High-speed physical key distribution is diligently pursued for secure communication. In this paper, we propose and experimentally demonstrate a scheme of high-speed key distribution using mode-shift keying chaos synchronization between two multi-longitudinal-mode Fabry–Perot lasers commonly driven by a super-luminescent diode. Legitimate users dynamically select one of the longitudinal modes according to private control codes to achieve mode-shift keying chaos synchronization. The two remote chaotic light waveforms are quantized to generate two raw random bit streams, and then those bits corresponding to chaos synchronization are sifted as shared keys by comparing the control codes. In this method, the transition time, i.e., the chaos synchronization recovery time is determined by the rising time of the control codes rather than the laser transition response time, so the key distribution rate is improved greatly. Our experiment achieved a 0.75-Gbit/s key distribution rate with a bit error rate of 3.8 × 10⁻³ over 160-km fiber transmission with dispersion compensation. The entropy rate of the laser chaos is evaluated as 16 Gbit/s, which determines the ultimate final key rate together with the key generation ratio. It is therefore believed that the method pays a way for Gbit/s physical key distribution.

高速物理密钥分发是为了安全通信而努力追求的。在本文中，我们提出并通过实验证明了一种高速密钥分配方案，该方案使用通常由超发光二极管驱动的两个多纵模法布里-珀罗激光器之间的模移键控混沌同步。合法用户根据私有控制码动态选择纵向模式之一，实现模式切换键控混沌同步。将两个远程混沌光波形量化生成两个原始随机比特流，然后通过比较控制码筛选出混沌同步对应的比特作为共享密钥。在这种方法中，过渡时间，即 混沌同步恢复时间由控制码的上升时间决定，而不是由激光跃迁响应时间决定，密钥分发率大大提高。我们的实验实现了 0.75-Gbit/s 的密钥分发率，误码率为 3.8 × 10⁻³超过 160 公里的光纤传输，带色散补偿。激光混沌的熵率被评估为16 Gbit/s，它与密钥生成率一起决定了最终的最终密钥率。因此认为该方法为Gbit/s物理密钥分发付出了代价。