User terminal in quantum key distribution system, MDI-QKD system and method and network system

Abstract

The invention provides a user terminal in a quantum key distribution system. The quantum key distribution system comprises a modulation light source, and the modulation light source comprises a phase preparation laser, an optical fiber circulator and a pulse production laser. The invention further provides a MDI-QKD system, which comprises a user terminal and a public measure terminal, wherein the user terminal comprises an Alice terminal and a Bob terminal; the public measurement terminal is a Charlie terminal; each of the Alice terminal and the Bob terminal comprises the modulation light source. The invention further provides a key distribution method of the MDI-QKD system based on light injection, and a networked MDI-QKD system. The user terminal provided by the invention simplifies a structure of each of a phase modulation laser and the pulse production laser, and is unnecessary to set a phase feedback system. The MDI-QKD system provided by the invention realizes the integrated structure of the light source, the phase modulator and an intensity modulator; the limitation to the system high-speed application by the phase modulator and the intensity modulator are relieved; the modulation light source can directly generate light pulse with pure phase difference information, and the consistency control on multiuser light pulse phase standards can be realized.

Description

technical field [0001] The present invention relates to the field of communication, relates to a user terminal including a quantum key distribution system, in particular to an MDI-QKD system, the technical field of optical fiber transmission quantum secret communication and a key distribution method in quantum secret communication. Background technique [0002] In 2012, Lo et al. proposed a measurement-device-independent QKD (MDI-QKD) protocol, in which Alice and Bob send encoded light pulses to Charlie, an untrusted third party, for Bell State measurement, immune to any detector side channel attack, greatly improving the real security of the QKD system. [0003] The MDI-QKD system based on phase encoding, because of the strong anti-interference ability of optical pulse phase modulation in optical fiber transmission, the system can obtain stable detection results and high coding rate, so it is very suitable for long-distance secure communication between both parties. The ma...

AI Technical Summary

Problems solved by technology

[0007] 1. The existing MDI-QKD system optical pulse phase encoding requires a phase modulator, and light intensity modulation requires an intensity modulator. The use of these two modulation devices not only limits the high-speed application of the system, but also the complex driving circuits of the two make the user end The structure is bulky and the cost increases, which is not conducive to the network expansion of MDI-QKD

[0008] 2. In the existing MDI-QKD system, the phase reference consistency of the front and back optical pulses sent by a single client needs to be guaranteed by a phase feedback system, and the design project in the networked system is huge

[0009] The above two major defects restrict the networked application of the MDI-QKD system based on phase encoding, especially when it comes to simultaneously ensuring the consistency of the optical pulse phase reference among multiple users, the phase feedback system of the entire network will be a huge engineering design

Images