A high-density fiber optic outdoor communication cable

Abstract

This invention belongs to the field of optical cables, specifically a high-density outdoor optical fiber communication cable. The optical fiber cable includes at least one bundle containing multiple non-tightly buffered optical fibers and a bonding element. The bonding element holds the multiple non-tightly buffered optical fibers within at least one bundle. A separation layer typically surrounds at least one bundle, and an optical cable sheath surrounds the separation layer, preventing adhesion between the at least one bundle and the optical cable sheath without requiring a separate sheath for each fiber bundle. This optical fiber cable eliminates grease or grease-like components that come into contact with at least one bundle, filling gaps in the cable and preventing moisture from flowing through. In this invention, the fiber bundle is fixed by the bonding element, eliminating the need for traditional protective sleeves or buffer tubes. Furthermore, the optimized cable structure significantly reduces the cable diameter, allowing for more optical fibers to be accommodated within the same size, thus increasing fiber density and meeting the miniaturization and high-density requirements of outdoor communication cables.

Description

Technical Field

[0001] This utility model relates to the field of optical cable technology, and in particular to a high-density optical fiber outdoor communication cable. Background Technology

[0002] In many applications, fiber optic cables need to contain multiple optical fibers. As the demand for optical communication increases, the number of optical fibers in fiber optic cables also needs to be increased. By increasing the number of optical fibers in a fiber optic cable, a single fiber optic cable can support more optical communication channels.

[0003] To meet the demand for increased fiber optic cables, modular fiber optic cables have been developed. For example... Figure 1 As shown, the unitized fiber optic cable 10 includes multiple fiber bundles 12 wound around a common central strength member 16. The unitized fiber optic cable 10 also includes a cable sheath 18 extruded outside the fiber bundles 12, and an optional tear line 22 for facilitating removal of the cable sheath 18. Figure 1 As shown, each fiber bundle 12 typically contains at least two fibers, more commonly six or twelve fibers, which are twisted together.

[0004] Optical fiber 14 is typically a tight-buffered optical fiber. The tight-buffered optical fiber 14 contains single-mode or multimode optical fibers and may be surrounded by an interface layer. This interface layer may be made of a material containing Teflon®, surrounding a tight-buffered layer; however, other suitable interface layer materials may also be used, such as ultraviolet (UV) cured acrylic resin. The tight-buffered layer is typically made of a plastic material, such as polyvinyl chloride (PVC). As an alternative to PVC, the tight-buffered layer may use non-halogenated polyolefins, such as polyethylene (PE) or polypropylene (PP). Furthermore, the tight-buffered layer may also be made of ethylene-vinyl acetate copolymer (EVA), nylon, or polyester materials.

[0005] Each fiber bundle 12 also includes a central strength member 26 around which the fiber bundle is wound. Each fiber bundle 12 further includes a sheath 28 surrounding the fiber, and an optional tear line 20 for facilitating removal of the sheath 28. The sheath 28 serves to protect the fiber 14 and maintain the winding structure of the fiber bundle around the central strength member 26. The sheath 28 is typically made of a polymer material, such as PVC. As an alternative to PVC, the sheath 28 may also be made of fluoroplastics (such as polyvinylidene fluoride PVDF), fluorinated compounds, or mixtures of PVC with PVDF, PVC with polyethylene (PE), etc.

[0006] The sheath 28 is typically thicker; in some embodiments, the sheath is about 0.8 mm thick.

[0007] During manufacturing, the fiber bundle 12 passes through an extruder crossover head, and the sheath 28 is extruded and wrapped around the outside of the fiber bundle to maintain the position of the fiber within the bundle. Since the tight-buffered layer of the tight-buffered fiber 14 is typically made of plastic, the extruded plastic sheath 28 can adhere to the outer layer of the tight-buffered fiber 14 without an intermediate insulating layer. To avoid this, an insulating layer is usually placed between the fiber bundle and the sheath to prevent them from sticking together during extrusion. Without an insulating layer, the extruded plastic partially melts the outermost layer of the tight-buffered layer, causing adhesion between the outer sheath of the optical cable and the tight-buffered fiber, thereby degrading the performance of the optical fiber.

