This paper theoretically investigates a secondary-encryption optical chaotic communication system scheme based on an optical injection structure with single optical feedback and dual-dispersion optical feedback lasers. In the scheme, a fiber reflector (FR) and Fabry–Perot interferometer (FPI) are selected as the laser feedback cavity and effectively conceals time delay signatures (TDSs) of the generated chaotic signals. By switching the responding laser connected to the driving laser with the message feeding method, messages directly participating in the process of encryption signal generation are avoided to generate the first encrypted chaotic sequence that can characterize a message. Subsequently, chaotic phase disturbance technology is used to complete the secondary encryption. By virtue of the spectral broadening effect of chaotic phase disturbance, the message rate and the randomness of the encrypted signal can be effectively enhanced. We use the synchronous power error to decrypt the message at the receiver, which simplifies the system structure and realizes the scheme with low hardware costs. The proposed scheme overcomes the shortcomings of existed schemes, which generate chaotic signal sensitive to channel noise and have complex system structures. In addition, the proposed scheme shows good robustness in terms of handling noise for transmitting digital signals, a bit error rate (BER) of 6.7 × 10⁻⁴ at a simulation signal-to-noise ratio of 10 dB, and good application prospects in harsh transmission environments, such as submarine optical fiber transmission.

本文从理论上研究了一种基于单光反馈和双色散光反馈激光器的光注入结构的二次加密光混沌通信系统方案。在该方案中，选择光纤反射器（FR）和法布里-珀罗干涉仪（FPI）作为激光反馈腔，有效地隐藏了产生的混沌信号的时延特征（TDS）。通过消息馈送方式切换与驱动激光器相连的响应激光器，避免消息直接参与加密信号的生成过程，生成能够表征消息的第一加密混沌序列。随后采用混沌相位扰动技术完成二次加密。凭借混沌相位扰动的频谱展宽效应，可以有效提高加密信号的报文率和随机性。我们在接收端利用同步功率误差对报文进行解密，简化了系统结构，实现了硬件成本低的方案。该方案克服了现有方案产生的混沌信号对信道噪声敏感、系统结构复杂的缺点。此外，该方案在处理传输数字信号的噪声方面表现出良好的鲁棒性，在10 dB的模拟信噪比下，误码率(BER)为6.7 × 10 ^{-4 ，具有良好的应用前景。}恶劣的传输环境，如海底光纤传输。