Fine-diameter low-loss optical fiber and optical cable

Abstract

Provided in the present application are a fine-diameter low-loss optical fiber and an optical cable. The fine-diameter low-loss optical fiber comprises a quartz layer, an adhesive layer, a first coating layer and a second coating layer which are successively arranged from inside to outside in the radial direction of the fine-diameter low-loss optical fiber; the adhesive layer is used for increasing the adhesive force between the first coating layer and the quartz layer, and the first coating layer is used for protecting the quartz layer; the second coating layer comprises a second coating layer base body and a plurality of reinforcing members, the base material of the second coating layer base body being the same as that of the first coating layer, and the plurality of reinforcing members being distributed in the second coating layer base body so as to increase the strength of the fine-diameter low-loss optical fiber. The fine-diameter low-loss optical fiber provided in the present application has relatively large strength, and the adhesive force between the coating layer and the quartz layer in the fine-diameter low-loss optical fiber is relatively large.

Description

Thin-diameter, low-loss optical fiber and cable

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 21, 2023, with application number 202311060443.5 and application name “Thin-diameter low-loss optical fiber and optical cable”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of optical cable technology, and in particular to a thin-diameter low-loss optical fiber and an optical cable. Background Art

[0003] With the development of communication technology, the demand for the transmission capacity of optical cables has further increased.

[0004] Optical cables consist of multiple optical fibers, the basic unit of optical communication. These fibers are laid in conduits after being cabled. Conventional optical fibers have a large diameter, and the number of fibers contained in an optical cable is small, resulting in a lower transmission capacity. Optical fibers consist of a quartz layer and a coating. By reducing the thickness of the coating, the diameter of the fiber can be reduced. Fibers with smaller diameters are called thin-diameter, low-loss fibers. Using thin-diameter, low-loss fibers in optical cables increases the number of fibers in the cable, thereby increasing the cable's transmission capacity.

[0005] In the related art, the thickness of the coating layer of a thin-diameter low-loss optical fiber is reduced, resulting in a decrease in the strength of the thin-diameter low-loss optical fiber and a decrease in the adhesion between the coating layer and the quartz layer.

[0006] Summary of the Invention

[0007] The present application provides a thin-diameter low-loss optical fiber and an optical cable. The thin-diameter low-loss optical fiber has greater strength and greater adhesion between the coating layer and the quartz layer in the thin-diameter low-loss optical fiber.

[0008] The present application provides a thin-diameter low-loss optical fiber, comprising a quartz layer, an adhesive layer, a first coating layer, and a second coating layer arranged in sequence from the inside to the outside along the radial direction of the thin-diameter low-loss optical fiber;

[0009] The adhesive layer is used to increase the adhesion between the first coating layer and the quartz layer; the first coating layer is used to protect the quartz layer; the second coating layer includes a second coating layer substrate and multiple reinforcement members. The second coating layer substrate is the same as the base material of the first coating layer, and the multiple reinforcement members are distributed in the second coating layer substrate to increase the strength of the thin-diameter, low-loss optical fiber.

[0010] In one possible embodiment, the thin-diameter, low-loss optical fiber provided herein comprises an adhesive layer comprising an adhesive layer matrix and an adhesive, wherein the adhesive is uniformly distributed in the adhesive layer matrix, the adhesive being a silane coupling agent, the silane coupling agent comprising a first functional group and a second functional group, the first functional group and the second functional group being connected by a chemical bond, the first functional group being one of a trimethoxy group and a triethoxy group, and the second functional group being one of a γ-methacryloxypropyl group, a γ-aminopropyl group, a 3-mercaptopropyl group, or a γ-mercaptopropyl group.

[0011] The first functional group is bonded to the quartz layer through a chemical bond, and the second functional group is bonded to the first coating layer through a chemical bond.

[0012] In a possible implementation, in the thin-diameter, low-loss optical fiber provided in the present application, the mass percentage of the adhesive in the adhesive layer is 2%-5%.

