Silicon Photonics for Quantum Fibre Networks

安全通信是敏感信息交换的基础，而基于经典密码协议的安全性已不能得到绝对保证。特别是当全容限量子计算机出现时，经典的加密和解密方法将不再安全，对密码系统构成严重威胁。量子密码学作为量子通信的一个分支，开创了信息安全传输的新纪元。尽管在过去的20年里，量子通信和量子密钥分发（QKD）已经取得了很大的进展，但量子通信的未来仍然面临着重大障碍的挑战。SQUARE项目通过开发基于硅光子学的下一代量子器件打破了这些障碍，实现了紧凑，可靠和高效的组件，允许构建完全连接的长距离，高速率QKD安全的量子通信网络。SQUARE项目基于硅光子学为量子通信和经典通信开发完全集成的发射机（Tx）和接收机（Rx），这是将集成光子学的资产与CMOS技术联合收割机相结合的有力手段。硅光子学背后的驱动力是硅代表了一个成熟的集成平台，它将光子电路带到了一个更高的集成水平，允许大规模生产，就像它对电子电路所做的那样。从这个意义上说，我们相信硅光子学将在未来的量子通信中发挥重要作用，从而为量子通信应用建立强大且具有成本效益的光子电路。SQUARE将开发突破当前最先进技术限制所需的集成量子技术，并将这些技术直接集成到量子子系统中。因此，这些组件将针对特定量子网络场景中的特定应用而开发。所提出的新型网络利用不同技术的优势，在覆盖范围、灵敏度、复杂性、实用性和总功耗方面获得全球利益。

Nowadays secure communication is essential for exchange of sensitive information, while the security based on classical cryptography protocols cannot be absolutely guaranteed. Especially when a full-tolerant quantum computer will be available, the classical encryption and decryption methods will be no longer secure, posing a serious threat to cryptosystems. Quantum cryptography (QCy), a branch of Quantum Communications (QCs), has opened a new era in the security of information transmission. Although big steps in QCs and Quantum Key Distribution (QKD) have been taken over the last 20 years, the future of QCs is still challenged by major barriers. The SQUARE project shatters these barriers by developing the next generation of quantum devices based on silicon photonics, enabling compact, reliable, and efficient components, allowing for the construction of fully connected long-reach, high-rate QKD-secured quantum communication networks. The SQUARE project develops a fully integrated transmitter (Tx) and receiver (Rx) for quantum communications and classical communication based on silicon photonics, which is a powerful means to combine the assets of integrated photonics with CMOS technologies. The driving force behind silicon photonics is that silicon represents a mature integration platform, which brings photonic circuits to a higher integration level allowing for mass-production as it has done for electronic circuits. In this sense, we believe that silicon photonics will play a significant role in future QCs, allowing to build up powerful and cost-effective photonic circuits for quantum communication applications. SQUARE will develop the integrated quantum technologies necessary to breach the limits of current state-of-the-art, and furthermore integrate these technologies directly in quantum subsystems. Hence the components will be developed for specific applications in specific quantum network scenarios. The proposed novel network leverages on the strengths of different technologies to obtain global benefits in terms of reach, sensitivity, complexity, practicality and total power consumption.