High-density flexible optical fiber ribbon micro-cluster cable containing hollow core optical fibers and multicore optical fibers and method of making the same

Abstract

The application discloses a high-density flexible optical fiber ribbon micro-cluster cable containing hollow optical fibers and multi-core optical fibers and a preparation method thereof, and belongs to the technical field of optical cables. The cable comprises optical fiber units and an outer sheath arranged on the periphery of the optical fiber units. The outer sheath is divided into a first sheath part and a second sheath part along the radial direction. The first sheath part is inlaid with a reinforcing member. The first sheath parts are arranged in pairs and are arranged on the two sides of the optical fiber units respectively. The second sheath part connects the two first sheath parts. The shrinkage rate of the sheath material in the first sheath part is greater than that in the second sheath part. The application controls the shrinkage rate of the circumferential sheath material of the outer sheath, so that the shrinkage rates of the sheath materials at different positions are different, and the internal optical fiber units are prevented from being squeezed, and the probability of fiber breakage in the production of the micro-cluster cable is reduced. The application adopts a conventional extrusion mode for forming, avoids the problem of optical fiber breakage caused by the vacuum sizing process of conventional micro-cluster cables, simplifies the forming process of the micro-cluster cable, and improves the production efficiency of the optical cable.

Description

Technical Field

[0001] This invention belongs to the field of optical cable technology, specifically relating to a high-density flexible fiber ribbon microcluster cable containing hollow-core optical fibers and multi-core optical fibers, and its preparation method. Background Technology

[0002] Based on the industry's development, there are now higher requirements for fiber optic products in terms of loss, core count, transmission mode, physical size, and transmission rate.

[0003] With the continuous advancement of urbanization, existing urban cable networks are primarily expanded using existing pipelines. Given the increasing scarcity of existing pipeline resources, high-density optical cables with large core counts have become the main means of urban network expansion. Micro-clustered optical cables are one type of cable structure that can improve fiber density. The reinforcing members of micro-clustered optical cables are located on both sides of the sheath, with a hollow tube structure in the center containing horizontally placed fiber units. The hollow tube structure requires no internal reinforcing members, and the fiber units do not need to be twisted, resulting in high internal space utilization and significantly increasing fiber density.

[0004] In contrast, due to the structural characteristics of micro-cluster optical cables, the fiber units are weakly twisted, and the hollow tube structure needs to reserve sufficient space to avoid squeezing the fiber units during sheath forming. Therefore, the outer sheath of micro-cluster cables is typically manufactured using a vacuum sizing process. Vacuum sizing mainly generates negative pressure through multiple spaced copper tube structures. This negative pressure is used to adsorb and form the outer sheath onto the inner wall of the copper tube structure. Cooling water is filled between the copper tubes, and the outer sheath is formed through vacuum negative pressure and cooling. During the forming process, the inner wall of the outer sheath does not compress the fiber units, and the vacuum-sizing formed outer sheath has a high overall roundness and a large internal space. However, the vacuum sizing process has its limitations. The copper tube structure is surrounded by cooling water and a negative pressure environment, which constrains the outer sheath. When the outer sheath leaves the area where the copper tube is located, it comes into contact with the cooling water and cools down. If the unconstrained outer sheath is significantly larger than the inner diameter of the copper tube, it will accumulate at the entrance of the next copper tube structure, causing congestion. As the optical cable take-up machine continues to pull, the accumulated sheath material at the copper tube increases until it completely blocks the cable, leading to core breakage and the "cable breakage" phenomenon. High-core-count optical cables contain a large number of optical fibers, and a single core breakage can cause significant losses. Even without a complete breakage, the breakage of some fibers can create numerous inconveniences for subsequent core inspection, affecting the overall production rate of the optical cable. Furthermore, as the number of optical cores gradually increases, the size of the outer sheath also gradually increases, making the "cable breakage" phenomenon increasingly common. Summary of the Invention

[0005] In response to one or more of the above-mentioned defects or improvement needs of the prior art, the present invention provides a high-density flexible fiber ribbon micro-cluster cable containing hollow fiber and multi-core fiber, which solves the problem of easy breakage in the manufacturing process of existing micro-cluster cables. To achieve the above objectives, the present invention provides a high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers, comprising: Fiber optic unit; An outer sheath is disposed on the outer periphery of the optical fiber unit, and the outer sheath is radially divided into a first sheath portion and a second sheath portion; The first sheath portion is embedded with a reinforcing member, and the first sheath portions are arranged in pairs on both sides of the optical fiber unit. The second sheath portion connects the two first sheath portions. The shrinkage rate of the sheath material in the first sheath portion is greater than the shrinkage rate of the sheath material in the second sheath portion.

