Performance Analysis of SDM, WDM, and PDM Techniques in High‐Capacity FSO Systems Under Diverse Atmospheric Conditions

ABSTRACT With growing demand for fast, reliable, and flexible communication, free‐space optical (FSO) systems have seen significant advancements. However, weather and altitude have a significant impact on their performance, which requires an optimum system design. Using OptiSystem simulations, this research compares four hybrid techniques using three different multiplexings: space division multiplexing (SDM), wavelength division multiplexing (WDM), and polarization division multiplexing (PDM). With a maximum quality factor (Q‐factor) of 149.47 and 0% bit error rate (BER) in clear circumstances, the WDM and SDM hybrid system performs the best among the evaluated setups. In ideal conditions, the more complicated WDM, SDM, and PDM configurations perform competitively, but interchannel interference causes them to suffer under high attenuation. WDM and SDM system maintain a Q‐factor of 20 and are the most robust in severe weather conditions like fog and torrential rain. All things considered, the WDM and SDM system provides the best balance between performance, complexity, and practical dependability for FSO communication. While the proposed system model 1 introduces a scalable, forward‐looking architecture, it also offers trade‐offs between capacity and robustness that can be fine‐tuned for future high‐performance FSO networks.