Anti-interference, low-loss encryption wire harness for quantum communication and preparation method thereof

Abstract

The application discloses an anti-interference and low-loss encryption wire harness for quantum communication and a preparation method thereof, and relates to the technical field of quantum communication. The wire harness comprises, from inside to outside, an inner core conductor, a quantum signal shielding layer, a phase stabilization medium layer and a comprehensive shielding sheath. The phase stabilization medium layer is arranged outside the quantum signal shielding layer. The comprehensive shielding sheath is arranged outside the phase stabilization medium layer and comprises a metal wire braiding layer and an outer sheath arranged from inside to outside. The quantum signal shielding layer made of a high magnetic permeability soft magnetic material is arranged between the inner core conductor and the outer quantum channel to actively suppress electromagnetic radiation. In combination with the phase stabilization medium layer made of a foamed fluorine-containing polymer with a specific dielectric constant and a loss tangent, the signal transmission phase stability is ensured, so that the quantum bit error rate is reduced, the security code rate is improved, and the high-frequency synchronous clock signal phase stable transmission is ensured.

Description

Technical Field

[0001] This invention relates to the field of quantum communication technology, specifically to an anti-interference, low-loss encryption wire bundle for quantum communication and its preparation method. Background Technology

[0002] Quantum communication, especially quantum key distribution (QKD) technology, utilizes the no-cloning and uncertainty principles of quantum states to theoretically achieve unconditionally secure key distribution, making it a crucial development direction for next-generation information security technologies. A complete QKD system typically comprises two physical channels: a quantum channel for transmitting quantum signals (such as single-photon or weakly coherent optical pulses) and a classical channel for system synchronization, basis vector comparison, data post-processing, and device power supply. In practical engineering deployments, the quantum channel often employs single-mode fiber transmission, while the classical channel needs to simultaneously carry a high-frequency synchronization clock signal (typically in the MHz to GHz band) and DC power to ensure precise time synchronization and stable power supply between the quantum transmitter and receiver. As QKD systems evolve towards higher speeds, longer distances, and greater integration, the physical isolation and electromagnetic compatibility issues between the classical and quantum channels become increasingly prominent, representing a key bottleneck restricting system performance improvement.

[0003] However, existing QKD systems typically use ordinary coaxial cables or twisted-pair cables for signal transmission in their classical channels. These conventional cables were not designed with the specific requirements of quantum communication scenarios in mind. The high-power synchronous electrical signals transmitted in classical channels (power levels typically in the milliwatt range) generate significant electromagnetic radiation during transmission. This electromagnetic leakage spreads outward in the form of near-field coupling and far-field radiation, easily interfering with quantum channels deployed on the same cable or in adjacent locations. Since quantum signals are at the single-photon level (power as low as nanowatts or even picowatts), any external electromagnetic interference will create in-band noise, severely overwhelming the fragile quantum signal. This directly leads to a sharp increase in the qubit error rate (QBER), a significant decrease in the secure key generation rate, and may even render the system unusable.

[0004] Meanwhile, existing solutions are mostly passive isolation measures, such as separating classical and quantum optical fibers into separate cables, increasing physical isolation distances, or adding metal shielding boxes at the equipment end. However, these methods not only increase system complexity and deployment costs but also fail to fundamentally eliminate interference from electromagnetic leakage sources. Furthermore, they are difficult to implement in space-constrained applications (such as internal interconnects of quantum computers and rack-mounted QKD devices). Therefore, how to actively suppress electromagnetic radiation generated by classical channels at the physical level without increasing system complexity, while ensuring the phase stability and low loss of the classical channel's own signal transmission, has become a technical problem that needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-interference, low-loss encrypted wire bundle for quantum communication and its preparation method. By setting a quantum signal shielding layer made of a soft magnetic material with high permeability between the inner conductor and the external quantum channel to actively suppress electromagnetic radiation, and combining it with a foamed fluoropolymer phase-stabilizing dielectric layer with a specific dielectric constant and loss tangent to ensure the phase stability of signal transmission, this invention solves the technical problems in existing QKD systems where electromagnetic radiation from the classical channel interferes with the quantum channel, leading to increased qubit error rate and insufficient phase stability of the synchronous clock signal.

[0006] This invention is achieved through the following technical solution: In a first aspect, embodiments of this invention provide an anti-interference, low-loss encryption harness for quantum communication, comprising, from the inside out: The inner conductor is used to transmit classical communication signals and / or electricity. A quantum signal shielding layer is disposed outside the inner core conductor. The quantum signal shielding layer is made of a soft magnetic material with an initial permeability of not less than 30,000 and is used to suppress the interference of electromagnetic radiation generated by the inner core conductor on the external quantum channel. A phase-stabilizing dielectric layer is disposed outside the quantum signal shielding layer. The phase-stabilizing dielectric layer is made of a foamed fluoropolymer with a dielectric constant of 1.2–2.2 and a loss tangent of 10°. -4 Magnitude; A comprehensive shielding sleeve is provided to cover the outside of the phase stabilizing dielectric layer. The comprehensive shielding sleeve includes a metal wire braided layer and an outer sheath arranged sequentially from the inside to the outside.

[0007] As an optional implementation, the quantum signal shielding layer includes at least one of nanocrystalline ribbon, permalloy ribbon, and ferrite material ribbon. The quantum signal shielding layer is wrapped around the outside of the inner core conductor in a longitudinal overlap manner, wherein the overlap rate is 30-66% and the wrapping tension is 2-8N.

[0008] As an optional implementation, the nanocrystalline ribbon comprises, by mass percentage: Ni: 2.5–7.5%, Si: 6.2–10.5%, B: 1.5–3.8%, Nb: 3.2–7.5%, Cu: 0.6–2.0%, Co: 0.5–2.5%, with the balance being Fe and impurities, the impurity content being less than 0.02%; the thickness of the nanocrystalline ribbon is 10–30 μm.

[0009] As an optional implementation, the permalloy strip comprises, by mass percentage: Fe: 13-50%, Mo: 0-6%, Si: 0.1-0.6%, Mn: 0.2-0.8%, Ce: 0.001-0.1%, with the balance being Ni and impurities, the impurity content being less than 0.03%; the thickness of the permalloy strip is less than or equal to 0.1 mm.

