Physical layer encryption based on digital chaos emerged as a promising methodology for securing data transmission. Discrete multi-tone (DMT) is a widely investigated advanced modulation format in intensity modulation and direct detection (IM/DD) systems, because of its high spectral efficiency, low cost and high dispersion tolerance. In this letter, we successfully performed a physical layer chaotic encryption method on an IM/DD system and experimentally demonstrated the transmission of 100 Gb/s encrypted 32QAM-DMT and 125 Gb/s pre-equalized encrypted 32QAM-DMT signals over 2-km standard single mode fiber (SSMF) with bit error rate (BER) under the hard decision forward error correction (HD-FEC) threshold of $3.8\times 10^{-3}$ . The proposed encryption algorithm utilizes three independent pseudo-random sequences generated by the multi-scroll chaotic system for secure data transmission, and has no substantial impact on the transmission performance.

中文翻译：

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基于数字多滚动混沌系统的DMT物理层加密

基于数字混沌的物理层加密成为保护数据传输的一种有前途的方法。离散多音 (DMT) 是强度调制和直接检测 (IM/DD) 系统中广泛研究的高级调制格式，因为它具有高频谱效率、低成本和高色散容限。在这封信中，我们成功地在 IM/DD 系统上执行了物理层混沌加密方法，并通过实验证明了 100 Gb/s 加密 32QAM-DMT 和 125 Gb/s 预均衡加密 32QAM-DMT 信号在 2 公里范围内的传输在硬判决前向纠错 (HD-FEC) 阈值为 $3.8\times 10^{-3}$ 下具有误码率 (BER) 的标准单模光纤 (SSMF)。