Description

The rapid growth in internet use has led to the requirement of much higher bit rates for home and office users and has increased the popularity of video-related services. Users have required at least 100 Mb/s bandwidth in recent years, and to provide this broadband service, several technologies such as digital subscriber and coaxial cable have been made available to subscribers. However, the bandwidth of copper wire is limited due to physical media constraints, and as a result optical access networks have been used to satisfy the required bandwidth. Time domain multiplexed (TDM) PONs is a cost-efficient solution for providing high bandwidth to users, but the bandwidth is still limited. Combining wavelength division multiplexing (WDM) with (TDM) PONs is very scalable and flexible network architectures are possible. Many researchers have demonstrated the effectiveness of the different architectures of WDM-PON and hybrid WDM/TDM-PONs. The existing technology is introduced to reduce infra-structure cost and the complexity of remote antenna units (RAU). In this project the system proposed a 2.5 Gb/s GPON downstream link, using the radio over fiber (RoF) technique in GPON network architecture. Within each group, four ONUs share one wavelength in a TDM mode. The TDM-PON downstream traffic is handled by broadcasts from the OLT to all connected ONUs. The system se the hybrid-WDM-TDM PON architecture combined with RoF technology, and compare the performance of network for 8-DPSK and 16-QAM digital modulation, for three data rates (2.5 Gbps, 4 Gbps and 5 Gbps), for 25 km optical fiber. The performance analysis is based on eye diagrams, constellation diagrams, OSNR, and received optical power. OptiSystem simulation software package is used for simulation.