Abstract: Orthogonal frequency division multiplexing (OFDM) is a modulation technique which is now used in most new and developing broadband wired and wireless communication systems. We propose WDM OFDM design to reach a data rate of 40 Gbps over 240 km optical fiber. 40 Gbps signal is generated by multiplexing four OFDM with 10 Gbps data rate for each OFDM. We present the performance of single OFDM system by measuring the BER and the constellation diagram. We will also check the performance of the CO-OFDM WDM system for 240 km by measuring the BER and constellation diagram.

Keywords: OFDM, WDM, BER, QAM, Optical Communication.