Dual-Polarization Quadrupling Generation for RoF-DWDM Transmission Using OCS with Dual-Parallel DD-MZM Under Nonlinear Effects

The rapid advancement of next-generation wireless networks is revolutionizingcommunication systems, focusing on providing high-speed connectivity, extensivebandwidth, and broad coverage. Within this framework, Radio over Fiber (RoF)technology has gained prominence as an innovative approach to enable broadbandwireless communication, utilizing micro and pico cells integrated with centralizedaccess networks. This paper presents and evaluates a dual-polarization quadruplingmillimeter-wave (mm-wave) generation technique based on Optical CarrierSuppressed (OCS) modulation to enhance RoF-DWDM system performance. Theproposed technique utilizes dual-polarization dual-parallel modulators integratedwith phase-shifting operations to enable OCS transmission, suppressing unwantedspectral components and facilitating efficient mm-wave generation. The approachgenerates dual-polarization RF signals at 28 GHz, supporting data rates of 10Gbps per polarization state, and achieves high-capacity transmission in a 40-channel system over 150 km of SMF with 75 GHz channel spacing. The impactof nonlinear effects poses significant limitations on the transmission capacitywhen utilizing a filterless OCS approach in each modulator within the system.These effects lead to a degradation in spectral integrity, impairing overall performance.the integration of a 4th-order Bessel filter into the transmission systemeffectively mitigates these issues. This solution suppresses unwanted sidebands, enhances spectral efficiency, and reduces interference, resulting in improved systemperformance and reliability. The performance of the proposed system hasbeen evaluated and optimized to achieve high-quality transmission while minimizingthe impact of nonlinear effects. Simulations reveal the most efficient inputpower levels between 5 dBm and 10 dBm, resulting in a quality factor of 8.16 and a BER of 1.66 x 10−16 using the filterless OCS communication method. Theincorporation of an OBPF improves transmission performance, achieving a qualityfactor of 14.59 and a BER of 1.12 x 10−48 The system demonstrates resilienceto nonlinearities, achieving an FWM efficiency of 42.5 dBm and reducing SRSeffects to 0.2 dBm. PMD analysis indicates a sensitivity range of -36.9 dBm to -9.8 dBm at a PMD coefficient of 0.2 ps/km; however, higher PMD values degradesensitivity. Despite these challenges, the system confirms its suitability for longdistance,high-capacity transmission in next-generation RoF-DWDM networks.