We present a pilot-assisted coherent intradyne reception methodology for CV-QKD with true local oscillator. An optically phase-locked reference tone, prepared using carrier-suppressed optical single-sideband modulation, is multiplexed in polarisation and frequency to the 250 Mbaud quantum signal in order to provide optical frequency- and phase matching between quantum signal and local oscillator. Our concept allows for high symbol rates and can be operated at an extremely low excess-noise level, as validated by experimental measurements.
QKD can be exercised with both, single photons or weak coherent states. The latter approach encodes the quantum information in the continuous phase and amplitude of the electromagnetic field of light and is therefore referred to as continuous-variable quantum key distribution (CV-QKD). As a main advantage of CV-QKD, this approach uses standard off-the-shelf components from the optical-telecommunication industry and can therefore be seamlessly integrated into existing telecom networks.
This article addresses an open problem in CV-QKD: to establish a stable phase- and frequency reference between transmitter and receiver (required for coherent detection) that does neither compromise the low noise level nor the symbol rate. As we believe, our method to co-transmit an optical reference signal, multiplexed to the quantum signal in modulation frequency and polarisation, constitutes a convincing answer to this problem. Harnessing the best practices from the highly advnced telecom industry, our transceiver operates at exceptionally high rate and low noise and thereby elevates QKD to a new level of technological maturity.
 F. Grosshans, N. J. Cerf, J. Wenger, R. Tualle-Brouri, and P. Grangier, Virtual entanglement and reconciliation protocols for quantum cryptography with continuous variables, arXiv:quant-ph/0306141 (2003).
 V. Scarani, H. Bechmann-Pasquinucci, N. J. Cerf, M. Dušek, N. Lütkenhaus, and M. Peev, The security of practical quantum key distribution, Rev. Mod. Physics 81, 1301 (2009).
 F. Laudenbach, C. Pacher, C. H. F. Fung, A. Poppe, M. Peev, B. Schrenk, M. Hentschel, P. Walther, and H. Hübel, Continuous-Variable Quantum Key Distribution with Gaussian Modulation – The Theory of Practical Implementations, Adv. Quantum Technol. 1, 1800011 (2018).
 P. Jouguet, S. Kunz-Jacques, A. Leverrier, P. Grangier, and E. Diamanti, Experimental demonstration of long-distance continuous-variable QKD, Nature Phot. 7, 378 (2013).
 S. Fossier, E. Diamanti, T. Debuisschert, A. Villing, R. Tualle-Brouri, and P. Grangier, Field test of a continuous-variable quantum key distribution prototype, New J. Phys. 11, 045023 (2009).
 J. Lodewyck, M. Bloch, R. García-Patrón, S. Fossier, E. Karpov, E. Diamanti, T. Debuisschert, N. J. Cerf, R. Tualle-Brouri, S. W. McLaughlin, and P. Grangier, Quantum key distribution over 25 km with an all-fiber continuous-variable system, Phys. Rev. A 76, 042305 (2007).
 B. Qi, L. L. Huang, L. Qian, and H. K. Lo, Experimental study on the Gaussian-modulated coherent-state quantum key distribution over standard telecommunication fibers, Phys. Rev. A 76, 052323 (2007).
 H. Häseler, Tobias Moroder, and Norbert Lütkenhaus, Testing quantum devices: Practical entanglement verification in bipartite optical systems, Phys. Rev. A 77, 032303 (2008).
 J. Z. Huang, C. Weedbrook, Z. Q. Yin, S. Wang, H. W. Li, W. Chen, G. C. Guo, and Z. F. Han, Quantum hacking of a continuous-variable quantum-key-distribution system using a wavelength attack, Phys. Rev. A 87, 062329 (2013).
 X. C. Ma, S. H. Sun, M. S. Jiang, and L. M. Liang, Wavelength attack on practical continuous-variable quantum-key-distribution system with a heterodyne protocol, Phys. Rev. A 87, 052309 (2013).
 H. Qin, R. Kumar, and R. Alléaume, Saturation attack on continuous-variable quantum key distribution system, in Proc. of SPIE Security + Defence, Dresden, GER, 88990N (2013).
 P. Jouguet, S. Kunz-Jacques, and E. Diamanti, Preventing calibration attacks on the local oscillator in continuous-variable quantum key distribution, Phys. Rev. A 87, 062313 (2013).
