Adding artificial noise for code rate matching in continuous-variable quantum key distribution

Title

Adding artificial noise for code rate matching in continuous-variable quantum key distribution

Authors

Sören Kreinberg, Igor Koltchanov, André Richter

Abstract

The reconciliation step of continuous-variable quantum key distribution protocols usually involves forward error correction codes. Matching the code rate and the signal-to-noise ratio (SNR) of the quantum channel is required to achieve the high reconciliation efficiencies that are crucial for long distance links. Puncturing and shortening is a way to adapt the code rate to the SNR at the cost of a slightly reduced reconciliation efficiencies. Instead of adapting the code rate to the SNR, we propose to add a controlled amount of artificial noise to the measured data, so that the resulting SNR could be reduced to match the given code rate. We show that our method can compete with puncturing and shortening and even outperform it in high-loss, high-excess noise scenarios.

Venue

ArXiv.org

Place and Date

https://arxiv.org/abs/1905.04925, Submitted on 13 May 2019

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Flexible User/Cloud-Centric Entanglement Distribution with Synthesizable Network Node

Title

Flexible User/Cloud-Centric Entanglement Distribution with Synthesizable Network Node

Authors

Fabian Laudenbach, Bernhard Schrenk, Martin Achleitner, Nemanja Vokic, Dinka Milovancev, Hannes Hübel

Abstract

The practical roll-out of quantum communication technologies in optical networks and the adoption of novel quantum applications demand the distribution of single or entangled photons. Flexibility and dynamicity is paramount for the provision of quantum resources, in order to scale with the number of users and to meet the demand of complex network architectures. We present a quantum network architecture that features this degree of reconfigurability, without being restricted to a rigid physical-layer network based on purely passive multiplexing componentry. We leverage spectral assets of photon-pair sources, from the short-wavelength band to the L-band, and agile spatial switching at a remote optical network node in order to realize a flexible distribution map that features different flavors, reaching from cloud-centric to user-centric quantum connectivity. Entanglement distribution is experimentally demonstrated at high visibility for five users in a 17-km reach, tree-shaped optical network. The delivered photon rate can be dynamically adjusted between the users by a factor of 2.5. Penalty-free operation is confirmed for integrating a co-existing classical control channel within the quantum.

Venue

Journal of Selected Topics in Quantum Electronics (JSTQE)

Place and Date

https://arxiv.org/abs/1908.01673,  5 August 2019

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We will be at Quantum.Tech in London!

Our project coordinator Hannes Hübel will be speaking at the 2nd edition of Quantum.Tech, which is being held at Twickenham Stadium, London, 20-22 April 2020.

Quantum.Tech is the world’s first, and largest event bringing together industry, research institutions, government agencies, and investors whose primary goal is to drive forward the commercialisation of Quantum technologies.

UNIQORN is very much looking forward to being a part of this event where 80 other world-class speakers from the entire Quantum ecosystem will participate.

If you’d like to view the full programme or learn more about this event go to: www.quantumtechcongress.co.uk , or to stay up to date on Twitter @QuantumTech_ #QT2020

We hope you will join us at Quantum.Tech this April!

Posted by admin in News

See you at OFC 2020

Part of our work will be presented by our partner AIT Austrian Institute of Technology at OFC 2020 on 8 – 12 March at San Diego Convention Center, San Diego, California, USA.

  • Monday 9 March 2020 at 11:45 – Room 9

F. Laudenbach, B. Schrenk, M. Achleitner, N. Vokic, D. Milovancev, and H. Hübel, “Flexible Entanglement Distribution Overlay for Cloud/Edge DC Interconnect as Seed for IT-Secure Primitives,” in Proc. OFC’20, San Diego, United States, Mar. 2020, M2K.5

  • Monday 9 March 2020 at 17:30 – Room 1A

N. Vokic, D. Milovancev, W. Boxleitner, H. Hübel, and B. Schrenk, “Compact Differential Phase-Shift Quantum Receiver Assisted by a SOI / BiCMOS Micro-Ring Resonator,” in Proc. OFC’20, San Diego, United States, Mar. 2020, M4A.4

  • Wednesday 11 March 2020 – Poster Session Exhibition Hall B

N. Vokic, D. Milovancev, B. Schrenk, M. Hentschel, and H. Hübel, “Deployment Opportunities for DPS-QKD in the Co-Existence Regime of Lit GPON / NG-PON2 Access Networks,” in Proc. OFC’20, San Diego, United States, Mar. 2020, W2A.56

See you there!

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UNIQORN at INFOCOM World 2019

Our partner COSMOTE presented the UNIQORN project in the INFOCOM World Conference took place in Athens, Greece on the 26th of November 2019.