[0010] As an optional implementation, the ferrite material strip comprises, by mass parts: Iron oxide: 60-65 parts, zinc oxide: 10.5-13 parts, magnesium oxide: 8-15 parts, nickel oxide: 1-5 parts, manganese oxide: 1.5-4 parts, copper oxide: 1.6-3.5 parts, bismuth oxide: 0.8-1.7 parts.

[0011] As an optional implementation, the foamed fluoropolymer includes at least one of ceramic-filled fluoropolymer composite material, foamed polytetrafluoroethylene, and foamed perfluoroethylene propylene. The foaming rate of the phase-stabilizing dielectric layer is 50-75%, and it is cross-linked by electron beam irradiation with a cross-linking degree of 65% or more.

[0012] As an optional implementation, the inner core conductor includes a coaxial line pair for transmitting a high-frequency synchronous clock signal and a power line pair for transmitting DC power. The coaxial line pair is formed by concentric stranding or twisting silver-plated copper wire with a diameter of 0.08 to 0.12 mm. The stranding pitch is 8 to 12 times the outer diameter of the strand. The characteristic impedance of the coaxial line pair in the 1 to 10 GHz frequency band is 50 ± 1 Ω.

[0013] Secondly, embodiments of the present invention provide a method for preparing an anti-interference, low-loss encrypted wire bundle for quantum communication, comprising the following steps: Preparation of the inner core conductor: Under constant temperature and humidity conditions, multiple wires are twisted together to form the inner core conductor. By controlling the twisting tension and pitch, the characteristic impedance is kept stable within the target frequency band. Applying a quantum signal shielding layer: A soft magnetic material tape with an initial permeability of not less than 30,000 is used to wrap around the inner core conductor in an overlapping manner, and the wrapping tension is controlled to avoid mechanical stress damage to the magnetic domain structure of the soft magnetic tape. Extruded phase-stabilized dielectric layer: Foamed fluoropolymer material is extruded outside the quantum signal shielding layer, and the foaming rate and crosslinking degree are controlled to obtain a dielectric layer with stable dielectric properties; Braided metal shielding layer: Metal wires are braided outside the phase-stabilizing dielectric layer to form a shielding mesh; Extruded outer sheath: A polymer sheath is extruded over the metal shielding layer.

[0014] As an optional implementation, in the step of preparing the inner core conductor, the ambient temperature is 23±2℃, the relative humidity is 50±5%, silver-plated copper wire with a diameter of 0.08~0.12mm is used, and the single-wire stranding tension is 0.5~1.5N; In the step of applying the quantum signal shielding layer, the longitudinal overlap of the soft magnetic material strip is not less than 30%, and the wrapping tension is 2-8N.

[0015] As an optional implementation, in the step of extruding the phase-stabilized dielectric layer, polytetrafluoroethylene or polytetrafluoroethylene is used, the extrusion temperature is 145-185°C, the nitrogen injection pressure is 8-20 MPa when using nitrogen physical foaming, and the electron beam energy is 1.5-3.0 MeV, the dose rate is 5-15 kGy / s, and the total absorbed dose is 100-180 kGy when using electron beam irradiation crosslinking. In the step of braiding the metal shielding layer, tin-plated copper wire or silver-plated copper wire with a diameter of 0.10 to 0.16 mm is used, the braiding density is not less than 95%, and the surface coverage is not less than 100%. In the step of extruding the outer sheath, a composite material with polyetheretherketone as the matrix and filled with copper powder, aramid fiber and graphite is used. The extruder die temperature is 200-240℃, the extrusion line speed is 20-60m / min, and the concentricity deviation of the outer sheath is no more than 0.1mm.

[0016] Compared with the prior art, the embodiments of the present invention have the following advantages and beneficial effects: 1. This invention achieves the dual goals of anti-interference and low loss through a four-layer synergistic structure: When the inner conductor transmits classical communication signals and / or power, the resulting low-to-medium frequency electromagnetic radiation is effectively absorbed and dissipated by the quantum signal shielding layer. This layer, made of a soft magnetic material with high initial permeability, guides electromagnetic energy into the material's interior and converts it into heat energy through hysteresis loss, thereby blocking electromagnetic leakage paths and preventing interference with single-photon level signals in the external quantum channel. The phase-stabilizing dielectric layer uses a foamed fluoropolymer, whose low dielectric constant reduces the phase velocity change rate of signal transmission, and its extremely low loss tangent reduces energy dissipation during dielectric polarization, ensuring that the high-frequency synchronous clock signal maintains phase consistency and waveform integrity during transmission. The integrated shielding sheath provides overall mechanical protection and environmental sealing, preventing external physical damage and chemical corrosion from affecting the performance of the wire harness. Through this structure, the wire harness achieves close coexistence of classical and quantum channels while reducing the qubit error rate, improving the secure code generation rate, and providing a stable physical transmission channel for high-precision time synchronization.

[0017] 2. This invention utilizes three selectable soft magnetic materials—nanocrystalline ribbon, permalloy ribbon, or ferrite ribbon—to achieve broadband electromagnetic interference suppression. The nanocrystalline ribbon maintains high permeability at high frequencies due to its ultrafine grain structure. The permalloy ribbon achieves extremely low coercivity and high permeability through the high magnetocrystalline anisotropy of nickel-iron alloy. The ferrite ribbon utilizes the resistivity advantage of ferrimagnetic oxides to suppress eddy current losses. All three materials form a seamless shielding layer through longitudinal overlapping and wrapping, with the overlap rate controlled between 30% and 66% to ensure magnetic circuit continuity. The wrapping tension is strictly limited to the range of 2–8 N. This low-tension process prevents irreversible changes in the magnetic domain structure of the soft magnetic material under mechanical stress, thus protecting its initial permeability from degradation and ensuring long-term stable shielding effectiveness. The synergistic effect of material selection and process control allows the wire harness to adaptively optimize shielding performance for different frequency interference sources.

[0018] 3. In this embodiment of the invention, the phase-stabilizing dielectric layer of the encrypted wire harness is made of foamed polytetrafluoroethylene, foamed perfluoroethylene propylene, or ceramic-filled fluoropolymer composite material. A uniform cell structure is formed through chemical foaming agents or nitrogen physical foaming processes, with the foaming rate precisely controlled within the range of 50-75%. The average cell diameter is maintained at 20-50 μm. This microporous structure reduces the dielectric constant of the material to 1.2-2.2, significantly reducing the sensitivity of signal propagation delay to temperature. Simultaneously, the electron beam irradiation crosslinking process achieves a crosslinking degree of over 65%. The three-dimensional network molecular structure effectively locks the cell morphology, preventing dielectric property drift caused by mechanical bending or thermal cycling, and maintaining the loss tangent at 10°. -4 The scale ensures minimal signal attenuation within the 1–10 GHz frequency band, providing a synchronization clock reference with extremely low phase jitter for quantum communication systems.

