In this talk, we will review the present status of continuous-variable quantum key distribution, including optical configuration and security analysis, and would like to discuss future prospects for integration with coherent optical communications.
Continuous variable quantum key distribution relies on the transmission of weakly modulated coherent states and the detection of optical field for secure communication. In this talk, we give an overview of recent developments in continuous variable quantum key distribution. In particular, we discuss a scheme that uses continuous-wave laser beams without optical pulsing. Due to its continuous wave nature, our scheme is intrinsically broadband and does not require measurement basis switching. Finally, we present a status report on integration of this system into existing communication infrastructures at the Parliamentary Triangle of Australia in Canberra.
Quantum key distribution provides secure keys with information-theoretic security ensured by the principle of quantum mechanics. The continuous-variable version of quantum key distribution using coherent states offers the advantages of its compatibility with telecom industry, e.g., using commercial laser and homodyne detector, is now going through a booming period. In this review article, we describe the principle of continuous-variable quantum key distribution system; focus on protocols based on coherent states, whose systems are gradually moving from proof-of-principle lab demonstrations to in-field implementations and technological prototypes. We start by reviewing the theoretical protocols and the current security status of these protocols. Then, we discuss the system structure, the key module, and the mainstream system implementations. The advanced progresses for future applications are discussed, including the digital techniques, system on chip, and point-to-multipoint system. Finally, we discuss the practical security of the system and conclude with promising perspectives in this research field.
To face the challenges of open and disaggregated 6G networks and the prospect/threat of quantum computing, we propose to adopt continuous-variable QKD (CV-QKD), as a promising technology compatible and suitable to be integrated with conventional optical systems, in combination with software defined networking (SDN). In this work, we present our most recent advances on SDN-enabled flexible CV-QKD for future secure communications. We describe the proposed network architecture, identifying the relevant parameters and interfaces. We consider and analyze a Gaussian-modulated coherent state CV-QKD system, reporting recent experimental results at the varying of the QKD system wavelength, as relevant adaptable parameter, that can be configured by the SDN controller, for distributing highly secure keys in metropolitan networks. The capabilities and potentialities of our proposed approach for future secure communications in open and disaggregated 6G networks are also discussed.