Prospects of Chip-Based Multi-Protocol Quantum Key Distribution Transceivers.

Quantum communications enable the transmission of information in a secure way that is ensured by the laws of quantum physics. Current quantum-safe communication systems are based on quantum key distribution (QKD) technology at their core. In the most recent years, a remarkable effort has been put into practical implementations of QKD with a focus on their integration into classical optical networks, some of which are becoming commercially available. However, even with the ongoing development of QKD systems, there are efforts toward their miniaturization, power efficiency improvement, and enhancement of their flexibility and functionality.In this paper, we outline major QKD protocols and review recent advances in QKD systems based on photonic integrated circuits. Finally, we will discuss the potential feasibility of multi-protocol QKD chips leveraging the advantages of different protocols in one solution.