[0013] In a possible implementation, the thin-diameter, low-loss optical fiber provided by the present application has an adhesion force between the first coating layer and the quartz layer in the range of 10g-20g.

[0014] In a possible embodiment, the thin-diameter low-loss optical fiber provided by the present application has a reinforcement member extending axially along the thin-diameter low-loss optical fiber, and the reinforcement member is a nanotube.

[0015] In a possible embodiment, the thin-diameter low-loss optical fiber provided by the present application, the second coating layer further includes a dispersant, and the dispersant is used to uniformly distribute the nanotubes in the second coating layer matrix.

[0016] In a possible embodiment, in the thin-diameter, low-loss optical fiber provided by the present application, the mass percentage of the nanotubes in the second coating layer is 0.25%-5%.

[0017] In a possible embodiment, in the thin-diameter low-loss optical fiber provided by the present application, the elastic modulus of the second coating layer along the axial direction of the thin-diameter low-loss optical fiber is greater than 800 MPa and less than or equal to 2000 MPa.

[0018] In a possible embodiment, the thin-diameter low-loss optical fiber provided in the present application has a bonding layer thickness of 5 μm-10 μm; a first coating layer thickness of 12.5 μm-32.0 μm; and a second coating layer thickness of 15-30 μm.

[0019] An embodiment of the present application further provides an optical cable, comprising a protective layer and the above-mentioned thin-diameter low-loss optical fiber, wherein a plurality of thin-diameter low-loss optical fibers are arranged in the protective layer.

[0020] The present application provides a thin-diameter low-loss optical fiber and an optical cable. The thin-diameter low-loss optical fiber is provided with a quartz layer, an adhesive layer, a first coating layer, and a second coating layer arranged in sequence from the inside to the outside along the radial direction of the thin-diameter low-loss optical fiber; the adhesive layer is provided between the quartz layer and the first coating layer to increase the adhesion between the first coating layer and the quartz layer; the first coating layer is used to protect the quartz layer; the second coating layer includes a second coating layer substrate and a plurality of reinforcement members, the second coating layer substrate being the same as the substrate of the first coating layer, and the adhesion between the second coating layer and the first coating layer being ensured by setting the second coating layer substrate and the first coating layer substrate to be the same substrate; the plurality of reinforcement members are distributed in the second coating layer substrate, and the reinforcement members can prevent the expansion of microcracks in the second coating layer substrate, reduce the elongation at break of the second coating layer substrate, thereby increasing the tensile and compressive strengths of the second coating layer, and thereby increasing the tensile and compressive strengths of the thin-diameter low-loss optical fiber. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0022] FIG1 is a schematic diagram of the internal structure of a thin-diameter, low-loss optical fiber along the radial direction provided by an embodiment of the present application;

[0023] FIG2 is a schematic diagram of the internal structure of a thin-diameter, low-loss optical fiber along the axial direction provided by an embodiment of the present application;

[0024] FIG3 is a schematic diagram of the bonding effect of the bonding layer in the thin-diameter low-loss optical fiber provided by an embodiment of the present application;

[0025] FIG4 is a schematic diagram of a stripping force test process for a thin-diameter, low-loss optical fiber according to an embodiment of the present application;

[0026] Figure 5 is an enlarged view of point A in Figure 4;

[0027] FIG6 is a diagram showing the fracture stress distribution of a thin-diameter, low-loss optical fiber at three strain rates provided by an embodiment of the present application;

[0028] FIG7 is a schematic diagram of the structure of the optical cable provided in an embodiment of the present application.

