BBN Technologies Smashes Speed Barriers with Worlds' Fastest Detector for Practical Quantum Cryptography

Cambridge, MA, Feb. 23: BBN Technologies, an advanced technology and research and development firm, today announced a significant breakthrough in the world's first quantum cryptography network. In close collaboration with the National Institute of Standards and Technology (NIST) in Boulder CO, BBN has successfully demonstrated a single-photon detector designed for standard telecom fibers that is 20 times faster than today's benchmark device and could produce even greater speed increases.

Greater speeds not only mean faster communications but, in a quantum cryptographic network, also enable greater distances. This breakthrough brings quantum communications beyond metropolitan distances closer to reality. Previously, the practical uses of quantum cryptography networks were limited by their relatively short range of transmission. Now, transmissions can travel over 100 km of telecommunications fiber to enable practical applications in any situation where an ultra-secure network would be useful, such as in banking or military communications.

"We've now demonstrated the first generation of ultra-fast detectors based on superconducting technology that permit extremely secure transmission of information at high rates and over longer distances," said Dr. Jonathan Habif, BBN Scientist who led BBN's detector team. "Detectors have been a terrible bottleneck before now, but our system runs 20 times faster and we've shown that it can run over 100 km of telecom fiber with our new single-photon detector. We expect to run much faster in the near future."

BBN and NIST built the new devices under DARPA sponsorship, in collaboration with the University of Rochester in New York and Moscow Institute of Physics and Technology. Laboratory trials have already confirmed continuous operation at a 100 million pulses per second. The technology is believed scalable to 10 billion pulses per second and beyond. The compact, rack-mounted detector system uses NIST-developed packaging and cooling technology which efficiently couples the superconducting detector to a standard telecom fiber and allows operation at a temperature of ~3K without using liquid cryogens.

BBN has operated the world's first quantum cryptography network, the DARPA Quantum Network, continuously since 2004, sending quantum keys between BBN, Harvard University and Boston University under the streets of Cambridge and Boston Mass. The network now has 10 nodes, exchanging quantum keys through both telecom fiber and the atmosphere.

The DARPA Quantum Network provides extremely high levels of information security guaranteed by the laws of quantum physics. It is fully integrated with the Internet and protects off-the-shelf Internet applications such as web surfing and video conferencing between the campuses.

Quantum cryptography is an approach to securing communications based on certain phenomena of Quantum physics, using single photons of light to distribute keys to encrypt and decrypt messages. Quantum cryptography is focused on the physics of information. The process of sending and storing information is always carried out by physical means, for example photons in optical fibers or electrons in electrical current. Eavesdropping can be viewed as measurements on a physical object -- in this case the carrier of the information. Using quantum phenomena allows for the design and implementation of a communication system which can always detect eavesdropping.