On the performance of optical codes for FSO systems using SAC-OCDMA technique to improve system performance

FSO (Free Space Optics) and SAC-OCDMA (Spectral Amplitude Coding-Optical Code Division Multiple Access) systems are the two important popular areas for research in communication engineering. This paper presents the performance analysis of a Multiplexed-FSO system based on SAC-OCDMA, considering the advantages of both techniques. The analysis focuses on the system's performance over Gamma–Gamma fading, utilizing the Double Diagonal Double Weight Code (DDDWC) and Zero Cross Correlation Optical Code (ZCCOC). Additionally, the analysis takes into account the impact of meteorological turbulence scenarios of various levels. Communication systems suggested in this study are simulated, and their performance is assessed for four users working with sufficient high bit rate of 10 Gbps. The evaluation is conducted based on parameters such as BER, Q factor, Received Power, and visualized through use of Eye-Diagrams. These systems developed in this study aims to mitigate the impact of noises namely MAIN and PIIN. In context of these designed systems, it is imperative to determine the optimal range limits for FSO links and subsequently evaluate system performance across all varying weather conditions. In addition, the communication systems under consideration are being examined to determine the impact of variations in Transmitted Source Power, Receiver Aperture Diameter, and Beam Divergence on their performance. This analysis aims to identify the optimal limits of these design parameters. The simulation findings demonstrate that the system described in this study exhibits reliable performance even at extended link ranges in the presence of turbulent weather conditions. Furthermore, this performance is achieved with a low source power level of less than 10 dBm, and without any notable distortion. The BER performance along with optimal-limiting values of link range attained by the suggested systems utilizing DDDW Code and ZCC Optical Code are also compared with an established system employing DDW (Diagonal Double Weight) Code.