In this paper, we compare the performance of WDM-PON system for NRZ and RZ data formats operating at bit rates up to 20Gb/s by varying fiber length. It is observed that the multicast signals can be delivered to the designated subscribers with acceptable performance almost upto 45km. At Optical Network Unit (ONU), upstream data can be remodulated on the downstream wavelength by using Array Wave Guide (AWG). It is found that the performance of the NRZ data format is better at low bit rates, Further it is reported that system gives optimum performance for the middle channel due to lower interchannel interference. The upstream signals can be effectively transmitted up to 20Gb/s, however downstream signals can be transmitted only at 2.5Gb/s. The faithful transmission of signal can be carried up to 50km for upstream and 60km for downstream, as the Bit Error Rate (BER) rises above 10
beyond this distance.