[0019] 4. The integrated shielding sheath of this invention adopts a double-layer composite structure. The inner metal wire braided layer uses tin-plated copper wire or silver-plated copper wire with a diameter of 0.10-0.16mm and a braiding density of not less than 95%, forming a dense conductive grid to provide high-frequency electromagnetic shielding and grounding continuity. The surface coverage reaches 100% optical shielding level, effectively blocking the intrusion of external electromagnetic pulses and radio frequency interference. The outer sheath can be based on polyetheretherketone, filled with copper powder to give it electromagnetic shielding continuity, filled with aramid fiber to improve tensile strength and wear resistance, and filled with graphite to achieve self-lubricating and antistatic properties. This modified composite material is formed by extruder die temperature of 200-240℃ and linear speed of 20-60m / min. The concentricity deviation is controlled within 0.1mm to ensure uniform wall thickness and structural symmetry, so that the wire harness has excellent mechanical flexibility, chemical corrosion resistance and long-term reliability in complex wiring environments.

[0020] 5. The method for preparing the encrypted wire harness in this embodiment of the invention is carried out in a constant temperature and humidity environment (temperature 23±2℃, relative humidity 50±5%). This environmental control eliminates the influence of temperature and humidity fluctuations on the uniformity of conductor stranding tension and the consistency of foam pore size of the dielectric layer. When extruding the phase-stabilized dielectric layer, the temperature of the cylinder and the mold is precisely controlled at 145~185℃. Nitrogen gas is injected at a pressure of 8~20MPa and uniformly mixed with the melt through a static mixer. Electron beam irradiation crosslinking adopts a parameter combination of energy 1.5~3.0MeV, dose rate 5~15kGy / s, and total absorbed dose 100~180kGy. This process range achieves a crosslinking degree of more than 65% while ensuring the stability of the foam structure. Compared with chemical crosslinking, irradiation crosslinking avoids the contamination of dielectric properties by residual catalysts. The overall preparation process minimizes the performance deviation between batches of wire harnesses through multi-parameter coupling control of environment, materials, and process, meeting the stringent requirements of quantum communication systems for the consistency and reliability of transmission links.

[0021] In summary, the present invention provides an anti-interference, low-loss encrypted wire bundle for quantum communication and its preparation method. By setting a quantum signal shielding layer made of a high-permeability soft magnetic material between the inner core conductor and the external quantum channel to actively suppress electromagnetic radiation, and by combining it with a foamed fluoropolymer phase-stabilizing dielectric layer with a specific dielectric constant and loss tangent to ensure the phase stability of signal transmission, the invention aims to reduce the quantum bit error rate, improve the secure code generation rate, and ensure the stable phase transmission of high-frequency synchronous clock signals. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the cross-sectional structure of the encrypted wire harness provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the nanoribbon wrapping structure provided in Embodiment 1 of the present invention; Figure 3 This is a flowchart illustrating the fabrication process of the encrypted wire harness provided in Embodiment 2 of the present invention.

[0023] Figure reference numerals and corresponding component names: 1-Inner core conductor, 2-Quantum signal shielding layer, 3-Phase stabilizing dielectric layer, 4-Comprehensive shielding sheath, 41-Metal wire braided layer, 42-Outer sheath. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0025] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] Example 1: This embodiment provides an anti-interference, low-loss encryption harness for quantum communication. This harness is designed specifically for quantum key distribution systems and is used to integrate the transmission of high-frequency synchronous clock signals and DC power supplies in the same physical carrier. At the same time, it suppresses electromagnetic interference from classical channels to external quantum channels through active electromagnetic shielding.

[0027] Reference Figure 1 As shown, the encrypted cable harness consists of four layers from the inside out: an inner conductor 1, a quantum signal shielding layer 2, a phase-stabilizing dielectric layer 3, and a comprehensive shielding sheath 4.

[0028] The inner conductor 1 is used to transmit classical communication signals and / or power. Multiple conductors can be used to transmit high-frequency synchronous clock signals and DC power respectively. The conductors transmitting clock signals can be coaxial or twisted pair. The inner core conductor 1 is formed by concentric stranding or twisting silver-plated copper wire with a diameter of 0.08–0.12 mm. The silver-plated copper wire can be annealed copper wire with a silver-plated surface and a silver layer thickness of 1–3 μm to reduce resistance loss caused by the skin effect at high frequencies. The concentric stranding can be a 1+6 structure, i.e., 1 central conductor with 6 conductors evenly distributed around the periphery, or a twisted structure, i.e., two conductors spirally wound together. The stranding direction can be left-handed or right-handed, and the stranding direction of adjacent layers is opposite to eliminate torsional stress. The stranding pitch is controlled to be 8–12 times the outer diameter of the strand. Through precise coordinated control of stranding tension and pitch, the characteristic impedance of the coaxial pair is stabilized at 50±1Ω in the 1–10 GHz frequency band. The compaction process can be achieved by compaction mold or roll pressing to achieve a compaction coefficient of 0.85–0.95 for the stranded conductor, eliminating conductor gaps, improving the effective cross-sectional area and structural stability of the conductor, and controlling the outer diameter tolerance within ±0.05 mm.

[0029] A quantum signal shielding layer 2, made of a soft magnetic material with an initial permeability of not less than 30,000, covers the outer surface of the inner core conductor 1 and is used to suppress the interference of electromagnetic radiation generated by the inner core conductor 1 on the external quantum channel. This quantum signal shielding layer 2 can be made of nanocrystalline ribbon, permalloy ribbon, or ferrite material ribbon, and is longitudinally overlapped and wrapped around the outer surface of the inner core conductor 1, with an overlap rate of 30%–66% and a wrapping tension of 2–8 N; (Refer to...) Figure 2 As shown, longitudinal overlap wrapping can be spiral wrapping, with the edges of the strip overlapping to form an overlap. The overlap rate is calculated as the percentage of the overlap width to the strip width. The precision wrapping machine is equipped with a constant tension control system. The tension sensor monitors and provides feedback adjustment in real time to ensure that the wrapping tension fluctuates within the range of 2 to 8N without exceeding ±0.5N. The wrapping angle is adjusted according to the outer diameter of the wire harness and the width of the strip, usually between 30 and 60°, to ensure a tight fit and uniform coverage of the shielding layer.

