Real-time operation of a multi-rate, multi-protocol quantum key distribution transmitter

TL;DR

This paper presents a versatile quantum key distribution transmitter capable of operating across multiple protocols and clock rates, facilitating practical, large-scale, and hardware-compatible quantum communication systems.

Contribution

The authors develop a multi-rate, multi-protocol QKD transmitter using optical injection locking, enabling compatibility with different hardware and protocols for scalable quantum networks.

Findings

Successfully operated with two receivers at different clock rates.

Demonstrated multi-protocol communication with diverse decoding circuits.

Achieved adaptable hardware for practical quantum key distribution deployment.

Abstract

Quantum key distribution (QKD) is the best candidate for securing communications against attackers, who may in the future exploit quantum-enhanced computational powers to break classical encryption. As such, new challenges are arising from our need for large-scale deployment of QKD systems. In a realistic scenario, transmitting and receiving devices from different vendors should be able to communicate with each other without the need for matching hardware. Therefore, practical deployment of QKD would require hardware capable of adapting to different protocols and clock rates. Here, we address this challenge by presenting a multi-rate, multi-protocol QKD transmitter linked to a correspondingly adaptable QKD receiver. The flexibility of the transmitter, achieved by optical injection locking, allows us to connect it with two receivers with inherently different clock rates. Furthermore, we demonstrate the multi-protocol operation of our transmitter, communicating with receiving parties employing different decoding circuits.