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Accueil du site > Recherche > Projets > Thème MOSAIQ > Distributed clock Synchronization of entangled photon sources for future long distance quantum cryptography (CONNEQT)

Distributed clock Synchronization of entangled photon sources for future long distance quantum cryptography (CONNEQT)

- Leader : D’Auria Virginia

- Collaborators within the LPMC : Alibart Olivier, Labonté Laurent, Tanzilli Sébastien

- External Collaborators : Daniel Olivier, FIST-SA

- PhD students/Post-doctoral fellows : Bin-Ngah Lutfi-Arif, Kaiser Florian

- Financial supports : ANR Emergence (2012/2013), Région PACA "volet exploratoire", CNRS PEPS

- Description :

During the process of economic globalization, information security has become more and more important for both organizations and individuals. Security of classical cryptography is based on the complexity of cipher algorithms proven to be non robust against the progress of future computational resources. Concurrently, quantum cryptography (QC) has been developed and subsequently appeared to meet the urgent demand for secure communication. Despite encouraging results, QC compatible with classical optical networks, as required for the fast inflation of user number, is still an unattained milestone. Currently, a full integration of QC within standard networking infrastructures is essentially blocked by losses occurring in optical fibers and by limited performances of optical detectors. CONNEQT aims at demonstrating a simple and high-speed scheme for long-distance quantum cryptography. The investigated quantum connection is based on a quantum relay configuration, exploiting independent entangled photon-pair sources that have to be properly synchronized. The requirement for high repetition rates excludes the possibility of using ordinary electronically based synchronization. The associated electrical-to-optical conversions would indeed lead to additional jitters and prevent reaching a perfect synchronization accuracy. CONNEQT proposes to overcome this problem by the use of an original all-optical distributed-clock synchronization scheme. The main idea relies on utilizing a 5 GHz repetition rate telecom laser as a master clock to allow, thanks to dedicated distribution channels, the generation of synchronized entangled pairs of photons at remote locations. This is a necessary condition for achieving a reliable quantum relay function over a significant distance. Beyond the validation of the synchronization scheme showing an efficient quantum relay operation over 400 km, the concept will be applied to carry out a quantum cryptography demonstrator over the longest fiber link ever. We expect reaching secret key rates on the order of 1 Hz, associated with error rates around 5%. Possible future commercial partners, who could be interested in the project, have been already been identified ; in particular preliminary contacts have been established, with two companies, Draka Comteq and idQuantique. Note that a patent application has already been proposed (30th of September) by the patent office Osha Liang, on behalf of the CNRS/LPMC and with the help of FIST-SA.