[0030] The composition of the nanocrystalline ribbon, by mass percentage, includes: Ni: 2.5–7.5%, Si: 6.2–10.5%, B: 1.5–3.8%, Nb: 3.2–7.5%, Cu: 0.6–2.0%, Co: 0.5–2.5%, with the balance being Fe and unavoidable impurities, the impurity content being less than 0.02%. The ribbon thickness is 0.01–0.03 mm, and the width is 2–20 mm. The preparation method of the nanocrystalline ribbon is as follows: raw materials with a purity greater than 99.9% are melted in an induction melting furnace under vacuum or inert gas protection. The melting temperature is controlled at 1300–1600℃, and the temperature is maintained to ensure uniform composition and remove gaseous impurities. The molten alloy is then sprayed through a nozzle onto the surface of a high-speed rotating water-cooled copper roller at a flow rate greater than 10... 6 Rapid cooling at a rate of K / s forms an amorphous precursor ribbon. The ribbon is then heated to 550°C in a vacuum at a rate of 50°C / min and held for 1 hour to complete the nanocrystallization heat treatment, resulting in a high-permeability nanocrystalline ribbon.

[0031] The composition of permalloy strip, by mass percentage, includes: Fe: 13-50%, Mo: 0-6%, Si: 0.1-0.6%, Mn: 0.2-0.8%, Ce: 0.001-0.1%, with the balance being Ni and unavoidable impurities, the impurity content being less than 0.03%. The preparation method of permalloy strip is as follows: high-purity raw materials are weighed according to the composition ratio and melted in a vacuum induction furnace. The melting temperature is controlled at 1550-1600℃, and the furnace pressure is controlled at 10... -2The alloy is degassed under vacuum below Pa to remove gaseous impurities such as oxygen, hydrogen, and nitrogen. The molten alloy is then cast into ingots and forged. The ingots are heated to 1150±10℃ and held for 30–60 minutes before forging. Subsequently, they are hot-rolled at 1100±10℃ into hot-rolled plates with a thickness of 2–5 mm. The hot-rolled plates are then subjected to multiple cold rolling passes to produce strips with a thickness of 0.1 mm or less. Finally, the strips are annealed in a pure hydrogen atmosphere or high vacuum by heating at 90±2℃ / h to 950±10℃ and holding for 1.5–3 hours, then heating at 120±2℃ / h to 1120±10℃ and holding for 5–6 hours, then cooling at 150±2℃ / h to 400±10℃ and holding for 2–3 hours, and finally air-cooled to obtain permalloy strips with optimized magnetic properties.

[0032] The components of the ferrite material strip by mass include: 60-65 parts iron oxide, 10.5-13 parts zinc oxide, 8-15 parts magnesium oxide, 1-5 parts nickel oxide, 1.5-4 parts manganese oxide, 1.6-3.5 parts copper oxide, and 0.8-1.7 parts bismuth oxide. The preparation method of ferrite material strip is as follows: Accurately weigh each oxide raw material according to the formula, and perform dry or wet mixing to ensure uniformity. Pre-calcine the uniformly mixed powder in air at 700–950℃ for 1–4 hours to allow preliminary solid-phase reactions to occur, forming the ferrite phase. Crush the pre-calcineed material and perform wet ball milling, adding deionized water and grinding media to ball mill to the desired average particle size. Add binder and dispersant to the ball-milled slurry and perform spray granulation to obtain free-flowing particles. Press the particles into green bodies of the desired shape in a mold. Place the green bodies in a controlled atmosphere sintering furnace for sintering using an atmospheric pressure sintering method. The sintering atmosphere is air or an oxidizing atmosphere with controllable oxygen partial pressure (content controlled between 10–1000%). Within the ppm range, to suppress the volatilization of elements such as Zn and Ni and promote uniform grain growth; the temperature is increased to 950℃ at 1-3℃ / min, then increased to 1100℃ at 2-4℃ / min, and finally increased to 1330-1380℃ at 1-3℃ / min and held for 7-9 hours; then the temperature is decreased to 800-900℃ at 2-4℃ / min, then decreased to 400-500℃ at 3-5℃ / min, and then naturally cooled to room temperature with the furnace to obtain a dense ferrite material strip; the binder can be at least one of polyvinyl alcohol, polyvinyl butyral or acrylic binder, whose main function is to give the spray-granulated particles suitable flowability and mechanical strength, and to ensure that the green strip has a uniform density distribution and sufficient green strength during the dry pressing process; the dispersant can be at least one of ammonium polyacrylate, polyethylene glycol or ammonium citrate, used to improve the dispersion stability of powder in ball mill slurry and prevent particle agglomeration.

[0033] The phase-stabilizing dielectric layer 3, which covers the outside of the quantum signal shielding layer 2, is made of foamed fluoropolymer. It can be made of foamed polytetrafluoroethylene, foamed perfluoroethylene propylene, or a ceramic-filled fluoropolymer composite material. Its dielectric constant is 1.2–2.2, and its loss tangent is within 10°. -4 The foaming rate of this medium layer is 50-75%, with an average cell diameter of 20-50 μm. It is formed using an electron beam irradiation crosslinking process, achieving a crosslinking degree of over 65%. The extrusion process uses a single-screw or twin-screw extruder equipped with a precision temperature control system and a static mixer. The chemical foaming agent can be azodicarbonamide, sodium bicarbonate, or a mixture of citric acid and sodium bicarbonate, added at a rate of 0.5-1.2 phr, with a decomposition temperature range matching the processing temperature of polytetrafluoroethylene. The physical foaming agent, nitrogen, is injected into the melt at a pressure of 8-20 MPa through a high-pressure injection system and dispersed by a static mixer to form uniform bubble nuclei. Electron beam irradiation crosslinking is carried out under nitrogen protection or a vacuum environment to prevent oxidative degradation. After irradiation, the gel content of the medium layer reaches over 65%, indicating that the crosslinking network is fully formed.

