Abstract: Coherent optical orthogonal frequency division multiplexing (CO-OFDM) system with dense wavelength division multiplexing (WDM) was analyzed to reach high data rates of 1.60 Tb/s over 4500 km single mode fiber (SMF). 1.60Tb/s signal was generated by multiplexing 16 OFDM signals with 100 Gb/s for each signal. The system performance has been studied by measuring optical signal to noise ratio (OSNR) of each WDM channel, bit error rate (BER) and signal to noise ratio (SNR). It was found that as the BER decreased both OSNR and SNR was increased.