5D bending radius grade non-metallic overhead optical cable and preparation method thereof

Abstract

This invention discloses a 5D bending radius-level non-metallic overhead optical cable and its manufacturing method. The 5D bending radius-level non-metallic overhead optical cable includes ultra-fine bend-insensitive fiber units. A high tensile strength layer is disposed on the outside of the ultra-fine bend-insensitive fiber units, and both are encased within an inner sheath. A protective layer is disposed on the outside of the inner sheath, and an outer sheath is disposed on the outside of the protective layer. The 5D bending radius-level non-metallic overhead optical cable and its manufacturing method provided by this invention utilize smaller diameter bend-insensitive fibers. Macro-bending and micro-bending losses are reduced through core layer partitioning and cladding doping with fluorine or chlorine, supporting the 5D bending radius requirement, improving the bending flexibility of the overhead optical cable, and achieving long-term stable operation under small-radius bending. It also possesses good waterproof, anti-interference, tensile strength, and flame-retardant properties, making it suitable for overhead cabling in narrow passages between buildings in densely populated urban areas and in high electromagnetic interference scenarios.

Description

Technical Field

[0001] This invention belongs to the field of overhead optical cable technology, specifically relating to a 5D bending radius level non-metallic overhead optical cable and its preparation method. Background Technology

[0002] The static bending radius of traditional aerial optical cables is usually 10 times the outer diameter, such as the GYXTC8S type optical cable. This results in insufficient bending flexibility of traditional aerial optical cables, which cannot meet the needs of current space-constrained scenarios. Therefore, how to improve the bending flexibility of aerial optical cables has become one of the key points in the industry. Summary of the Invention

[0003] To address the technical problems existing in the prior art, the present invention aims to provide a 5D bending radius level non-metallic overhead optical cable and its preparation method.

[0004] To achieve the above objectives and technical effects, the technical solution adopted by this invention is as follows:

[0005] A 5D bending radius-level non-metallic overhead optical cable includes an ultra-fine bend-insensitive optical fiber unit. The ultra-fine bend-insensitive optical fiber unit has a high tensile strength layer on its outer side, and both layers are encased in an inner sheath. A protective layer is provided on the outer side of the inner sheath, and an outer sheath is provided on the outer side of the protective layer.

[0006] Furthermore, the ultra-fine bend-insensitive fiber unit includes a loose tube and at least one bend-insensitive fiber with a diameter ≤180μm disposed therein, wherein the loose tube is filled with modified fiber paste.

[0007] Furthermore, the loose tube is filled with a modified fiber paste made by compounding nano-silica and polyethylene glycol.

[0008] Furthermore, the core of the bend-insensitive optical fiber includes at least two partitions with different doping concentrations, and the cladding is doped with fluorine or chlorine.

[0009] Furthermore, the core layer comprises three zones with different doping concentrations, namely, a central zone, a transition zone, and an edge zone, from the inside out:

[0010] Central region: GeO2 doping concentration 6.5-7.5wt%, relative refractive index difference 0.39-0.42%, ensuring basic light guiding capability and reducing transmission loss;

[0011] Transition region: GeO2 doping concentration 3.5-4.5wt%, relative refractive index difference 0.27-0.32%, suppressing intermodal dispersion and higher-order modes, and reducing bending loss;

[0012] Edge region: F or Cl doping concentration 0.3-0.7wt%, relative refractive index difference 0.15-0.2%, smoothing refractive index gradient, reducing microbending sensitivity, and reducing bending edge distortion.

[0013] Furthermore, the cladding dopant concentration is 0.6-1 wt%.

[0014] Furthermore, the cladding is doped with Cl at a concentration of 0.3-0.5 wt%.

[0015] Furthermore, the high tensile strength layer is formed by stranding glass fiber reinforced plastic FRP or aramid fibers with a carbon nanotube-reinforced epoxy resin coating around the outside of an ultra-fine bend-insensitive optical fiber unit and curing it with epoxy resin.

[0016] Furthermore, the thickness of the carbon nanotube-reinforced epoxy resin coating is 10-35 μm.