[0008] Due to the adhesion between the optical fibers 14, the degrees of freedom of the optical fibers are restricted when the fiber optic cable is bent or subjected to stress, which in turn increases signal attenuation. To avoid this effect, an insulating layer 30 is typically added between the fiber bundle and the sheath 28. This insulating layer is usually formed of strength members (such as aramid yarns), which are generally wound around the outside of the optical fibers. This strength member layer is also typically thick, and in some embodiments, its thickness is approximately 0.2 mm.

[0009] Each fiber 12 is typically wound around the central strength member 16 of the fiber optic cable 10. Similar to the central strength member 26 of each fiber 12, the central strength member 16 of the fiber optic cable 10 is typically made of a relatively rigid optical fiber or glass-reinforced plastic material, or a combination of relatively flexible aramid fibers and plastic materials. The fiber optic cable 10 also includes a protective cable sheath 18 surrounding each fiber 12. The cable sheath 18 is typically made of a plastic material, such as PVC. Alternatively, the cable sheath 18 may be made of fluoroplastics (such as PVDF), fluorinated compounds, or mixtures of PVC and PVDF or PVC and PE.

[0010] As described above, the optical cable sheath 28 is typically extruded and wrapped around the outside of the optical fiber bundle. Due to the adhesion between the optical cable sheath 28 and the optical fiber bundle, the flexibility of the optical fiber cable 10 may be affected to some extent.

[0011] To reduce this effect, the fiber optic cable 10 may have a surface coating, typically composed of talc powder, applied to the surface of the outer sheath 28 of each fiber bundle 12. This coating helps prevent or reduce adhesion between the cable sheath 18 and the outer sheath 28 of the fiber bundle.

[0012] The unitized fiber optic cable 10 is designed as described above, supporting more optical communication channels by increasing the number of optical fibers (e.g., the number of fiber bundles and fibers). In some applications, although fiber optic cables require a large number of optical fibers, it is generally desirable to maintain a small size. Therefore, we propose a high-density outdoor fiber optic communication cable to address the aforementioned issues. Utility Model Content

[0013] The purpose of this invention is to address the shortcomings of existing technologies by proposing a high-density fiber optic outdoor communication cable.

[0014] To achieve the above objectives, the present invention adopts the following technical solution:

[0015] A high-density outdoor fiber optic communication cable includes at least one bundle containing a plurality of non-tightly buffered optical fibers and a bonding element. The bonding element holds the plurality of non-tightly buffered optical fibers within the at least one bundle. A separation layer typically surrounds the at least one bundle, and an optical cable sheath surrounds the separation layer to prevent adhesion between the at least one bundle and the optical cable sheath without requiring a separate sheath for each fiber bundle. The fiber optic cable excludes grease or grease-like components in contact with the at least one bundle, which are used to fill gaps in the cable to prevent moisture from flowing through it.

[0016] Preferably, the fiber optic cable includes at least one bundle containing multiple loosely packed fiber optic cables, and at least one bonding wire is wound around the multiple fiber optic cables to hold them within the bundle. A separation layer surrounds at least one bundle, and an optical cable sheath surrounds the separation layer to prevent adhesion between the at least one bundle and the optical cable sheath, without requiring a separate sheath for each fiber bundle. The fiber optic cable excludes grease or grease-like components that come into contact with at least one bundle, which are used to fill gaps in the cable to prevent moisture from flowing through it.

[0017] Preferably, it includes a central support and at least one bundle of optical fibers. The at least one bundle of optical fibers includes a plurality of loosely buffered optical fibers and a bonding element. The bonding element holds the plurality of loosely buffered optical fibers within the at least one bundle of optical fibers, and an optical cable sheath surrounds the at least one bundle of optical fibers. A separation layer prevents adhesion between the at least one bundle of optical fibers and the optical cable sheath. This optical fiber cable excludes grease or grease-like components that come into contact with the at least one bundle of optical fibers, filling gaps in the optical cable and thus preventing moisture from flowing through the optical cable.

[0018] Preferably, it includes at least one bundle containing multiple optical fibers and a bonding element. The bonding element holds the multiple optical fibers within at least one bundle. An armor layer surrounds at least one bundle. The optical fiber cable excludes the cable sheath within the armor layer.

[0019] The beneficial effects of this utility model are:

[0020] 1. The dry cable design eliminates the need for grease filling, avoiding problems such as grease dripping at high temperatures, chaotic operation, and time-consuming grease removal. Craftsmen can directly operate the optical fiber, improving operational efficiency.

