Quantum Information Group, QKD Network Field Trials
Networking will be critical for QKD to make a strong impact in the information security
sector. To achieve this, Toshiba have been involved in many international efforts
to demonstrate the feasibility of QKD networks, notably the Tokyo QKD network and
the SECOQC network in Vienna.
The Tokyo QKD network organised by NICT consists of multiple QKD-links in a metropolitan
network in Tokyo and was established through international cooperation on 18 October
2010. For this network, Toshiba installed a gigahertz QKD system serving a 45-km
fibre link between Koganei and Otemachi. Despite the high loss (14.5 dB) of the
installed fibre, Toshiba's system achieved a secure bit rate of 304 kb/s averaged
over 24 hours, which is the world-best key rate for installed fibre. The high key
rate of Toshiba's system was able to support secure video conferencing in real time.
Toshiba have also collaborated in an EC-funded initiative to develop technology
for Quantum Key Distribution. The objective of the SECOQC collaboration was to develop
the hardware and protocols required for network operation of QKD. The project began
in April 2004 and concluded in October 2008 with a field trial of the technology
developed. It involved 41 R&D teams from 12 European countries and was funded by
the EC under the Framework 6 Information Society Technologies Programme with a budget
of 11.4 M Euro.
Toshiba's main contribution to SECOQC has been to develop component and QKD hardware.
We created a highly stable QKD link suitable for continuous and reliable operation
in a network. The system uses weak laser pulses as the information carriers and
phase to encode the bit information. It uses Toshiba's actively-compensated one-way
architecture to achieve continuous operation. The system implements the decoy pulse
protocol, which has been proven to be unconditionally secure from all forms of eavesdropping
on the optical fibre. Trials of this system demonstrated stable operation over many
days with an average bit rate over 10 kb/s for a 20 km link.
The QKD hardware developed by the SECOQC partners was implemented in a network field
test in Vienna in October 2008. Toshiba supplied a QKD system which operated stably
over a 32 km link in the network.
Another significant outcome of the SECOQC project is the formation of a standardisation
initiative for QKD. This will take place under the direction of the European Telecommunications
Standards Institute (ETSI). Toshiba have joined the ETSI working group on Quantum
Key Distribution and Quantum Technologies as a founder member.
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