[0034] The integrated shielding sheath 4 covers the phase-stabilizing dielectric layer 3 and includes an inner metal wire braided layer 41 and an outer high-density wear-resistant polymer sheath 42. The metal wire braided layer 41 is woven with tin-plated copper wire or silver-plated copper wire, with a single wire diameter of 0.10-0.16 mm, a braiding density of not less than 95%, and a surface coverage of 100%. The tin-plated copper wire or silver-plated copper wire can be annealed soft copper wire with a tensile strength of 200-300 MPa and an elongation of not less than 15% to ensure flexibility and fatigue resistance during the braiding process. The braiding machine can be a high-speed braiding machine, with the spindle speed and traction speed controlled synchronously to ensure uniform braiding pitch. The filler braiding can be double-layer braiding or high-density single-layer braiding, with the braiding angle controlled at 45-60° to achieve the best balance between shielding effectiveness and bending performance. The high-density wear-resistant polymer sheath can be a black flame-retardant high-density wear-resistant polymer, such as a composite material with polyetheretherketone, polyimide, or polyphenylene sulfide as the matrix, filled with copper powder, aramid fiber, graphite, and flame retardant. The flame retardant can be at least one of magnesium hydroxide, aluminum hydroxide, or phosphorus-based flame retardant. Black coloring can be achieved by adding carbon black or black masterbatch. The flame retardant, during combustion, decomposes endothermically or forms a carbon layer to block oxygen, giving the sheath self-extinguishing or flame-retardant properties. Copper powder filling gives the sheath electromagnetic shielding continuity and thermal conductivity, aramid fiber improves tensile strength and cut resistance, and graphite provides self-lubricating and antistatic properties. The synergistic effect of the various functional fillers enables the sheath to have flame-retardant properties while reducing the wear rate by 30-50% compared to the pure matrix polymer. The high-density wear-resistant polymer sheath is extruded onto the surface of the metal shielding layer after being heated and plasticized by an extruder. The extrusion temperature is set according to the melting characteristics of the matrix material, and the nominal thickness is not less than 0.30 mm to provide sufficient mechanical protection and environmental sealing performance. The extrusion concentricity deviation is not greater than 0.1 mm.

[0035] In an embodiment of the present invention, exemplarily, the inner conductor 1 includes a coaxial line pair for transmitting a high-frequency synchronous clock signal and a power line pair for transmitting DC power. The coaxial line pair is formed by concentrically stranding silver-plated copper wire with a diameter of 0.08 mm in a 1+6 structure. The silver layer thickness is 2 μm, the stranding direction is right-handed, the stranding pitch is 8 times the outer diameter of the strand, and the compaction coefficient is 0.90. The quantum signal shielding layer 2 is made of nanocrystalline ribbon with the following composition: Ni: 5.8%, Si: 8.5%, B: 2.5%, Nb: 5.0%, Cu: 1.2%, Co: 1.5%, and the balance being Fe. The ribbon thickness is 0.02 mm, the width is 20 mm, and the nanocrystalline ribbon is prepared at a melting temperature of 1450℃ and sprayed onto a water-cooled copper roller with a rotation speed of 30 m / s. The overlap rate during wrapping is 40%, the wrapping tension is 4 N, and the wrapping angle is 45°. The phase-stabilizing dielectric layer 3 is made of foamed polytetrafluoroethylene with a dielectric constant of 1.3, a foaming rate of 60%, an average cell diameter of 35 μm, and a chemical foaming agent of azodicarbonamide at an addition amount of 0.8 phr. During electron beam irradiation crosslinking, the electron beam energy is 2.0 MeV, the dose rate is 10 kGy / s, the total absorbed dose is 140 kGy, and the degree of crosslinking is 70%. The metal wire braided layer 41 uses annealed silver-plated copper wire with a diameter of 0.12 mm, a tensile strength of 250 MPa, an elongation of 20%, a braiding density of 96%, and a braiding angle of 50°. The high-density wear-resistant polymer sheath uses polyetheretherketone (PEEK) as the matrix, filled with copper powder, aramid fiber, graphite, and magnesium hydroxide flame retardant, and colored black with carbon black. The extrusion temperature is 220℃, the nominal thickness is 0.35 mm, and the concentricity deviation is 0.08 mm.

[0036] In summary, the embodiments of this invention achieve anti-interference and low-loss technical effects through the synergistic effect of a four-layer structure: When the inner conductor 1 transmits high-frequency synchronous clock signals and DC power, the electromagnetic radiation it generates is effectively absorbed and shielded by the quantum signal shielding layer 2. This layer is made of soft magnetic material with an initial permeability of not less than 30,000. It forms a continuous magnetic circuit through longitudinal overlapping and wrapping, actively suppressing electromagnetic leakage and avoiding in-band noise to single-photon level quantum signals. This can reduce the quantum bit error rate of the QKD system by an order of magnitude and significantly improve the secure code generation rate; the phase stabilizing dielectric layer 3 uses a dielectric constant of 1.2 to 2.2 and a loss tangent of 10°. -4The harness utilizes a high-volume foamed fluoropolymer, cross-linked with electron beam irradiation to ensure structural stability, maintaining phase constancy and speed consistency in signal transmission. This provides the physical basis for high-precision time synchronization, while the low loss factor ensures high signal strength even after long-distance transmission, helping to extend relay distances. The integrated shielding sheath 4 provides high-frequency electromagnetic shielding and grounding continuity through a metal braided layer, and mechanical protection and environmental sealing through a high-density, wear-resistant polymer sheath. This harness integrates the transmission requirements of classical and quantum channels into a single unit, replacing traditional passive isolation with active magnetic shielding. This simplifies system cabling, reduces deployment and maintenance costs, and is suitable for the practical and large-scale deployment of QKD systems.

[0037] Example 2: This embodiment provides a method for preparing an anti-interference, low-loss encryption bundle for quantum communication, referring to... Figure 3 As shown, the method includes the following steps: preparing an inner core conductor 1, applying a quantum signal shielding layer 2, extruding a phase-stabilizing dielectric layer 3, braiding a metal shielding layer, and extruding an outer sheath 42.