[0021] 2. The fiber bundle is fixed by binding elements, eliminating the need for traditional protective sleeves or buffer tubes. Furthermore, the optimized optical cable structure significantly reduces the cable diameter, allowing for more optical fibers to be accommodated within the same size, thus increasing fiber density and meeting the demands of outdoor communication for miniaturized and high-density optical cables.

[0022] 3. A separation element is installed to prevent the outer sheath of the optical cable from adhering to the fiber bundle or optical fiber, allowing the optical fiber to move relative to the fiber when the optical cable is bent or folded, thus ensuring the stability of optical signal transmission and reducing optical attenuation.

[0023] 4. Optical fibers and fiber bundles have identifiers, which makes it easy for craftsmen to identify them and improves the convenience of construction and maintenance.

[0024] 5. A variety of materials are available for the outer sheath of the optical cable and each component. It can be designed to have properties such as flame retardancy and UV resistance, making it suitable for complex outdoor environments. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of a traditional optical fiber cable that employs a modular design found in existing technologies.

[0026] Figure 2 This is a partial perspective view of an exemplary fiber optic cable.

[0027] Figure 3 yes Figure 2 The cross-sectional view of the optical fiber cable shown is shown.

[0028] Figure 2A yes Figure 2 A partial perspective view of a fiber bundle in the optical fiber cable shown.

[0029] Figure 4 This is a partial perspective view of an exemplary optical fiber cable according to another embodiment of the present invention;

[0030] Figure 5 This is a cross-sectional view of an exemplary optical fiber cable conduit assembly according to another embodiment of the present invention;

[0031] Figure 6 This is a cross-sectional view of an optical fiber cable according to another embodiment of this utility model;

[0032] Figure 7 This is a cross-sectional view of an optical fiber cable according to another embodiment of this utility model;

[0033] Figure 8 This is a partial perspective view of an optical fiber cable according to another embodiment of the present invention.

[0034] In the diagram: 40, optical fiber cable; 42, optical fiber bundle; 44, optical fiber; 46, strength member; 50, outer sheath of optical cable; 54, guy wire; 48, binding element; 52, separation layer; 56, tubular member; 60, conduit assembly. Detailed Implementation

[0035] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0036] This application discloses a high-density fiber optic outdoor communication cable.

[0037] Reference Figure 1-8 A high-density outdoor fiber optic communication cable, the fiber optic cable 40 includes at least one fiber bundle 42, within which a non-tightly bundled buffered fiber 44 is contained; however, the fiber 44 may also be a tightly bundled buffered type or bundled fibers. The fiber 44 may include conventional single-mode or multimode fibers; however, other suitable optical waveguides may also be used. Strength members 46, such as aramid yarns, may be arranged around the fiber bundle 42; however, in other embodiments, multiple fiber bundles 42 may surround a strength member 46 arranged at the center of the cable 40. More specifically, the strength member 46 comprises multiple layers of aramid yarn twisted around two layers of fiber bundle 42; however, other suitable strength members, such as glass fiber yarns, may also be used. Other embodiments of the invention may include different fiber bundles 42 with different numbers of fibers 44, or different types of optical waveguides within the same cable.

[0038] The fiber optic cable 40 also includes an outer sheath 50 surrounding the fiber bundles 42 and 44, and may also include an optional pull wire 54 for easy removal of the outer sheath 50. Furthermore, a strength member 46 provides a separation layer between the fiber bundles 42 and the outer sheath 50 to prevent the outer sheath 50 from adhering to the fiber 44 and / or fiber bundles 42 during extrusion.

[0039] The optical fiber cable of the present invention employs a dry cable design. In other words, the optical fiber bundle 42 of the present invention does not contain grease or similar grease-like components that come into contact with it, used to fill the gaps in the optical cable, thereby preventing moisture from flowing through these gaps. However, the optical fiber cable of the present invention may include a lubricant to allow relative movement between the optical fiber bundle 42 and / or the optical fiber 44, for example, improving optical performance when bent. Grease components are prone to dripping at high temperatures and can easily cause mess during use. Furthermore, craftsmen must remove grease from the optical fiber before handling it, a very time-consuming process. On the other hand, the dry cable design of the present invention allows craftsmen to handle the optical fiber directly without first removing grease or similar grease-like components.

