Scientific Publications

Adding Artificial Noise for Dynamic Code Rate Matching in Continuous-Variable Quantum Key Distribution

Title

Adding Artificial Noise for Dynamic Code Rate Matching in Continuous-Variable Quantum Key Distribution

Authors

S. Kreinberg, I. Koltchanov, A. Richter

Abstract

CV-QKD over long distances requires high reconciliation efficiencies, hence matching error correction code rate vs. SNR. For time-varying quantum channels, we achieve this by adding a controlled amount of digital noise to the measured data.

Venue

CLEO 2020

Place and Date

All-virtual, web conference format 11 – 15 May 2020

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Modelling Weak-Coherent QKD Systems Using a Classical Simulation Framework

Title

Modelling Weak-Coherent QKD Systems Using a Classical Simulation Framework

Authors

S. Kreinberg, P. Novik, I. Koltchanov, A. Richter

Abstract

We demonstrate how an existing simulation framework for modelling classical optical systems can be utilized for simulations of weak-coherent QKD links.

Venue

CLEO 2020

Place and Date

All-virtual, web conference format 11 – 15 May 2020

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Monolithically integrated differential phase shift transmitter for quantum key distribution

Title

Monolithically integrated differential phase shift transmitter for quantum key distribution

Authors

Ozan Çirkinoglu, Rui Santos, Kevin A. Williams, Xaveer J.M. Leijtens

Abstract

An integrated differential phase shift QKD transmitter, which consist of a distributed Bragg reflector laser, a phase modulator, and Mach-Zehnder modulator sections for pulse carving and optical attenuation has been designed and fabricated. Initial characterization shows single mode operation of the laser with a linewidth around 2 MHz, and an achievable optical attenuation of more than 60 dB.

Venue

22nd European Conference on Integrated Optics, 2020 (ECIO)

Place and date

Online, 23 – 24 June 2020

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An InP-based integrated modulated coherent state source for differential phase shift quantum key distribution

Title

An InP-based integrated modulated coherent state source for differential phase shift quantum key distribution

Authors

Ozan Çirkinoglu, Rui Santos, Kevin A. Williams, Xaveer J.M. Leijtens

Abstract

A low-cost integrated differential phase shift QKD transmitter, which consist of a distributed Bragg reflector laser, a phase modulator, and Mach-Zehnder modulator sections for pulse carving and optical attenuation is presented. Initial characterization results of the laser, and the modulator sections are demonstrated.

Venue

24th annual IEEE Photonics Benelux Symposium 2019

Place and Date

Netherlands, Amsterdam, 21 – 22 November 2019

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Differential Phase-Shift QKD in a 2:16-Split Lit PON with 19 Carrier-Grade Channels

Title

Differential Phase-Shift QKD in a 2:16-Split Lit PON with 19 Carrier-Grade Channels

Authors

N. Vokić, D. Milovančev, B. Schrenk, M. Hentschel, and H. Hübel

Abstract

We investigate the practical network integration of differential phase shift quantum key distribution following a cost-optimized deployment scheme where complexity is off-loaded to a centralized location. User terminal equipment for quantum state preparation at 1 GHz symbol rate is kept technologically lean through use of a directly-modulated laser as optical encoder. Integration in a passive optical network infrastructure is experimentally studied for legacy and modern optical access standards. We analyze the implications that result from Raman scattering arising from different spectral allocations of the classical channels in the O-, S-, C- and L-band, and prove that the quantum channel can co-exist with up to 19 classical channels of a fully-loaded modern access standard. Secure-key generation at a rate of 5.1×10 −7 bits/pulse at a quantum bit error ratio of 3.28% is obtained over a 13.5 km reach, 2:16 split passive network configuration. The high power difference of 93.8 dB between launched classical and quantum signals in the lit access network leads to a low penalty of 0.52% in terms of error ratio.

Venue

IEEE Journal Selected Topics in Quantum Electronics

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11.2 Tb/s Classical Channel Coexistence with DV-QKD over a 7-Core Multicore Fiber

Title 

11.2 Tb/s Classical Channel Coexistence with DV-QKD over a 7-Core Multicore Fiber

Author

E. Hugues-Salas, O. Alia, R. Wang, K. Rajkumar, G. T. Kanellos, R. Nejabati and D. Simeonidou

Abstract

The feasibility of transmitting discrete-variable quantum key distribution channels with carrier-grade classical optical channels over multicore fibers is experimentally explored in terms of achievable quantum bit error rates, secret key rates as well as classical signal bit error rates. A coexistence transmission record of 11.2Tb/s is achieved for the classical channels simultaneously with a DV-QKD channel over a 1km-long 7-core multicore fiber. Coexistence over the same multicore fiber core is identified as a dominant factor for the performance of the quantum channel requiring optical bandpass filtering of 17nm for the quantum channel to avoid the effect of Raman noise. Also, counter-propagation of classical channels and quantum channels probe more tolerance to noise proliferation than co-propagation. In addition, the performance of the quantum channel is maintained when more than three cores are used for the classical channels. Furthermore, by adding a second DV-QKD channel in the multicore fiber, the simultaneous transmission of classical channels as well as the generation of quantum-secured keys of two QKD channels is achieved with an operational range of 10dBs of launched power into the MCF.

