128-QAM x 8 Channels DWDM Communication for Optical Fiber Networks

Dense Wavelength Division multiplexing (DWDM) is a promising technology that has ability to provide potentially unlimited transmission capacity to meet the growing demand of bandwidth in optical fiber communication systems. In this paper, we have proposed a dual polarized 128-QAM DWDM communication system consisting of 8 channels. The data rate of each channel is set to 90 Gbits/sec and simulations are carried out by using single mode fiber (SMF) of 80 km. Dispersion compensation fiber (DCF) of appropriate length is used for dispersion compensation. Linear impairments are controlled by using appropriate optical amplifier in addition to the DCF. The model is tested by varying the data rates, length of SMF and filter gain. Lumped and distributed configurations of amplifiers are used to find the optimal results. Comparison of Gaussian and Bessel optical filters is also made in the proposed system. The results are presented by using constellation diagrams, EVM and BER plots in licensed version of Optisystem v.14.