[0029] Explanation of the accompanying symbols: 10-winding wheel; 20-stripping tool; 100-fine-diameter low-loss optical fiber; 110-quartz layer; 111-fiber core; 112-cladding; 120-adhesive layer; 121-adhesive layer matrix; 122-adhesive; 1211-first functional group; 1212-second functional group; 130-first coating layer; 140-second coating layer; 141-second coating layer matrix; 142-reinforcement member; 200-protective layer; 1000-optical cable; H1-first length; H2-second length; L-fine-diameter low-loss optical fiber axial direction; R-fine-diameter low-loss optical fiber radial direction. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0031] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to a fixed connection, an indirect connection via an intermediate medium, internal communication between two components, or an interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0032] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0033] The terms "first," "second," and "third" (if any) in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the application described herein can, for example, be implemented in orders other than those illustrated or described herein.

[0034] In addition, the terms "comprises" and "having" and any variations thereof are intended to cover a non-exclusive inclusion. For example, a process, method, system, product or service tool that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, product or service tool.

[0035] With the development of communication technology, the demand for the transmission capacity of optical cables has further increased.

[0036] Optical cables consist of multiple optical fibers, the basic unit of optical communications. These fibers are cabled and laid in conduits. Conventional optical fibers have a large diameter, and the number of fibers contained in a cable is small, resulting in a low transmission capacity. To increase the transmission capacity of an optical cable, the number of fibers in the cable must be increased. However, this increase in fiber count increases the cable's diameter. However, the diameter of the conduit used to lay the cable is fixed, and any increase in the cable's diameter requires re-laying the conduit, which is costly.

[0037] Optical fiber consists of a quartz layer and a coating. The coating protects the quartz layer. Reducing the coating thickness can reduce the fiber diameter. Fibers with smaller diameters are called thin-diameter, low-loss fibers. Using thin-diameter, low-loss fibers in optical cables increases the number of fibers in the cable, thereby increasing the cable's transmission capacity.

[0038] In related art, the coating thickness of thin, low-loss optical fibers is reduced, resulting in reduced strength and decreased adhesion between the coating and the quartz layer. This reduced strength makes the thin, low-loss optical fiber susceptible to deformation or damage due to external stress, and the reduced adhesion between the coating and the quartz layer causes the coating to fall off the quartz layer, making it difficult to protect the quartz layer.

[0039] Based on this, the present application provides a thin-diameter, low-loss optical fiber and an optical cable. The thin-diameter, low-loss optical fiber has greater strength and greater adhesion between the coating layer and the quartz layer in the thin-diameter, low-loss optical fiber.

[0040] FIG1 is a schematic diagram of the internal structure of a thin-diameter, low-loss optical fiber along the radial direction provided by an embodiment of the present application; FIG2 is a schematic diagram of the internal structure of a thin-diameter, low-loss optical fiber along the axial direction provided by an embodiment of the present application.

[0041] 1 and 2 , the thin-diameter, low-loss optical fiber 100 provided herein includes a quartz layer 110, an adhesive layer 120, a first coating layer 130, and a second coating layer 140, which are sequentially arranged from the inside out along the radial direction R of the thin-diameter, low-loss optical fiber. The adhesive layer 120 is used to increase the adhesion between the first coating layer 130 and the quartz layer 110. The first coating layer 130 is used to protect the quartz layer 110. The second coating layer 140 includes a second coating layer substrate 141 and a plurality of reinforcement members 142. The second coating layer substrate 141 is made of the same base material as the first coating layer 130. The plurality of reinforcement members 142 are distributed within the second coating layer substrate 141 to increase the strength of the thin-diameter, low-loss optical fiber 100.

[0042] Specifically, referring to Figure 1 , quartz layer 110 includes a core 111 and a cladding 112. Both core 111 and cladding 112 are constructed from quartz glass (silicon dioxide, SiO2). The doping in the core 111 and cladding 112 base materials differs, resulting in different refractive indices for light. Light propagates through core 111, while cladding 112 provides a reflective surface for the light and also serves as mechanical protection.

[0043] The base material of the first coating layer 130 can be an acrylic polymer resin. The elastic modulus of the first coating layer 130 is relatively small. The elastic modulus of the first coating layer 130 is usually set within the range of 0.3Mpa-0.6Mpa, so that the first coating layer 130 has good flexibility and can buffer the stress on the quartz layer 110 to protect the quartz layer 110.