[0038] The preparation of the inner core conductor 1 was carried out under a constant temperature and humidity environment. The ambient temperature was 23±2℃ and the relative humidity was 50±5%. The constant temperature and humidity environment was controlled by a central air conditioning system and a dehumidifier, with temperature fluctuations not exceeding ±1℃ and relative humidity fluctuations not exceeding ±3%. Multiple silver-plated copper wires were twisted together to form the inner core conductor 1. The silver-plated copper wires could be annealed copper wires with a silver layer thickness of 1-3μm and a diameter of 0.08-0.12mm. A 1+6 structure was adopted. The wires are twisted in a concentric or twisted manner, with the twisting direction being either left-handed or right-handed. The twisting directions of adjacent layers are opposite to eliminate torsional stress. The single-wire twisting tension is 0.5–1.5 N, and the twisting pitch is 8–12 times the outer diameter of the wire. The wires are compacted using a pressing die or roller pressing method, with a compaction coefficient of 0.85–0.95, to eliminate conductor gaps and control the outer diameter tolerance within ±0.05 mm, so that the characteristic impedance of the coaxial cable pair is stable at 50 ± 1 Ω in the 1–10 GHz frequency band.

[0039] Step 2 of applying the quantum signal shielding layer uses a soft magnetic material tape with an initial permeability of not less than 30,000, which is wrapped around the inner core conductor 1 in an overlapping manner. The wrapping tension is controlled to avoid mechanical stress damage to the magnetic domain structure of the soft magnetic tape. The longitudinal overlap of the soft magnetic material tape is not less than 30%, and the wrapping tension is 2 to 8 N. The longitudinal overlap wrapping adopts a spiral wrapping, and the edges of the tape overlap to form an overlap. The overlap rate is calculated as the percentage of the overlap width to the tape width. A precision wrapping machine equipped with a constant tension control system is used. The tension sensor monitors and provides feedback adjustment in real time to ensure that the wrapping tension fluctuation does not exceed ±0.5 N. The wrapping angle is adjusted according to the outer diameter of the wire harness and the width of the tape, usually 30 to 60°, to ensure a tight fit and uniform coverage of the shielding layer.

[0040] When using nanocrystalline ribbons, the preparation method is as follows: Raw materials with a purity greater than 99.9% are melted in an induction melting furnace under vacuum or inert gas protection. The melting temperature is controlled at 1300–1600℃, and the temperature is maintained to ensure uniform composition and remove gaseous impurities. The molten alloy is then sprayed through a nozzle onto the surface of a high-speed rotating water-cooled copper roller at a spray rate greater than 10... 6 Rapid cooling at a rate of K / s forms an amorphous precursor ribbon. The ribbon is then heated to 550°C in a vacuum at a rate of 50°C / min and held for 1 hour to complete the nanocrystallization heat treatment, resulting in a high-permeability nanocrystalline ribbon.

[0041] When using permalloy strip, the preparation method is as follows: weigh high-purity raw materials according to the component ratio, melt them in a vacuum induction furnace at 1550-1600℃, and control the furnace pressure at 10. -2 The alloy is degassed under vacuum below Pa to remove gaseous impurities such as oxygen, hydrogen, and nitrogen. The molten alloy is then cast into ingots and forged. The ingots are heated to 1150±10℃ and held for 30–60 minutes before forging. Subsequently, they are hot-rolled at 1100±10℃ into hot-rolled plates with a thickness of 2–5 mm. The hot-rolled plates are then subjected to multiple cold rolling passes to produce strips with a thickness of 0.1 mm or less. Finally, the strips are annealed in a pure hydrogen atmosphere or high vacuum by heating at 90±2℃ / h to 950±10℃ and holding for 1.5–3 hours, then heating at 120±2℃ / h to 1120±10℃ and holding for 5–6 hours, then cooling at 150±2℃ / h to 400±10℃ and holding for 2–3 hours, and finally air-cooled to obtain permalloy strips with optimized magnetic properties.

[0042] When using ferrite material belts, the preparation method is as follows: Accurately weigh each oxide raw material according to the formula, perform dry or wet mixing to ensure uniformity, pre-calcine the uniformly mixed powder in air at 700–950°C for 1–4 hours to allow preliminary solid-phase reactions to form the ferrite phase, crush the pre-calcineed lumps, and then perform wet ball milling, adding deionized water and grinding media to ball mill to the desired average particle size. Add a binder and dispersant to the ball-milled slurry and perform spray granulation to obtain particles with good flowability. The binder can be at least one of polyvinyl alcohol, polyvinyl butyral, or acrylic binders, and the dispersant can be at least one of ammonium polyacrylate, polyethylene glycol, or ammonium citrate. Place the green body in a controlled atmosphere sintering furnace for sintering, using an atmospheric pressure sintering method. The sintering atmosphere is air or an oxidizing atmosphere with controllable oxygen partial pressure (content controlled between 10–1000%). Within the ppm range, to suppress the volatilization of elements such as Zn and Ni and promote uniform grain growth; the temperature is increased to 950℃ at 1-3℃ / min, then increased to 1100℃ at 2-4℃ / min, and finally increased to 1330-1380℃ at 1-3℃ / min and held for 7-9 hours; then the temperature is decreased to 800-900℃ at 2-4℃ / min, then decreased to 400-500℃ at 3-5℃ / min, and then naturally cooled to room temperature with the furnace to obtain a dense ferrite material band.

[0043] The third step of extruding the phase-stabilized dielectric layer involves extruding a foamed fluoropolymer material onto the outside of the quantum signal shielding layer 2, controlling the foaming rate and crosslinking degree to obtain a dielectric layer with stable dielectric properties. This step is carried out in a constant temperature and humidity environment, with the temperature control accuracy of the extruder die head and mold being ±1℃. Key processes should be carried out in a clean booth or clean room. A single-screw or twin-screw extruder is used, equipped with a precision temperature control system and a static mixer, with an extrusion temperature of 145~185℃. When using a chemical foaming agent, it can be azodicarbonamide, sodium bicarbonate, or a mixture of citric acid and sodium bicarbonate, with an addition amount of [missing information]. 0.5–1.2 phr; When using nitrogen physical foaming, nitrogen is injected into the melt at a pressure of 8–20 MPa through a high-pressure injection system, and dispersed by a static mixer to form uniform bubble nuclei; the foaming rate is 50%–75%, and the average pore diameter is 20–50 μm; When using electron beam irradiation crosslinking, it is carried out under nitrogen protection or vacuum environment, with an electron beam energy of 1.5–3.0 MeV, a dose rate of 5–15 kGy / s, and a total absorbed dose of 100–180 kGy. After irradiation, the gel content of the dielectric layer reaches more than 65%, indicating that the crosslinking network is fully formed.

