Coexistence of discrete-variable QKD with WDM classical signals in the C-band for fiber access environments

Title
Coexistence of discrete-variable QKD with WDM classical signals in the C-band for fiber access environments

Authors
D. Zavitsanos, G. Giannoulis, A. Raptakis, C. Papananos, F. Setaki, E. Theodoropoulou, G. Lyberopoulos, Ch. Kouloumentas, and H. Avramopoulos.

Abstract
In this paper, a coexistence scheme between a Discrete-Variable Quantum Key Distribution (DV-QKD) and four bidirectional classical channels in a Passive Optical Network (PON) topology is theoretically investigated. The study aims to explore the imposed limitations considering the coexistence of weak quantum channels with realistic traffic flows of classical streams through shared fiber infrastructures. Based on a ‘plug and play’ phase coding DV-QKD implementation, we conducted numerical simulations of the QBER and the secure key rate for fiber distances up to 10km. The reported results suggest that in a fixed C-band grid, the spectral isolation between classical and quantum channels is essential at dense grids. By removing the leakage noise through stronger spectral isolation, the photons linked with the Raman scattering becomes the dominant noise source, since this mechanism covers an ultra-broadband window and gets stronger as the propagation distance increases.

Venue
21st International Conference on Transparent Optical Networks ICTON 2019 (http://www.icton2019.com/)

Place and Date
Angers, France, July 9-13, 2019

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A strong UNIQORN presence at ICTON 2019

21st International Conference on Transparent Optical Networks
ICTON 2019
Place: Angers, France
Date: July 9 -13, 2019

The UNIQORN partners will present recent project results at ICTON 2019 during the following dedicated talks!

Flexible entanglement distribution based on WDM and active switching technology

Session: QC I Wednesday, July 10, 9:10-10:50

Authors
Hannes Hübel, Bernhard Schrenk, Sophie Zeiger, Fabian Laudenbach and Michael Hentschel  (AIT Austrian institute of Technology)

Abstract
In future, the distribution of single or entangled photons inside optical networks will be a prerequisite for a general roll-out and adoption of quantum communication technologies. In particular, on-demand routing and active wavelength allocation will be needed to meet the demand of complex network architectures. In the last years several attempts have been made, based either on passive optical WDM technology or active switching of channels. Here we present a novel approach whereby we combine spectral slicing of the emission spectrum of SPDC sources together with space-switches to generate a reconfigurable distribution node for entanglement.  The increased switching complexity offered by our hybrid solution allows us to realise quantum ROADMs with up to three degrees.

Modelling Weak-Coherent CV-QKD Systems Using a Classical Simulation Framework

Session: QC III Wednesday, July 10, 14:20-16:20

Authors
Sören Kreinberg(1), Igor Koltchanov(1), Piotr Novik(2), Saleem Alreesh(1), Fabian Laudenbach(3), Christoph Pacher(3), Hannes Hübel(3), André Richter(1)

Affiliations
(1) VPIphotonics GmbH, Carnotstr. 6, 10587 Berlin, Germany
(2) VPI Development Center, ul. Filimonova 15-50831, 220037 Minsk, Belarus
(3) Austrian Institute of Technology GmbH, Donau-City-Str. 1, 1220 Vienna, Austria

Abstract
Due to their compatibility to existing telecom technology, continuous variable (CV) weak coherent state protocols are promising candidates for a broad deployment of quantum key distribution (QKD) technology. We demonstrate how an existing simulation framework for modelling classical optical systems can be utilized for simulations of weak-coherent CV-QKD links. The quantum uncertainties for the measured characteristics of coherent signals are modelled in the electrical domain by shot noise, while a coherent signal in the optical domain is described by its quadrature components. We simulate various degradation effects such as attenuation, laser RIN, Raman noise (from classical channels in the same fibre), and device imperfections and compare the outcome with analytical theory. Having complemented the physical simulation layer by the post-processing layer (reconciliation and privacy amplification), we are able to estimate secure key rates from simulations, greatly boosting the development speed of practical CV-QKD schemes and implementations.

