Implementation of continuous variable quantum cryptography

Title: Implementation of continuous variable quantum cryptography

Speaker:Hao Qin

Time29th October 20182:30pm-5:30pmCommunication Building 725

Location818 Conference Room, Communication Building




Dr. Hao Qin received the bachelor degree in optical information science and technology from Southeast University, China in 2009. In 2011 he obtained the research master degree in photonic and information processing from Telecom Bretagne, France. In the same year, he joined the quantum information group Telecom ParisTech as a Ph.D. student.  In 2015, Hao received his Ph.D. degree with thesis “attacks and countermeasures in practical continuous variable quantum key system”. Hao then spent one and a half year in Institute for Quantum Computing at university of Waterloo in Canada as a postdoctoral fellow, where he joined the quantum hacking lab to perform research on implementation security in quantum cryptography systems. Currently, Hao is now a quantum scientist in CAS Quantum Network Co., Ltd., whose main task is constructing and operating the national quantum backbone network, Hao's research interests include continuous variable quantum key distribution, practical security and applications of quantum key distribution systems, quantum hacking attacks and countermeasures, and standardization and certification in quantum cryptography systems.


Continuous-variable (CV) quantum key distribution (QKD) is another promising approach to perform quantum key distribution other than discrete variable (DV) QKD. It relies on continuous modulation of the light field quadrature and measurements with coherent detection instead of single photon detectors in DV-QKD. Benefiting from coherent detection, CV-QKD can be fully implemented with off-the-shelf optical communication components. Moreover, the local oscillator in the coherent detection acts as a "built-in" filter to efficiently reduce any noise photons in different modes, which enables CV-QKD to be deployed in co-existence with intense classical channels over optical networks and to be possibly implemented in day light free space environments.


In this talk, Hao Qin will introduce the basic concepts of continuous variable quantum key distribution including homodyne detection, main principal, typical implementation, post processing and some advanced topics including security proofs, quantum hackings and wavelength multiplexing applications.