| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a quantum cipher communication device enabling a fast pulse repetition speed although a BB84-"plug&play" quantum cipher system is used as a basis. <P>SOLUTION: In the configuration of the conventional BB84-"plug&play", a light phase modulator 120 driven by an RF frequency signal of a fixed frequency f<SB>1</SB>is added to Alice 100, and filters 250, 260 for transmitting only a specified frequency each are added to the prestage of two photon detectors 230, 240 of Bob 200. The light phase modulator 120 driven by the frequency f<SB>1</SB>generates the modulation sideband waves of an optical pulse frequency f<SB>0</SB>and a frequency (f<SB>0</SB>±f<SB>1</SB>), when an optical pulse advances in one direction. The frequency of Rayleigh scattering light is f<SB>0</SB>, thus detecting the modulation sideband waves as a signal without any noise by setting the specified frequency of the filters 250, 260 to be the frequency (for example, f<SB>0</SB>+f<SB>1</SB>) of one modulation sideband wave by Rayleigh scattering. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