 X. C. Ma, S. H. Sun, M. S. Jiang, and L. M. Liang, Local oscillator fluctuation opens a loophole for Eve in practical continuous-variable quantum-key-distribution systems, Phys. Rev. A 88, 022339 (2013).
 B. Qi, P. Lougovski, R. Pooser, W. Grice, and M. Bobrek, Generating the local oscillator locally in continuous-variable quantum key distribution based on coherent detection, Phys. Rev. X 5, 041009 (2015).
 D. B. S. Soh, C. Brif, P. J. Coles, N. Lütkenhaus, R.M. Camacho, J. Urayama, and M. Sarovar, Self-referenced continuous-variable quantum key distribution protocol, Phys. Rev. X 5, 041010 (2015).
 T. Wang, P. Huang, Y. Zhou, W. Liu, and Guihua Zeng, Pilot-multiplexed continuous-variable quantum key distribution with a real local oscillator, Phys. Rev. A 97, 012310 (2018).
 T. Wang, P. Huang, Y. Zhou, W. Liu, H. Ma, S. Wang, and G. Zeng, High key rate continuous-variable quantum key distribution with a real local oscillator, Opt. Express 26, 2794 (2018).
 S. Kleis, R. Herschel, and C. Schaeffer, Simple and Efficient Detection Scheme for Continuous Variable Quantum Key Distribution with m-ary Phase-Shift-Keying, in Proc. of 2015 Conference on Lasers and Electro-Optics (CLEO), San Jose, USA, SW3M–7 (2015).
 H. H. Brunner, L. C. Comandar, F. Karinou, S. Bettelli, D. Hillerkuss, C. H. F. Fung, D. Wang, S. Mikroulis, Q. Yi, M. Kuschnerov, A. Poppe, C. Xie, and M. Peev, A low-complexity heterodyne CV-QKD architecture, in Proc. of 19th International Conference on Transparent Optical Networks (ICTON), Girona, ESP, We.C1.2 (2017).
 L. C. Comandar, H. H. Brunner, S. Bettelli, C. H. F. Fung, F. Karinou, D. Hillerkuss, S. Mikroulis, D. Wang, M. Kuschnerov, C. Xie, A. Poppe, and M. Peev, A flexible continuous-variable QKD system using off-the-shelf components, in Proc. SPIE 10442, Quantum Information Science and Technology III, Warsaw, POL, 104420A (2017).
 S. Kleis, M. Rueckmann, and C. G. Schaeffer, Continuous variable quantum key distribution with a real local oscillator using simultaneous pilot signals, Opt. Lett. 42, 1588 (2017).
 B. Schrenk and Hannes Hübel, Pilot-Assisted Local Oscillator Synchronisation for CV-QKD, in Proc. of QCrypt 2016, Washington DC, USA, 195 (2016).
 B. Schrenk, F. Laudenbach, F. Fung, C. Pacher, A. Poppe, R. Lieger, D. Hillerkuss, E. Querasser, G. Humer, M. Hentschel, M. Peev, and H. Hübel, High-rate continuous-variable quantum key distribution with pilot-disciplined local oscillator, in Proc. of European Conference on Optical Communication (ECOC 2017), Gothenburg, SWE, P2.SC6.q10 (2017).
 F. Laudenbach, B. Schrenk, C. Pacher, R. Lieger, E. Querasser, G. Humer, M. Hentschel, C. H. F. Fung, A. Poppe, M. Peev, and H. Hübel, Pilot-Disciplined CV-QKD with True Local Oscillator, in Proc. of QCrypt 2017, Cambridge, GBR, Mo33 (2017).
 H. H. Brunner, S. Bettelli, L. C. Comandar, D. Hillerkuss, C. H. F. Fung, D. Wang, S. Mikroulis, A. Poppe, and M. Peev, Precise Noise Calibration for CV-QKD, in Proc. of Optical Fiber Communication Conference (OFC 2019), San Diego, USA, Th1J.2 (2019).
 F. Laudenbach and C. Pacher, Analysis of the Trusted-Device Scenario in Continuous-Variable Quantum Key Distribution, Adv. Quantum Technol. 2, 1900055 (2019).
