This paper has proposed an experimental system for non-orthogonal multiple access (NOMA) wireless optical communication in challenging underwater turbulent environments, employing the gallium nitride (GaN)-based micro-LED array. This design of the GaN-based micro-LED array enables the independent transmission of signals from distinct data streams within the NOMA framework, facilitating direct optical power-domain superposition of NOMA signals. The experimental setup involves emulating oceanic turbulence channels, characterized by varying the level of scintillation intensity, to thoroughly investigate the bit error rate (BER) performance. The outcomes unequivocally demonstrate the superiority of our proposed NOMA scheme, as compared to conventional circuit-driven optical NOMA systems utilizing fixed LED array grouping, particularly in the presence of turbulent underwater channels. The proposed NOMA scheme exhibits consistently superior BER performance and maintains excellent linearity at the lower frequencies while effectively mitigating signal distortion at the higher frequencies.

Although the 5G wireless network has made significant advances, it is not enough to accommodate the rapidly rising requirement for broader bandwidth in post-5G and 6G eras. As a result, emerging technologies in higher frequencies including visible light communication (VLC), are becoming a hot topic. In particular, LED-based VLC is foreseen as a key enabler for achieving data rates at the Tb/s level in indoor scenarios using multi-color LED arrays with wavelength division multiplexing (WDM) technology. This paper proposes an optimized multi-color LED array chip for high-speed VLC systems. Its long-wavelength GaN-based LED units are remarkably enhanced by V-pit structure in their efficiency, especially in the “yellow gap” region, and it achieves significant improvement in data rate compared with earlier research. This work investigates the V-pit structure and tries to provide insight by introducing a new equivalent circuit model, which provides an explanation of the simulation and experiment results. In the final test using a laboratory communication system, the data rates of eight channels from short to long wavelength are 3.91 Gb/s, 3.77 Gb/s, 3.67 Gb/s, 4.40 Gb/s, 3.78 Gb/s, 3.18 Gb/s, 4.31 Gb/s, and 4.35 Gb/s (31.38 Gb/s in total), with advanced digital signal processing (DSP) techniques including digital equalization technique and bit-power loading discrete multitone (DMT) modulation format.

为了提高发光二极管（light emitting diode，LED）光源阵列的光照均匀度，提出一种改进粒子群算法和新型等差LED阵列排布方式。根据光照分布模型建立了照射面的光照均匀度评价函数，使用改进的粒子群算法对新型等差LED阵列、矩形及圆形阵列进行优化。将优化后的LED阵列数据导入光学软件TracePro中进行仿真验证，得到优化后等差、矩形及圆形LED阵列的光照均匀度分别为82.89%、73.31%及78.56%，比优化前LED阵列的光照均匀度分别提高了15.84%、10.65%及15.57%。研究结果表明，改进后的粒子群算法收敛速度更快、精度更高，且提出的新型等差LED阵列有着更好的光照均匀度。

针对当前视觉检测系统LED光源照度优化研究中存在的照度效果评价因素单一、照度优化方法通用性不足等问题，以芯片封装质量视觉检测为例，提出一种基于改进樽海鞘算法的LED光源照度优化方法。该方法在单个LED光源照度数学模型基础上，建立标准条形LED阵列光源照度数学模型，获取条形LED阵列在任意空间位姿与被测面的照度值；基于照度均匀度、照度梯度变化与对中度、平均照度、目标与背景区分度等因素建立平面照度效果评价函数；提出改进樽海鞘算法，通过改进算法收敛系数、速度、领导者与追随者位置等更新策略，增强区域搜索的多样性；应用改进樽海鞘算法对平面照度效果评价函数进行优化求解，获取具有最优照度效果的空间位姿参数。实验结果表明：考察优化区域的相对照度分布，文中提出的LED光源照度优化方法所得照度分布与实际测量所得照度分布结果基本一致，目标区域理论照度均匀度在98.78%以上，误差在5.57%以内。因此文中提出方法优化目标合理，可用于视觉检测系统具有最优照度效果时光源位姿信息参数的获取。

大功率LED阵列动态光源工作过程中光电热参数具有不确定性和时变时滞非线性特点，利用动态核主元分析方法（DKPCA）对大功率LED阵列动态光源进行在线状态观测与故障诊断能有效地捕捉观测数据的非线性和相关性特征，根据历史数据的主元特征计算出的统计量阈值和在线数据的统计特征实现故障检测，利用重构贡献图法实现故障的分离。仿真实验表明，对大功率LED阵列动态光源典型的传感器和执行器故障进行有效监测和诊断相对于核主元分析方法对故障更为敏感，故障检测率最高提高了7.5%，误检率下降了4.2%。