[0040] Figure 2 and Figure 3The fiber optic cable 40 has 12 fiber bundles 42, each containing 12 optical fibers 44, forming a 144-fiber-count cable with a relatively small diameter. Each fiber bundle 42 may contain 12 different colored optical fibers 44 to help craftsmen identify the optical fibers 44 in each bundle 42. The optical fibers 44 are unstretched, but may also be stranded. In this embodiment, the fiber bundles 42 are arranged in layers, with the first layer containing 3 fiber bundles spirally stranded, and the second layer containing 9 fiber bundles spirally stranded in the opposite direction around the first layer and the strength member 46. In other embodiments, the first layer of fiber bundles 42 may be stranded around a central member (e.g., aramid yarn, glass-reinforced plastic, or glass fiber yarn). Another embodiment may use filler rods or other suitable filler members instead of optical waveguide bundles 42 to form the fiber optic cable 40.

[0041] However, the concept of the present invention can include any suitable number of fiber bundles and optical waveguides. For example, the fiber optic cable 40 can be configured as: a single layer containing three fiber bundles, each containing 12 fibers, forming a 36-fiber-count cable; a single layer containing six fiber bundles surrounding a strength member, forming a 72-fiber-count cable; a connecting cable containing 8 fibers; or a 288-fiber-count cable. The concept of the present invention can also be applied to other suitable cable structures, such as SZ stranding or planetary stranding of fiber bundles 42.

[0042] The fiber bundle 42 in the fiber optic cable 40 includes multiple non-tightened buffered fibers 44, allowing direct contact between the fibers 44 and / or the fiber bundle 42. However, other embodiments of the invention may include tightened buffered fibers 44. By removing the tightened buffer layer surrounding the fibers 44, the diameter of the cable can be effectively reduced, allowing for higher fiber density. For example, in one embodiment, the diameter of a 144-fiber-count cable is approximately 10 mm or less. Embodiments including tightened buffered fibers 44 typically increase the cable diameter while reducing fiber density. For example, in one embodiment, the diameter of a 144-fiber-count cable with tightened buffered fibers 44 is approximately 20 mm or less, while the diameter of a conventional unitized cable is approximately 30 mm. Embodiments including tightened buffered fibers 44 may be surrounded by an interface layer, typically made of a material containing Teflon (E). The interface layer acts as a release layer, providing controlled bonding between the tightened buffer layer and the fibers, allowing a craftsman to easily remove the tightened buffer layer during end-of-life processing. The tightened buffer layer is typically a plastic, such as PVC. However, the cable buffer layer can also be made of other plastics, including halogen-free polyolefins such as PE or polypropylene, or fluoroplastics such as PVDF, or UV-curable materials.

[0043] Each fiber bundle 42 also includes a binding element 48 that surrounds the fiber to hold the fiber 44 within the fiber bundle. Figure 2 and Figure 2A In one embodiment shown, at least one bonding wire 48 is wrapped around the optical fiber 44. The optical fiber cable 40 may include various bonding wires 48 or bonding yarns. The bonding wire 48 is preferably an air-wound, textured, continuous multifiber thread. Furthermore, the bonding wire 48 may be a synthetic fiber with antibacterial and antidegrading properties to prevent the generation of hydrogen gas, thereby avoiding signal attenuation. For example, the bonding wire 48 may be made of materials such as polyester, rayon, or nylon. Additionally, the bonding wire 48 is preferably pre-shrinked.

[0044] The binding wire 48 has a large spread factor, so it flattens out after being wound around the optical fiber 44. Furthermore, the binding wire 48 can easily deform when subjected to external forces such as bending. Typically, the number of turns per inch of the binding wire 48 does not exceed 25 to avoid signal attenuation. Most commonly, the number of turns per inch of the binding wire 48 is between 2 and 6, more preferably about 4 turns per inch. The TEX value of the binding wire 48 is typically between 18 and 60, more preferably between 30 and 40, for example, about 35. Furthermore, the denier value of the binding wire 48 is typically between 150 and 2600, for example, about 250.

