Liu Weijie, Yuan Weihao, Huang Nuo, Xu Zhengyuan
Appl Opt. 2024 Apr 10;63(11):2783-2790. doi: 10.1364/AO.516465.
Orthogonal frequency division multiplexing (OFDM) utilizes numerous sub-carriers to achieve high transmission data rates. The frequency selectivity of the channel becomes a crucial factor influencing the communication performance of OFDM-based systems. In optical wireless communication (OWC) systems, the photomultiplier tube (PMT) may experience saturation when the incident optical power approaches its saturation threshold. This paper, for the first time, characterizes the saturation levels of a high-speed PMT based on the measured amplitude in the time domain and the output response of the PMT in the frequency domain. Additionally, an adaptive optical saturation compensation algorithm, leveraging an electronically controlled variable optical attenuator, is proposed to realize a reliable OWC system. Experimental results demonstrate that the proposed saturation compensation method achieves a higher tolerance to large dynamic signal and background radiation compared with that without compensation, while maintaining a satisfactory bit error rate.
正交频分复用（OFDM）利用大量子载波来实现高传输数据速率。信道的频率选择性成为影响基于OFDM的系统通信性能的关键因素。在光无线通信（OWC）系统中，当入射光功率接近其饱和阈值时，光电倍增管（PMT）可能会出现饱和现象。本文首次基于时域测量幅度和频域PMT输出响应来表征高速PMT的饱和水平。此外，提出了一种利用电控可变光衰减器的自适应光饱和补偿算法，以实现可靠的OWC系统。实验结果表明，与无补偿方法相比，所提出的饱和补偿方法对大动态信号和背景辐射具有更高的容忍度，同时保持了令人满意的误码率。