[0006] As a further improvement of the present invention, the first sheath portion covers the area where the reinforcing member is located, the second sheath portion covers other areas of the outer sheath, and the first sheath portion protrudes from the outer peripheral curved surface of the second sheath portion.

[0007] As a further improvement of the present invention, the outer sheath has a circular cross-section.

[0008] As a further improvement of the present invention, the outer wall cross-section of the outer sheath is circular, the inner wall cross-section of the outer sheath is elliptical, and the radial thickness of the first sheath portion is greater than the radial thickness of the second sheath portion.

[0009] As a further improvement of the present invention, both the first sheath portion and the second sheath portion are made of polyethylene, and the degree of branching of the sheath material in the first sheath portion is greater than the degree of branching of the sheath material in the second sheath portion.

[0010] As a further improvement of the present invention, the first sheath is made of polyethylene and the second sheath is made of polyvinyl chloride.

[0011] As a further improvement of the present invention, a compatibilizer is added at the interface between the first sheath portion and the second sheath portion.

[0012] As a further improvement of the present invention, the optical fiber unit is one of an optical fiber, an optical fiber ribbon, or a flexible optical fiber ribbon.

[0013] As a further improvement of the present invention, the optical fiber unit is a flexible optical fiber ribbon, which includes multiple hollow optical fibers and / or multi-core optical fibers.

[0014] As a further improvement of the present invention, the cladding of the multi-core optical fiber contains multiple fiber cores, and at least one of the fiber cores is a marker fiber core, wherein the marker fiber core is an irregularly shaped fiber core.

[0015] This invention also includes a method for preparing a high-density flexible fiber ribbon microcluster cable containing hollow-core optical fibers and multi-core optical fibers, which includes the following steps: Select an optical fiber unit; select a first sheath material and a second sheath material, wherein the shrinkage rate of the first sheath material is greater than the shrinkage rate of the second sheath material; The fiber optic unit and the reinforcing member are pulled together, and the sheath material of the first sheath part and the sheath material of the second sheath part are melted and co-extruded in sections, so that the reinforcing member is embedded in the first sheath part, and the outer sheath is formed on the outer periphery of the fiber optic unit. After cooling and shaping, a high-density flexible fiber ribbon micro-cluster cable containing hollow fiber and multi-core fiber is obtained.

[0016] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0017] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include: (1) The high-density flexible fiber ribbon micro-cluster cable containing hollow-core and multi-core optical fibers of the present invention is prepared by using two types of sheath materials with different shrinkage rates for the outer sheath. The sheath material with reinforcement has a high shrinkage rate, and the reinforcement provides support, preventing the sheath material from shrinking and squeezing the internal optical fiber units. In areas without reinforcement, the sheath material has a relatively low shrinkage rate and a smaller shrinkage amplitude, thus avoiding squeezing the optical fiber units. The present invention controls the shrinkage rate of the circumferential sheath material of the outer sheath, resulting in different shrinkage rates in different parts, thereby avoiding squeezing of the internal optical fiber units and reducing the probability of fiber breakage during micro-cluster cable production. The high-density flexible fiber ribbon micro-cluster cable containing hollow-core and multi-core optical fibers of the present invention is formed using a conventional extrusion method, avoiding the fiber breakage problem caused by vacuum sizing processes used in micro-cluster cables, simplifying the micro-cluster cable forming process, and improving optical cable production efficiency.