Venue

IEEE Journal of Lightwave Technology

 

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Compact, low-threshold squeezed light source

Title

Compact, low-threshold squeezed light source

Authors

J. Arnbark, C. S. Jacobsen, R. B. Andrade, X. Guo, J. S. Neergaard-Nielsen, U. L. Andersen, T. Gehring

Abstract

Strongly squeezed light finds many important applications within the fields of
quantum metrology, quantum communication and quantum computation. However, due to the
bulkiness and complexity of most squeezed light sources of today, they are still not a standard tool
in quantum optics labs. We have taken the first steps in realizing a compact, high-performance
1550 nm squeezing source based on commercially available fiber components combined with
a free-space double-resonant parametric down-conversion source. The whole setup, including
single-pass second-harmonic generation in a waveguide, fits on a 30 cm×45 cm breadboard and
produces 9.3 dB of squeezing at a 5 MHz sideband-frequency. The setup is currently limited
by phase noise, but further optimization and development should allow for a 19″ sized turn-key
squeezing source capable of delivering more than 10 dB of squeezing.

Venue

Optics Express, vol 27

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End-to-End Quantum Secured Inter-Domain 5G Service Orchestration Over Dynamically Switched Flex-Grid Optical Networks Enabled by a q-ROADM

Title

End-to-End Quantum Secured Inter-Domain 5G Service Orchestration Over Dynamically Switched Flex-Grid Optical Networks Enabled by a q-ROADM

Authors

Rui Wang, Rodrigo Stange Tessinari, Emilio Hugues Salas, Anderson Bravalheri, Navdeep Uniyal, Abubakar Muqaddas, Rafael Silva Guimaraes, Thierno Diallo, Shadi Moazzeni, Qibing Wang, George Kanellos, Reza Nejabati, Dimitra Simeonidou

Abstract

Dynamic and flexible optical networking enabled by NFV and SDN are the key technology enablers for supporting the dynamicity and bandwidth requirements of emerging 5G network services. To achieve the objective of 5G, Network Services (NSes) must be often deployed transparently over multiple administrative and technological domains. Such case often presents security risks since a typical NS may comprise a chain of network functions, each executed in different remote locations, and tampering within the network infrastructure may compromise their communication. To avoid such threats, QKD has been identified and proposed as a future-proof method immune to any algorithmic cryptanalysis based on quantum-physics mechanisms. The maturity of QKD has enabled the R&D of quantum networks coexisting with optical networks using telecom equipment. This makes the QKD a suitable candidate for the security of distributed and virtualised network services.
In this paper, for the first time, we propose a dynamic quantum-secured optical network for supporting network services that are dynamically created by chaining VNF over multiple network domains. This work includes a new quantum-ROADM, extensions to SDN-enabled optical control plane, and extensions to NFV orchestration to achieve quantum-aware, on-demand chaining of VNFs. The experimental results verify the capability of routing quantum and classical data channels both individually and dynamically over shared fibre links. Moreover, quantum secured chaining of VNFs in 5G networks is experimentally demonstrated via interconnecting four autonomous 5G islands simultaneously through the q-ROADM with eight optical channels using the 5GUK Exchange orchestration platform. The experimental scenarios and results confirm the benefit of the proposed data plane architecture and control/management plane framework.

Venue

Journal of Lightwave Technology (Invited), vol. 38, no. 1, pp. 139-149, 1 Jan.1, 2020

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Coexistence of 11.2Tb/s Carrier-Grade Classical Channels and a DV-QKD Channel over a 7-Core Multicore Fibre

Title

Coexistence of 11.2Tb/s Carrier-Grade Classical Channels and a DV-QKD Channel over a 7-Core Multicore Fibre

Authors

Emilio Hugues-Salas, Qibing Wang, Rui Wang, Kalyani Rajkumar, George T. Kanellos, Reza Nejabati, Dimitra Simeonidou

Abstract

We successfully demonstrate coexistence of record-high 11.2 Tb/s (56x200Gb/s) classical channels with a discrete-variable-QKD channel over a multicore fibre. Continuous secret key generation is confirmed together with classical channel performance below the SDFEC limit and a minimum quantum channel spacing of 17nm in the C-band.

Venue

European Conference on Optical Communication (ECOC),

Place and Date

Dublin, Ireland, 22 – 26 September 2019, Dublin

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Field Trial of Dynamic DV-QKD Networking in the SDNControlled Fully-Meshed Optical Metro Network of the Bristol City 5GUK Test Network

Title

Field Trial of Dynamic DV-QKD Networking in the SDNControlled Fully-Meshed Optical Metro Network of the Bristol City 5GUK Test Network

Authors

R. S. Tessinari, A. Bravalheri, E. Hugues-Salas, R. Collins, D. Aktas, R.S. Guimaraes, O. Alia, J. Rarity, G. T. Kanellos, R. Nejabati, and D. Simeonidou

Abstract

We demonstrate for the first time a field trial of a fully meshed metro network with dynamic QKD networking capabilities across four optical network nodes in the 5GUK Test Network, where the DV-QKD quantum channels co-exist with classical channels and are dynamically switched and rerouted utilising QKD-aware SDN control.

Venue

European Conference on Optical Communications (ECOC’19). Post-deadline Paper PD3.6

Place and Date

Dublin, Ireland. September, 2019. 

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