<p>A number of applications are growing day by day and so the traffic. The need for bandwidth is also increasing at a rapid rate. The bandwidth and speed with which data can be transferred was very less when compared to core networks. The access network which was once a bottleneck is no longer so because of use of optic fiber (FTTH networks). A number of variants of Passive Optical Network (PON) have been proposed like the WDM PON and the Hybrid PON. Hybrid PON is a combination of TDM PON and WDM PON and is advantageous over WDMPON. This paper focuses on high capacity networks that can provide high data rate and long reach in the access part of the network. NRZ modulation format is normally used for transmission.  We consider the advantages provided by the advanced modulation formats like DPSK. This modulation format is used to here and its benefits are evaluated in Hybrid PON network to increase the capacity and the reach of the network. Parameters like the BER and the Q factors are analysed using Optisystem Software. Distortion and the phenomena of dispersion can limit the performance of such a system. Hence Dispersion compensation mechanisms like the Dispersion Compensation Fiber (DCF) are used in the system to transmit data over large distance.</p>

This paper demonstrates the performance of erbium-doped fiber amplifier (EDFA) and avalanche photodiode receiver in a dynamic wavelength division multiplexing (WDM) system. A four channel 10 Gb/s system is taken into consideration, and the performance of EDFA is assessed. The experimental setup consists of a transmitter, a receiver, and two intermediate nodes. The transmitted system is tested for bit error rate and eye pattern at the receiver. The spectrum is also analyzed for different lengths of fiber. Add drop experiment was carried out on in which a laser source was switched on and off continuously to assess the transient response of WDM system. Then, the eye pattern is analysed in which EDFA system will provide a clear open eye with no degradation of signal.