# Adaptive Equalization for Dispersion Mitigation in Multi-Channel Optical Communication Networks
## 4 Results and Discussion  
This section explains the obtained results from the proposed model. The simulations were performed using Optisystem, which enables designing, analyzing, and simulating optoelectronics and fiber optics used in OCNs. Moreover, it provides scalability through the ease of connection with other softwares such as MATLAB. EE is one of the important parameters which exists in Optisystem software. FFE and DFE techniques are applied by using EE element, whose purpose is to mitigate CD and PMD impairments. The solutions of the proposed model enable high spectral efficiency and flexibility to up-scale the system. The parameters used for the proposed OCN are listed in Table 1.  
The graphical results of the simulation data and comparison with and without equalization OCN with 10, 40 and 60 Gbps data rates are presented in Figures 7-9. For transmission distance beyond 300 km on a SMF, the results compare received power with BER without and with equalization in Figure 7a-c for 10, 40 and 100 Gbps data rates, respectively. The results show that EE achieves performance gain above 3 dBm for BER between \(10^{-5}\) and \(10^{-16}\) as compared to an OCN without equalizer after 100 km transmission distance. Similarly, Figure 8a-c shows results in terms of BER against transmission length. The results are compared with and without DEF/FFE employed networks at 10, 40 and 100 Gbps speed. From these results, it is clear that the value of BER rises with increasing transmission fiber length. The results also indicate that the performance of the proposed system with set of equalizers is more efficient than without equalizer. Without equalization, the system performance degrades significantly after 100 km length of fiber. Without equalizer, the achieved BER for transmission distance of 50 km is recorded above \(10^{-17}\). However, in contrast, our results show BER below \(10^{-22}\). This is beneficial in terms of high data rate transmission. These figures indicate that the performance gain of the proposed OCN at 10, 40 and 100 Gbps speed are better than without equalization OCN. Figure 6: Decision feedback equalization. Figure 7: BER comparison with received power with and without equalization: (**a**) at 10 Gbps data rate; (**b**) at 40 Gbps data rate; and (**c**) at 100 Gbps data rate. Figure 8: BER vs. transmission fiber length for the two cases (with and without equalization) (**a**) at 10 Gbps data rate; (**b**) at 40 Gbps data rate; and (**c**) at 100 Gbps data rate. Moreover, we analyzed OCN performance in terms of Q-factor with and without equalization at 10, 40 and 100 Gbps data rates. The results of the proposed OCN are presented in Figure 9a-c in terms of Q-factor against length of the fiber at 10, 40 and 100 Gbps, respectively. The results are accurate below 100 km due to fewer dispersion losses in the considered OCN. Dispersion of the system depends upon the length of the fiber, and rises as the length of the fiber increases, and, hence, the system performance degrades. It is evident from the results in Figure 9a that CD and PMD losses are treated up to 300 km of length with less error by using DFE/FFE based techniques. Similarly, Figure 9a-c displays that the CD and PMD effects become severer at higher data rates. It is also evident from the figures that the tolerance against CD and PMD effects are stronger as compared to the OCN without equalization. Furthermore, Figures 10 and 11 present eye-diagrams of the results. These open eye-diagrams show improvement in the quality of the received signal. The behavior of the proposed system performance can also be viewed from these eye-diagrams. In these diagrams, many signals are superimposed on each other. From its appearance, various parameters such as noise, jitter, ISI, and signal distortion are estimated. The clear and wide eye shows that efficient and error free transmission has been achieved from the proposed set up.