[0045] The bonding wire 48 may also include a surface treatment that is non-reactive to other components or materials of the optical fiber cable 40. For example, the bonding wire 48 may include a silicone wax emulsion treatment to facilitate the treatment of the wire. The bonding wire 48 may also be designed to be non-hygroscopic or may include a superabsorbent polymer to reduce or prevent moisture migration through the optical fiber cable 40.

[0046] The binding wire 48 is typically wound spirally around the fiber bundle 42, with a pitch between 10 mm and 70 mm, more preferably about 50 mm, to facilitate the fabrication of the fiber bundle. For example... Figure 2A As shown, an advantageous embodiment of the bonding wire 48 includes a pair of wires, a loop wire and a pin wire. One wire (which can be a loop wire or a pin wire) alternately passes through the upper portion of the fiber bundle, while the other wire alternately passes through the lower portion of the fiber bundle. According to... Figure 2A In this embodiment (for example only), the leftmost line at the end of the fiber bundle extends along the length of the bundle until the first stitching point, where the line is secured by an overlapping stitch. The line is then spirally wound around the lower portion of the fiber bundle until the second overlapping stitching point on the other side of the fiber bundle, where the line is re-secured. This process is repeated along the length of the fiber bundle, securing fiber 44 to form a unified fiber bundle.

[0047] In this embodiment, the looped wire and the needle wire are typically fixed together at multiple stitching points in the fiber bundle, with the pitch at the stitching points typically ranging from 10 mm to 70 mm, more preferably 50 mm. The resulting binding wire has a zigzag appearance and is therefore sometimes referred to as a "zigzag binding wire".

[0048] In addition, the binding wire 48 may include identifiers, such as markings or colors, to identify the fiber bundles wrapped by the binding wire and to distinguish different fiber bundles. For example, a white binding wire 48 can be used in conjunction with 12 binding wires 48 of different colors to identify 12 fiber bundles 42; or two sets of 12 different colored binding wires 48 can be used to identify multiple fiber bundles 42.

[0049] The binding wire 48 securely holds the optical fibers 44 within the fiber bundle 42 while maintaining the shape and size of the fiber bundle, thus eliminating the need for individual protective sleeves or buffer tubes typically required in conventional optical fiber cables. By removing the protective sleeves or buffer tubes usually placed in the fiber bundle, the resulting fiber bundle and optical fiber cable 40 can be smaller than conventional optical fiber cables with the same number of optical fibers. Furthermore, the binding wire 48 also prevents the optical fibers 44 from becoming entangled with other materials such as aramid fibers.

[0050] While the binding lines described above are highly advantageous for holding optical fibers within the fiber bundle, other types of binding elements can be used if desired. For example, binding element 48 can be made of a ribbon material or a thin film (such as a polymer film) and wound around optical fiber 44, as shown below. Figure 4 As shown. Unlike the polymer protective sheath that wraps the fiber bundle in traditional unitized fiber optic cables, the polymer film is typically very thin, for example, between 1 and 10 mils in one embodiment. Furthermore, since the polymer film does not require extrusion, the fiber bundle 42 can be directly wound around it without creating an obstruction between the polymer film and the fiber, as the polymer film does not adhere to the buffer layer on the fiber as it does with an extruded polymer protective sheath.

[0051] Although the polymer film can be made of a variety of materials, in one embodiment the polymer film is made of polyester (e.g., polyethylene terephthalate, MYLAR® film), has a thickness of about 1 mil, and may contain markings such as different colors for identifying different fiber bundles 42.

[0052] Furthermore, the fiber bundle 42 can also be housed within a soft outer shell. The fiber optic sheath 50 can be made of various materials, but is typically made of plastic, such as PVC. As an alternative to PVC, the fiber optic sheath 50 can also be made of other plastics, including fiber-reinforced polyethylene and fluoroplastics. As mentioned above, in conjunction with the tight-cable buffer layer of the tight-cable buffer fiber 44, the fiber optic sheath 50 can also be designed to have enhanced flame retardancy, thereby giving the fiber optic cable an uplift, climate-tolerant, and / or low-smoke zero-halogen rating. In this regard, the fiber optic sheath 50 can contain aluminum trihydrate, antimony trioxide, or other known additives to improve the flame retardancy of the fiber optic sheath. Additionally, the fiber optic sheath 50 can also be designed to be UV resistant, if necessary.