[0044] The metal shielding layer braiding step involves braiding metal wires outside the phase-stabilizing dielectric layer 3 to form a shielding mesh. Tin-plated copper wire or silver-plated copper wire can be annealed soft copper wire with a tensile strength of 200-300 MPa, an elongation of not less than 15%, and a single wire diameter of 0.10-0.16 mm. A high-speed braiding machine is used, with the spindle speed and traction speed controlled synchronously to ensure uniform braiding pitch. A double-layer braiding or high-density single-layer braiding filler braiding method is adopted, with the braiding angle controlled at 45-60°, the braiding density not less than 95%, and the surface coverage not less than 100%, to achieve the best balance between shielding effectiveness and bending performance.

[0045] Step 42 involves extruding a polymer sheath over the metal shielding layer. This sheath is made of a composite material with polyetheretherketone, polyimide, or polyphenylene sulfide as the matrix, filled with copper powder, aramid fiber, graphite, and a flame retardant. The flame retardant can be at least one of magnesium hydroxide, aluminum hydroxide, or phosphorus-based flame retardants. Carbon black or black masterbatch is added to achieve black coloring. The copper powder filler imparts electromagnetic shielding continuity and thermal conductivity to the sheath. Aramid fiber enhances tensile strength and cut resistance. Graphite provides self-lubrication and antistatic properties. The flame retardant, during combustion, decomposes endothermally or forms a char layer to block oxygen, giving the sheath self-extinguishing or flame-retardant properties. The sheath is extruded onto the surface of the metal shielding layer after being heated and plasticized in an extruder. The extruder die temperature is 200–240°C, and the extrusion line speed is 20–60 m / min. The extrusion temperature is set according to the melting characteristics of the matrix material. The nominal thickness is not less than 0.30 mm, and the concentricity deviation of the outer sheath 42 is not greater than 0.1 mm, to provide sufficient mechanical protection and environmental sealing performance.

[0046] In this embodiment of the invention, specifically, in step 1 of preparing the inner core conductor, the ambient temperature is 23℃, the relative humidity is 50%, the temperature fluctuation does not exceed ±1℃, and the relative humidity fluctuation does not exceed ±3%. Silver-plated copper wire with a diameter of 0.10mm and a silver layer thickness of 2μm is used, concentrically stranded in a 1+6 structure, with a right-hand twisting direction, a single-wire stranding tension of 1.0N, a stranding pitch of 10 times the outer diameter of the strand, a compaction coefficient of 0.90, and an outer diameter tolerance of ±0.03mm. In step 2 of applying the quantum signal shielding layer, permalloy strip is used, specifically composed of Fe: 15.5%, Mo: 4.8%, Si: 0.3%, Mn: 0.5%, Ce: 0.05%, with the balance being Ni. The strip thickness is 0.08mm, the longitudinal overlap is 35%, the wrapping tension is 6N, and the wrapping angle is 50°. The permalloy strip is prepared at a melting temperature of 1580℃, and the furnace pressure is controlled at 10... -2Below Pa, the final annealing process involves heating at 90℃ / h to 950℃ and holding for 2 hours, then heating at 120℃ / h to 1120℃ and holding for 5.5 hours, followed by cooling at 150℃ / h to 400℃ and holding for 2.5 hours, and finally air cooling. The three-step extrusion of the phase-stabilized medium layer is carried out in a cleanroom, using perfluoroethylene propylene material. The extrusion temperature is 165℃ for the barrel and 160℃ for the die, with a temperature control accuracy of ±1℃ for the die head and die. The chemical foaming agent is azodicarbonamide, added at 0.8 phr. The nitrogen injection pressure is 12 MPa, the foaming rate is 65%, and the average cell diameter is 30 μm. Electron beam irradiation crosslinking is carried out under nitrogen protection, with an electron beam energy of 2.0 MeV, a dose rate of 10 kGy / s, a total absorbed dose of 140 kGy, a crosslinking degree of 68%, and a gel content of 70%. The braided metal shielding layer uses annealed tin-plated copper wire with a diameter of 0.14 mm, a tensile strength of 280 MPa, an elongation of 18%, a braiding density of 97%, and a braiding angle of 55°. The extrusion outer sheath (step 42) uses a composite material with polyetheretherketone (PEEK) as the matrix, filled with copper powder, aramid fiber, graphite, and magnesium hydroxide flame retardant. Carbon black is added for coloring, and the extruder die temperature is 220°C, the extrusion line speed is 40 m / min, the nominal thickness is 0.35 mm, and the concentricity deviation is 0.05 mm.

[0047] Overall, the embodiments of this invention ensure the performance consistency and manufacturing reliability of the encrypted wire harness through the synergy of environmental control and process parameters: the entire preparation process is carried out in a constant temperature and humidity environment, with the temperature controlled at 23±2℃ and the relative humidity controlled at 50±5%, eliminating the influence of temperature and humidity fluctuations on the uniformity of conductor stranding tension, the magnetic domain stability of the soft magnetic tape, and the consistency of the foamed pore size of the dielectric layer; vacuum melting, rapid cooling, and crystallization heat treatment are used for nanocrystalline ribbons, vacuum induction melting, multi-pass cold rolling, and stepped annealing are used for permalloys, and pre-sintering, wet ball milling, and controlled atmosphere sintering are used for ferrites, respectively optimizing the initial magnetic properties of different soft magnetic materials. Conductivity and magnetic loss characteristics; impedance stability of 50±1Ω is achieved by controlling the stranding tension to 0.5–1.5N and the pitch to 8–12 times the stranding outer diameter; mechanical stress damage to the magnetic domain structure of the flexible magnetic tape is avoided by controlling the wrapping tension to 2–8N; the foaming rate of the dielectric layer is ensured to be 50%–75% and the crosslinking degree to be above 65% by controlling the extrusion temperature to 145–185℃, the nitrogen injection pressure to 8–20MPa, and the irradiation dose to 100–180kGy; surface coverage is ensured by controlling the braiding density to be no less than 95%; and the concentricity deviation of the sheath is ensured to be no greater than 0.1mm by controlling the extrusion line speed and die temperature. This preparation method keeps the key parameters of each process within the optimization window, ensuring that the performance deviation between batches of wire harnesses is minimized, meeting the requirements of quantum communication systems for extremely high consistency and reliability of transmission links, and providing a process foundation for the large-scale production of QKD technology.

