Mariella Minder

Asynchronous measurement-device-independent quantum key distribution (AMDI-QKD) stands out for its experimental simplicity and high key rate generation. To simplify the system further, we devise a post-measurement compensation scheme to accurately estimate the mutual frequency offset between two compact lasers using just the announced quantum-signal detection results, thereby obviating the need for optical reference light. As a result, we demonstrate an AMDI-QKD system operating at 2.5 GHz and achieving secure key rates (SKRs) of 537 and 101 kbit/s at distances of 100 and 201 km, respectively. By leveraging ultra-stable lasers, we achieve the highest SKRs with measurement-device-independent security within the 100 to 400 km range.

We demonstrate the first experimental overcoming of the repeaterless secret key capacity (PLOB) bound through the implementation of the Twin Field Quantum Key Distribution (TF-QKD) protocol. We distribute secret keys at record channel losses (> 90 dB). We assess the prospects for real-world implementation of TF-QKD.

We demonstrate a simple and compact MDI-QKD system design based on optical injection locking and gain-switching techniques, capable of directly encoding phase-modulated time-bin bits. Our results improve upon the state-of-the-art key rates by an order of magnitude.