Quantum key distribution system with switchable coding modes
By introducing switchable phase coding and polarization coding into the quantum key distribution system, the problem of insufficient stability under a single coding method is solved, and the system achieves high stability and low-cost deployment in different environments.
Patent Information
- Application Number
- CN202423287315.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-31
AI Technical Summary
Existing quantum key distribution systems use only a single encoding method, which cannot adapt to complex environmental changes, resulting in insufficient stability.
Design a quantum key distribution system with switchable encoding methods, combining phase encoding and polarization encoding. By multiplexing lasers and detection modules, the encoding method is optimally selected based on environmental factors to improve system stability.
This system achieves high stability and high performance operation in different environments, reduces system construction costs, and enhances the value of on-site deployment.
Smart Images
Figure CN223613353U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to quantum network and quantum key distribution equipment field, concretely relates to a quantum key distribution system of switchable encoding mode. BACKGROUND
[0002] Quantum technology is a new race track of future industry, and is one of the hot spots of global technology competition. Quantum key distribution (QKD) research adopts various modulation modes, and expands and applies in scale in the positive quantum network architecture. In the optical communication system, information is encoded and transmitted through specific physical quantities of light waves. These physical quantities include intensity, phase, polarization, spectrum, time and space, and the phase and polarization of photons are important encoding modes.
[0003] Among them, the quantum key distribution system based on photon phase encoding can resist the change of system polarization state, but is sensitive to the phase change physical quantity such as temperature; and the quantum key distribution system based on photon polarization encoding is sensitive to polarization disturbance, but the phase difference between polarization components is constant, and has phase disturbance stability.
[0004] The existing quantum key distribution system only adopts a single encoding mode, and cannot adapt to the complex environmental changes in practice, and the stability is not high enough. UTILITY MODEL CONTENTS
[0005] The utility model discloses in order to solve the problem that the existing quantum key distribution system only adopts single encoding mode, and proposes a quantum key distribution system of switchable encoding mode.
[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the utility model is as follows:
[0007] A quantum key distribution system of switchable encoding mode, comprising a laser, a sending end encoding module, a receiving end encoding module and a detection module;
[0008] The sending end encoding module comprises a first circulator, a first optical path converter, a first phase encoding module and a first polarization encoding module;
[0009] The receiving end encoding module comprises a second circulator, a second optical path converter, a second phase encoding module and a second polarization encoding module;
[0010] The output end of the laser is connected with a first port of a first circulator, a second port of the first circulator is connected with a first port of a first optical path switch, a second port of the first optical path switch is connected with a first phase encoding module, a third port of the first optical path switch is connected with a first polarization encoding module; a third port of the first circulator is connected with a first port of a second circulator, a second port of the second circulator is connected with a first port of a second optical path switch, a second port of the second optical path switch is connected with a second phase encoding module, a third port of the second optical path switch is connected with a second polarization encoding module; a third port of the second circulator is connected with an input end of a detection module.
[0011] In the above scheme, the phase encoding and the polarization encoding have the ability of resisting polarization disturbance and phase disturbance respectively, and the encoding mode can be selected according to the main environmental factors affecting the bit error rate, so that the system can be operated with high stability and high performance. Meanwhile, the laser and the detection module are multiplexed, so that the cost of building the system is reduced, and the system has more value for field deployment.
[0012] Preferably, the detection module comprises a beam splitter, a first detector and a second detector.
[0013] The third port of the second circulator is connected with an input end of the beam splitter, a first output end of the beam splitter is connected with an input end of the first detector, and a second output end of the beam splitter is connected with an input end of the second detector.
[0014] Preferably, the length difference of the long arm and the short arm of the first phase encoding module is 2 ns.
[0015] Preferably, the length difference of the long arm and the short arm of the second phase encoding module is 5 ps.
[0016] Preferably, the first polarization encoding module and the second polarization encoding module both adopt a Sagnac ring structure.
[0017] Preferably, the sending end encoding module further comprises a first master control module; a signal output end of the first master control module is connected with a signal input end of the first optical path switch.
[0018] Preferably, the receiving end encoding module further comprises a second master control module; a signal output end of the second master control module is connected with a signal input end of the second optical path switch.
[0019] Preferably, an attenuator is further included; a third port of the first circulator is connected with one end of the attenuator, and the other end of the attenuator is connected with a first port of the second circulator.