[0044] In this embodiment, by disposing the adhesive layer 120 between the quartz layer 110 and the first coating layer 130 , the adhesion between the first coating layer 130 and the quartz layer 110 can be increased.

[0045] Specifically, one side of the adhesive layer 120 is bonded to the cladding layer 112 , and the other side of the adhesive layer 120 is bonded to the first coating layer 130 . The adhesive layer 120 can increase the adhesion between the first coating layer 130 and the cladding layer 112 of the quartz layer 110 .

[0046] The second coating layer 140 includes a second coating layer substrate 141. In this embodiment, the second coating layer substrate 141 is set to be the same as the substrate of the first coating layer 130. The second coating layer substrate 141 can also be an acrylic polymer resin. Since the second coating layer substrate 141 is the same as the substrate of the first coating layer 130, the adhesion between the second coating layer substrate 141 and the first coating layer 130 is relatively large.

[0047] The second coating layer 140 is disposed on the outermost side of the thin-diameter low-loss optical fiber 100 . Therefore, the second coating layer 140 also needs to have greater tensile and compressive strength to increase the tensile and compressive strength of the thin-diameter low-loss optical fiber 100 .

[0048] In this embodiment, the elastic modulus of the second coating layer 140 is increased by providing the reinforcement 142 in the second coating layer base 141 .

[0049] Specifically, please continue to refer to Figures 1 and 2. The reinforcement members 142 are evenly distributed in the second coating layer matrix 141. The reinforcement members 142 can prevent the expansion of microcracks in the second coating layer matrix 141 and reduce the elongation at break of the second coating layer matrix 141 to increase the tensile and compressive strength of the second coating layer 140, thereby increasing the tensile and compressive strength of the thin-diameter low-loss optical fiber 100.

[0050] Therefore, in this embodiment, by setting the second coating layer substrate 141 and the substrate of the first coating layer 130 to the same substrate, the adhesion between the second coating layer 140 and the first coating layer 130 can be guaranteed. At the same time, multiple reinforcement members 142 are set on the second coating layer substrate 141 to increase the strength of the second coating layer 140, so that the second coating layer 140 and the first coating layer 130 have greater adhesion, and the second coating layer 140 also has greater tensile and compressive strength.

[0051] The thin-diameter low-loss optical fiber 100 provided in an embodiment of the present application is provided with a quartz layer 110, an adhesive layer 120, a first coating layer 130, and a second coating layer 140 arranged in sequence from the inside to the outside along the radial direction R of the thin-diameter low-loss optical fiber; the adhesive layer 120 is provided between the quartz layer 110 and the first coating layer 130 to increase the adhesion between the first coating layer 130 and the quartz layer 110; the first coating layer 130 is used to protect the quartz layer 110; the second coating layer 140 includes a second coating layer base 141 and a plurality of reinforcement members 142, and the second coating layer base 141 and the second coating layer base 141 are connected to the quartz layer 110. The substrate of the first coating layer 130 is the same. By setting the second coating layer base 141 and the substrate of the first coating layer 130 to be the same substrate, the adhesion between the second coating layer 140 and the first coating layer 130 can be ensured. A plurality of reinforcement members 142 are distributed in the second coating layer base 141. The reinforcement members 142 can prevent the expansion of microcracks in the second coating layer base 141 and reduce the elongation at break of the second coating layer base 141, so as to increase the tensile and compressive strength of the second coating layer 140, thereby increasing the tensile and compressive strength of the thin-diameter low-loss optical fiber 100.

[0052] Next, the specific structure of the adhesive layer 120 will be described.

[0053] FIG3 is a schematic diagram of the bonding effect of the bonding layer in the thin-diameter low-loss optical fiber provided by an embodiment of the present application.

[0054] As shown in Figure 3, the bonding layer 120 includes an bonding layer matrix 121 and an adhesive 122. The adhesive 122 is uniformly distributed in the bonding layer matrix 121. The adhesive 122 is a silane coupling agent. The silane coupling agent includes a first functional group 1211 and a second functional group 1212. The first functional group 1211 and the second functional group 1212 are connected by a chemical bond. The first functional group 1211 is one of trimethoxy or triethoxy; the second functional group 1212 is one of γ-methacryloyloxypropyl, γ-aminopropyl, 3-mercaptopropyl or γ-mercaptopropyl; the first functional group 1211 is bonded to the quartz layer 110 through a chemical bond, and the second functional group 1212 is bonded to the first coating layer 130 through a chemical bond.

[0055] The adhesive layer matrix 121 may also be an acrylic polymer resin, and the adhesive 122 is a silane coupling agent added to the acrylic polymer resin. The silane coupling agent can interact with both organic and inorganic materials.

[0056] Specifically, the first functional group 1211 in the silane coupling agent can be a trimethoxy group or a triethoxy group. At the interface between the adhesive layer 120 and the cladding 112 in the quartz layer 110, the silicon in the first functional group 1211 bonds to the silicon element in the cladding 112 via hydrogen bonds, thereby increasing the adhesion between the adhesive 122 and the cladding 112. The strong adhesion between the adhesive 122 and the cladding 112 can also slow down the growth of microcracks in the cladding 112.

[0057] The second functional group 1212 in the silane coupling agent can be one of γ-methacryloxypropyl, γ-aminopropyl, 3-mercaptopropyl, or γ-mercaptopropyl. At the interface between the adhesive layer 120 and the first coating layer 130, the second functional group 1212 forms a bond with the hydrogen bond in the resin, thereby increasing the adhesion between the adhesive 122 and the first coating layer 130.

[0058] In other words, the role of the silane coupling agent is to build a molecular bridge between the interface of inorganic and organic substances, connecting the two materials with greatly different properties more tightly together through chemical bonds, and increasing the adhesion between the first coating layer 130 and the quartz layer 110 through the bonding layer 120.

[0059] The molecular formula of the silane coupling agent is YR-Si(OR)3. In this embodiment, the silane coupling agent can be one or more of γ-methacryloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, 3-mercaptopropyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0060] If the adhesive 122 content in the adhesive layer 120 is too low, the adhesive 122 will increase the adhesion between the first coating layer 130 and the quartz layer 110. If the adhesive 122 content in the adhesive layer 120 is too high, it will affect the curing of the acrylic polymer resin in the adhesive layer 120 that serves as the adhesive layer matrix 121. Therefore, in this embodiment, the mass percentage of the adhesive 122 in the adhesive layer 120 is 2%-5%.

[0061] When laying optical cables, it is often necessary to fusion-splice thin-diameter, low-loss optical fibers 100 from different optical cables. Prior to fusion-splice thin-diameter, low-loss optical fibers 100, the first coating layer 130 and the second coating layer 140 at the ends of the thin-diameter, low-loss optical fibers 100 must be stripped. Therefore, if the adhesion between the first coating layer 130 and the cladding 112 of the quartz layer 110 is too strong, it can be difficult to strip the first coating layer 130 and the second coating layer 140 from the quartz layer 110.

[0062] In this embodiment, the weight percentage of the adhesive 122 in the adhesive layer 120 is controlled within a range of 2%-5%, so that the bonding force between the first coating layer 130 and the cladding layer 112 is within a range of 10g-20g.

[0063] The peeling force test can be used to test the bonding strength between the first coating layer 130 and the cladding layer 112. FIG4 is a schematic diagram of the peeling force test process of the thin-diameter low-loss optical fiber provided in an embodiment of the present application; FIG5 is an enlarged view of point A in FIG4.

[0064] As shown in Figures 4 and 5 , a thin, low-loss optical fiber 100 is wound on a winding wheel 10, and the other end of the thin, low-loss optical fiber 100 is clamped in a stripping tool 20. A first length H1 between the winding wheel 10 and the stripping tool 20 is 500 mm, and a second length H2 of the thin, low-loss optical fiber 100 clamped by the stripping tool 20 is typically 30-50 mm. The winding wheel 10 is moved relative to the stripping tool 20 at a speed of 500 mm / min, thereby stripping the first coating layer 130 and the second coating layer 140 from the quartz layer 110. In the thin, low-loss optical fiber 100 provided in the present embodiment, by controlling the weight percentage of the adhesive 122 in the adhesive layer 120, the measured stripping force is typically in the range of 1.5N-5N. A stripping force of 1.5N-5N corresponds to an adhesive force of 10g-20g.

[0065] Next, the specific structure of the second coating layer 140 will be described.

[0066] Continuing with FIG2 , the reinforcement member 142 extends along the axial direction L of the thin-diameter low-loss optical fiber. The reinforcement member 142 is a nanotube. The nanotube can be one or more of carbon nanotubes, boron nitride nanotubes, silicon nanotubes, and titanium dioxide nanotubes. The nanotube extends along the axial direction L of the thin-diameter low-loss optical fiber in the second coating layer matrix 141. Nanotubes are light in weight, have good toughness, and high tensile strength. Therefore, by adding nanotubes to the second coating layer matrix 141, the expansion of microcracks in the second coating layer 140 can be prevented, thereby increasing the elastic modulus of the second coating layer 140 along the axial direction L of the thin-diameter low-loss optical fiber and reducing the elongation at break of the second coating layer 140 along the axial direction L of the thin-diameter low-loss optical fiber. As a result, the tensile and compressive strengths of the second coating layer 140 along the axial direction L of the thin-diameter low-loss optical fiber can be increased.

[0067] The nanotube is a hollow structure, and has good toughness and strain along the radial direction R of the thin-diameter low-loss optical fiber, so as to increase the bending and compression resistance of the thin-diameter low-loss optical fiber 100 along the radial direction R of the thin-diameter low-loss optical fiber.

[0068] In this embodiment, the size of the nanotube along the radial direction R of the thin-diameter low-loss optical fiber can be less than 100 nm, and the ratio of the size of the nanotube along the axial direction L to the size of the nanotube along the radial direction R of the thin-diameter low-loss optical fiber is greater than 100:1.

[0069] In this embodiment, the second coating layer 140 further includes a dispersant, which is used to uniformly distribute the nanotubes in the second coating layer matrix 141 .

[0070] Specifically, the acrylic polymer resin is applied in a liquid state, to which a dispersant and nanotubes are added. The dispersant has a group with affinity for the nanotubes at one end and a hydrophobic group at the other. The dispersant evenly distributes the nanotubes within the second coating layer matrix 141. During application of the acrylic polymer resin containing the dispersant and nanotubes, as the acrylic polymer resin flows along the axial direction L of the thin-diameter low-loss optical fiber, the dispersant causes the nanotubes to extend along the axial direction L of the thin-diameter low-loss optical fiber. After the acrylic polymer resin solidifies to form the second coating layer matrix 141, the nanotubes are arranged within the second coating layer matrix 141 along the axial direction L of the thin-diameter low-loss optical fiber.

[0071] Among them, the dispersant can be one or more of carbon nanotube resin dispersant, hexadecyltrimethylammonium bromide, and anthracene octadecyl stearyl chloride. Different dispersant dosages can be selected according to the diameter of the nanotubes and the number of stacked layers. The dosage of the dispersant is 0.3-2.5 times the mass of the nanotubes.

[0072] When the proportion of nanotubes in the second coating layer 140 is small, the strength of the second coating layer 140 increased by the nanotubes is limited. When the proportion of nanotubes in the second coating layer 140 is large, the strength of the second coating layer 140 is too high, resulting in greater attenuation and loss of the thin-diameter low-loss optical fiber 100 when bending.

[0073] Therefore, in this embodiment, the mass percentage of the nanotubes in the second coating layer 140 is 0.25%-5%.

[0074] By controlling the mass percentage of the nanotubes in the second coating layer 140 , the elastic modulus of the second coating layer 140 along the axial direction L of the thin-diameter low-loss optical fiber is greater than 800 MPa and less than or equal to 2000 MPa.

[0075] When the elastic modulus of the second coating layer 140 along the axial direction L of the thin-diameter, low-loss optical fiber is less than 800 Mps, the overall tensile strength of the thin-diameter, low-loss optical fiber 100 is low, making it difficult to meet the operating requirements of the thin-diameter, low-loss optical fiber 100. When the elastic modulus of the second coating layer 140 along the axial direction L of the thin-diameter, low-loss optical fiber is greater than 2000 Mps, the overall strength of the thin-diameter, low-loss optical fiber 100 is too high, resulting in significant optical attenuation of the thin-diameter, low-loss optical fiber 100.

[0076] FIG6 is a diagram showing the fracture stress distribution of a thin-diameter, low-loss optical fiber provided in an embodiment of the present application at three strain rates.

[0077] As shown in Figure 6 , a 500mm-long sample of thin-diameter, low-loss optical fiber 100 was tested. The strain rates were 5mm / s, 50mm / s, and 500mm / s, respectively, with the ratios of 1%, 10%, and 100% of the sample length to time. The abscissa of Figure 3 shows the fracture stress at each strain rate for fifteen tests. As can be seen from Figure 3 , the fracture stress of thin-diameter, low-loss optical fiber 100 at each strain rate was consistently greater than 5.0 GPa, demonstrating the high tensile strength of thin-diameter, low-loss optical fiber 100.

[0078] Next, the thickness of each coating layer of the thin-diameter low-loss optical fiber 100 provided in the embodiment of the present application is described.

[0079] Specifically, the adhesive layer 120 is disposed at the interface between the first coating layer 130 and the cladding layer 112. The thickness of the adhesive layer 120 only needs to meet the space required by the adhesive 122, and does not need to be too thick. Therefore, in this embodiment, the thickness of the adhesive layer 120 is 5 μm-10 μm.

[0080] First coating layer 130 is used to protect quartz layer 110. In this embodiment, the thickness of first coating layer 130 is 12.5 μm to 32.0 μm. Second coating layer 140, which requires the addition of nanotubes, can be slightly thicker than first coating layer 130. In this embodiment, the thickness of second coating layer 140 is 15 to 30 μm.

[0081] The narrow-diameter, low-loss optical fiber 100 includes single-mode and multimode optical fibers. The core 111 diameters of the single-mode and multimode optical fibers differ. The diameter of the core 111 of the single-mode optical fiber is in the range of 8.0 μm to 12 μm, and the diameter of the cladding 112 is in the range of 124 μm to 126 μm. After the adhesive layer 120 and the first coating layer 130 are added, the resulting diameter is in the range of 150 μm to 200 μm. After the second coating layer is added, the resulting diameter is in the range of 180 μm to 255 μm. The thickness of the adhesive layer 120 is in the range of 5 μm to 10 μm. The provision of the adhesive layer 120 reduces the diameter of the single-mode optical fiber.

[0082] The attenuation coefficient of single-mode optical fiber at a wavelength of 1550nm is less than 0.184dB / km. Single-mode optical fiber has low bending loss. For example, when the bending radius is 30mm and the bending is completed 100 times, the additional loss is less than 0.05dB.

[0083] The diameter of the core 111 of the multimode optical fiber is in the range of 47.5μm-52.5μm, the diameter of the cladding 112 is in the range of 124μm-126μm, the diameter after adding the adhesive layer 120 and the first coating layer 130 is in the range of 150μm-200μm, and the diameter after adding the second coating layer 140 is in the range of 180μm-255μm, wherein the thickness of the adhesive layer 120 is in the range of 5μm-10μm. By setting the adhesive layer 120, the diameter of the single-mode optical fiber is made smaller.

[0084] The attenuation coefficient of multimode optical fiber at a wavelength of 1300nm is less than 1.0dB / km.

[0085] Table 1 lists the parameters of single-mode fiber and multimode fiber.

[0086] Table 1 Parameters of single-mode fiber and multimode fiber

[0087] FIG7 is a schematic diagram of the structure of the optical cable provided in an embodiment of the present application.

[0088] 7 , an embodiment of the present application further provides an optical cable 1000 , comprising a protective layer 200 and a plurality of thin-diameter low-loss optical fibers 100 provided in the above embodiments, wherein the plurality of thin-diameter low-loss optical fibers 100 are arranged in the protective layer 200 .

[0089] The specific structure of the thin-diameter low-loss optical fiber 100 has been described in detail in the above embodiments and will not be repeated here. The protective layer 200 is used to protect the thin-diameter low-loss optical fiber 100.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A thin-diameter low-loss optical fiber, characterized in that: It includes a quartz layer, an adhesive layer, a first coating layer and a second coating layer which are sequentially arranged from inside to outside along the radial direction of the thin-diameter low-loss optical fiber; The adhesive layer is used to increase the adhesion between the first coating layer and the quartz layer; the first coating layer is used to protect the quartz layer; the second coating layer includes a second coating layer substrate and a plurality of reinforcing members, the second coating layer substrate is the same as the substrate of the first coating layer, and the plurality of reinforcing members are distributed in the second coating layer substrate to increase the strength of the thin-diameter low-loss optical fiber.

2. The thin-diameter low-loss optical fiber according to claim 1, characterized in that: The adhesive layer comprises an adhesive layer matrix and an adhesive, wherein the adhesive is uniformly distributed in the adhesive layer matrix, the adhesive is a silane coupling agent, the silane coupling agent comprises a first functional group and a second functional group, the first functional group and the second functional group are connected by a chemical bond, the first functional group is one of a trimethoxy group and a triethoxy group; the second functional group is one of a γ-methacryloxypropyl group, a γ-aminopropyl group, a 3-mercaptopropyl group or a γ-mercaptopropyl group; The first functional group is bonded to the quartz layer through a chemical bond, and the second functional group is bonded to the first coating layer through a chemical bond.

3. The thin-diameter low-loss optical fiber according to claim 2, characterized in that: The mass percentage of the adhesive in the adhesive layer is 2%-5%.

4. The thin-diameter low-loss optical fiber according to claim 3, characterized in that: The adhesion between the first coating layer and the quartz layer is in the range of 10g-20g.

5. The thin-diameter low-loss optical fiber according to any one of claims 1 to 4, characterized in that: The reinforcement member extends axially along the thin-diameter low-loss optical fiber, and the reinforcement member is a nanotube.

6. The thin-diameter low-loss optical fiber according to claim 5, characterized in that: The second coating layer further includes a dispersant, and the dispersant is used to make the nanotubes uniformly distributed in the second coating layer matrix.

7. The thin-diameter low-loss optical fiber according to claim 6, characterized in that: The mass percentage of the nanotubes in the second coating layer is 0.25%-5%.

8. The thin-diameter low-loss optical fiber according to claim 7, characterized in that: The elastic modulus of the second coating layer along the axial direction of the thin-diameter low-loss optical fiber is greater than 800 MPa and less than or equal to 2000 MPa.

9. The thin-diameter low-loss optical fiber according to any one of claims 1 to 4, characterized in that: The thickness of the bonding layer is 5 μm-10 μm; the thickness of the first coating layer is 12.5 μm-32.0 μm; and the thickness of the second coating layer is 15-30 μm.

10. An optical cable, characterized in that: It comprises a protective layer and a plurality of thin-diameter low-loss optical fibers according to any one of claims 1 to 9, wherein the plurality of thin-diameter low-loss optical fibers are arranged in the protective layer.

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