Self-Adaptive All-Optical Feedback-Based Free- Space Optical Communication System With Attention-Enhanced Turbulence Awareness

Free-Space Optical (FSO) communication is poised to play an increasingly important role in future wireless communications due to its high bandwidth and the absence of spectrum licensing requirements. However, FSO links are significantly impacted by atmospheric turbulence and pointing errors, resulting in considerable fluctuations in transmission link reliability and communication performance. Here, we introduce an FSO communication system that utilizes a novel neural network algorithm based on an attention mechanism to fuse optical field intensity and phase features for detecting turbulence intensity, enabling adaptive adjustments to launch power and communication rate. The entire system utilizes an all-optical feedback link with a simplified receiver design, offering a cost-effective solution. The experiment was conducted on a 10-meter free-space link, where turbulence intensity varied over time across seven levels, with the maximum slow fading difference between the weakest and strongest turbulence reaching 11dB. Over 6 hours, the FSO link achieved an average total effective rate of 135Gbps across three wavelengths. Compared to schemes with fixed launch power and communication rate, our system improved the average effective rate by 58.4% and an average reliability gain of up to 34.2%. The proposed optimization technique significantly enhances both capacity and reliability, thereby making FSO technology a more practical solution for long-distance wireless communication.