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

Job description

about the role

Context

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 exchangemechanisms 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 “stor 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.

about you

PhD thesis in the field of quantum cryptography.

Good knowledge of the field of coherent optical telecommunications.

Good experience in the field of digital communications.

The skills required are those corresponding to a thorough initial
training in optical telecommunications and cryptography (master's level or engineering degree).

The key scientific and technical thematics that will be addressed in the post-doc are:

- Coherent optical telecommunications systems

- Digital communications, signal processing

- Cryptography

- Quantum physics

Experimental skills and in particular a good knowledge of optical
measurement devices and coherent optical telecommunications devices are also required.

You will also have to demonstrate autonomy, a real capacity for
analysis and adaptation to teamwork: contribution to a collaborative project, frequent discussions with Orange Labs experts working on quantum communications and cryptography. You will also need to be able to communicate well internally and externally.

Fluency in English is essential: this post-doc will be partly conducted as part of a European cooperative project.

additional information

State of the art

An abundant literature on QKD has been produced since the early 1980s. ID Quantique in Switzerland, has been offering a commercial DV-QKD system for several years [1]. Toshiba has a DV-QKD prototype. Many field trials have been conducted. We can mention the field test of British Telecom, Toshiba, Adva and the University of Cambridge connecting three sites separated by a few tens of kilometers. In the Chinese experiment MICIUS [2] quantum keys were sent by a satellite at two earth stations separated by several thousand miles. The literature on the CV-QKD technique is more recent [3] and therefore less abundant
but we can cite at least two articles published in 2018 where the CV-QKD quantum channel is co-propagated with several tens of WDM channels on a shared fiber [4,5].

Challenges

The objective is to study the CV-QKD quantum communications systems and to implement in the laboratory a complete CV-QKD system (source, fiber transmission line and coherent detector). The specific signal processing of quantum cryptography will have to be implemented in order to be able to detect potential intrusions. The evaluation of the system performance (range and throughput) should also be carried out: in co-propagation with WDM channels on a shared fiber and on a dedicated
fiber without co-propagation. The limitations of the system will have to be identified and solutions to circumvent them eventually found.

department

Within the Wireline Networks and Infrastructure (WNI) Department and attached to the Architecture and Programmable Optical Transmission (AOT) department, the SOAN team is in charge of Research and Anticipation activities on WDM transmission systems and agile and programmable
optical transport networks. To do this, the team of fifteen people has experimental optical transmission test-beds and powerful test and  measurement tools to recreate the conditions of propagation of optical signals in the fiber and to assess the latest technologies in Research and in Anticipation contexts.

What makes the added value of this offer?

Your scientific reflection and your creativity will be stimulated and
reinforced by the pragmatic and operational vision of Orange, a
world-class operator with a wide range of businesses. Targeted
applications (security of optical transport networks) will allow you to benefit from the skills and synergy of complementary teams, with the possibility of training in various fields. You will develop your skills in the most advanced cryptography techniques and integrate one of the best optical communications operator research laboratories, with the best experimental tools in metrology, tests and measurements. Finally, participation in a European collaborative project (H2020 Flagship CiViQ)
bringing together major players in the QKD domain will help you expand your vision of the field.

References :

1. ID Quantique, « Cerberis QKD blade - The world first carrier-grade quantum key distribution platform », White Paper, 2018.
2. Q. Zhang, F. Xu,Y-A. Chen, C-.Z. Peng, and J. Pan, « Large scale quantum key distribution: challenges and solutions », Optics Express, Vol. 26, No. 18, pp. 24260-24273, 3rd Sept 2018.
3. P. Jouguet, S. Kunz-Jacques, A. Leverrier, P. Grangier, and E. Diamanti, « Experimental demonstration of long-distance continuous-variable quantum key distribution », Nature Photonics, vol. 7, no. 5, pp. 378-381, 2013.
4. T. A. Eriksson, T. Hirano, G. Rademacher, B. J. Puttnam, R. S. Luis, M. Fujiwara, R. Namiki, Y. Awaji, M. Takeoka, N. Wada, and M. Sasaki, « Joint propagation of continuous variable quantum key distribution and 18x24.5 Gbaud PM-16QAM channels », in European Conference on Optical Communication (ECOC), 2018, paper We2.37”.

5. Gbaud PM-16QAM channels », in European Conference on Optical Communication (ECOC), 2018, paper We2.37. T. A. Eriksson, T. Hirano, B. J. Puttnam, G. Rademacher, R. S. Luis, M. Fujiwara, R. Namiki, Y. Awaji, M. Takeoka, N. Wada, and M. Sasaki, « Wavelength Division Multiplexing of Continuous
Variable Quantum Key Distribution and 18.3 Tbit/s Data Channels », Communications Physics, Nature, 2018.

contract

Post Doc