Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Quantum key distribution over a 40-dB channel loss using superconducting single-photon detectors

Abstract

We report the first quantum key distribution (QKD) experiment to enable the creation of secure keys over 42 dB channel loss and 200 km of optical fibre. We used the differential phase shift QKD (DPS-QKD) protocol, implemented with a 10-GHz clock frequency and superconducting single-photon detectors (SSPD) based on NbN nanowires. The SSPD offers a very low dark count rate (a few Hz) and small timing jitter (60 ps, full width at half maximum, FWHM). These characteristics allowed us to achieve a 12.1 bit s–1 secure key rate over 200 km of fibre, which is the longest terrestrial QKD over a fibre link yet demonstrated. Moreover, this is the first 10-GHz clock QKD system to enable secure key generation. The keys generated in our experiment are secure against both general collective attacks on individual photons and a specific collective attack on multiphotons, known as a sequential unambiguous state discrimination (USD) attack.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Secure key rate as a function of channel loss.
Figure 2: Experimental set-up for 10-GHz clock DPS-QKD
Figure 3: An SSPD.
Figure 4: Histogram of received 10-GHz clock signal.
Figure 5: DPS-QKD experimental results.

Similar content being viewed by others

References

  1. Gisin, N., Ribordy, G., Tittel, W. & Zbinden, H. Quantum cryptography. Rev. Mod. Phys. 74, 145–195 (2002).

    Article  ADS  Google Scholar 

  2. Vernam, G. S. Cipher printing telegraph systems for secret wire and radio telegraphic communications. J. Am. Inst. Elec. Eng. 45, 109–115 (1926).

    Google Scholar 

  3. Bennett, C. H., Bessette, F., Brassard, G., Salvail, L. & Smolin, J. Experimental quantum cryptography. J. Cryptology 5, 3–28 (1992).

    Article  Google Scholar 

  4. Bennett, C. H. & Brassard, G. Quantum cryptography: Public key distribution and coin tossing, in Proceedings of IEEE International Conference of Computer Systems and Signal Processing, Bangalore, India, 175–179 (IEEE, New York, 1984).

  5. Lütkenhaus, N. Security against individual attacks for realistic quantum key distribution. Phys. Rev. A 61, 052304 (2000).

    Article  ADS  Google Scholar 

  6. Brassard, G., Lütkenhaus, N., Mor, T. & Sanders, B. C. Limitations on practical quantum cryptography. Phys. Rev. Lett. 85, 1330–1333 (2000).

    Article  ADS  Google Scholar 

  7. Santori, C., Fattal, D., Vuc̆ković, J., Solomon, G. S. & Yamamoto, Y. Indistinguishable photons from a single-photon device. Nature 419, 594–597 (2002).

    Article  ADS  Google Scholar 

  8. Kuhn, A., Hennrich, M. & Rempe, G. Deterministic single-photon source for a distributed quantum networking. Phys. Rev. Lett. 89, 067201 (2002).

    Article  ADS  Google Scholar 

  9. McKeever, J. et al. Deterministic generation of single photons from one atom trapped cavity. Science 303, 1992–1994 (2004).

    Article  ADS  Google Scholar 

  10. Waks, E. et al. Quantum cryptography with a photon turnstile. Nature 420, 762 (2002).

    Article  ADS  Google Scholar 

  11. Beveratos, A. et al. Single photon quantum cryptography. Phys. Rev. Lett. 89, 187901 (2002).

    Article  ADS  Google Scholar 

  12. Waks, E., Santori, C. & Yamamoto, Y. Security aspects of quantum key distribution with sub-Poisson light. Phys. Rev. A 66, 042315 (2002).

    Article  ADS  Google Scholar 

  13. Hwang, W. Y. Quantum key distribution with high loss: toward global secure communication. Phys. Rev. Lett. 91, 057901 (2003).

    Article  ADS  Google Scholar 

  14. Lo, H. K., Ma, X. & Chen, K. Decoy state quantum key distribution. Phys. Rev. Lett. 94, 230504 (2005).

    Article  ADS  Google Scholar 

  15. Wang, X. B. Beating the photon-number-splitting attack in practical quantum cryptography. Phys. Rev. Lett. 94, 230503 (2005).

    Article  ADS  Google Scholar 

  16. Ma, X., Qi, B., Zhao, Y. & Lo, H. K. Practical decoy state for quantum key distribution. Phys. Rev. A 72, 012326 (2005).

    Article  ADS  Google Scholar 

  17. Bennett, C. H. Quantum cryptography using any two nonorthogonal states. Phys. Rev. Lett. 68, 3121–3124 (1992).

    Article  ADS  MathSciNet  Google Scholar 

  18. Koashi, M. Unconditional security of coherent-state quantum key distribution with a strong phase-reference pulse. Phys. Rev. Lett. 93, 120501 (2004).

    Article  ADS  Google Scholar 

  19. Scarani, V., Acín, A., Ribordy, G. & Gisin, N. Quantum cryptography protocols robust against photon number splitting attacks for weak laser pulse implementation. Phys. Rev. Lett. 92, 057901 (2004).

    Article  ADS  Google Scholar 

  20. Stucki, D., Brunner, N., Gisin, N., Scarani, V. & Zbinden, H. Fast and simple one-way quantum key distribution. Appl. Phys. Lett. 87, 194108 (2005).

