DSP-Based Compensation of Signal Impairments in High-Speed Optical Access

As high-speed networks continue to grow, bringing Fiber-to-the-Home (FTTH) via Passive Optical Networks (PONs) into urban homes is becoming the norm. To meet the growing demands at all levels of the network, PONs are evolving to support faster data rates. Recently, the industry has advanced to systems that can handle 50 Gbps per wavelength. These systems mainly rely on a combination of intensity-modulation (IM) and direct detection (DD), which are not only simpler but also more cost-effective compared to the more intricate coherent systems. This affordability is crucial as it makes high-speed optical access more accessible, especially where budget is a concern. Looking ahead, the need to support emerging technologies like 5G and 6G is driving the push towards developing PON systems that can deliver speeds of up to 200 Gbps per wavelength. This jump in capability presents significant challenges, especially in keeping the existing DD systems affordable and compatible with older PON technologies. Here, IM-DD systems play an essential role due to their affordability and simpler architecture, making them ideal for widespread implementation required to keep up with increasing data needs. A primary challenge in this evolution is managing the significant effects of chromatic dispersion on the quality of data transmission. This thesis addresses these challenges by delving into the effects of various signal impairments, with a particular focus on chromatic dispersion, and proposes strategies to mitigate their impact. It also fine-tunes DSP (Digital Signal Processing) parameters to effectively pre-compensate for and mitigate these issues. Additionally, the research takes into account scenarios involving multiple users to ensure that the network remains reliable for everyone. By striking a balance between theoretical research and practical tests, this study uses simulations to test the effectiveness of proposed solutions and carries out detailed experiments to confirm that these strategies hold up under the pressures of real-world use. These comprehensive evaluations cover both individual and multiple-user situations, thoroughly assessing how well the system performs and how robust it is. The findings contribute significantly to the field of optical communications, setting the stage for further research to enhance and streamline high-speed PON systems. The strategies and knowledge gleaned from this work are poised to drive forward the development of advanced optical network technologies, pushing the limits of what’s possible in high-speed optical transmission, all while keeping an eye on cost-effectiveness through the continued use of IM-DD technologies.