[0018] (2) The high-density flexible fiber ribbon micro-cluster cable containing hollow fiber and multi-core fiber of the present invention can ensure the effective forming of the optical cable and solve the compatibility problem between different sheath materials by selecting polyethylene with different shrinkage rates as the first sheath layer and the second sheath layer, thereby reducing the difficulty of the preparation process of the high-density flexible fiber ribbon micro-cluster cable containing hollow fiber and multi-core fiber.

[0019] (3) The high-density flexible fiber ribbon micro-cluster cable containing hollow fiber and multi-core fiber of the present invention, by preparing the inner part of the outer sheath into an elliptical structure, reduces the thickness of the outer sheath in the area without reinforcement while ensuring that the outer sheath covers the reinforcement, thereby increasing the inner space of the outer sheath, increasing the accommodating space of the fiber unit, and further increasing the fiber density. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a high-density flexible fiber ribbon microcluster cable containing hollow fiber and multi-core fiber, according to one embodiment of the present invention. Figure 2This is a schematic diagram of the overall structure of a high-density flexible fiber ribbon microcluster cable containing hollow fiber and multi-core fiber, according to one embodiment of the present invention. Figure 3 This is a schematic diagram of the overall structure of a high-density flexible fiber ribbon microcluster cable containing hollow fiber and multi-core fiber, according to one embodiment of the present invention. Figure 4 This is an optical cable diagram prepared by the high-density flexible optical fiber ribbon micro-cluster cable preparation method containing hollow optical fiber and multi-core optical fiber in the embodiments of the present invention.

[0021] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Fiber optic unit; 2. Reinforcing member; 3. First sheath; 4. Second sheath; 5. Water-blocking yarn; 6. Cable unwinding rope. Detailed Implementation

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] Example: Please see Figures 1-4 The high-density flexible fiber ribbon micro-cluster cable containing hollow-core and multi-core optical fibers in a preferred embodiment of the present invention includes an optical fiber unit 1 and an outer sheath. The outer sheath is disposed on the outer periphery of the optical fiber unit 1 and is radially divided into a first sheath portion 3 and a second sheath portion 4. Simultaneously, a reinforcing member 2 is embedded within the first sheath portion 3. The first sheath portions 3 are arranged in pairs and respectively on both sides of the optical fiber unit 1. The second sheath portion 4 connects the two first sheath portions 3. Furthermore, the shrinkage rate of the sheath material in the first sheath portion 3 is greater than the shrinkage rate of the sheath material in the second sheath portion 4. It is worth noting that the first sheath portion 3 and the second sheath portion 4 in the present invention are assembled to form a ring structure, and the first sheath portion 3 and the second sheath portion 4 are located at different circumferential positions of the optical fiber unit 1.

[0028] This invention relates to a high-density flexible fiber ribbon micro-cluster cable containing hollow-core and multi-core optical fibers, which is manufactured by using two types of sheath materials with different shrinkage rates for the outer sheath. The sheath material with reinforcement member 2 has a high shrinkage rate, providing support and preventing the sheath material from compressing the internal fiber unit 1. In areas without reinforcement member 2, the sheath material has a relatively low shrinkage rate and a smaller shrinkage amplitude, thus also preventing compression of the fiber unit 1. This invention controls the circumferential shrinkage rate of the outer sheath material, resulting in different shrinkage rates in different parts, thereby avoiding compression of the internal fiber unit 1 and reducing the probability of fiber breakage during micro-cluster cable production. This high-density flexible fiber ribbon micro-cluster cable containing hollow-core and multi-core optical fibers is formed using a conventional extrusion method, avoiding the fiber breakage problem caused by the vacuum sizing process used in conventional micro-cluster cables, simplifying the micro-cluster cable forming process and improving optical cable production efficiency.

