Zhang, GongHaw, Jing YanCai, HongXu, FengAssad, SyedFitzsimons, Joseph F.Zhou, XianzhongZhang, Y.Yu, S.Wu, J.Ser, W.Kwek, L. C.2020-11-061749-4885http://hdl.handle.net/1885/214108Quantum 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 networks1,2,3. 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.This work was supported by the Singapore Ministry of Education (MOE) Tier 3 grant (MOE2017-T3-1-001), the Singapore National Research Foundation (NRF) National Natural Science Foundation of China (NSFC) joint grant (NRF2017NRF-NSFC002-014) and the Singapore National Research Foundation under the Competitive Research Program (NRF-CRP13-2014-01).application/pdfen-AU© 2019 The Author(s), under exclusive licence to Springer Nature Limited2019-08-1210.1038/s41566-019-0504-52020-07-06