[0048] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An anti-interference, low-loss encryption wire bundle for quantum communication, characterized in that, From the inside out, the following are included: The inner conductor (1) is used to transmit classical communication signals and / or electricity; A quantum signal shielding layer (2) is disposed outside the inner core conductor (1). The quantum signal shielding layer (2) is made of a soft magnetic material with an initial permeability of not less than 30,000 and is used to suppress the interference of electromagnetic radiation generated by the inner core conductor (1) on the external quantum channel. A phase-stabilizing dielectric layer (3) is disposed outside the quantum signal shielding layer (2). The phase-stabilizing dielectric layer (3) is made of a foamed fluoropolymer with a dielectric constant of 1.2 to 2.2 and a loss tangent of 10°. -4 Magnitude; The integrated shielding sleeve (4) covers the outside of the phase stabilizing medium layer (3). The integrated shielding sleeve (4) includes a metal wire braided layer (41) and an outer sheath (42) arranged sequentially from the inside to the outside.

2. The anti-interference, low-loss encryption wire bundle for quantum communication according to claim 1, characterized in that, The quantum signal shielding layer (2) includes at least one of nanocrystalline ribbon, permalloy ribbon, and ferrite material ribbon. The quantum signal shielding layer (2) is wrapped around the outer side of the inner core conductor (1) by longitudinal overlap, wherein the overlap rate is 30-66% and the wrapping tension is 2-8N.

3. The anti-interference, low-loss encryption wire bundle for quantum communication according to claim 2, characterized in that, The components of the nanocrystalline ribbon, by mass percentage, include: Ni: 2.5–7.5%, Si: 6.2–10.5%, B: 1.5–3.8%, Nb: 3.2–7.5%, Cu: 0.6–2.0%, Co: 0.5–2.5%, with the balance being Fe and impurities, the impurity content being less than 0.02%; the thickness of the nanocrystalline ribbon is 10–30 μm.

4. The anti-interference, low-loss encryption wire bundle for quantum communication according to claim 2, characterized in that, The composition of the permalloy strip, by mass percentage, includes: Fe: 13-50%, Mo: 0-6%, Si: 0.1-0.6%, Mn: 0.2-0.8%, Ce: 0.001-0.1%, with the balance being Ni and impurities, the impurity content being less than 0.03%; the thickness of the permalloy strip is less than or equal to 0.1 mm.

5. The anti-interference, low-loss encryption wire bundle for quantum communication according to claim 2, characterized in that, The components of the ferrite material strip, by mass parts, include: Iron oxide: 60-65 parts, zinc oxide: 10.5-13 parts, magnesium oxide: 8-15 parts, nickel oxide: 1-5 parts, manganese oxide: 1.5-4 parts, copper oxide: 1.6-3.5 parts, bismuth oxide: 0.8-1.7 parts.

6. The anti-interference, low-loss encryption wire bundle for quantum communication according to claim 1, characterized in that, The foamed fluoropolymer includes at least one of ceramic-filled fluoropolymer composite material, foamed polytetrafluoroethylene, and foamed perfluoroethylene propylene. The foaming rate of the phase-stabilized dielectric layer (3) is 50-75%, and it is cross-linked by electron beam irradiation with a cross-linking degree of more than 65%.

7. The anti-interference, low-loss encryption wire bundle for quantum communication according to claim 1, characterized in that, The inner core conductor (1) includes a coaxial line pair for transmitting high-frequency synchronous clock signals and a power line pair for transmitting DC power. The coaxial line pair is formed by concentric twisting or twisting silver-plated copper wire with a diameter of 0.08 to 0.12 mm. The twisting pitch is 8 to 12 times the outer diameter of the twisting. The characteristic impedance of the coaxial line pair in the 1 to 10 GHz frequency band is 50 ± 1 Ω.

8. A method for preparing an anti-interference, low-loss encrypted wire bundle for quantum communication as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Preparation of inner core conductor (1): Under constant temperature and humidity environment, multiple wires are twisted together to form inner core conductor (1), and the characteristic impedance is kept stable in the target frequency band by controlling the twisting tension and pitch; Apply a quantum signal shielding layer (2): Use a soft magnetic material tape with an initial permeability of not less than 30,000 to wrap around the inner core conductor (1) in an overlapping manner, and control the wrapping tension to avoid mechanical stress damage to the magnetic domain structure of the soft magnetic tape. Extruded phase-stabilized dielectric layer (3): Foamed fluoropolymer material is extruded outside the quantum signal shielding layer (2), and the foaming rate and crosslinking degree are controlled to obtain a dielectric layer with stable dielectric properties; Braided metal shielding layer: Metal wires are braided outside the phase-stabilizing dielectric layer (3) to form a shielding mesh; Extruded outer sheath (42): A polymer sheath is extruded over the metal shielding layer.

9. A method for preparing an anti-interference, low-loss encrypted wire bundle for quantum communication according to claim 8, characterized in that, In the step of preparing the inner core conductor (1), the ambient temperature is 23±2℃, the relative humidity is 50±5%, silver-plated copper wire with a diameter of 0.08~0.12mm is used, and the single wire stranding tension is 0.5~1.5N; In the step of applying the quantum signal shielding layer (2), the longitudinal overlap rate of the soft magnetic material strip is not less than 30%, and the wrapping tension is 2-8N.

10. A method for preparing an anti-interference, low-loss encrypted wire bundle for quantum communication according to claim 8, characterized in that, In the step of extruding the phase-stabilized dielectric layer (3), polytetrafluoroethylene or polytetrafluoroethylene is used, the extrusion temperature is 145-185℃, the nitrogen injection pressure is 8-20MPa when using nitrogen physical foaming, and the electron beam energy is 1.5-3.0MeV, the dose rate is 5-15kGy / s, and the total absorbed dose is 100-180kGy when using electron beam irradiation crosslinking. In the step of braiding the metal shielding layer, tin-plated copper wire or silver-plated copper wire with a diameter of 0.10 to 0.16 mm is used, the braiding density is not less than 95%, and the surface coverage is not less than 100%. In the step of extruding the outer sheath (42), a composite material with polyether ether ketone as the matrix and filled with copper powder, aramid fiber and graphite is used. The extruder die temperature is 200-240℃, the extrusion line speed is 20-60m / min, and the concentricity deviation of the outer sheath (42) is no more than 0.1mm.

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