[0017] This invention also discloses a method for preparing a 5D bending radius level non-metallic overhead optical cable, comprising the following steps:

[0018] 1) Fabrication of ultra-thin, bend-insensitive fiber units;

[0019] 2) Glass fiber reinforced plastic FRP or aramid fiber with a carbon nanotube-reinforced epoxy resin coating is stranded around the outside of the ultra-fine bend-insensitive optical fiber unit and cured with epoxy resin to form a high tensile strength layer.

[0020] 3) The inner protective layer is formed by extrusion of high-modulus polyethylene (HDPE) or polyamide materials;

[0021] 4) Wrap a protective layer around the outside of the inner sheath;

[0022] 5) An outer protective layer is formed by extruding thermoplastic elastomer (TPE) or flame-retardant polyethylene material on the outside of the protective layer.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] This invention discloses a 5D bending radius-level non-metallic overhead optical cable and its manufacturing method. It uses a smaller diameter, bend-insensitive optical fiber and reduces macro-bending and micro-bending losses by partitioning the core layer and doping the cladding with fluorine or chlorine. It supports the 5D (5 times the outer diameter of the optical cable) bending radius requirement, improves the bending flexibility of the overhead optical cable, and enables long-term stable operation under small-radius bending. The overhead optical cable also has good waterproof, anti-interference, tensile strength, flame retardancy and other properties, and is suitable for overhead wiring in narrow passages between buildings in densely populated urban areas and high electromagnetic interference scenarios. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail so that its advantages and features can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0027] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.

[0028] The 5D bending radius refers to the minimum bending radius of an optical cable during installation or use, which is 5 times its outer diameter.

[0029] like Figure 1 As shown, a 5D bending radius level non-metallic overhead optical cable includes:

[0030] The ultra-fine bend-insensitive fiber unit includes a loose tube 1 and at least one bend-insensitive fiber 2 with a diameter ≤180μm disposed therein. The loose tube 1 is filled with a modified fiber paste made of nano-silica and polyethylene glycol to improve temperature stability and waterproof performance. The core layer of the bend-insensitive fiber 2 includes at least two partitions with different doping concentrations. Its cladding is doped with fluorine or chlorine to reduce macro-bending and micro-bending losses, achieving macro-bending and micro-bending losses ≤0.1dB / km at a 5D bending radius, and achieving macro-bending losses ≤0.03dB / turn at a 15mm bending radius at a wavelength of 1550nm, supporting the 5D (5 times the outer diameter of the optical cable) bending radius requirement.

[0031] The high tensile strength layer 3 is made of glass fiber reinforced plastic FRP or aramid fiber with a carbon nanotube-reinforced epoxy resin coating on the surface. It is twisted around the outside of the loose tube 1 and formed by epoxy resin curing. It replaces the traditional metal armor and fills the gaps with water-blocking materials (such as water-blocking yarn or gel) to improve the anti-interference ability while making the structure of the overhead optical cable compact to reduce the outer diameter and adapt to the space constraints of the overhead scene. By coating the surface with a carbon nanotube-reinforced epoxy resin coating with a thickness of 10-35μm, the interfacial shear strength between the fiber and the resin can be improved.

[0032] Inner sheath 4 is made of high-modulus polyethylene (HDPE) or polyamide material extruded on the outside of the ultra-fine bend-insensitive optical fiber unit and the high tensile strength layer 3.

[0033] Protective layer 5 is made of polyaramid tape wrapped around the outside of the inner protective layer 4 to enhance tensile strength and weather resistance;

[0034] The outer protective layer 6 is made of thermoplastic elastomer TPE or flame-retardant polyethylene material extruded on the outside of the protective layer 5. It has the characteristics of UV resistance, wear resistance and flame retardancy, and can adapt to temperature and humidity changes and wind impact in the overhead environment.

[0035] In some implementations, the core layer comprises three regions with different doping concentrations, namely, a central region, a transition region, and an edge region, from the inside out:

[0036] Central region: GeO2 doping concentration 6.5-7.5wt%, relative refractive index difference 0.39-0.42%, ensuring basic light guiding capability and reducing transmission loss;

[0037] Transition region: GeO2 doping concentration 3.5-4.5wt%, relative refractive index difference 0.27-0.32%, suppressing intermodal dispersion and higher-order modes, and reducing bending loss;

[0038] Edge region: F or Cl doping concentration 0.3-0.7wt%, relative refractive index difference 0.15-0.2%, smoothing refractive index gradient, reducing microbending sensitivity, and reducing bending edge distortion.

