Wohlgemuth Eyal, Yoffe Yaron, Nadimi Goki Pantea, Imran Muhammad, Fresi Francesco, Doddaballapura Lakshmijayasimha Prajwal, Cohen Roi, Anandarajah Prince, Potì Luca, Sadot Dan
Opt Express. 2021 Nov 22;29(24):40462-40480. doi: 10.1364/OE.431070.
A novel all-optical stealth and secured transmission is proposed and demonstrated. Spectral replicas of the covert signal are carried by multiple tones of a gain switched optical frequency comb, optically coded with spectral phase mask, and concealed below EDFA's noise. The secured signal's spectrum is spread far beyond the bandwidth of a coherent receiver, thus forcing real time all-optical processing. An unauthorized user, who does not possess knowledge on the phase mask, can only obtain a noisy and distorted signal, that cannot be improved by post-processing. On the other hand, the authorized user decodes the signal using an inverse spectral phase mask and achieves a substantial optical processing gain via multi-homodyne coherent detection. A transmission of 20 Gbps under negative -7.5 dB OSNR is demonstrated here, yielding error-free detection by the eligible user.
提出并演示了一种新型的全光隐身与安全传输技术。隐蔽信号的频谱副本由增益开关光频梳的多个频率分量携带，通过频谱相位掩模进行光学编码，并隐藏在掺铒光纤放大器（EDFA）的噪声之下。安全信号的频谱扩展到远远超出相干接收机的带宽，从而需要进行实时全光处理。没有相位掩模知识的未经授权用户只能获得有噪声且失真的信号，且无法通过后处理改善。另一方面，授权用户使用逆频谱相位掩模对信号进行解码，并通过多零差相干检测实现可观的光处理增益。这里演示了在-7.5 dB光信噪比（OSNR）为负的情况下20 Gbps的传输，使合格用户能够实现无误码检测。