[0029] Furthermore, as an optional embodiment of the present invention, the outer sheath of the present invention includes multiple sheath portions radially, which together form the outer sheath. The sheath material near the reinforcing member 2 has a high shrinkage rate, while the sheath material far from the reinforcing member 2 has a low shrinkage rate. The sheath material near the reinforcing member 2 is affected by the reinforcing member 2, resulting in a low shrinkage rate and less pressure on the internal optical fiber unit 1. The sheath material far from the reinforcing member 2 is less affected by the reinforcing member 2, resulting in a high shrinkage rate and easier pressure on the internal optical fiber unit 1. By forming sheath material with a gradient shrinkage rate, the outer sheath is formed neatly overall and does not pressure the internal optical fiber unit 1, thus avoiding signal attenuation of the optical fiber unit 1. It is worth noting that when using sheath materials with multiple shrinkage rates, multiple feed ports need to be correspondingly opened on one extrusion die to extrude the outer sheath in combination, which increases the difficulty and complexity of the extrusion process in practice. In actual design, the number of sheath portions can be reasonably selected based on the complexity of the extrusion process and the shrinkage of the outer sheath.

[0030] Furthermore, such as Figure 3 As shown, in an optional embodiment of the present invention, the first sheath portion 3 covers the area where the reinforcing member 2 is located, and the second sheath portion 4 covers other areas. The first sheath portion 3 protrudes from the outer peripheral curved surface of the second sheath portion 4. Theoretically, an outer sheath can still be formed by using a sheath material with a high shrinkage rate only in the area where the reinforcing member 2 is located, and using a sheath material with a low shrinkage rate in areas without the reinforcing member 2. In this case, the micro-clustered cable forms a bulge structure in the area where the reinforcing member 2 is located, while other areas tend to be circular. The area where the reinforcing member 2 is located can be formed by extruding the sheath material covering the reinforcing member 2 using a stripe extruder.

[0031] When the first sheath portion 3 protrudes, the high-density flexible fiber ribbon micro-cluster cable containing hollow-core and multi-core optical fibers is an irregular circle, which is inconvenient for connecting the optical cable to optical devices. Furthermore, the protruding portion affects the utilization rate of the optical cable within the conduit, impacting subsequent connections and waterproofing repairs. Therefore, this invention can adjust the amount of sheath material extruded from the first sheath portion 3 to make the outer perimeter of the outer sheath formed by the first sheath portion 3 and the second sheath portion 4 a regular circle.

[0032] Furthermore, as an optional embodiment of the present invention, the cross-section of the outer sheath of the high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers is annular. Since the shrinkage rate of the sheath material in the first sheath portion 3 is higher than that in the second sheath portion 4, there is a certain difference in the shrinkage rate of the inner wall of the outer sheath. Therefore, it is necessary to control the extrusion pressure of the sheath material in the first sheath portion 3 and the second sheath portion 4 to maintain nearly synchronous shrinkage rates, thus forming a regular annular structure. It is worth noting that in this invention, the annular shape refers to an outer sheath with a non-circularity of 6% or less.

[0033] Furthermore, such as Figure 2 As shown in the optional embodiment of the present invention, the outer wall cross-section of the high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers is circular, and the inner wall cross-section of the outer sheath is elliptical. Furthermore, the radial thickness of the first sheath portion 3 is greater than the radial thickness of the second sheath portion 4. A reinforcing member 2 is embedded inside the first sheath portion 3. The first sheath portion 3 must radially enclose the reinforcing member 2, and its thickness must be at least greater than the diameter of the reinforcing member 2 to ensure that the outer sheath does not break at the reinforcing member 2. Therefore, the first sheath portion 3 is thicker. The second sheath portion 4 does not need to consider the reinforcing member 2. While ensuring that the outer sheath does not break, the thickness of the second sheath portion 4 can be appropriately reduced. Therefore, the outer sheath can form a structure with an outer circular shape and an inner elliptical shape. This structure can further increase the internal space of the optical cable, thereby further increasing the fiber density without changing the cable size.

[0034] Preferably, the materials of the first sheath portion 3 and the second sheath portion 4 are compatible in this invention. The material compatibility between the first sheath portion 3 and the second sheath portion 4 ensures the integrity of the outer sheath formed by the two, and guarantees the normal extrusion molding of the optical cable.