[0053] The fiber optic cable sheath 50 is typically extruded around multiple fiber bundles 42. Since the fiber bundles 42 do not need to be encased in the sheath as described below, the fiber optic cable 40 preferably includes a separation element and / or separation layer 52 (see [link to documentation]). Figure 4 This is used to prevent adhesion between the fiber bundles and the optical cable sheath 50. The separating element 52 includes a separating layer disposed within the optical cable sheath 50, surrounding the multiple fiber bundles 42. The separating layer 52 is preferably made of a material with a melting point higher than that of the optical cable sheath 50 (if used, the melting point of the cable buffer layer of the cable buffer fiber 44) to suppress adhesion between the optical cable sheath 50 and the fiber bundles. For example, for an optical cable sheath 50 made of PVC with a melting point of 190°C, the separating element 52 can be made of polyester, such as MYLAR® film, with a melting point of approximately 235°C.

[0054] The optical cable sheath 50 is typically extruded around a bundle of optical fibers 42 at the melting temperature of the plastic forming the sheath. Because the release layer 52 is made of a material, such as polyester, with a melting point higher than the plastic forming the sheath 50, it does not melt during extrusion. Therefore, the release layer 52 suppresses adhesion between the sheath 50 and the fiber bundles 42, allowing the optical fibers to move relative to the sheath 50 when the optical fiber cable 10 is bent or folded, thus allowing optical signals to be transmitted through the optical fiber without adverse optical attenuation caused by bending or folding. Figure 2 As shown, the strength member 46 (e.g., aramid yarn, such as Kevlar®) at least partially serves as the separation layer 52, providing tensile strength to the fiber optic cable 40 while also acting as a separator. However, other suitable strength members 46, such as Zylon®, Vectran®, Technora®, or Spectra®, may also be used. The strength members 46 may be arranged parallel to the direction of the fiber bundle 42 or may be twisted around the fiber bundle 42. To reduce the amount of aramid yarn used rather than to provide strength, the separation layer 52 may be formed from various other strip materials, films, yarns, and / or fiber materials. For example, the separation layer 52 may consist of multiple Kevlar® yarns and multiple polyester yarns twisted around the fiber bundle 44. In these embodiments, the separation layer 52 is designed to suppress adhesion between the multiple fiber bundles 42 and the cable sheath 50. Furthermore, the separation layer 52 in these embodiments is generally relatively thin to avoid unnecessarily increasing the volume of the fiber optic cable 40.

[0055] If desired, the release layer 52 can also be made of other non-polymer materials. For example, the release layer 52 can be made of water-swellable tape to enhance the waterproof performance of the fiber optic cable 40. Alternatively, the release layer 52 can be made of MYLAR® film with a thickness of approximately 1 mil.

[0056] The separating element 52 can be formed in other ways without departing from the spirit and scope of the invention. For example, in Figure 4 In the illustrated embodiment of the optical fiber cable 40, each fiber bundle 42 comprises a polymer film 48 surrounding multiple tightly buffered optical fibers 44; however, the optical fibers 44 may also be non-tightly buffered. By appropriately designing the polymer film 48, it can serve not only as a bonding material for the respective fiber bundles 42 but also as a separating element. In this case, the polymer film 48 is preferably made of a material with a melting point higher than that of the plastic used in the cable sheath 50. For example, for a PVC cable sheath 50 with a melting point of 190°C, the polymer film 48 could be made of polyester (such as MYLAR® film) with a melting point of 235°C. Therefore, the polymer film 48 surrounding each fiber bundle 42 will not melt during the extrusion of the cable sheath 50, thereby suppressing adhesion between the cable sheath 50 and the tightly buffered optical fibers 44 in each fiber bundle 42.

[0057] Furthermore, the separating element 52 can also be formed by a surface coating applied to each fiber bundle 42. In this case, the surface coating is preferably applied to at least a portion of each fiber bundle 42 that would otherwise be in contact with the fiber sheath 50. The surface coating is preferably made of a material with a melting point higher than that of the plastic used for the fiber sheath 50. For example, the surface coating can be made of powdered talc and applied to the outer surface of the fiber bundle 42. The talc surface coating effectively suppresses adhesion between the fiber sheath 50 and the tightly buffered fiber 44, as the fiber sheath does not adhere to it during extrusion.

