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Postdoc Study of CV-QKD solutions for quantum communications F/H


Telecommunications operators have an increased need for security in their networks in order to cope with malicious intentions and also to offer high quality services to their customers with a high level of security (i.e. defense, banking, health, industry 4.0 …).
Encryption algorithms associated with ever more complex key exchange mechanisms are thus used to ensure the security of the transported data. Nevertheless, the arrival of powerful computers (quantum ones or not) could endanger the current cryptographic mechanisms. In addition, attack strategies like “store now and attack later” consist in listening to and recording the data streams today in order to decipher them later. Finally, finding techniques to detect an intrusion while increasing the level of security of data flows protected by the usual encryption algorithms is of utmost interest. Thus, it was demonstrated in the early 80s that quantum physics could meet these specifications. Experiments with entangled photons have been carried out; in addition, Bennett and Brassard introduced in 1984 a cryptography protocol based on the polarization of single photons (BB84).With the growth of optical communications networks, it became clear to use these quantum cryptography techniques to secure the optical transmission of data. Quantum cryptography technologies include the discrete variable quantum key distribution (DV-QKD) that uses the BB84 protocol as well as unique photon sources and detectors. Another so-called continuous variable key distribution technique (CV-QKD) relies on the sending of coherent states in the fiber, which are detected by receivers such as those used in WDM transport systems.
Your role will be to participate in the laboratory implementation of a complete line of CV-QKD (source, fiber optic link, detector). You will evaluate the performance in different contexts to identify the limitations: fiber with co-propagation or dedicated fiber. You will also seek to improve the technique used today taking into account the WDM coherent transmission knowledge. Incidentally, you will study the solutions to increase the transmission range of QKD systems (i.e. quantum repeaters) and to generalize the use of these techniques in a free space or mobile environment.

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40 48 Avenue de la Republique,
92320 CHATILLON, France

Published on December 02, 2019

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