[0035] Further, as an optional embodiment of the present invention, both the first sheath portion 3 and the second sheath portion 4 are made of polyethylene, and the branching degree of the sheath material in the first sheath portion 3 is higher than that in the second sheath portion 4. The higher the branching degree of polyethylene, the weaker its interchain interactions, the stronger the chain segment mobility during cooling, and the higher the shrinkage rate. The first sheath portion 3 uses polyethylene with a higher branching degree to improve the shrinkage rate. As an optional embodiment of the present invention, the first sheath portion 3 is made of low-density polyethylene, and the second sheath portion 4 is made of high-density polyethylene; or, the first sheath portion 3 is made of low-density polyethylene, and the second sheath portion 4 is made of medium-density polyethylene; or, the first sheath portion 3 is made of medium-density polyethylene, and the second sheath portion 4 is made of high-density polyethylene.

[0036] Furthermore, as an optional embodiment of the present invention, the first sheath portion 3 is made of polyethylene, and the second sheath portion 4 is made of polyvinyl chloride (PVC). Polyethylene has a non-polar linear molecular chain structure, high overall regularity, and strong crystallinity. Typically, the shrinkage rate of low-density polyethylene is 1.5% to 5%, and that of high-density polyethylene is 1.5% to 3.5%. PVC, on the other hand, contains polar chlorine atoms in its molecular chain, resulting in large steric hindrance and poor molecular chain regularity. It exhibits no significant crystallization shrinkage upon cooling after processing, and its shrinkage rate is typically 0.1% to 0.5%, much lower than that of polyethylene. By selecting polyethylene and PVC with different shrinkage rates, the first sheath portion 3 and the second sheath portion 4 shrink asynchronously, completing the outer sheath molding without compressing the internal optical fiber unit 1. Additionally, polyethylene and PVC have good compatibility, allowing them to be molded together without delamination or splitting.

[0037] Of course, alternatively, in addition to the materials mentioned above, other materials with different shrinkage rates and good compatibility can also be used as the first sheath portion 3 and the second sheath portion 4 in this invention. Optionally, the first sheath portion 3 is polyethylene, and the second sheath portion 4 is thermoplastic polyurethane. Optionally, the first sheath portion 3 is high-density polyethylene, and the second sheath portion 4 is polypropylene.

[0038] Optionally, when the first sheath portion 3 and the second sheath portion 4 have poor compatibility, the interface between the two can be modified, such as by adding a compatibilizer or silicone masterbatch to complete the bonding.

[0039] Furthermore, as an optional embodiment of the present invention, the optical fiber unit 1 in the present invention can be either a flexible optical fiber ribbon or an optical fiber or an optical fiber ribbon. In the present invention, the outer sheath forms a hollow tube structure, the internal space of which can accommodate any type of optical fiber unit 1 structure, which can be a loosely placed optical fiber, a stacked optical fiber ribbon, or a flexible optical fiber ribbon. It is worth noting that when a flexible optical fiber ribbon is used, the core density of the high-density flexible optical fiber ribbon micro-cluster cable containing hollow-core and multi-core optical fibers is relatively high.

[0040] Furthermore, as an optional embodiment of the present invention, the optical fiber unit 1 is a flexible optical fiber ribbon, and the flexible optical fiber ribbon includes multiple hollow-core optical fibers and / or multi-core optical fibers. Besides flexible optical fiber ribbons formed by conventional solid optical fiber combinations, the flexible optical fiber ribbon in the present invention can also be formed by combining hollow-core optical fibers and / or multi-core optical fibers.

[0041] Furthermore, as an optional embodiment of the present invention, the cladding of the multi-core optical fiber contains multiple fiber cores, and at least one of these cores is a marker core, which is an irregularly shaped core. Since the cross-section of an optical fiber is typically circular, the multiple cores within the multi-core optical fiber lack directional order, posing an identification problem. Therefore, by setting a marker core inside the multi-core optical fiber, and using this irregularly shaped marker core as a starting point, the other cores can be marked in a predetermined order to facilitate identification of each core.

