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Time phase encoding device and quantum key distribution system

An encoding device and time phase technology, applied to key distribution, can solve problems such as increasing system complexity and sensitivity to the ambient temperature of the intensity modulator, and achieve the effect of improving stability and practicability, and consistent loss

Active Publication Date: 2021-12-31
北京正道量子科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, the intensity modulator is sensitive to ambient temperature and requires real-time calibration, which increases the complexity of the system

Method used

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  • Time phase encoding device and quantum key distribution system
  • Time phase encoding device and quantum key distribution system
  • Time phase encoding device and quantum key distribution system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] The structure of the time-phase encoding device is: the unequal arm interferometer includes a second beam splitter BS2, a third beam splitter BS3 and an optical fiber delay line DL, and the second beam splitter BS2 and the third beam splitter Beamer BS3 is connected by optical fibers L1 and L2 to form an unequal-arm Mach-Zehnder interferometer. The optical fiber L1 is the short arm of the Mach-Zehnder interferometer. The optical fiber delay line DL is located on the optical fiber L2 as a Mach-Zehnder interferometer. - the long arm of the Zehnder interferometer, the second beam splitter BS2 and the third beam splitter BS3 are connected to the optical fiber A1 and the optical fiber A2 respectively, and the unequal-arm Mach-Zehnder interferometer is used to split the input light The pulse is divided into front and rear sub-pulses with time difference and same polarization.

[0042] Embodiment 1 The time phase encoding process includes:

[0043] The horizontally polarized ...

Embodiment 2

[0048] The structure of the time-phase encoding device is: the optical fiber at the first port of the first beam splitter BS1 is fused at 45°, and the unequal arm interferometer includes a first polarization beam splitter PBS1, a first Faraday reflector mirror FM1 and the second Faraday mirror FM2, the first port and the third port of the first polarization beam splitter PBS1 are respectively connected to the optical fiber A1 and the optical fiber A2, and the second port and the fourth port are respectively connected to the optical fiber L3 and the optical fiber L4 Connected with the first Faraday mirror FM1 and the second Faraday mirror FM2, the unequal-arm interferometer is used to divide the input optical pulse into front and rear sub-pulses with time difference and polarization perpendicular to each other, the first phase modulator PM1 and the second phase modulator PM2 support dual polarization operation.

[0049] Embodiment 2 The time phase encoding process includes:

...

Embodiment 3

[0055] The structure of the time phase encoding device is: the optical fiber at the first port of the first beam splitter BS1 is fused at 45°, the unequal arm interferometer includes a second polarization beam splitter PBS2, and the second The first port and the third port of the polarization beam splitter PBS2 are respectively connected with the optical fiber A1 and the optical fiber A2, and the second port and the fourth port are directly connected through the optical fiber L5, and the unequal arm interferometer is used to divide the input optical pulse into The first phase modulator PM1 and the second phase modulator PM2 support dual-polarization operation with a time difference between the front and rear sub-pulses and the polarizations are perpendicular to each other.

[0056] Embodiment 3 The time phase encoding process includes:

[0057] The horizontally polarized optical pulse P0 enters the time-phase encoding device from the input port In, first the polarization state...

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Abstract

A time phase encoding device comprises a first beam splitter BS1, a first phase modulator PM1, a second phase modulator PM2 and an unequal-arm interferometer; and the unequal-arm interferometer comprises a first port and a second port, a first port and a second port of the unequal-arm interferometer are correspondingly connected with a third port and a second port of the first beam splitter BS1 through an optical fiber A1 and an optical fiber A2 respectively to form a Sagnac ring, the first phase modulator PM1 and the second phase modulator PM2 are located on the optical fiber A1 and the optical fiber A2 respectively, and the invention further provides a quantum key distribution system. Compared with the prior art, the Sagnac ring and unequal-arm interferometer combined structure is adopted, time phase coding is carried out by carrying out phase modulation on two time window modes respectively, and meanwhile preparation of a signal state and a decoy state can be achieved. Stable time phase coding can be achieved, stable preparation of a signal state and a decoy state can be completed at the same time, and extra intensity modulators and phase compensation are not needed.

Description

technical field [0001] The invention relates to the technical field of quantum polarization encoding, in particular to a time-phase encoding device and a quantum key distribution system. Background technique [0002] Quantum key distribution has the security of information theory, and its security is guaranteed by the basic principles of quantum mechanics. It can resist the threat from quantum computers and plays an important role in secure communication. The most mature quantum key distribution (QKD) protocol is the BB84 protocol, which has entered the practical stage. The commonly used coding methods of QKD include polarization coding, phase coding and time phase coding. Since the polarization state is extremely unstable in the fiber channel, polarization encoding needs to add an active polarization compensation module at the receiving end, which increases the complexity and instability of the system. Phase encoding has high stability, but due to the large loss at the re...

Claims

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Application Information

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IPC IPC(8): H04B10/548H04B10/70H04B10/25H04L9/08
CPCH04B10/548H04B10/70H04B10/25H04L9/0852
Inventor 王东
Owner 北京正道量子科技有限公司
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