demultiplexers are investigated. Finally, the application of a reconfigurable multi-carrier transmitter, employed in access and data centre networks, as well as analog-radio over fibre (A-RoF) distribution systems, is experimentally demonstrated.
Item Type:Thesis (PhD)
Date of Award:November 2022
Supervisor(s):Anandarajah, Prince and Kaszubowska-Anandarajah, Aleksandra
Subjects:Engineering > Optical communication
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Engineering and Computing > School of Electronic Engineering
Funders:Science Foundation Ireland
ID Code:27686
Deposited On:10 Nov 2022 16:29 by Prince Anandarajah . Last Modified 10 Nov 2022 16:29

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