[0042] Furthermore, as an optional embodiment of the present invention, the outer periphery of the optical fiber unit 1 is covered with water-blocking yarn 5 or a sleeve. The water-blocking yarn 5 or the sleeve can isolate the optical fiber unit 1 from the outer sheath, preventing the optical fiber from being burned when the outer sheath is extruded. It is worth noting that when a sleeve is fitted around the outer periphery of the optical fiber unit 1, water-blocking powder, water-blocking paste, or water-blocking yarn needs to be added inside the sleeve to ensure the water-blocking capability of the optical cable. At the same time, the sleeve is preferably a flexible sleeve, which can be deformed by mutual compression between flexible sleeves, thereby improving the utilization rate of the internal space of the optical cable and increasing the optical fiber density. Optionally, the water-blocking yarn 5 can be water-blocking aramid yarn or water-blocking glass yarn, etc. Of course, the water-blocking yarn 5 can also be replaced by water-blocking tape.

[0043] Furthermore, as an optional embodiment of the present invention, there are multiple optical fiber units 1, each including a flexible optical fiber ribbon, and water-blocking yarn 5 is wound around the outer periphery of the optical fiber unit 1. The water-blocking yarn 5 or binding yarn of different optical fiber units 1 are different colors. In addition to preventing direct contact between the flexible optical fiber ribbon and the sheath material, the water-blocking yarn 5 can also distinguish between different flexible optical fiber ribbons, thereby facilitating optical fiber branching and splicing.

[0044] Furthermore, as an optional embodiment of the present invention, the reinforcing member 2 in the present invention is one of FRP rods, steel wires, stranded steel wires, or FRP sheets. The present invention does not impose any special restrictions on the reinforcing member 2; it only requires that the reinforcing member 2 serves a supporting, tensile, and bending function, and any of the above-mentioned materials that can be used as the reinforcing member 2 are acceptable.

[0045] Furthermore, as an optional embodiment of the present invention, the reinforcing members 2 are symmetrically arranged on both sides of the outer sheath, and multiple reinforcing members 2 are provided on each side of the outer sheath. In the simplest form, one reinforcing member 2 is provided on each side of the outer sheath; however, depending on the usage conditions, multiple reinforcing members 2, such as 2 to 4, can also be arranged on each side of the outer sheath to increase the tensile, bending, and compressive strength of the optical cable.

[0046] Furthermore, as an optional embodiment of the present invention, the reinforcing member 2 in the present invention comprises multiple members, and the multiple reinforcing members 2 are evenly distributed along the circumference of the outer sheath. As a modified structure of the micro-cluster cable, the multiple reinforcing members 2 arranged circumferentially on the outer sheath collectively restrict the contraction of the outer sheath, thereby preventing the contraction of the outer sheath from squeezing the internal optical fiber unit 1. It is worth noting that when the outer sheath contains multiple reinforcing members 2, the overall thickness of the outer sheath increases. Under the condition of a fixed optical cable size, this will sacrifice internal space, resulting in a corresponding decrease in optical fiber density.

[0047] The high-density flexible fiber ribbon micro-cluster cable containing hollow-core and multi-core optical fibers of this invention uses flexible fiber ribbons as fiber units 1 internally. With a cable diameter of 35mm~40mm, B6A1 or B6A2 optical fibers are selected, and the maximum fiber density in the cable can reach 6912 cores. Optionally, in actual use, micro-cluster cables with different core counts can be manufactured according to customer needs, such as 3456 cores, 1728 cores, 864 cores, 288 cores, etc. Optionally, the minimum bending radius of the optical fiber in this invention is 7.5mm~10mm.

[0048] Furthermore, as an optional embodiment of the present invention, the inner side of the outer sheath is also provided with a cable opening rope 6.

[0049] Furthermore, regarding the high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers in this invention, a method for preparing the high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers is also included, comprising the following steps: Select fiber unit 1, and select sheath material for first sheath part 3 and sheath material for second sheath part 4; and the shrinkage rate of sheath material for first sheath part 3 is greater than the shrinkage rate of sheath material for second sheath part 4. The fiber unit 1 and the reinforcing member 2 are pulled together, and the sheath material of the first sheath part 3 and the sheath material of the second sheath part 4 are melted and co-extruded in sections, so that the reinforcing member 2 is embedded in the first sheath part 3, and the outer sheath is formed on the outer periphery of the fiber unit 1. After cooling and shaping, a high-density flexible fiber ribbon micro-cluster cable containing hollow fiber and multi-core fiber is obtained.

