Future 6G communication systems are envisioned to expand their carrier frequency to the THz region, where a broad unexplored region of spectrum is available. With this expansion, THz wireless communication has the potential to achieve ultra-high data transmission rates of up to 100Gbit/s. However, as large amounts of data are transmitted in an open wireless environment, there are significant concerns regarding communication security due to the susceptibility to eavesdropping, interception, and jamming. In this work, we proposed a secure approach for THz wireless communication based on spatial wave mixing and flexible beam steering. To achieve this, two frequency-modulated THz waves, which are generated by photonic THz sources and carry encrypted information with true randomness, are mixed at a THz envelope detector with an exclusive-OR logic operation. We analyzed the possible spatial location for the THz detector to ensure a secure microcell network deployment. Our results demonstrate that the size of the decryptable region is directly dependent on the directivity and width of the emitted THz beam. To address this, we have developed an array antenna with integrated uni-traveling-carrier photodiodes (UTC-PDs), which is capable of generating THz waves while also improving the flexibility of beam pointing, allowing for greater control over the location and size of the decodable region. By controlling fiber-optic delay lines, we successfully demonstrated that the directional gain of a 200GHz wave is increased by 8dB through a 1 × 3 UTC-PD-integrated planar bowtie antenna (PBA) array, together with continuous beam steering from -20° to 10°. Additionally, using a 1 × 4 UTC-PD-integrated PBA array to emulate two encryption transmitters and a Femi-level managed barrier diode to detect spatially mixed THz waves, we successfully achieved a feasibility experiment for real-time 200Mbit/s location-based decryption in the 200GHz band. These results indicate that the proposed scheme is feasible for secured THz communication, and would be a powerful candidate to mitigate security risks in 6G microcell networks.

中文翻译：

---

基于受控光束空间波混合的光子微蜂窝网络中的安全太赫兹通信


未来的 6G 通信系统预计将其载波频率扩展到太赫兹区域，该区域有广阔的未开发频谱区域。通过这种扩展，太赫兹无线通信有潜力实现高达 100Gbit/s 的超高数据传输速率。然而，随着大量数据在开放无线环境中传输，由于容易受到窃听、拦截和干扰，通信安全受到极大关注。在这项工作中，我们提出了一种基于空间波混合和灵活波束控制的太赫兹无线通信安全方法。为了实现这一目标，由光子太赫兹源生成并携带具有真正随机性的加密信息的两个调频太赫兹波在太赫兹包络检测器中通过异或逻辑运算进行混合。我们分析了太赫兹探测器可能的空间位置，以确保安全的微蜂窝网络部署。我们的结果表明，可解密区域的大小直接取决于发射的太赫兹光束的方向性和宽度。为了解决这个问题，我们开发了一种集成单行载流子光电二极管（UTC-PD）的阵列天线，它能够产生太赫兹波，同时提高波束指向的灵活性，从而可以更好地控制太赫兹波的位置和尺寸。可解码区域。通过控制光纤延迟线，我们成功证明了通过 1 × 3 UTC-PD 集成平面蝴蝶结天线 (PBA) 阵列，200GHz 波的方向增益增加了 8dB，同时从 -20° 进行连续波束控制至 10°。 此外，利用1×4 UTC-PD集成PBA阵列模拟两个加密发射机和Femi级管理势垒二极管来检测空间混合太赫兹波，我们成功实现了实时200Mbit/s基于位置的可行性实验200GHz频段解密。这些结果表明，所提出的方案对于安全太赫兹通信是可行的，并且将成为减轻 6G 微蜂窝网络安全风险的有力候选方案。