[0058] According to one embodiment of the invention, each fiber bundle 42 is unsheathed. That is, each fiber bundle 42 is bound together by a binding element 48 (such as a binding wire, a thin polymer layer, etc.) and does not contain a polymer sheath like conventional monolithic fiber optic cables. Therefore, in these embodiments, the fiber optic cable 40, with each fiber bundle 42 bound by the binding wire 48, allows direct contact between non-tightly buffered fibers and / or tightly buffered fibers, and fibers between adjacent bundles can contact each other.

[0059] In traditional monolithic optical fiber cables, the sheath surrounding the fiber bundles is typically thick. Similarly, the reinforcement layer, tight buffer layer, etc., located between the sheath and the fiber in each fiber bundle are also relatively thick. By designing the optical fiber cable 40 so that the fiber bundles 42 do not need to include polymer sheaths and / or reinforcement layers to separate the fibers from the polymer sheath, the volume of each fiber bundle can be significantly reduced, and correspondingly, the volume of the optical fiber cable 40 can also be significantly reduced. Similarly, the non-tight buffered fiber 44 can also significantly reduce the size of the fiber bundles, thereby greatly reducing the size of the optical fiber cable 40. For comparison, according to one embodiment of the invention, the optical fiber cable 40 includes six fiber bundles 42, each fiber bundle including six tight buffered fibers wound around a central strength member 46. While the dimensions and thicknesses of various optical cable components can vary depending on the application—for example, by adjusting the thickness of the optical cable sheath 50 to alter compressive and impact resistance and / or flame retardancy—the optical fiber cable 40 of this embodiment also includes an insulating layer 52 made of polyester (such as MYLAR® film) that encloses the fiber bundle 42, and is further encased in a 1.3 mm thick optical cable sheath 50, resulting in a total diameter of 10.9 mm for the optical fiber cable 40. As described above, conventional monolithic optical fiber cables, with the same number of fiber bundles and total fiber count, typically have a significantly larger diameter, such as 18.8 mm. Therefore, the cross-sectional area of ​​a conventional optical fiber cable is approximately three times that of the optical fiber cable of this embodiment. Consequently, the optical fiber cable 40 according to this invention can contain the same number of optical fibers while being much smaller than a conventional optical fiber cable. Alternatively, the optical fiber cable 40 can also contain more optical fibers within the same dimensions, i.e., a higher fiber count.

[0060] While various embodiments of the optical fiber cable 40 have been described above, the optical fiber cable 40 may also include other characteristics without departing from the spirit and scope of the invention. For example, the optical fiber cable 40 may be constructed by including various water-swellable tapes, wires, and / or powders to improve its water resistance. For example, the insulating layer 52 may be made of the water-swellable tape described above. In another embodiment, the insulating layer 52 may be formed of a sheath layer, such as a metal or dielectric layer, which may consist of one or more components. In addition to serving as an insulating layer, the sheath layer may also provide, for example, compressive and / or tensile strength. In another embodiment, the fiber bundle 42 may be wound around a phosgene assembly, such as a coaxial cable or other suitable phosgene assembly.

[0061] While the single-unit design of the optical fiber cable 40 has been described above, the optical fiber cable 40 can also have other configurations. In this regard, Figure 2The illustrated fiber optic cable 40 embodiment includes multiple fiber bundles 42, each having a strength member 46, and is surrounded by a cable sheath 50. However, in other embodiments, the fiber optic cable 40 may include multiple conduit assemblies surrounded by the cable sheath 50, each conduit assembly containing multiple fiber bundles. To minimize the required size of each conduit assembly to accommodate a predetermined number of fibers, the fiber bundles in each conduit assembly should preferably be unsheathed, as shown in... Figure 2 and Figure 3 As described in the embodiments.

[0062] Although fiber bundles can be arranged in various ways, the conduit assembly 60 of each fiber optic cable 40 may include concentrically arranged fiber bundles 42, wherein some fiber bundles are located inside other fiber bundles, such as... Figure 5 As illustrated in the embodiment, the conduit assembly 60 includes an inner fiber bundle 42a containing a plurality of optical fibers 44, and at least one bundle line 48 surrounding these fibers to maintain the integrity of the fiber bundle. Although not shown, the inner fiber bundle 42a may also include a central strength member along which the optical fibers 44 extend (if desired). The inner fiber bundle 42a may contain any type of optical fiber. Each optical fiber in the inner fiber bundle 42a preferably includes an identifier, such as a color, for uniquely identifying the respective fiber relative to the other optical fibers in the inner fiber bundle. Although the inner fiber bundle 42a may contain various bundle lines, in an advantageous embodiment, the bundle line 48 is an air-wound, textured, continuous multifiber bundle line as described above.

