We demonstrate secure optical coherent communications employing low-coherence matched detection based on the randomness of amplified spontaneous emission (ASE) noise. Two-level physical-layer optical encryption is achieved through temporal and spectral coding over a broadband ASE source. An ASE-carried signal and unmodulated carrier are polarization multiplexed, transmitted over a same single-mode fiber (SMF), and separated with the aid of polarization tracking before having matched detection at the receiving side. The impact of chromatic dispersion on the low-coherence matched detection system is analyzed and experimentally investigated. We experimentally realize optically coded 20 Gbaud QPSK and 8-PSK signals transmission over a 43 km SMF span with a maximum line rate of 60 Gbits/s.

中文翻译：

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对放大的自发发射进行时域和频谱编码，以确保光学相干通信。

我们演示了基于放大的自发发射（ASE）噪声的随机性，采用低相干匹配检测的安全光相干通信。二级物理层光学加密是通过宽带ASE源上的时间和频谱编码实现的。携带ASE的信号和未调制的载波进行偏振复用，在同一单模光纤（SMF）上传输，并在接收端进行匹配检测之前借助偏振跟踪进行分离。分析并实验研究了色散对低相干匹配检测系统的影响。我们通过实验实现了在43 km SMF跨度上以20 Gbit / s的最大线速传输光编码的20 Gbaud QPSK和8-PSK信号。