AirQKD: The Role of Free-Space Optics Quantum Key Distribution Enabling Pragmatic Secure and Scalable Communications

Next generation communications will require the exploration of alternatives to existing technologies to enable end-to-end connections for secure data exchange. 5G presents advanced connectivity opportunities even for remote rural areas. However, existing 5G platforms will benefit from complementary methods to enhance network capabilities and fulfill trust requirements. Due to high throughput data links, high-beam directivity, and energy efficiency, free-space optics (FSO) is an alternative solution with the potential to deliver high-performance and efficient security. FSO systems can be improved by adding quantum-key-distribution security to overcome advances in quantum computation. However, practical FSO quantum key distribution (FSO-QKD) requires simultaneous engineering of many elements. To oversee this requirement, the Innovate-UK project addresses the possibility of metropolitan-scale "last-mile" quantum secure connectivity through the use of free-space QKD links to support real-life use cases. In this article, we outline the design, development, and deployment of these elements within the AirQKD project.