Effect of channel spacing and launch power on performance of DCF, FBG, and OPC based 8 × 10 Gbps DWDM optical transmission systems with nonlinear penalty analysis

In this paper, three dispersion compensation techniques – dispersion compensation fiber (DCF), fiber Bragg grating (FBG), and optical phase conjugation (OPC) – are used to analyze the performance of 8 × 10 Gbps dense wavelength division multiplexing (DWDM) optical transmission systems under various channel spacing conditions. The proposed system is designed for 50 GHz, 100 GHz, and 200 GHz channel spacing over a 150 km single mode fiber (SMF) transmission distance using OptiSystem software. Simulation studies show that OPC outperforms DCF (17.15 dB) and FBG (8.63 dB) at 10 dBm input power, achieving a quality factor (Q-factor) of 34.16 dB at 100 GHz channel spacing. FBG offers a maximum optical signal-to-noise ratio (OSNR) of 25.24 dB compared to DCF and OPC due to its low insertion loss and passive design, while OPC offers the best bit error rate (BER) of 2.68E-256 compared to DCF (2.04E-66) and FBG (2.41E-18) at 100 GHz spacing. System performance is assessed with and without self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM) effects to analyze nonlinear penalty for DCF and OPC approaches. OPC reduces the nonlinear penalty by 75.6 % at +10 dBm input power (0.70 dB) compared to DCF (2.87 dB), demonstrating better nonlinearity compensation through phase conjugation.