Gigabit-capable PON is a fiber-based access technology that offers high bandwidth efficiently and cost-effectively. It comprises an optical line terminal (OLT), an optical splitter, and multiple optical network units (ONUs). The passive optical splitter/combiner distributes traffic from the OLT to the ONUs downstream and from the ONUs to the OLT upstream. The paper investigates the performance and power link budget of optical transmission systems, focusing on the challenges posed by increased user numbers and power consumption in modern optical fiber communication infrastructure. It evaluates the performance of Time Division Multiplexing (TDM) in gigabit-capable Passive Optical Networks (PON) for multiple users, considering a single operating wavelength, fiber cable length, and power across various scenarios for upstream and downstream transmission. The system is evaluated using Optisystem simulation software, focusing on bit error rate, Q-factor, and eye diagram results. The analysis shows improvements in power savings, balanced against potential network performance and PON architecture lifetime degradation. However, these degradations can be managed using the power-efficient TDM-GPON access technology for high bit-rate transmission.