[0039] In some embodiments, the cladding doping concentration is 0.6-1 wt% F or 0.3-0.5 wt% Cl.

[0040] In some implementations, the relative refractive index difference of the cladding is -0.2 to -0.35%, which enhances bending resistance and reduces the critical radius of macrobending.

[0041] This invention also discloses a method for preparing a 5D bending radius level non-metallic overhead optical cable, comprising the following steps:

[0042] 1) Fabrication of ultra-thin, bend-insensitive fiber units;

[0043] 2) Glass fiber reinforced plastic FRP or aramid fiber with a carbon nanotube-reinforced epoxy resin coating is stranded around the outside of the ultra-fine bend-insensitive optical fiber unit and cured with epoxy resin to form a high tensile strength layer 3.

[0044] 3) The inner protective layer is formed by extrusion of high-modulus polyethylene (HDPE) or polyamide material;

[0045] 4) Wrap a protective layer 5 around the outside of the inner sheath 4;

[0046] 5) An outer protective layer 6 is formed by extruding thermoplastic elastomer TPE or flame-retardant polyethylene material on the outside of the protective layer 5.

[0047] Example 1

[0048] like Figure 1 As shown, a 5D bending radius level non-metallic overhead optical cable includes:

[0049] The ultra-fine bend-insensitive fiber unit includes a loose tube 1 and six bend-insensitive fibers 2, each 180μm in diameter and manufactured by Prysmian, housed within it. The loose tube 1 is filled with a modified fiber paste made of nano-silica and polyethylene glycol to improve temperature stability and waterproof performance. The core of the bend-insensitive fiber 2 includes three partitions with different doping concentrations, and its cladding is doped with fluorine to reduce macro-bending and micro-bending losses, achieving macro-bending and micro-bending losses ≤0.1dB / km at a 5D bending radius, and achieving macro-bending losses ≤0.03dB / turn at a 15mm bending radius and a 1550nm wavelength, supporting the 5D (5 times the outer diameter of the optical cable) bending radius requirement.

[0050] The high tensile strength layer 3 is made of glass fiber reinforced plastic FRP with a carbon nanotube-reinforced epoxy resin coating on the surface. It is twisted around the outside of the loose tube 1 and formed by epoxy resin curing. It replaces the traditional metal armor and fills the gaps with water-blocking yarn to improve the anti-interference ability while making the structure of the overhead optical cable compact to reduce the outer diameter and adapt to the space constraints of the overhead scene. By coating the surface with a 10μm thick carbon nanotube-reinforced epoxy resin coating, the interfacial shear strength between the fiber and the resin can be improved.

[0051] Inner sheath 4 is made of high-modulus polyethylene (HDPE) extruded on the outside of the ultra-fine bend-insensitive optical fiber unit and the high tensile strength layer 3.

[0052] Protective layer 5 is made of polyaramid tape wrapped around the outside of the inner protective layer 4 to enhance tensile strength and weather resistance;

[0053] The outer protective layer 6 is made of thermoplastic elastomer TPE extruded on the outside of the protective layer 5. It has the characteristics of UV resistance, wear resistance and flame retardancy, and can adapt to temperature and humidity changes and wind impact in the overhead environment.

[0054] In this embodiment, the core layer includes three partitions with different doping concentrations, which are, from the inside out, the central region, the transition region, and the edge region:

[0055] Central region: GeO2 doping concentration 7.3wt%, relative refractive index difference 0.4%, ensuring basic light guiding capability and reducing transmission loss;

[0056] Transition region: GeO2 doping concentration 4wt%, relative refractive index difference 0.3%, suppressing intermodal dispersion and higher-order modes, and reducing bending loss;

[0057] Edge region: F doping concentration 0.6wt%, relative refractive index difference 0.18%, smoothing refractive index gradient, reducing microbending sensitivity, and reducing bending edge distortion.

[0058] The cladding doping concentration is 0.8wt%, the relative refractive index difference is -0.2%, which enhances bending resistance and reduces the critical radius of macrobending.

