Network Field Trials

Image courtesy of the U.S. Geological Survey

For general operation it is important that QKD can operate in ordinary communication networks. Toshiba have been involved in several international demonstrations of QKD networks. They include the SECOQC network in Vienna, Austria in 2008 and more recent trials the Tokyo QKD network in Japan collaboration with the National Institute for Information and Communication Technologies (NICT).

The Tokyo QKD network field trials showcased a QKD system with bit rates in excess of 1Mbit/s. This allows high bandwidth applications such as high speed video encryption to be secure by quantum methods. Both secure video encryption and a foiled eavesdropping attack were demonstrated.

Long term field trials have also been performed. The transmitter was installed in a server room of a high rise building in the Otemachi area of central Tokyo. The receiver was located at NICT’s Koganei premises in Greater Tokyo. The two ends were linked by a 45km metropolitan optical fibre. Although around 50% of this fibre was routed over-ground on utility poles, and therefore subject to weather and traffic disturbances, the resulting QKD secure bit rate was found to be very stable.

The high bit rate prototype QKD system distributed a total of 878 Gbit of secure key data over a 34 day period corresponding to a sustained key rate of around 300 kbit/s. The system was deployed over a standard 45 km link of an installed metropolitan telecommunication fibre network in central Tokyo. The prototype QKD system is compact, robust and automatically stabilised, enabling key distribution during diverse weather conditions. It operates at GHz clock rates and all necessary optics and high speed electronics are enclosed inside compact 19" rack units.

Image courtesy of the U.S. Geological Survey

Further Information

  1. [Easy] UQCC2010 - Updating Quantum Cryptography and Communications 2010 [open access].
  2. [Easy] View from UQCC 2010: Quantum secure video by N. Horiuchi Nature Photonics 5, 10 (2011).
  3. [Technical] Continuous operation of high bit rate quantum key distribution by A R Dixon et al. Applied Physics Letters 96, 161102 (2010).
  4. [Technical] Field test of quantum key distribution in the Tokyo QKD Network by M. Sasaki et al. Optics Express 19, 10387 (2011) [open access].
  5. [Technical] The SECOQC quantum key distribution network in Vienna by M Peev et al. New Journal of Physics 11, 075001 (2009) [open access].
  6. [Technical] High speed prototype quantum key distribution system and long term field trial by A. R. Dixon et al. Optics Express, 23, 7583 (2015) [open access].