Design and Performance Analysis of Ultra-Long-Haul DWDM RFoF Systems Using EDFA and Raman Amplifiers under Variable Launched Power Levels

The research explains the design and simulation of a Dense Wavelength Division Multiplexing (DWDM) Radio Frequency over Fiber (RFoF) system. The performance of a 64channel system with a total data rate of 2.56 Tbps was examined for long-haul transmission over 500 km and more distances. Erbium-Doped Fiber Amplifiers (EDFAs) and Raman amplifiers were used adaptively at different locations to prevent signal distortion. At the same time, the effects of launching power changes (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0 \text{dBm}, 5, \text{dBm}, 10 \text{dBm}$</tex>) on the system's performance were investigated. This work revealed that Raman amplifiers outperformed EDFAs because higher QF and lower BER were obtained using the former above all the distances tested. The QF remained above a limit of 6 dB and still held up to 500 km, proving the system can be potentially used for ultra-long-haul applications. The initial launching power, where the lowest QF and negligible amount of BER states were observed, is at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{5 ~ d B m}$</tex>, demonstrating the optimal trade-off between minimizing the effects of nonlinearity and simultaneously preserving the signal. At zero dBm, signal attenuation needed repeated amplifiers, while at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{1 0 ~ d B m}$</tex>, increased nonlinear effects degraded performance. These results indicate that the system can realize long-haul highspeed distance communication. The system presented in this paper, RANS, and the leverage of launching power are the two main factors of the state of the signal. This work brings photonic systems with proper efficiency and scalability catering to modern communication networks like 5 G and beyond.