Free Space Optics (FSO) is an innovative optical communication technology that leverages light propagation in free space for direct line-of-sight interactions. This technology is characterized by several benefits, including secure transmission, high bandwidth, and rapid data transfer rates, making it a promising candidate for integration into emerging 6G networks. However, the efficiency of FSO systems is adversely affected by various weather conditions, such as rain, temperature fluctuations, snow, and fog, as well as atmospheric disturbances. This paper presents a Particle Swarm Optimization (PSO)-based approach to optimize the divergence angle of FSO systems. PSO is a type of artificial intelligence that excels at managing complex settings and adapting to changes in the environment, thus making FSO systems more robust against such challenges. By optimizing this critical parameter, the proposed method significantly improves the reliability and efficiency of data transmission in FSO systems, supporting the advanced performance demands of future 6G networks. This optimization ensures FSO systems can achieve faster and more reliable connectivity, essential for the next generation of wireless communication.

This paper investigates the potential improvements in Free Space Optics (FSO) communication systems using Particle Swarm Optimization (PSO) and the Pachycondyla Apicalis Algorithm (API). FSO technology transmits data using laser beams, offering benefits like high bandwidth and enhanced security, with the capability to achieve data rates of up to 10 Gbps over distances of up to 2 km under favorable weather conditions. However, this technology faces challenges due to environmental factors such as rain, fog, and atmospheric turbulence, which can impact its performance. This study specifically addresses link margin degradation caused by these impairments and applies PSO as an efficient baseline metaheuristic, selected for its computational simplicity, rapid convergence, and robustness, while benchmarking its performance against the API algorithm. Simulation results indicate that PSO optimization significantly increases the link margin for various divergence angles compared to the API algorithm. For divergence angles of 1, 1.5, 2.4, and 3 mrad, the link margin improved by 6.4, 11.1, 9.8, and 7.6 dB, respectively, at a fixed transmitted power of 10 dBm. This demonstrates that PSO maintains a higher link margin at divergence angles above 2 mrad compared to both the API algorithm and the conventional scenario. The main contributions of this study are: the development of a bio-inspired optimization framework for FSO systems, enhancement of link robustness against turbulence, beam misalignment, and fading, and demonstration of the framework’s applicability to both current 5G backhaul scenarios and prospective 6G optical wireless networks. Beyond simulation, the framework has been verified for practical feasibility and shown to align with commercially available optical hardware. In addition, PSO can be integrated with real-time atmospheric sensing and predictive weather models to enable proactive parameter tuning, ensuring resilient and efficient 6G FSO deployment. Overall, the results confirm that misalignment-optimized PSO enhances resilience under severe conditions, supporting 6G availability requirements.

The increasing demand for higher bandwidth and reliable communication networks driven by next-generation mobile technologies (5G/6G) and the Internet of Things (IoT) poses challenges for existing communication infrastructures. Free Space Optics (FSO) offers high-speed wireless data transmission comparable to fiber optics but suffers from significant performance degradation due to environmental factors such as rain, fog, and atmospheric turbulence. This study investigates the potential of a hybrid Dense Wavelength Division Multiplexing (DWDM)-FSO system to overcome these challenges. By combining DWDM’s high capacity with the flexibility of FSO links, the system achieves a data rate of 5.4 Tbps across 90 users. Simulations conducted using OptiSystem software evaluate the impact of different weather conditions – clear skies, heavy rain, and dense fog – on performance. Key metrics, including bit error rate (BER), quality factor (Q-factor), and eye diagrams, are analyzed to assess signal integrity and reliability. A comparative study of Single Input Single Output (SISO) and MIMO configurations (2 × 2 and 3 × 3) shows that the 3 × 3 MIMO-FSO setup significantly enhances performance, maintaining signal quality and extending range under adverse weather. These findings highlight the hybrid DWDM-FSO system’s potential to deliver high-speed, resilient communication, ensuring seamless connectivity in dynamic environments.

Context: Free Space Optics (FSO) transmission is a promising alternative to conventional wired networks, offering high bandwidth, low latency, and enhanced security. However, FSO performance is highly sensitive to physical factors, particularly the divergence angle of the optical beam. Objective: This study aims to evaluate the impact of beam divergence on key FSO system performance metrics to guide optimal system design. Method: MATLAB-based simulations were conducted to model Signal-to-Noise Ratio (SNR), Bit Error Rate (BER), and Q factor under varying divergence angles. The sensitivity of system performance to beam alignment and signal strength was analyzed across different divergence configurations. Results: Results indicate that smaller divergence angles provide higher SNR and Q factor values and lower BER, ensuring superior communication quality but requiring precise alignment. Conversely, larger divergence angles tolerate misalignment more effectively but at the cost of reduced signal quality. Conclusion: These findings emphasize the critical role of optimizing beam divergence to balance alignment tolerance and signal integrity, thereby enhancing the efficiency and reliability of optical wireless communication systems.

The performance of free-space optical (FSO) communication systems is significantly affected by weather conditions and alignment losses between the transmitter and receiver, which can degrade signal quality. These challenges can be mitigated by optimizing key system parameters, particularly the divergence angle, which controls the optical beam’s spread during transmission. In this paper, we present a multi-verse optimizer (MVO) model to identify the optimal divergence angle, enhancing FSO system reliability under adverse conditions. Our approach evaluates the impact of divergence angles on system metrics such as link margin, deviation angle, and signal-to-noise ratio (SNR). We compare the performance of MVO with particle swarm optimization (PSO), demonstrating that MVO achieves an average improvement of 20 %–30 % in link margin across different conditions. Simulation results validate the efficiency of MVO in optimizing FSO systems, identifying configurations that minimize link margin degradation and maximize system robustness. These findings offer actionable insights for designing resilient and efficient FSO communication links, ensuring dependable performance in diverse environmental scenarios.