Comparative Simulation Analysis of Dispersion Mitigation Techniques Using Symmetrical-DCF, FBG and CFBG in High Speed DWDM Networks

The performance of the dense wavelength division multiplexing (DWDM) network is severely limited by the chromatic dispersion. So, it is crucial to mitigate and compensate this dispersion. In this paper, the different dispersion compensation techniques are discussed and compared. The DWDM system performance is evaluated by utilizing these dispersion mitigation techniques. The techniques used are dispersion compensation fiber (DCF) with symmetrical compensation scheme, Fiber Bragg Grating (FBG) and Chirped Fiber Bragg Grating (CFBG). The system performance is investigated for 16-channels DWDM network using Return-to-Zero (RZ) and Non-Return-to-Zero (NRZ) modulation formats over transmission distance up to 200 km at 2.5 and 5 Gb/s data flow rate per channel. The system performance is evaluated according to Quality factor (Q-factor), Optical Signal to Noise Ratio (OSNR) and Signal to Noise Ratio (SNR) through Eye Diagrams. The DWDM network is implemented by using Optisystem simulator. The simulation results are outlined in tables indicating the most efficient dispersion compensation technique. The simulation results revealed that the systems using FBG as dispersion compensator offers better performance and larger Q-factor especially for longer transmission distance. FBG achieved Q-factor of approximately 38 and 62 which are the larger Q-factor values compared to other dispersion compensation methods at data rate of 2.5 Gb/s over 200 km fiber length for NRZ and RZ respectively. Furthermore, as data rate increases, the performance is reduced adversely due to pulse broadening causing interference with adjacent channels. Finally, the systems using RZ format provides better performance than those that using NRZ although, NRZ has less pulse broadening due to its reduced bandwidth.