| 摘要 |
PROBLEM TO BE SOLVED: To provide a quantum key distribution system that improves continuity of communication without reducing encryption key generation speed.SOLUTION: A quantum key distribution system includes a transmitter, a receiver, and first and second communication paths with which communication between the transmitter and the receiver is performed. The transmitter includes a first Mach-Zehnder interferometer having an input end and an output end for an optical signal; the receiver includes a second Mach-Zehnder interferometer having first and second input ends and at least first and second output ends. The first transmission path is connected to the first input end of the second interferometer; the second transmission path is connected to the second input end of the second interferometer. The transmitter includes a first changeover unit for receiving an optical signal from the output end of the first interferometer to perform changeover so as to perform communication using either of the first transmission path and the second transmission path. The transmitter or receiver includes a function for correcting inversion of phases of optical signals at the first and second output ends of the second interferometer in the case of having changed over the transmission paths.SELECTED DRAWING: Figure 1 |