[0059] A method for fabricating a 5D bending radius-level non-metallic overhead optical cable includes the following steps:

[0060] 1) Fabrication of ultra-thin, bend-insensitive fiber units;

[0061] Six 180μm diameter bend-insensitive optical fibers 2 sold by Prysmian were taken, arranged as required, and modified fiber paste was used as a filler to fill the loose tube 1. After molding, an ultra-fine bend-insensitive optical fiber unit was obtained.

[0062] 2) Glass fiber reinforced plastic FRP with a surface coated with carbon nanotube-reinforced epoxy resin is stranded around the outside of the ultra-fine bend-insensitive optical fiber unit and cured with epoxy resin to form a high tensile strength layer 3.

[0063] 3) The inner protective layer is formed by extrusion of high-modulus polyethylene (HDPE);

[0064] 4) Wrap a protective layer 5 around the outside of the inner sheath 4;

[0065] 5) An outer protective layer 6 is formed by extruding thermoplastic elastomer TPE on the outside of the protective layer 5.

[0066] Any parts or structures not specifically described in this invention can be made using existing technologies or products, and will not be elaborated upon here.

[0067] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A 5D bend radius rated non-metallic aerial optical cable characterized in that, It includes an ultra-fine bend-insensitive fiber unit, wherein a high tensile strength layer is disposed on the outside of the ultra-fine bend-insensitive fiber unit and both are covered within an inner sheath, a protective layer is disposed on the outside of the inner sheath, and an outer sheath is disposed on the outside of the protective layer. The core of the bend-insensitive optical fiber includes at least two partitions with different doping concentrations, and the cladding is doped with fluorine or chlorine. The core layer comprises three zones with different doping concentrations, from the inside out: a central zone, a transition zone, and an edge zone. Central region: GeO2 doping concentration 6.5-7.5wt%, relative refractive index difference 0.39-0.42%; Transition region: GeO2 doping concentration 3.5-4.5wt%, relative refractive index difference 0.27-0.32%; Edge region: F or Cl doping concentration 0.3-0.7wt%, relative refractive index difference 0.15-0.2%.

2. A 5D bend radius grade non-metallic aerial optical cable as claimed in claim 1, wherein, The ultra-fine bend-insensitive fiber unit includes a loose tube and at least one bend-insensitive fiber with a diameter ≤180μm disposed therein, wherein the loose tube is filled with modified fiber paste.

3. A 5D bend radius grade non-metallic aerial optical cable as claimed in claim 2, wherein, The loose tube is filled with a modified fiber paste made by compounding nano-silica and polyethylene glycol.

4. A 5D bend radius grade non-metallic aerial optical cable as claimed in claim 1, wherein, The cladding is doped with an F concentration of 0.6-1 wt%.

5. A 5D bending radius level non-metallic overhead optical cable according to claim 1, characterized in that, The cladding is doped with Cl at a concentration of 0.3-0.5 wt%.

6. A 5D bending radius level non-metallic overhead optical cable according to claim 1, characterized in that, The high tensile strength layer is formed by stranding glass fiber reinforced plastic FRP or aramid fibers with a carbon nanotube-reinforced epoxy resin coating around the outside of an ultra-fine bend-insensitive optical fiber unit and curing it with epoxy resin.

7. A 5D bending radius level non-metallic overhead optical cable according to claim 6, characterized in that, The thickness of the carbon nanotube-reinforced epoxy resin coating is 10-35 μm.

8. A method for preparing a 5D bending radius level non-metallic overhead optical cable according to any one of claims 1-7, characterized in that, Includes the following steps: 1) Fabrication of ultra-thin, bend-insensitive fiber units; 2) Glass fiber reinforced plastic FRP or aramid fiber with a carbon nanotube-reinforced epoxy resin coating is stranded around the outside of the ultra-fine bend-insensitive optical fiber unit and cured with epoxy resin to form a high tensile strength layer. 3) The inner protective layer is formed by extrusion of high-modulus polyethylene (HDPE) or polyamide materials; 4) Wrap a protective layer around the outside of the inner sheath; 5) An outer protective layer is formed by extruding thermoplastic elastomer (TPE) or flame-retardant polyethylene material on the outside of the protective layer.

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