Coexistence of discrete-variable QKD with WDM classical signals in the C-band for fiber access environments

Session: QC V Thursday, July 11, 8:30-10:10

Authors
D. Zavitsanos (1), G. Giannoulis (1), A. Raptakis (1), C. Papananos (1), F. Setaki (2), E. Theodoropoulou (2), G. Lyberopoulos (2), Ch. Kouloumentas (1), (3), and H. Avramopoulos (1)

Affiliations
(1) National Technical University of Athens, Greece
(2) COSMOTE Kinites Tilepikoinonies A.E., Athens, Greece
(3) Optagon Photonics, Athens, Greece

Abstract
In this paper, a coexistence scheme between a Discrete-Variable Quantum Key Distribution (DV-QKD) and four bidirectional classical channels in a Passive Optical Network (PON) topology is theoretically investigated. The study aims to explore the imposed limitations considering the coexistence of weak quantum channels with realistic traffic flows of classical streams through shared fiber infrastructures. Based on a ‘plug and play’ phase coding DV-QKD implementation, we conducted numerical simulations of the QBER and the secure key rate for fiber distances up to 10km. The reported results suggest that in a fixed C-band grid, the spectral isolation between classical and quantum channels is essential at dense grids. By removing the leakage noise through stronger spectral isolation, the photons linked with the Raman scattering becomes the dominant noise source, since this mechanism covers an ultra-broadband window and gets stronger as the propagation distance increases.

Official ICTON 2019 website:http://www.icton2019.com/

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2nd UNIQORN General Assembly

On May 21 – 22, 2019 we organised the 2nd general assembly of our project in Vienna, Austria!

The main topics discussed were the technical work plan, the communication and dissemination strategy and the project contributions to the Quatum Flaghsip! In addition to the plenary sessions, parallel technical sessions about the use cases  e-Health, e-Government and Smart City, and the different work packages were organised.

Actions, next steps and goals for the near future have been defined!

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European Quantum Community Meeting 2019

Date: October 17 – 18, 2019

Place: Helsinki, Finland

Join the Finnish Presidency–Quantum Flagship event that will take place in October in Helsinki.  The two day event will be dedicated to the Quantum Technology community, the Quantum Flagship as well as setting the Strategic Research Agenda, which will be presented and discussed among the community attending the event.  The program is currently being finalised and will be published very soon.

Source: https://qt.eu/newsroom/save-the-date-exploring-and-making-quantum-technology/

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Co-existence of 9.6 Tb/s Classical Channels and a Quantum Key Distribution (QKD) Channel over a 7-core Multicore Optical Fibre

This paper presents a record-high co-existence DP-16QAM coherent transmission of 9.6Tb/s for classical channels with one discrete-variable quantum key distribution channel over a 7-core Multicore fibre. We demonstrate that effective secret key generation is possible even with the combined crosstalk effect of the six adjacent cores over the quantum channel. Additional measurements show the impact on the secret key rate and QBER by adding coherent optical channels in different cores.

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UNIQORN – Making quantum photonics affordable

Title

UNIQORN – Making quantum photonics affordable

Abstract

Blending on-chip ultrathin-film elements, nonlinear crystals, polymer interposers, and single-photon detectors, the UNIQORN project aims to develop a quantum system-on-chip methodology that brings low-cost assembly to the field of quantum optics.

Venue

LaserFocusWorld journal

[Download]

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Quantum, which colour suits you best?

At OFC 2019 in San Diego we posed the question how a practical integration of quantum channels into passive optical access networks could look like. To do so, we should first pay attention to the FSAN roadmap. 5G is on the brink of being rolled out together with its optical fronthauling over cloud-radio limited reach of ~20 km, while access standards incorporate wavelength stacking towards 4 lanes of 10 Gb/s. The good news is: NG-PON2 with its WDM overlay is spectrally allocated at the C- and L-bands. This blanks out the O-band, and if we expect fiber deployment to dismiss legacy solutions, there is really much unoccupied space down there at 1310 nm.

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