BBN Technologies Demos Photon Detector
CAMBRIDGE, Mass., March 16, 2006 -- A single-photon detector designed for standard telecommunications fibers that is 20 times faster than today's benchmark device -- and could become even faster -- was recently demonstrated by BBN Technologies, a Cambridge-Mass.-based research and development firm.
Jonathan Habif, a BBN scientist who led its detector team, said, "We've now demonstrated the first generation of ultrafast detectors based on superconducting technology that permit extremely secure transmission of information at high rates and over longer distances. 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 said it achieved this "significant breakthrough in the world's first quantum cryptography network" in close collaboration with the National Institute of Standards and Technology (NIST) in Boulder, Colo.
Higher speeds mean faster communications and, in a quantum cryptographic network, greater distance, BBN said.
"This breakthrough brings quantum communications beyond metropolitan distances closer to reality," the company said. Previously, the practical uses of quantum cryptography networks were limited by their relatively short range of transmission. Now, it said, transmissions can travel over 100 km of telecommunications fiber to enable practical applications in any situation where an ultrasecure network would be useful, such as in banking or military communications.
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 100 million pulses per second. The technology is believed to be 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 telecommunications 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 among BBN, Harvard University and Boston University under the streets of Cambridge and Boston. The network now has 10 nodes, exchanging quantum keys through both telecommunications fiber and the atmosphere.
The DARPA Quantum Network provides extremely high levels of information security, guaranteed by the laws of quantum physics, BBN said. It is integrated with the Internet and protects off-the-shelf Internet applications such as Web surfing and video conferencing among 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," BBN said in a statement. "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."
For more information, visit: www.bbn.com
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