This year’s InfoCom World, was focused on suggestions, implementations and plans, for the development of the Smart Home industry, as well as challenges, opportunities and prospects.

During the “Prospects and Challenges for Developing Innovative Applications and 5G Services” workshop the UNIQORN representatives had the chance to discuss and exchange ideas with many other interesting projects in the field.

 

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D8.4 Promotion video availability

Contributing Partners

AIT

Executive Summary

In this document we present the official UNIQORN video, which can be used by the project partners and the European Commission to further communicate the scope of the project.
The UNIQORN video explains in simple words the project’s ambition and idea and it can be found on the project’s website as well as on the project’s YouTube channel.
UNIQORN Video: https://youtu.be/SJKmg-qsA_o

Posted by admin in project deliverables

General framework for the analysis of imperfections in nonlinear systems

Title

General framework for the analysis of imperfections in nonlinear systems

Authors

Matteo Santandrea, Michael Stefszky, and Christine Silberhorn

Abstract

In this Letter, we derive a framework to understand the effect of imperfections on the phase-matching spectrum of a wide class of nonlinear systems. We show that this framework is applicable to many physical systems, such as waveguides or fibers. Furthermore, this treatment reveals that the product of the system length and magnitude of the imperfections completely determines the phase-matching properties of these systems, thus offering a general rule for system design. Additionally, our framework provides a simple method to compare the performance of a wide range of nonlinear systems.

Venue 

Optics Letters, 15 November 2019, Volume 44, Issue 22, pp. 5394-5649

[Download]

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Characterisation of fabrication inhomogeneities in Ti:LiNbO3 waveguides

Title

Characterisation of fabrication inhomogeneities in Ti:LiNbO3 waveguides

Authors

Matteo Santandrea, Michael Stefszky, Ganaël Roeland and Christine Silberhorn

Abstract

Nonlinear processes in integrated, guiding systems are fundamental for both classical and quantum experiments. Integrated components allow for compact, modular and stable light-processing systems and as such their use in real-world systems continues to expand. In order to use these devices in the most demanding applications, where efficiency and/or spectral performance are critical, it is important that the devices are fully optimised. In order to achieve these optimisations, it is first necessary to gain a thorough understanding of current fabrication limits and their impact on the devices’ final performance. In this paper we investigate the current fabrication limits of titanium indiffused lithium niobate waveguides produced using a masked photolithographic method. By dicing a long (~8 cm) sample into smaller pieces and recording the resulting phase matching spectra, the fabrication error present in the UV photolithographic process is characterised. The retrieved imperfections fit well with theoretical expectations and from the measured imperfection profile it is shown that one can directly reconstruct the original distorted phase matching spectrum. Therefore, our measurements directly quantify the intrinsic limitations of the current standard UV photolitographically produced titanium-indiffused lithium niobate waveguides.

Venue

New Journal of PhysicsVolume 21December 2019

[Download]

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Deployment Opportunities for DPS-QKD in the Co-Existence Regime of Lit GPON / NG-PON2 Access Networks

Title

Deployment Opportunities for DPS-QKD in the Co-Existence Regime of Lit GPON / NG-PON2 Access Networks

Authors

N. Vokic, D. Milovancev, B. Schrenk, M. Hentschel, and H. Hübel

Abstract 

We demonstrate cost-effective QKD integration for GPON and NG-PON2. Operation at 5.1×10-7 secure bits/pulse and a QBER of 3.28% is accomplished for a 13.5-km reach, 2:16-split PON, with 0.52% co-existence penalty for 19 classical channels.

Venue

The Optical Fiber Communication Conference & Exhibition (OFC 2020)

Place and Date

San Diego Convention Center, San Diego, California, USA, 8 – 12 March 2020

[Download]

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Flexible Entanglement Distribution Overlay for Cloud/Edge DC Interconnect as Seed for IT-Secure Primitives

Title

Flexible Entanglement Distribution Overlay for Cloud/Edge DC Interconnect as Seed for IT-Secure Primitives

Authors

F. Laudenbach, B. Schrenk, M. Achleitner, N. Vokic, D. Milovancev, and H. Hübel

Abstract 

We leverage spectral assets of entanglement and spatial switching to realize a flexible distribution map for cloud-to-edge and edge-to-edge quantum pipes that seed IT-secure primitives. Dynamic bandwidth allocation and co-existence with classical control are demonstrated.

Venue

The Optical Fiber Communication Conference & Exhibition (OFC 2020)

Place and Date

San Diego Convention Center, San Diego, California, USA, 8 – 12 March 2020

[Download]

Posted by admin in scientific publications