【摘要】 双向水下无线光通信（UWOC）系统中存在的后向散射光子会干扰正常的光通信信号，降低接收信号信噪比（SNR），甚至导致接收机内部探测器的光学饱和。因此，深入研究后向散射光子的功率空间分布特性和到达角分布规律对水下双向无线光通信系统具有重要意义。提出了一种改进的蒙特卡罗（MC）仿真方法，不直接增大探测器靶面面积，而通过统计面积更大的圆环内的光子特性来代替探测器靶面内的光子特性，可缩减仿真时间58%以上。仿真综合考虑了典型水质参数以及不同光源发散角下后向散射光功率分布和光子到达角分布情况，同时搭建了实验平台进行验证。仿真结果表明，光源发散角小于60°时，后向散射光功率分布以及光子到达角分布情况均没有明显区别。实验结果表明，随着氢氧化镁浓度上升，其后向散射光功率相对更高。光源发散角分别为3°和48°时，两者的后向散射光功率分布曲线基本重合，与仿真结果类似。通过仿真和实验方法证实了水体参数是影响后向散射光分布的主要因素，而光源发散角的改变对系统后向散射特性影响有限。该发现可为双向UWOC系统接收端设计提供参考。更多还原

【Abstract】 Backscattered photons in bidirectional underwater wireless optical communication(UWOC) systems can interfere with optical signals, reduce the signal-to-noise ratio(SNR) at the receiver, and even cause optical saturation in the detector. Therefore, in-depth research on the power distribution and arrival angle distribution of backscattered photons holds significant importance for bidirectional UWOC systems. An improved Monte Carlo(MC) simulation method was proposed. Instead of directly enlarging the detector’s target area, photon characteristics within a larger annular region were statistically analyzed to approximate those within the detector’s target area. This approach was capable of reducing the simulation time by more than 58%. The power distribution and photon arrival angle distribution of backscattered photons for different water types and light source divergence angles were comprehensively analyzed. An experimental platform was also established for validation. Simulation results demonstrate that when the light source divergence angle is below 60°, there is no significant difference in the backscattered light power distribution or photon arrival angle distribution. Experimental results indicate that as magnesium hydroxide concentration increases, the backscattered light power becomes relatively higher. When the light source divergence angles are 3° and 48°, their backscattered light power distribution curves nearly overlap, aligning with simulation results. Through simulations and experiments, this study confirms that water types are the primary factor influencing backscattered light distribution, while the light source divergence angle has limited impact on system backscattering characteristics. This finding provides valuable references for the design of receivers in bidirectional UWOC systems.更多还原