Wavelength division multiplexing of continuous variable quantum key distribution and 18.3 Tbit/s data channels

Tobias A Eriksson,Yoshinari Awaji,Masahiro Takeoka,Naoya Wada,Georg Rademacher,Mikio Fujiwara,Ryo Namiki,Benjamin J Puttnam,Masahide Sasaki,Ruben S Luís,Takuya Hirano

doi:10.1038/s42005-018-0105-5

Abstract

Quantum key distribution (QKD) can offer communication with unconditional security and is a promising technology to protect next generation communication systems. For QKD to see commercial success, several key challenges have to be solved, such as integrating QKD signals into existing fiber optical networks. In this paper, we present experimental verification of QKD co-propagating with a large number of wavelength division multiplexing (WDM) coherent data channels. We show successful secret key generation over 24 h for a continuous-variable QKD channel jointly transmitted with 100 WDM channels of erbium doped fiber amplified polarization multiplexed 16-ary quadrature amplitude modulation signals amounting to a datarate of 18.3 Tbit/s. Compared to previous co-propagation results in the C-band, we demonstrate more than a factor of 10 increase in the number of WDM channels and more than 90 times higher classical bitrate, showing the co-propagation with Tbit/s data-carrying channels.

Highlights

Quantum key distribution (QKD) can offer communication with unconditional security and is a promising technology to protect generation communication systems
We have experimentally demonstrated that continuous variable (CV)-QKD can co-exist in wavelength division multiplexing (WDM) fiber optical networks with 100 WDM channels of erbium doped fiber amplifiers (EDFAs) amplified coherent 24.5 Gbaud PM-16QAM channels, summing up to a total classical bitrate of 18.3 Tbit/s
The results represent an important step towards practical implementation of QKD technology as we show that it is possible for CV-QKD to share the infrastructure of fiber optical networks in densely populated links with 100 channels

Summary

Introduction

Quantum key distribution (QKD) can offer communication with unconditional security and is a promising technology to protect generation communication systems. Even post-quantum cryptography cannot be provably secure against so-called “store decrypt later” attacks in which an attacker can undetectably wiretap a link and store the information until sufficient technological advances have been made to break the encryption[4] This is especially a threat for users of sensitive data, that may have secrecy periods of 100 years or more, such as military, healthcare institutions, and government departments[4]. If QKD channels can be integrated into the existing communication network architecture, the total cost of a QKD link may be greatly reduced This means that QKD channels should be able to co-propagate with classical data channels in the same fiber, using multiplexing techniques such as wavelength division multiplexing (WDM) without suffering significant penalties from crosstalk, and/or compromising the security. CV-QKD has many features which makes it an interesting alternative to the more developed

Methods

Results

Conclusion