 Tobias A. Eriksson, Ruben S. Luis, Benjamin J. Puttnam, Georg Rademacher, Mikio Fujiwara, Yoshinari Awaji, Hideaki Furukawa, Naoya Wada, Masahiro Takeoka, and Masahide Sasaki, "Wavelength Division Multiplexing of 194 Continuous Variable Quantum Key Distribution Channels", Journal of Lightwave Technology 38 8, 2214 (2020).
 R. Valivarthi, S. Etcheverry, J. Aldama, F. Zwiehoff, and V. Pruneri, "Plug-and-play continuous-variable quantum key distribution for metropolitan networks", Optics Express 28 10, 14547 (2020).
 Heng Wang, Yaodi Pi, Wei Huang, Yang Li, Yun Shao, Jie Yang, Jinlu Liu, Chenlin Zhang, Yichen Zhang, and Bingjie Xu, "High-speed Gaussian-modulated continuous-variable quantum key distribution with a local local oscillator based on pilot-tone-assisted phase compensation", Optics Express 28 22, 32882 (2020).
 S. Pirandola, U. L. Andersen, L. Banchi, M. Berta, D. Bunandar, R. Colbeck, D. Englund, T. Gehring, C. Lupo, C. Ottaviani, J. L. Pereira, M. Razavi, J. Shamsul Shaari, M. Tomamichel, V. C. Usenko, G. Vallone, P. Villoresi, and P. Wallden, "Advances in quantum cryptography", Advances in Optics and Photonics 12 4, 1012 (2020).
 Sören Kreinberg, Piotr Novik, Igor Koltchanov, and André Richter, Conference on Lasers and Electro-Optics ATh1I.4 (2020) ISBN:978-1-943580-76-7.
 Ivan Derkach and Vladyslav C. Usenko, "Applicability of Squeezed- and Coherent-State Continuous-Variable Quantum Key Distribution over Satellite Links", Entropy 23 1, 55 (2020).
 Jie Lin and Norbert Lütkenhaus, "Trusted Detector Noise Analysis for Discrete Modulation Schemes of Continuous-Variable Quantum Key Distribution", Physical Review Applied 14 6, 064030 (2020).
 Feihu Xu, Xiongfeng Ma, Qiang Zhang, Hoi-Kwong Lo, and Jian-Wei Pan, "Secure quantum key distribution with realistic devices", Reviews of Modern Physics 92 2, 025002 (2020).
 Fabian Laudenbach, Christoph Pacher, Chi-Hang Fred Fung, Andreas Poppe, Momtchil Peev, Bernhard Schrenk, Michael Hentschel, Philip Walther, and Hannes Hübel, "Continuous-Variable Quantum Key Distribution with Gaussian Modulation -- The Theory of Practical Implementations", arXiv:1703.09278.
 Ryo Namiki, Akira Kitagawa, and Takuya Hirano, "Secret key rate of a continuous-variable quantum-key-distribution scheme when the detection process is inaccessible to eavesdroppers", Physical Review A 98 4, 042319 (2018).
 Sebastian Kleis, Max Rueckmann, and Christian G. Schaeffer, "Continuous-Variable Quantum Key Distribution with a Real Local Oscillator and without Auxiliary Signals", arXiv:1908.03625.
 Mi Zou, Yingqiu Mao, and Teng-Yun Chen, "Phase estimation using homodyne detection for continuous variable quantum key distribution", Journal of Applied Physics 126 6, 063105 (2019).
 Sören Kreinberg, Igor Koltchanov, Piotr Novik, Saleem Alreesh, Fabian Laudenbach, Christoph Pacher, Hannes Hübel, and André Richter, "Modelling Weak-Coherent CV-QKD Systems Using a Classical Simulation Framework", arXiv:2004.14703.
 Hou-Man Chin, Nitin Jain, Darko Zibar, Tobias Gehring, and Ulrik L. Andersen, "Effect of filter shape on excess noise performance in continuous variable quantum key distribution with Gaussian modulation", arXiv:1808.04573.
The above citations are from Crossref's cited-by service (last updated successfully 2021-01-16 02:54:04) and SAO/NASA ADS (last updated successfully 2021-01-16 02:54:06). The list may be incomplete as not all publishers provide suitable and complete citation data.
This Paper is published in Quantum under the Creative Commons Attribution 4.0 International (CC BY 4.0) license. Copyright remains with the original copyright holders such as the authors or their institutions.