An integrated silicon photonic chip platform for continuous-variable quantum key distribution

• Main Authors: Zhang, Gong, Haw, J. Y., Cai, H., Xu, F., Assad, S. M., Fitzsimons, J. F., Zhou, X., Zhang, Y., Yu, S., Wu, J., Ser, Wee, Kwek, L. C., Liu, Ai Qun
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Electrical and electronic engineering; Optics And Photonics; Quantum Information
• Online Access: https://hdl.handle.net/10356/139150
• Institution: Nanyang Technological University

Quantum key distribution (QKD) is a quantum communication technology that promises unconditional communication security. High-performance and cost-effective QKD systems are essential for the establishment of quantum communication networks1–3. By integrating all the optical components (except the laser source) on a silicon photonic chip, we have realized a stable, miniaturized and low-cost system for continuous-variable QKD (CV-QKD) that is compatible with the existing fibre optical communication infrastructure4. Here, the integrated silicon photonic chip is demonstrated for CV-QKD. It implements the widely studied Gaussian-modulated coherent state protocol that encodes continuous distributed information on the quadrature of laser light5,6. Our proof-of-principle chip-based CV-QKD system is capable of producing a secret key rate of 0.14 kbps (under collective attack) over a simulated distance of 100 km in fibre, offering new possibilities for low-cost, scalable and portable quantum networks.