[0020] The utility model discloses beneficial technical effect:
[0021] This invention provides a quantum key distribution system with switchable encoding methods. Phase encoding and polarization encoding offer resistance to polarization and phase perturbations, respectively. The optimal encoding method can be selected based on the main environmental factors affecting the bit error rate, achieving high stability and high performance operation of the system. Furthermore, by reusing the laser and detection module, the cost of system construction is reduced, making it more valuable for field deployment. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the module connection of this utility model;
[0023] The components are: 1. Laser; 2. Transmitter encoding module; 21. First circulator; 22. First optical path converter; 23. First phase encoding module; 24. First polarization encoding module; 25. First main control module; 3. Receiver encoding module; 31. Second circulator; 32. Second optical path converter; 33. Second phase encoding module; 34. Second polarization encoding module; 35. Second main control module; 4. Detector module; 41. Beam splitter; 42. First detector; 43. Second detector; 5. Attenuator. Detailed Implementation
[0024] To make the objectives, technical solutions and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments. However, the scope of protection of this utility model is not limited to the specific embodiments described below.
[0025] Example 1
[0026] like Figure 1 As shown, a quantum key distribution system with switchable encoding methods includes a laser 1, a transmitting encoding module 2, a receiving encoding module 3, and a detection module 4;
[0027] The transmitting end encoding module 2 includes a first circulator 21, a first optical path converter 22, a first phase encoding module 23, and a first polarization encoding module 24;
[0028] The receiver encoding module 3 includes a second circulator 31, a second optical path converter 32, a second phase encoding module 33, and a second polarization encoding module 34.
[0029] The output end of the laser 1 is connected with the first port of the first circulator 21, the second port of the first circulator 21 is connected with the first port of the first optical path switch 22, the second port of the first optical path switch 22 is connected with the first phase encoding module 23, the third port of the first optical path switch 22 is connected with the first polarization encoding module 24; the third port of the first circulator 21 is connected with the first port of the second circulator 31, the second port of the second circulator 31 is connected with the first port of the second optical path switch 32, the second port of the second optical path switch 32 is connected with the second phase encoding module 33, the third port of the second optical path switch 32 is connected with the second polarization encoding module 34; the third port of the second circulator 31 is connected with the input end of the detection module 4.
[0030] In the specific implementation process, the phase encoding and the polarization encoding have the ability of resisting the polarization disturbance and the phase disturbance respectively, and in practice, the encoding mode can be selected according to the evaluation of the system environment factors which mainly contribute to the bit error rate, for example, the influence of the vibration environment on the polarization encoding and the bit error rate can reduce the system bit error rate by switching to the phase encoding protocol, and the influence of the high temperature environment on the phase encoding and the bit error rate can reduce the system bit error rate by switching to the polarization encoding protocol, so as to realize the high stability and high performance operation of the system.
[0031] Embodiment 2
[0032] A quantum key distribution system with switchable encoding mode, comprising a laser 1, a sending end encoding module 2, a receiving end encoding module 3 and a detection module 4.
[0033] The sending end encoding module 2 comprises a first circulator 21, a first optical path switch 22, a first phase encoding module 23 and a first polarization encoding module 24.
[0034] The receiving end encoding module 3 comprises a second circulator 31, a second optical path switch 32, a second phase encoding module 33 and a second polarization encoding module 34.
[0035] The output end of the laser 1 is connected with the first port of the first circulator 21, the second port of the first circulator 21 is connected with the first port of the first optical path switch 22, the second port of the first optical path switch 22 is connected with the first phase encoding module 23, the third port of the first optical path switch 22 is connected with the first polarization encoding module 24; the third port of the first circulator 21 is connected with the first port of the second circulator 31, the second port of the second circulator 31 is connected with the first port of the second optical path switch 32, the second port of the second optical path switch 32 is connected with the second phase encoding module 33, the third port of the second optical path switch 32 is connected with the second polarization encoding module 34; the third port of the second circulator 31 is connected with the input end of the detection module 4.
[0036] More specifically, the detection module 4 comprises a beam splitter 41, a first detector 42 and a second detector 43.
[0037] The third port of the second circulator 31 is connected with the input end of the beam splitter 41, the first output end of the beam splitter 41 is connected with the input end of the first detector 42, and the second output end of the beam splitter 41 is connected with the input end of the second detector 43.
[0038] More specifically, the difference between the arm lengths of the long and short arms of the first phase encoding module 23 is 2ns.
[0039] More specifically, the difference between the arm lengths of the long and short arms of the second phase encoding module 33 is 5ps.
