An autocompensating fiber-optic quantum cryptography system based on polarization splitting of light

We have developed a system for quantum key distribution (QKD), based on standard telecommunication lasers, detectors, and optical fiber, that passively compensates for time-dependent variations of the fiber-optic path due to stress, temperature changes, or birefringence. This approach allows informa...

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Bibliographic Details
Published in:IEEE journal of quantum electronics 2000-03, Vol.36 (3), p.340-347
Main Authors: Bethune, D.S., Risk, W.P.
Format: Article
Language:English
Subjects:
Classical and quantum physics: mechanics and fields
Cryptography
Exact sciences and technology
Fiber lasers
Infrared detectors
Laser transitions
Local area networks
Optical detectors
Optical fiber LAN
Optical fibers
Optical pulses
Optics
Physics
Quantum cryptography
Quantum information
Standards development
Telecommunication standards
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Summary:We have developed a system for quantum key distribution (QKD), based on standard telecommunication lasers, detectors, and optical fiber, that passively compensates for time-dependent variations of the fiber-optic path due to stress, temperature changes, or birefringence. This approach allows information encoded in phase shifts imposed on single-photon-level pulses to be accurately read out after transmission over many kilometers of uncontrolled fiber. Cooled InGaAs avalanche photodiodes, pulse-biased using a special noise canceling circuit, are used to detect single 1.31-/spl mu/m infrared photons with a high efficiency, low dark-count rate, and subnanosecond time resolution. A single optical fiber carries both the quantum information and precise 1.55 /spl mu/m timing pulses between the two end stations. Overall synchronization of end-station activities, public discussion of basis choices, error correction, and privacy amplification have all been implemented over a local area network (LAN). The system at present generates raw, error-corrected, and privacy-amplified key data at rates of /spl sim/1000, 600, and 200 bits/s, respectively, over a 10-km single-mode fiber link.
ISSN:0018-9197
1558-1713
DOI:10.1109/3.825881