Xie Yunhao, Yang Zhao, Shi Mengyue, Hu Weisheng, Yi Lilin
Opt Lett. 2023 Oct 1;48(19):5005-5008. doi: 10.1364/OL.497061.
Chaotic optical communication encrypts transmitted signals through physical noise; this ensures high security while causing a certain decrease in the signal-to-noise ratio (SNR). Thus, it is necessary to analyze the SNR degradation of decrypted signals after chaotic encryption and the minimum requirements for the SNR of the fiber channel to meet the required bit error rate (BER) performance. Accordingly, an SNR model of decrypted signals for optoelectronic feedback-based chaotic optical communication systems is proposed. Under different channel SNRs, the SNR degradation of 40 Gbit/s phase chaos and intensity chaos models is investigated by simulation and experiment, respectively, with a 15 GHz wideband chaotic carrier. Comparing decrypted signals with original signals, the simulation results show that there is a 2.9 dB SNR degradation for both intensity chaos and phase chaos. Further, in experiments, SNR degradation from 4.5 dB to 5.6 dB, with various channel SNRs for intensity chaos, is analyzed, while there is an SNR degradation from 7.1 dB to 8.3 dB for phase chaos. The simulation and experimental results provide guidance for long-distance transmission chaotic optical communication systems.
混沌光通信通过物理噪声对传输信号进行加密；这确保了高安全性，但会导致信噪比（SNR）有所下降。因此，有必要分析混沌加密后解密信号的SNR退化情况以及光纤信道SNR满足所需误码率（BER）性能的最低要求。相应地，提出了一种基于光电反馈的混沌光通信系统解密信号的SNR模型。在不同的信道SNR下，分别通过仿真和实验研究了具有15 GHz宽带混沌载波的40 Gbit/s相位混沌和强度混沌模型的SNR退化情况。将解密信号与原始信号进行比较，仿真结果表明强度混沌和相位混沌的SNR均退化了2.9 dB。此外，在实验中，分析了强度混沌在不同信道SNR下从4.5 dB到5.6 dB的SNR退化情况，而相位混沌的SNR退化则为7.1 dB到8.3 dB。仿真和实验结果为长距离传输混沌光通信系统提供了指导。
