Designing and Improving NG-PON2-RoF with Inelastic Scattering and Nonlinear Impairments by Signal Processing Techniques

In the recent years, there has been an unpredicted increase in data transmission. To cope with this increase, a reliable technology is required. The next-generation passive optical network 2 (NG-PON2) was used in integration with future technology that works on radio over fiber (RoF). However, the optical communication system is subject to the following nonlinear effects: Self-phased modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM), stimulated Brillouin scattering (SBS), and stimulated Raman scattering (SRS). These effects are dominant, and they risk the performance of the optical fiber system. Therefore, digital signal processing (DSP) technique is used in this study to minimize and offset the nonlinear effects. In this study, three digital filters working on (DSP) are compared for the same data transmission rate at different distances from the transmitter without using compensation techniques. The results were compared by bit error rate (BER) and the error vector magnitude (EVM). Thus, the error vector magnitude (EVM) was noticed to be ~19.58% without using DSP. Nonlinear effects were mitigated by filters of Gaussian, Bessel and DSP-64QAM raised cosine to ~9.09%, ~14.22% and ~17.54%, respectively. Hence, the bit error rate (BER) of the best technique after comparison was minimized to DSP-64QAM raised cosine. It occurred after minimizing the nonlinear effects as 1.11E−14 at a distance of 40 km and 100 km. The BER value was 3.43E−10, which is within the acceptable values of performance for the proposed optical communication system with nonlinear effects. The system was simulated using the optical simulator optisystem 15.