Toshiba Corp and the Tohoku Medical Megabank Organization (ToMMo) at Tohoku University have successfully applied high-speed quantum cryptographic communications technologies to achieve quantum cryptography communication at one-month-average key distribution speeds exceeding 10 Mbits/s over installed optical fibre lines. This is said to be a world first.
Using technologies developed at Toshiba and Toshiba Research Europe’s Cambridge Research Laboratory, the companies constructed an application for data transmission via optical fibre lines. Combined with high-speed quantum cryptography communications technologies, this demonstrated practical key distribution speeds in a real-world environment. The companies also constructed and operated a wireless sensor network that continuously monitors installed fibre optic lines, and clarified the relationships between characteristic changes in optical fibre due to year-round variations in weather, vibration, and other factors, and the performance characteristics of quantum cryptographic communications. This is reckoned to be a large advance toward the practical application of high-speed quantum cryptography communications.
In the joint research project, Toshiba and ToMMo have applied high-speed quantum cryptographic communications technologies to develop a system that has been introduced into applications that transmit genome analysis data, and to perform field demonstration experiments. In these experiments, quantum cryptographic devices were introduced at the Toshiba Life Science Analysis Center (Minamiyoshinari, Aoba-ku, Sendai) and at ToMMo (Seiryo-machi, Aoba-ku, Sendai). Communications were then performed over dedicated installed optical fibre lines between the sites, a distance of approximately 7 km.
The companies also developed and incorporated a system for managing distributed cryptographic keys, along with data encryption software that operates in coordination with that system. The system encrypted and transmitted genome analysis data between the two sites using these quantum cryptographic communications technologies. The system continuously stabilised the speed of quantum key distribution and achieved an average key distribution rate of 10.2 Mbits/s in continuous operations lasting over one month. This is a world-first demonstration of quantum cryptographic key distribution at speeds exceeding 10 Mbits/s in a real-world environment.
Introducing a wireless sensor network into the above-mentioned installed optical fibre lines allowed measurement of environmental fluctuations external to communications such as year-round variations in optical fibre vibration due to factors such as temperature change, rainfall, snow covering, strong wind, and earthquakes, clarifying their relationships with quantum encryption communication performance.
Toshiba says it will continue to pursue operational field trials with the goal of practical applications of quantum cryptography technology in various fields and use cases, including medical, financial, and communications infrastructure.