[0050] The high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers in this invention uses sheath materials with different shrinkage rates to make the shrinkage rates of the reinforcing member 2 region and the non-reinforcing member 2 region in the outer sheath different. By controlling the shrinkage degree of the outer sheath, the internal optical fiber unit 1 is not squeezed while ensuring the formation of the optical cable, which reduces the probability of fiber interruption in the production of micro-cluster cable and improves the production efficiency of optical cable.

[0051] Furthermore, when the outer sheath is formed by co-extruding the sheath material of the first sheath part 3 and the sheath material of the second sheath part 4, two extruders are used to extrude the sheath material of the first sheath part 3 and the sheath material of the second sheath part 4 respectively. Then the flow channel of the extrusion die is adjusted so that the sheath material of the first sheath part 3 and the sheath material of the second sheath part 4 occupy different areas of the outer sheath respectively, and thus they are combined to form the outer sheath.

[0052] like Figure 4 As shown, the method for preparing high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fiber and multi-core optical fiber in this invention has a high internal fiber density and does not cause compression of the optical fiber during the outer sheath forming process. The fiber attenuation loss is low. The preparation of high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fiber and multi-core optical fiber is achieved without the use of vacuum sizing process.

[0053] 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 high-density flexible fiber optic ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers, characterized in that, include: Fiber optic unit; An outer sheath is disposed on the outer periphery of the optical fiber unit, and the outer sheath is radially divided into a first sheath portion and a second sheath portion; The first sheath portion is embedded with a reinforcing member, and the first sheath portions are arranged in pairs on both sides of the optical fiber unit. The second sheath portion connects the two first sheath portions. The shrinkage rate of the sheath material in the first sheath portion is greater than the shrinkage rate of the sheath material in the second sheath portion. The first sheath portion covers the area where the reinforcing member is located, and the second sheath portion covers other areas of the outer sheath. The first sheath portion protrudes from the outer peripheral curved surface of the second sheath portion. The outer sheath has a circular cross-section.

2. The high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers according to claim 1, characterized in that, The outer wall of the outer sheath has a circular cross-section, the inner wall of the outer sheath has an elliptical cross-section, and the radial thickness of the first sheath portion is greater than the radial thickness of the second sheath portion.

3. The high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers according to claim 1 or 2, characterized in that, Both the first sheath portion and the second sheath portion are made of polyethylene, and the degree of branching of the sheath material in the first sheath portion is greater than the degree of branching of the sheath material in the second sheath portion.

4. The high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers according to claim 1 or 2, characterized in that, The first sheath is made of polyethylene, and the second sheath is made of polyvinyl chloride.

5. The high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers according to claim 1 or 2, characterized in that, A compatibilizer is added at the interface between the first sheath and the second sheath.

6. The high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers according to claim 1, characterized in that, The optical fiber unit is a flexible optical fiber ribbon, which includes multiple hollow optical fibers and / or multi-core optical fibers.

7. The high-density flexible fiber ribbon micro-cluster cable containing hollow-core optical fibers and multi-core optical fibers according to claim 6, characterized in that, The cladding of the multi-core optical fiber contains multiple fiber cores, and at least one of the fiber cores is a marker fiber core, which is an irregularly shaped fiber core.

8. A method for preparing a high-density flexible fiber ribbon microcluster cable containing hollow-core optical fibers and multi-core optical fibers, used to prepare the high-density flexible fiber ribbon microcluster cable containing hollow-core optical fibers and multi-core optical fibers as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Select an optical fiber unit; select a first sheath material and a second sheath material, wherein the shrinkage rate of the first sheath material is greater than the shrinkage rate of the second sheath material; The fiber optic unit and the reinforcing member are pulled together, and the sheath material of the first sheath part and the sheath material of the second sheath part are melted and co-extruded in sections, so that the reinforcing member is embedded in the first sheath part, and the outer sheath is formed on the outer periphery of the fiber optic unit. After cooling and shaping, a high-density flexible fiber ribbon micro-cluster cable containing hollow fiber and multi-core fiber is obtained.

Images