Multiplexing techniques in optical communication systems need to be carefully examined because of the growing need for high-speed data transmission across long distances. The performance of Time Division Multiplexing and Wavelength Division Multiplexing in long-haul optical communication scenarios is the main emphasis of this study's thorough comparison of the two technologies.Signal integrity, dispersion control, and overall system efficiency are all examined in the study, which clarifies the complex trade-offs that are present in each multiplexing technique. A combination of theoretical analysis and simulations is used in this research to examine the performance of WDM and TDM across long fibre links with the goal of a comprehensive evaluation. Quality of signal, reach, and susceptibility to dispersion effects are the main criteria that are taken into account. Initial findings highlight WDM superiority in preserving signal integrity over long distances.WDM outperforms TDM under comparable conditions, this system attains BER of 5.02E-14 and a Q-factor of 7.1 at a distance of 135 km of fibre link.The study clarifies the subtle effects of dispersion compensation strategies, demonstrating how they could improve both multiplexing methods' performance.The paper examines the nuances of both the WDM and TDM methodologies.For network architects and researchers who are trying to decide which multiplexing strategy is best for long-haul optical communication networks, it offers insightful information. by providing a detailed knowledge of the parameters impacting the decision between WDM and TDM in the context of extended reach applications,the research adds to the continuing conversation on the design and optimization of optical networks.