3QN: Towards A New UK Industry for Novel Quantum Receivers in Nascent Satellite QKD Global Markets

量子密钥分发(QKD)是量子技术的一种广为人知的应用，已经为QKD服务建立了几个城域光纤网络。然而，密钥分发受到光纤内部吸收的限制，这意味着超过150公里的距离传输是不切实际的。然而，自由空间通信没有遭受同样程度的衰减，已经证明了与在数百公里处绕地球轨道运行的卫星进行单光子通信。因此，卫星提供了一个理想的工具，可以在分布在不同国家或大陆的最终用户之间非常远的距离内分发量子密钥信息。然而，为了从卫星技术的进步中获益，需要一个光学地面接收器网络(OGR)来接收和探测携带关键信息的光子。英国作为先进光学和光子技术发展的主要参与者，处于有利地位，可以满足OGR未来的市场需求。该项目与用户一起指定OGR要求和原型，并测试QKD接收器，同时为英国的规模化生产设计和制定计划。

Quantum Key Distribution (QKD) is a well understood application of quantum technology and there are several metropolitan fibre networks already established for QKD services. However, key distribution is limited by absorption inside optical fibres which mean that transmissions over distances greater than about 150 km are impractical. Free space communications, though, does not suffer the same degree of attenuation and single photon communication with satellites orbiting the Earth at several hundred kilometres has been demonstrated. Satellites then, provide an ideal vehicle for distributing quantum key information across very large distances between end users spread across countries or continents. However, in order to benefit from the advances in satellite technology, a network of Optical Ground Receivers (OGRs) are required to receive and detect the photons carrying the key information. The UK, as a major player in the development of advanced optical & photonic technologies, is well positioned to address this future market for OGR. This project works with users to specify OGR requirements and prototypes and tests a QKD receiver, whilst designing and making plans for scaled manufacture in the UK.