[0040] In the specific implementation process, the first phase encoding module 23 and the second phase encoding module 33 adopt the same structure, and the encoding interference ring is composed of unequal arm FM; wherein the difference between the arm lengths of the long and short arms of the first phase encoding module 23 is 2ns, and the long arm is modulated by a phase modulator to realize phase encoding; the difference between the arm lengths of the long and short arms of the second phase encoding module 33 is not more than 5ps.
[0041] More specifically, the first polarization encoding module 24 and the second polarization encoding module 34 both adopt Sagnac ring structure.
[0042] In the specific implementation process, the Sagnac ring is composed of a polarization beam splitter and a phase modulator, which is a system phase modulation module. After the 45° linearly polarized light passes through the polarization beam splitter, it is divided into mutually perpendicular and equal intensity horizontal H polarization component and vertical V polarization component, the distance between the left and right ends of the phase modulator from the polarization beam splitter is not equal, and the difference is 10ns, so H and V polarization components arrive at PM at different times, only one component will be modulated, and then a phase difference is introduced between the two components, realizing the polarization state modulation of light. The modulated H and V polarization components are combined and output at the polarization beam splitter.
[0043] More specifically, the sending end encoding module 2 further comprises a first master control module 25; the signal output end of the first master control module 25 is connected with the signal input end of the first optical path converter 22.
[0044] More specifically, the receiving end encoding module 3 further comprises a second master control module 35; the signal output end of the second master control module 35 is connected with the signal input end of the second optical path converter 32.
[0045] In the specific implementation process, by setting the first master control module 25 and the second master control module 35, the switching of the two encoding modes is realized by the first master control module 25 and the second master control module 35 according to the feedback bit error rate:
[0046] When the bit error rate increases due to environmental temperature and other factors, switch to polarization encoding mode;
[0047] When the bit error rate increases due to vibration and other factors, switch to phase encoding mode.
[0048] More specifically, it also includes an attenuator 5; the third port of the first circulator 21 is connected with one end of the attenuator 5, and the other end of the attenuator 5 is connected with the first port of the second circulator 31.
[0049] According to the disclosure and teaching of the above description, the skilled in the art of the utility model can also change and modify the above-mentioned embodiments. Therefore, the utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes of the utility model should also fall within the protection scope of the claims of the utility model. In addition, although some specific terms are used in the specification, these terms are only for convenience and do not constitute any limitation on the utility model.
Claims
1. A quantum key distribution system capable of switching encoding modes, characterized by comprising: a quantum key distribution system according to any one of claims 1 to 6; and a quantum key distribution system according to any one of claims 1 to 6. The laser, a transmitting end encoding module, a receiving end encoding module and a detection module are included. The transmitting end encoding module includes a first circulator, a first optical path converter, a first phase encoding module and a first polarization encoding module. The receiving end encoding module includes a second circulator, a second optical path converter, a second phase encoding module and a second polarization encoding module. The output end of the laser is connected with the first port of the first circulator, the second port of the first circulator is connected with the first port of the first optical path converter, the second port of the first optical path converter is connected with the first phase encoding module, the third port of the first optical path converter is connected with the first polarization encoding module; the third port of the first circulator is connected with the first port of the second circulator, the second port of the second circulator is connected with the first port of the second optical path converter, the second port of the second optical path converter is connected with the second phase encoding module, the third port of the second optical path converter is connected with the second polarization encoding module; the third port of the second circulator is connected with the input end of the detection module.
2. The quantum key distribution system according to claim 1, wherein The detection module includes a beam splitter, a first detector and a second detector. The third port of the second circulator is connected with the input end of the beam splitter, the first output end of the beam splitter is connected with the input end of the first detector, the second output end of the beam splitter is connected with the input end of the second detector.
3. The quantum key distribution system of claim 1, wherein, The arm length difference of the long and short arms of the first phase encoding module is 2 ns.
4. The quantum key distribution system of claim 1, wherein The arm length difference of the long and short arms of the second phase encoding module is 5 ps.
5. The quantum key distribution system of claim 1, wherein The first polarization encoding module and the second polarization encoding module both adopt Sagnac ring structure.
6. The quantum key distribution system of claim 1, wherein The transmitting end encoding module further includes a first master control module; the signal output end of the first master control module is connected with the signal input end of the first optical path converter.
7. The quantum key distribution system of claim 1, wherein The receiving end encoding module further includes a second master control module; the signal output end of the second master control module is connected with the signal input end of the second optical path converter.
8. The quantum key distribution system of claim 1, wherein, An attenuator is further included; the third port of the first circulator is connected with one end of the attenuator, and the other end of the attenuator is connected with the first port of the second circulator.