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

量子密钥分发（QKD）是量子技术的一个很好的应用，并且已经建立了几个城域光纤网络用于QKD服务。然而，密钥的分配受到光纤内部吸收的限制，这意味着超过150公里的传输距离是不切实际的。但是，自由空间通信没有受到同样程度的衰减，并且已经证明在几百公里处与绕地球轨道运行的卫星进行单光子通信。因此，卫星提供了一种理想的载体，可以在分布在各国或各大洲的终端用户之间长距离分发量子密钥信息。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（ogr）网络来接收和探测携带关键信息的光子。作为先进光学和光子技术发展的主要参与者，英国在解决OGR的未来市场方面处于有利地位。该项目与用户一起指定OGR要求和原型，并测试QKD接收器，同时设计和制定在英国大规模生产的计划。

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.