    Article  ADS  Google Scholar 

  21. Inoue, K., Waks, E. & Yamamoto, Y. Differential-phase-shift quantum key distribution. Phys. Rev. Lett. 89, 037902 (2002).

    Article  ADS  Google Scholar 

  22. Rosenberg, D. et al. Long distance decoy state quantum key distribution in optical fiber. Phys. Rev. Lett. 98, 010503 (2007).

    Article  ADS  Google Scholar 

  23. Waks, E., Takesue, H. & Yamamoto, Y. Security of differential-phase-shift quantum key distribution against individual attacks. Phys. Rev. A 73, 012344 (2006).

    Article  ADS  Google Scholar 

  24. Takesue, H. et al. Differential phase shift quantum key distribution over 105 km fibre. New J. Phys. 7, 232 (2005).

    Article  ADS  Google Scholar 

  25. Diamanti, E., Takesue, H., Langrock, C., Fejer, M. M. & Yamamoto, Y. 100 km secure differential phase shift quantum key distribution with low jitter up-conversion detectors. Opt. Express 14, 13073–13082 (2006).

    Article  ADS  Google Scholar 

  26. Gol'tsman, G. N. et al. Picosecond superconducting single-photon optical detector. Appl. Phys. Lett. 79, 705–707 (2001).

    Article  ADS  Google Scholar 

  27. Verevkin, A. et al. Detection efficiency of large-active area NbN single-photon superconducting detectors in the ultraviolet to near-infrared range. Appl. Phys. Lett. 80, 4687–4689 (2002).

    Article  ADS  Google Scholar 

  28. Curty, M., Zhang, L.-L., Lo, H.-K. & Lütkenhaus, N. Sequential attacks against differential-phase-shift quantum key distribution with weak coherent states. Preprint at <http://arxiv.org/abs/quant-ph/0609094> (2006).

  29. Bennett, C. H., Brassard, G., Crépeau & Maurer, U. M. Generalized privacy amplification. IEEE Trans. Inf. Theory 41, 1915–1923 (1995).

    Article  MathSciNet  Google Scholar 

  30. Fasel, S. et al. High-quality asynchronous heralded single-photon source at telecom wavelength. New J. Phys. 6, 163 (2004).

    Article  ADS  Google Scholar 

  31. Trifonov, A. & Zavriyev, A. Secure communication with a heralded single-photon source. J. Opt. B 7, S772–S777 (2005).

    Article  ADS  Google Scholar 

  32. Soujaeff, A. et al. Quantum key distribution at 1550 nm using a pulse heralded single photon source. Opt. Express 15, 726–734 (2007).

    Article  ADS  Google Scholar 

  33. Hadfield, R. H. et al. Single photon source characterization with a superconducting single photon detector. Opt. Express 13, 10846–10853 (2005).

    Article  ADS  Google Scholar 

  34. Il'in, K. S. et al. Picosecond hot-electron energy relaxation in NbN superconducting photodetectors. Appl. Phys. Lett. 76, 2752–2754 (2000).

    Article  ADS  Google Scholar 

  35. Kurtsiefer, C. et al. A step towards global key distribution. Nature 419, 450 (2002).

    Article  ADS  Google Scholar 

  36. Ursin, R. et al. Free-space distribution of entanglement and single photons over 144 km. Preprint at <http://arxiv.org/abs/quant-ph/0607182> (2006).

  37. Schmitt-Manderback, T. et al. Experimental demonstration of free-space decoy-state quantum key distribution over 144 km. Phys. Rev. Lett. 98, 010504 (2007).

    Article  ADS  Google Scholar 

  38. Collins, R. J., Hadfield, R. H., Fernandez, V., Nam, S. W. & Buller, G. S. Low timing jitter detector for gigahertz quantum key distribution. Electron. Lett. 43, 180–182 (2007).

    Article  Google Scholar 

  39. Hiskett, P. A. et al. Long-distance quantum key distribution in optical fibre. New J. Phys. 8, 193 (2006).

    Article  ADS  Google Scholar 

Download references

Acknowledgements

The authors thank E. Diamanti, M. M. Fejer, G. N. Gol'tsman, E. Ip, J. M. Kahn, G. Kalogerakis, L. G. Kazovsky, N. Y. Kim, C. Langrock, R. V. Roussev and Y. Tokura for their support during this research. Financial support was provided by the CREST and SORST programs of the Japan Science and Technology Agency (JST), the National Institute of Information and Communications Technology (NICT) of Japan, the MURI Center for Photonic Quantum Information Systems (ARO/ARDA DAAD19-03-1-0199), DTO, DARPA and the NIST Quantum Information Science Initiative.

Author information

Authors and Affiliations

Authors

Contributions

H. Takesue designed and performed the experiments, analysed the data and wrote the paper, S. W. Nam performed the experiments and analysed the data, Q. Zhang performed the experiments, R. H. Hadfield performed the experiments, T. Honjo analysed the data, K. Tamaki analysed the data, and Y. Yamamoto planned the experiments.

Corresponding author

Correspondence to Hiroki Takesue.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Takesue, H., Nam, S., Zhang, Q. et al. Quantum key distribution over a 40-dB channel loss using superconducting single-photon detectors. Nature Photon 1, 343–348 (2007). https://doi.org/10.1038/nphoton.2007.75

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nphoton.2007.75

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing