A hollow-core optical fiber easy-to-split optical cable and its preparation method

Abstract

This invention discloses a hollow-core fiber easy-splitting optical cable and its preparation method, belonging to the field of optical cable technology. It includes an outer sheath and two reinforcing members embedded within the outer sheath; the inner edge cross-section of the outer sheath is elliptical; and a hollow-core fiber ribbon disposed within the outer sheath, comprising multiple hollow-core fibers. A bridging resin layer is disposed between adjacent hollow-core fibers, with one end of the bridging resin layer connected to the hollow-core fiber and the other end forming an adhesive mesa. An adhesive layer is disposed between the two adhesive mesas, and the modulus of the adhesive layer is lower than that of the bridging resin layer. By configuring the hollow-core fibers in a ribbon-like form, this invention allows multiple hollow-core fibers to form a single structure. When the hollow-core fiber easy-splitting optical cable is subjected to pressure bending or stripping, the bridging resin layer and adhesive layer on the hollow-core fiber ribbon can distribute the pressure on the hollow-core fibers throughout the entire hollow-core fiber ribbon, resulting in uniform stress distribution. This avoids localized stress accumulation in the hollow-core fibers and alleviates the problem of excessive bending loss in hollow-core fibers.

Description

Technical Field

[0001] This invention belongs to the field of optical cable technology, specifically relating to an easy-to-split hollow fiber optical cable and its preparation method. Background Technology

[0002] Easy-splitter fiber optic cable is a special type of fiber optic cable designed to simplify fiber optic network branching and splicing. It is a type of multi-core fiber optic cable commonly used for indoor and outdoor cabling, in-building and inter-building backbones, distribution frames, telecommunications equipment rooms, and as connection cables in riser and pressurized environments. It is also used in FTTD (Fiber to the Desktop) horizontal cabling, data center EDA (Equipment Distribution Area) areas, and factory automation. The key feature of easy-splitter fiber optic cable is that the cable core is not stripped from the end face; instead, an opening is made in the side of the cable to remove the optical unit for splicing – a process known as easy-splitter splicing.

[0003] When making an opening on the side of the cable body of the easy-to-strip optical cable, it is necessary to use a knife to cut open the outer sheath with high mechanical strength. Because the outer sheath is strong, the lateral pressure during stripping is not easy to control, the outer sheath bends greatly, and the knife can easily scratch the optical unit inside the outer sheath.

[0004] Hollow-core fiber is a new type of optical fiber with an air core, where optical signals are primarily transmitted through air holes rather than the glass core of traditional optical fibers. This structure brings advantages such as ultra-low latency and low nonlinearity. However, unlike conventional solid-core fiber, hollow-core fiber relies on photonic bandgap or anti-resonance effect for light guidance. Any irregular bending or compression (micro-bending) will disrupt the light propagation path, leading to energy leakage from the hollow core and causing significant bending loss. Therefore, when existing hollow-core fiber is used in easily spliced ​​optical cables, there is a problem of significant bending loss due to the large degree of bending during construction. Summary of the Invention

[0005] In view of one or more of the above-mentioned defects or improvement needs of the prior art, the present invention provides a hollow fiber easy-to-split optical cable to solve the problem of high bending loss in existing hollow fiber easy-to-split optical cables.

[0006] To solve the above-mentioned technical problems, the present invention provides an easy-to-split hollow fiber optical cable, which includes: An outer sheath, and two reinforcing members embedded within the outer sheath; The inner cross-section of the outer sheath is elliptical, and the two reinforcing members are respectively embedded on both sides of the minor axis of the elliptical cross-section. A hollow fiber ribbon is disposed within the outer sheath; the hollow fiber ribbon includes multiple hollow fibers, and a bridging resin layer is provided between each pair of adjacent hollow fibers; one end of the bridging resin layer is bonded to the hollow fiber, and the other end has a bonding mesa extending toward another hollow fiber, and an adhesive layer is provided between two adjacent bonding mesas, the modulus of the adhesive layer being lower than the modulus of the bridging resin layer.

[0007] As a further improvement of the present invention, the modulus of the bridging resin layer is 300~600MPa.

[0008] As a further improvement of the present invention, the modulus of the adhesive layer is 50~300MPa, the adhesive layer is a light-cured acrylic resin, and the bridging resin layer comprises, by weight, 30~60 parts of acrylate oligomer, 30~50 parts of reactive monomer diluent, 1~6 parts of photoinitiator and 1~4 parts of additives.

[0009] As a further improvement of the present invention, the elongation at break of the adhesive layer is 60% to 100%.

[0010] As a further improvement of the present invention, the coefficient of thermal expansion of the adhesive layer is 50~200ppm / ℃.

[0011] As a further improvement of the present invention, the ratio of the coefficient of thermal expansion of the adhesive layer to the coefficient of thermal expansion of the bridging resin layer is 0.8 to 1.2.

[0012] As a further improvement of the present invention, a self-healing layer is coated on one side of two adjacent bridging resin layers, the self-healing layer bonding the two bridging resin layers respectively, and the self-healing layer covering the joint of the bonding surface.

[0013] As a further improvement of the present invention, the self-healing layer is formed by curing polyurethane adhesive.

[0014] As a further improvement of the present invention, the cross-sections of the two reinforcing members at least partially coincide with the extension of the minor axis of the elliptical cross-section.

[0015] As a further improvement of the present invention, when the hollow fiber ribbon is wound and arranged, and when the hollow fiber ribbon is pressed against one end of the major axis of the elliptical cross section, the outer edge of the hollow fiber ribbon does not protrude from any end face of the reinforcing member along the major axis of the elliptical cross section.

[0016] As a further improvement of the present invention, the bridging resin layer is arranged axially discontinuously between each pair of adjacent hollow optical fibers.

[0017] As a further improvement of the present invention, an identification strip is provided on the outer wall of the outer sheath, the identification strip extends along the axial direction of the outer sheath, and the identification strip and the two reinforcing members are arranged in a triangular distribution.

[0018] As a further improvement of the present invention, the hollow fiber ribbon is stranded, and the stranding pitch of the hollow fiber ribbon is 200~400mm.

[0019] As a further improvement of the present invention, the hollow fiber ribbon is multiple, preferably two, and the two hollow fiber ribbons can be arranged side by side or twisted together.

[0020] As a further improvement of the present invention, the reinforcing member is an FRP rod or a GFRP rod.

[0021] As a further improvement of the present invention, water-blocking powder is also provided inside the outer sheath.

[0022] This invention also includes a method for preparing a hollow-core optical fiber easy-to-split optical cable, which is used to prepare the hollow-core optical fiber easy-to-split optical cable, comprising the following steps: Select multiple hollow optical fibers, arrange them side by side, and apply adhesive between adjacent hollow optical fibers to form a hollow optical fiber ribbon. The hollow fiber ribbon is curled and twisted together; An outer sheath is extruded around the periphery of the hollow optical fiber to form an easy-to-split hollow optical fiber cable.

[0023] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0024] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include: (1) The hollow fiber easy-to-split optical cable of the present invention, by setting the hollow fiber in the form of a hollow fiber ribbon, makes multiple hollow fibers form an integral structure. When the hollow fiber easy-to-split optical cable is subjected to pressure bending or stripping, when the external pressure is transmitted to the hollow fiber ribbon, the bridging resin layer and adhesive layer on the hollow fiber ribbon can distribute the pressure on a single hollow fiber to the entire hollow fiber ribbon, so that the stress is evenly distributed, avoiding the accumulation of local stress in the hollow fiber, thereby alleviating the problem of excessive bending loss of the hollow fiber. On the other hand, the present invention sets an adhesive layer with a lower modulus at the joint end face of the bridging resin layer, so that the fiber ribbon forms a weak area and a buffer area in the adhesive layer. The buffer area is used to absorb the stress transmitted by the hollow fiber and avoid stress concentration; the weak area facilitates the splitting and tearing of the hollow fiber, making it convenient to remove the split of the hollow fiber, and improving the splicing efficiency of the hollow fiber easy-to-split optical cable.

[0025] (2) The hollow fiber easy-to-split optical cable of the present invention has a weak area formed at the adhesive layer of the hollow fiber ribbon. When branching, the hollow fiber ribbon can be torn at the adhesive layer to form a single hollow fiber, which facilitates the connection to the home. When splicing, a second adhesive can be applied at the adhesive layer, and the adhesive layer can be formed again by photocuring. The remaining hollow fiber ribbon can be put into the hollow fiber easy-to-split optical cable to ensure the normal use of the optical cable. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the hollow-core optical fiber easy-to-split optical cable in an embodiment of the present invention; Figure 2 This is a schematic diagram of the hollow fiber ribbon in an embodiment of the present invention; Figure 3 This is a schematic diagram of the overall structure of another hollow fiber easy-to-split optical cable according to an embodiment of the present invention.

[0027] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Hollow-core optical fiber; 2. Bridging resin layer; 3. Adhesive layer; 4. Outer sheath; 5. Reinforcing member; 6. Identification tape. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] In the description of this invention, it should be understood that, unless otherwise stated, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0030] Furthermore, unless otherwise stated, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0031] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0033] Example: Please see Figures 1-3 In a preferred embodiment of the present invention, the hollow-core optical fiber easy-splitting cable includes an outer sheath 4 and two reinforcing members 5 embedded within the outer sheath 4; wherein the inner edge cross-section of the outer sheath 4 is elliptical, and the two reinforcing members 5 are respectively embedded on both sides of the minor axis of the elliptical cross-section. Additionally, a hollow-core optical fiber strip is disposed within the outer sheath 4, the hollow-core optical fiber strip including multiple hollow-core optical fibers 1, and a bridging resin layer 2 is provided between each pair of adjacent hollow-core optical fibers 1; one end of the bridging resin layer 2 is bonded to a hollow-core optical fiber 1, and the other end has a bonding mesa extending toward another hollow-core optical fiber 1, and an adhesive layer 3 is provided between adjacent bonding mesas, the modulus of the adhesive layer 3 being lower than the modulus of the bridging resin layer 2.

[0034] The hollow-core fiber easy-splitting optical cable of this invention, by setting the hollow-core fiber 1 in the form of a hollow-core fiber ribbon, allows multiple hollow-core fibers 1 to form an integral structure. When the hollow-core fiber easy-splitting optical cable is subjected to pressure bending or stripping, when the external pressure is transmitted to the hollow-core fiber ribbon, the bridging resin layer 2 and adhesive layer 3 on the hollow-core fiber ribbon can distribute the pressure on a single hollow-core fiber 1 to the entire hollow-core fiber ribbon, resulting in uniform stress distribution and avoiding local stress accumulation in the hollow-core fiber 1, thereby alleviating the problem of excessive bending loss of the hollow-core fiber 1. On the other hand, by setting an adhesive layer 3 with a lower modulus at the joint end face of the bridging resin layer 2, this invention creates a weak area and a buffer area in the adhesive layer 3 for the fiber ribbon. The buffer area is used to absorb the stress transmitted by the hollow-core fiber 1 and avoid stress concentration; the weak area facilitates the tearing of the hollow-core fiber 1 branches, making it easier to remove the branches of the hollow-core fiber 1, thus improving the splicing efficiency of the hollow-core fiber easy-splitting optical cable.

[0035] Specifically, in conventional easy-splitting optical cables, the outer sheath 4 has a circular outer shape and an elliptical inner structure. This provides sufficient sheath material on both sides of the elliptical structure's minor axis to facilitate the embedding of the reinforcing member 5, thereby improving the overall tensile and bending strength of the easy-splitting optical cable. The elliptical structure creates weak areas on the sides of the outer sheath 4 away from the reinforcing member 5, thus facilitating the stripping of the optical cable. Simultaneously, the elliptical structure inside the outer sheath 4 increases the internal space for the optical fiber, facilitating fiber splicing. However, correspondingly, when the outer sheath 4 has a large internal space, the optical fiber is less constrained internally. During construction or bending of the easy-splitting optical cable, stress concentration can occur in the optical fiber, leading to a large-angle bend at a certain point. The bending sensitivity of the hollow fiber 1 causes a sharp increase in its loss. Based on this, the present invention sets up a fiber optic ribbon structure and connects a flexible resin structure to the surface of the rigid optical fiber. On the one hand, it constrains the hollow optical fiber 1, and on the other hand, it can distribute the bending of a single optical fiber evenly to the entire fiber optic ribbon, thereby avoiding the problem of local stress accumulation and solving the problem of high loss in optical cables caused by easy splicing of hollow optical fibers.

[0036] Furthermore, as an optional embodiment of the present invention, the modulus of the bridging resin layer 2 is 600~900MPa. When the bridging resin layer 2 with a modulus of 600~900MPa is used as the connection structure of the hollow fiber 1, the bridging resin layer 2 is relatively rigid, making it difficult to bend the hollow fiber ribbon. During the splicing of the optical cable, the hollow fiber 1 is easily cut. In this case, a lower modulus adhesive layer 3 is needed as a flexible structure to allow the hollow fiber ribbon to bend and retract when contacted, thus avoiding damage to the hollow fiber 1. It is worth noting that when the adhesive layer 3 is used as a bending buffer structure, the adhesive layer 3 itself needs to have a certain thickness. The thickness of the adhesive layer 3 along the extension direction of the bridging resin layer 2 is preferably between 200~300μm. At this thickness, the adhesive layer 3 can complete large-angle bending, effectively avoiding the problem of the adhesive layer 3 breaking due to excessive stress concentration when the hollow fiber ribbon is bent.

[0037] Optionally, when the modulus of the bridging resin layer 2 is 600~900MPa, the modulus of the adhesive layer 3 is 50~600MPa.

[0038] Further, as an optional embodiment of the present invention, the modulus of the bridging resin layer 2 is 300~600MPa. When the bridging resin layer 2 with a modulus of 300~600MPa is used as the connection structure of the hollow fiber 1, the overall flexibility of the resin is relatively high, the hollow fiber ribbon can be curled and placed, and the bridging resin layer 2 can directly absorb the bending stress of the hollow fiber 1, avoiding the problem of stress concentration in the hollow fiber 1. Correspondingly, the adhesive layer 3 only needs to form a weak part between the two bridging resin layers 2 to facilitate the branching of the hollow fiber 1. Optionally, the thickness of the adhesive layer 3 along the extension direction of the bridging resin layer 2 is preferably 50~200μm.

[0039] Further, as an optional embodiment of the present invention, the modulus of the adhesive layer 3 is 50-300 MPa, and the adhesive layer 3 is a photocurable acrylic resin. The bridging resin layer 2 comprises, by weight, 30-60 parts of acrylate oligomer, 30-50 parts of reactive monomer diluent, 1-6 parts of photoinitiator, and 1-4 parts of additives. Specifically, the acrylate oligomer is the main component of the resin, which mainly participates in free radical cross-linking under UV irradiation to form a three-dimensional network insoluble and infusible structure; the reactive monomer diluent is used to reduce the overall viscosity of the resin, facilitating flow and coating; the photoinitiator is mainly used to absorb photons in a specific ultraviolet band, synergistically cross-linking and curing the resin; the additives are mainly defoamers, adhesion promoters, antioxidants, or wetting and dispersing agents. The present invention mainly controls the modulus of the adhesive layer 3 by adjusting the ratio of the photocurable acrylic resin, so that it has good flexibility after curing, facilitating the bending of the hollow fiber ribbon. The hollow-core fiber easy-to-split optical cable of this invention has a weak area formed at the adhesive layer 3 of the hollow-core fiber ribbon. During branching, the hollow-core fiber ribbon can be torn at the adhesive layer 3 to form a single hollow-core fiber 1, facilitating in-home splicing. During splicing, a second application of adhesive can be made at the adhesive layer 3, and the adhesive layer 3 can be formed again through photocuring. The remaining hollow-core fiber ribbon can be placed inside the hollow-core fiber easy-to-split optical cable, ensuring the normal use of the optical cable.

[0040] Furthermore, as an optional embodiment of the present invention, the elongation at break of the adhesive layer is 60% to 100%. The modulus of the adhesive layer 3 is lower than that of the bridging resin layer 2. When the hollow fiber is bent, the bending stress on the bridging resin layer 2 will concentrate on the adhesive layer 3. To avoid irreversible damage to the adhesive layer 3 during construction, the present invention controls the elongation at break of the adhesive layer 3 between 60% and 100%, ensuring that the hollow fiber easy-to-split optical cable does not break during construction.

[0041] Furthermore, the coefficient of thermal expansion of the adhesive layer 3 in this invention is 50~200ppm / ℃. As the adhesive layer 3 is a different structure from the bridging resin layer 2, if its coefficient of thermal expansion is too large when the external ambient temperature changes, it will cause excessive spacing between adjacent fibers in the hollow fiber ribbon, which is detrimental to the fusion splicing of the hollow fiber ribbon. Moreover, an excessively large coefficient of thermal expansion of the adhesive layer 3 will also compress the fibers on both sides, causing additional stress inside the hollow fiber ribbon and leading to abnormal attenuation of the fibers. Therefore, this invention controls the coefficient of thermal expansion of the adhesive layer 3 to 50~200ppm / ℃, allowing the hollow fiber ribbon to contract and expand synchronously as a whole, reducing the abnormal attenuation of the hollow fiber 1 within the hollow fiber ribbon.

[0042] Optionally, the ratio of the thermal expansion coefficient of the adhesive layer 3 to that of the bridging resin layer 2 in this invention is 0.8 to 1.2. In this invention, adjacent optical fibers are synchronously bonded to the bridging resin layer 2 via the adhesive layer 3. When the difference in thermal expansion coefficients between the adhesive layer 3 and the bridging resin layer 2 is too large, misalignment between the bridging resin layer 2 and the adhesive layer 3 can easily occur. Under external force, this can easily lead to separation between the bridging resin layer 2 and the adhesive layer 3, which is detrimental to the construction and long-term use of the hollow-core fiber easy-to-split optical cable. Therefore, this invention controls the ratio of the thermal expansion coefficients of the adhesive layer 3 to the bridging resin layer 2, making them close to a synchronous contraction state, ensuring the overall performance of the hollow-core fiber ribbon, and improving the service life of the hollow-core fiber easy-to-split optical cable.

[0043] Furthermore, as an optional embodiment of the present invention, a self-healing layer is also coated on one side of each of the two adjacent bridging resin layers 2. This self-healing layer bonds the two bridging resin layers 2 respectively, and covers the joint of the bonding surface. When the bridging resin layer 2 is a conventional resin, its hardness is high. When the hollow fiber ribbon is bent, the bending stress of the hollow fiber ribbon will be concentrated at the bonding layer 3. The secondary-formed bonding layer 3 is easy to separate from the two bridging resin layers 2. By coating the sides of the bridging resin layer 2 with a self-healing layer, the self-healing layer can bear part of the bending stress, thereby reducing the probability of the bonding layer 3 separating from the bridging resin layer 2, and ensuring that the hollow fiber ribbon is stably formed inside the easy-to-split optical cable.

[0044] Furthermore, as an optional embodiment of the present invention, the self-healing layer in the present invention is cured and molded by polyurethane adhesive. After curing, the polyurethane forms a layered microstructure with hard segment aggregation region and soft segment elastic region. When stretched, it dissipates energy first, which can avoid instantaneous brittle fracture. Its internal disulfide bonds will spontaneously and reversibly recombine at room temperature, so that the self-healing layer can stably bond the two bridging resin layers 2, reducing the probability of separation between the adhesive layer 3 and the bridging resin layer 2.

[0045] Further, as an optional embodiment of the present invention, the bonding mesa formed on the end face of the bridging resin layer 2 is planar. A planar bonding mesa facilitates the alignment of the two bridging resin layers 2 and the secondary molding and gluing of the bonding portion. Optionally, the bonding mesa is laterally perpendicular to the hollow fiber 1, facilitating the adjustment of the hollow fiber 1's position and ensuring the flatness of the spliced ​​hollow fiber ribbon; the bonding mesa can also be arranged at an angle to the fiber ribbon as a whole, facilitating the pressing of adjacent bridging resin layers 2 and realizing the splicing of the hollow fiber ribbon. Optionally, the bonding mesa on the end face of the bridging resin layer 2 can also be a complementary arc surface structure, a groove-concave-convex mating structure, a wave structure, or a toothed structure. Hollow fiber ribbons spliced ​​in this way are firmly bonded after curing, ensuring the stable use of the hollow fiber ribbon.

[0046] Optionally, the cross-sections of the two reinforcing members 5 in this invention at least partially coincide with the extension of the minor axis of the elliptical cross-section. The reinforcing members 5 are positioned at the center of the hollow fiber easy-to-split optical cable, such that the reinforcing members 5 divide the elliptical space inside the outer sheath 4 into two substantially equal parts. During the splicing operation, regardless of which side the splice is performed from, the hollow fiber strip is squeezed to the side far away from the stripper. During the process of the stripper cutting open the outer sheath 4, the reinforcing members 5 will block the stripping path of the stripper, preventing the stripper from damaging the hollow fiber 1.

[0047] Furthermore, as an optional embodiment of the present invention, the bridging resin layer 2 is arranged axially discontinuously between each pair of adjacent hollow optical fibers 1. Besides the fiber ribbon structure, the hollow optical fibers 1 of the present invention can also form a discontinuously bonded flexible fiber ribbon structure.

[0048] Optionally, the hollow fiber ribbon in this invention is stranded with a stranding pitch of 200~400mm. This stranding arrangement facilitates the bending, winding, and unfolding of the hollow fiber ribbon during construction, and the larger stranding pitch does not affect the splicing of the optical cable.

[0049] Optionally, such as Figure 3 As shown, the hollow fiber ribbons inside the outer sheath 4 of this invention consist of multiple fibers. Preferably, there are two fibers, which can be arranged side by side or twisted together.

[0050] Optionally, the reinforcing member 5 in this invention is an FRP rod or a GFRP rod.

[0051] Optionally, the outer sheath 4 of the present invention is further provided with water-blocking powder.

[0052] Furthermore, as an optional embodiment of the present invention, an identification strip 6 is provided on the outer wall of the outer sheath 4. The identification strip 6 extends along the axial direction of the outer sheath 4 and is arranged in a triangular configuration with the two reinforcing members 5. The identification strip 6 is located on the side away from the reinforcing members 5, opposite to the weak area of ​​the outer sheath 4, so as to guide the workers to peel off the outer sheath 4.

[0053] Furthermore, the present invention also includes a method for preparing an easily spliced ​​hollow fiber optical cable, which includes the following steps: Select multiple hollow optical fibers 1, arrange them side by side, and apply adhesive between two adjacent hollow optical fibers 1 to form a hollow optical fiber ribbon. The hollow fiber ribbon is curled and twisted together; An outer sheath 4 is extruded around the periphery of the hollow optical fiber to form an easy-to-split hollow optical fiber cable.

[0054] Optionally, when the outer sheath 4 is extruded around the hollow fiber ribbon, a reinforcing member 5 is also simultaneously pulled, and the reinforcing member 5 is extruded and embedded in the outer sheath 4.

[0055] Optionally, the through hole in the outer sheath 4 extrusion die for the hollow fiber ribbon to pass through is elliptical.

[0056] Optionally, the surface of the outer sheath 4 is also simultaneously extruded with a marking strip 6.

[0057] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hollow core fiber easy access fiber optic cable characterized by, include: An outer sheath, and two reinforcing members embedded within the outer sheath; The inner cross-section of the outer sheath is elliptical, and the two reinforcing members are respectively embedded on both sides of the minor axis of the elliptical cross-section. A hollow fiber ribbon is disposed within the outer sheath; the hollow fiber ribbon includes multiple hollow fibers, and a bridging resin layer is provided between each pair of adjacent hollow fibers; one end of the bridging resin layer is bonded to the hollow fiber, and the other end has a bonding mesa extending toward another hollow fiber, and an adhesive layer is provided between two adjacent bonding mesas, the modulus of the adhesive layer being lower than the modulus of the bridging resin layer.

2. The hollow-core fiber easy-access cable of claim 1, wherein, The modulus of the bridging resin layer is 300~600MPa.

3. The hollow-core optical fiber easy-to-split optical cable according to claim 1 or 2, characterized in that, The modulus of the adhesive layer is 50-300 MPa, the adhesive layer is a light-cured acrylic resin, and the bridging resin layer comprises, by weight, 30-60 parts of acrylate oligomer, 30-50 parts of reactive monomer diluent, 1-6 parts of photoinitiator and 1-4 parts of additives.

4. The hollow-core optical fiber easy-to-split optical cable according to claim 1, characterized in that, The elongation at break of the adhesive layer is 60% to 100%.

5. The hollow-core optical fiber easy-to-split optical cable according to claim 1, characterized in that, The coefficient of thermal expansion of the adhesive layer is 50~200ppm / ℃.

6. The hollow-core optical fiber easy-to-split optical cable according to claim 5, characterized in that, The ratio of the coefficient of thermal expansion of the adhesive layer to that of the bridging resin layer is 0.8 to 1.

2.

7. The hollow-core optical fiber easy-to-split optical cable according to claim 1, characterized in that, The cross-sections of the two reinforcing members at least partially coincide with the extension of the minor axis of the elliptical cross-section.

8. The hollow-core optical fiber easy-to-split optical cable according to claim 1, characterized in that, The bridging resin layer is arranged axially discontinuously between each pair of adjacent hollow optical fibers.

9. The hollow-core optical fiber easy-to-split optical cable according to claim 1, characterized in that, The outer wall of the outer sheath is provided with an identification strip, which extends along the axial direction of the outer sheath and is arranged in a triangular distribution with the two reinforcing members.

10. A method for preparing an easily spliced ​​hollow fiber optical cable, used to prepare an easily spliced ​​hollow fiber optical cable as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Select multiple hollow optical fibers, arrange them side by side, and apply adhesive between adjacent hollow optical fibers to form a hollow optical fiber ribbon. The hollow fiber ribbon is curled and twisted together; An outer sheath is extruded around the periphery of the hollow optical fiber to form an easy-to-split hollow optical fiber cable.

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