| 摘要 |
PROBLEM TO BE SOLVED: To provide a quantum number delivery system which is firm for a photon number branching attack. SOLUTION: A transmitter performs phase modulation of respective pulses of optical pulses sequence generated by a constant time interval T in ä0,π} or äπ/2, 3π/2}, and transmits the optical pulse sequence less than one photon per a pulse in average. A receiver receives the photon pulse sequence from the transmitter, performs phase modulation of respective pulses in ä0,π/2}, and combines by a branching, delaying, and combining circuit of the delay time T. When the phase difference of the pulses of the combined pulse sequence is 0, a first detector detects the photon, and when the phase difference isπ, a second detector detects the photon. The receiver notices the detected time of the photon and the modulation phase differenceΔθ<SB>b</SB>of the pulse detecting the photon to the transmitter. The transmitter notices whether the modulation phase differenceΔθ<SB>a</SB>of the pulse detecting the photon is ä0,π} or äπ/2, 3π/2} group. By the way, the transmitter and the receiver can generate a common bit value. COPYRIGHT: (C)2010,JPO&INPIT |
