Eureka! Institutional Repository

With the increasing demand for high-speed broadband access, Wavelenght Division Multiplexing- Passive Optical Network (WDM-PON) architectures have emerged as promising solutions to deliver high-capacity and scalable optical communication services to end-users. In WDM-PONs, the choice of digital modulation plays a critical role in determining the system performance, including bandwidth efficiency, signal quality, and cost-effectiveness. This paper presents a comparative study of different digital modulations employed in WDM-PON optical networks, focusing on their advantages, limitations and trade-offs. The study investigates six different digital modulations, in a 16-channel WDM. Those are: RZ (Return to Zero), NRZ (non-Return-to-Zero), SCRZ (Carrier-Supressed-Return-to-Zero), DuoBinary, DPSK (Differential-Phase-Shift-Keying) and DQPSK (Differential-Quandrature-Phase-Shift-Keying). Each modulation is evaluated based on key performance metrics such as transmission distance and power budget. Additionally, the impact of digital configurations on system complexity, cost, and scalability is analyzed to provide insights into practical development considerations. Through simulation-based analysis and experimental validation, the comparative study highlights the strengths and weaknesses of these different modulations in WDM-PON optical networks. Finally it examines how factors such as network topology and service requirements influence the choice of modulation and its implications for system performance.