Method and apparatus for free-space quantum key distribution in daylight
A quantum cryptography apparatus securely generates a key to be used for secure transmission between a sender and a receiver connected by an atmospheric transmission link. A first laser outputs a timing bright light pulse; other lasers output polarized optical data pulses after having been enabled by a random bit generator. Output optics transmit output light from the lasers that is received by receiving optics. A first beam splitter receives light from the receiving optics, where a received timing bright light pulse is directed to a delay circuit for establishing a timing window for receiving light from the lasers and where an optical data pulse from one of the lasers has a probability of being either transmitted by the beam splitter or reflected by the beam splitter. A first polarizer receives transmitted optical data pulses to output one data bit value and a second polarizer receives reflected optical data pulses to output a second data bit value. A computer receives pulses representing receipt of a timing bright timing pulse and the first and second data bit values, where receipt of the first and second data bit values is indexed by the bright timing pulse.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-36
- Assignee:
- University Of California, The Regents Of
- Patent Number(s):
- 6,748,083
- Application Number:
- 09/844,176
- OSTI ID:
- 1174891
- Country of Publication:
- United States
- Language:
- English
An autocompensating fiber-optic quantum cryptography system based on polarization splitting of light
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journal | March 2000 |
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