ComPQT · Compact plug-and-play quantum network terminals based on deterministic semiconductor sources

Communications networks have brought incredible convenience to our lives, making it possible for billions of people to connect and communicate at the touch of a button. However, despite their ease of use, these networks remain vulnerable to security threats, with frequent cyber-attacks and the growing danger of quantum computing underscoring the need for stronger protections. Quantum communication offers a potential solution against these security threats. Research institutions worldwide are making significant investments in this field, with many companies commercializing relevant products. However, most of these devices predominantly use lasers as light sources, which are probabilistic by nature and can cause security vulnerability. This proposal aims to address this limitation. Compact plug-and-play quantum terminals will be built by using genuinely deterministic quantum light sources. They will serve as nodes in a clocked quantum network. Two mobile 19-inch rack-based terminals (‘transmitter’ and ‘receiver’) will be tested on a 79-kilometre quantum communication testbed that connects Hannover and Braunschweig. For demonstration purposes, one-way quantum key distribution will be realized by using these two terminals that are strictly time and frequency synchronized. This proposal builds on the successful scientific outcome from the PI’s ERC Starting Grant 'QD-NOMS', i.e., semiconductor single and entangled photon pair sources. Combined with the ultra-stable time and frequency synchronization technologies that are being developed in the current ERC Consolidator Grant 'MiNet', the full-fledged plug-and-play terminals proposed here will be instrumental in demonstrating multipartite quantum communication in a large-scale photonic network. With the Proof-of-Concept grant, we aim to narrow the gap between the lab-based quantum photonic devices and real-world applications, and finally bring ComPQT to the pre-commercial stage via market analysis and IPR activities.