Tokyo QKD Network

On the first day of the conference you are invited to take part in the inauguration of the Tokyo QKD network with the first Japanese live demonstration of an operational quantum key distribution (QKD) network in the Tokyo metropolitan area based on the latest QKD technologies. The live demonstration will be performed in a spirit of international collaboration with participation from Japan by NEC, Mitsubishi Electric, NTT and NICT, and participation from Europe by Toshiba Research Europe Ltd. (UK), ID Quantique (Switzerland) and All Vienna (Austria). "All Vienna" is represented by researchers from the Austrian Institute of Technology (AIT), the Institute for Quantum Optics and Quantum Information (IQOQI) and the University of Vienna.

The live demonstration will include:

  • an eavesdropping attempt on the network and its detection,
  • demonstration of uncrackable one-time pad encryption of a live audio or video stream over a distance of 45 km with a line loss of some 13 dB

Besides the live demonstration, an ultra-stable frequency dissemination experiment will also be performed and its result will be reported at the conference.

Fig.1 Network Layout of the Tokyo QKD Network

The Tokyo QKD network, whose topology is depicted in Fig. 1, makes use of JGN2plus (Japan's Gigabit Network). JGN2plus represents an open testbed network that provides a platform for new R&D activities and leading-edge experiments in the field of network technologies. Currently over 100 research projects utilize the services of JGN2plus. The Tokyo QKD network is configured as a star network connecting the JGN2plus operation center in Otemachi with NICT's Headquarter in Koganei as well as Tokyo University in Hongo and NICT's research facility in Hakusan.

Fig.2 Network Layer Structure of the Tokyo QKD Network

As shown in Fig. 2, the structure of the Tokyo QKD network consists of three layers: the quantum layer, the key management (KM) layer and the communication layer. In the quantum layer, the QKD devices generate quantum keys via a point-to-point connection. The key data is then sent to the KM layer comprising several KM agents and a central KM server. The KM agents collect and store the key data from the QKD devices. The KM server monitors the amount of key data in each agent and supervises the overall key distribution in the network. Finally, in the communication layer, secure communications is ensured by using the distributed keys for encryption and decryption of text, audio or video data produced by various applications such as a TV conference system.

Fig.3 Topological Map of the Tokyo QKD Network

A detailed topological map including data link distances and transmission losses is shown in Fig. 3. The Koganei node is composed of three subnodes Koganei-1 to Koganei-3 accommodating QKD devices operated by engineers from NEC, NTT, Toshiba Research Europe Ltd (TREL) and All Vienna, respectively. The Otemachi node is divided into two subnodes Otemachi-1 and Otemachi-2 accommodating the devices of NEC, Mitsubishi, Toshiba and ID Quantique. Finally, the Hongo node is equipped with a single device from ID Quantique. The gray-colored nodes represent two loopback configurations to gain additional link distance. One doubles the distance between Koganei and Otemachi for the link managed by NTT-NICT and the other doubles the distance between Otemachi and Hakusan for the link managed by Mitsubishi Electric.