[0063] Figure 5 The conduit assembly 60 in the illustrated embodiment further includes an outer fiber bundle 42b that surrounds the inner fiber bundle 42a. The outer fiber bundle 42b contains a plurality of fibers distributed circumferentially. While the outer fiber bundle 42b can contain any number of fibers, in the illustrated embodiment, it includes 12 fibers. Similar to the inner fiber bundle 42a, each fiber 44 in the outer fiber bundle 42b preferably includes an identifier, such as a color, to uniquely identify the respective fiber relative to the other fibers in the outer fiber bundle. Although each fiber in the inner fiber bundle 42a and each fiber in the outer fiber bundle 42b are uniquely identified (e.g., by a unique color) within their respective fiber bundles, fibers in the inner fiber bundle 42a and the outer fiber bundle 42b can also be distinguished by the fiber bundles they contain if they share the same color. The outer fiber bundle 42b also includes at least one bundle wire 48 that surrounds the plurality of fibers in the fiber bundle to maintain the integrity of the outer fiber bundle around the inner fiber bundle 42a. While the inner fiber bundle 42a may contain various bundles, in an advantageous embodiment, the bundle 48 is also an air-wound, textured, continuous multifiber bundle as described above.

[0064] also, Figure 5 The conduit assembly 60 may include a tubular member 56, such as a buffer tube, surrounding the outer fiber bundle 42b, as described above. Furthermore, any voids within the tubular member 56 may be filled with a compound to prevent moisture migration.

[0065] like Figure 5 As shown, at least the outer fiber bundle 42b, or more preferably, both the inner and outer fiber bundles are unsheathed, thus minimizing the cross-sectional area of ​​the resulting conduit assembly 60 to accommodate a predetermined number of optical fibers. To prevent adhesion between the tubular member 56 and the outer fiber bundle 42b, Figure 5 The conduit assembly 60 may also include a separation element, such as a separation layer surrounding the outer fiber bundle or a surface coating on the outer layer of the fiber bundle, as described above.

[0066] By wrapping the fiber 44 of the outer fiber bundle 42b around the inner fiber bundle 42a, Figure 5 The conduit assembly 60 in the intermediate embodiment will include a dense array of optical fibers to maximize the number of optical fibers contained in a buffer tube of a given cross-sectional area. However, each optical fiber in the conduit assembly 60 can be uniquely identified by markings on each fiber (e.g., color) and by the way the fiber is divided into inner and outer fiber bundles.

[0067] In one embodiment, using conduit assemblies 60, multiple conduit assemblies extend along a central strength member 46, typically by twisting them around the central strength member 46. An extruded fiber optic sheath 50 is then applied over the multiple conduit assemblies 54. To suppress adhesion between the tubular members 56 of the conduit assembly 60 and the fiber optic sheath 50, the fiber optic cable 40 may also include a separating element positioned between the conduit assembly 60 and the fiber optic sheath 50, as described in the other embodiments above. By including conduit assemblies, each conduit assembly typically comprising multiple fiber bundles, this embodiment of the fiber optic cable 40 can contain a greater number of fibers, such as 288 fibers or more, while continuing to reduce the overall cross-sectional area of ​​the cable. However, each fiber 44 in this embodiment can still be uniquely identified by markings (e.g., color) that may be included on the tubular members of each conduit assembly 56, and the markings (e.g., color) of each fiber, as well as the manner in which the fibers are divided into inner and outer fiber bundles, allow for unique identification of each fiber in each conduit assembly in the manner described above.

[0068] Figure 6 An optical fiber cable 40 according to another embodiment of the present invention is shown. Figure 6The optical fiber cable 40 includes an optical cable sheath 50 that typically surrounds a strength member 46 (such as aramid yarn) and a bundle 42. The bundle 42 includes a group of non-tight-buffered optical fibers 44, for example, eight optical fibers secured together by a binding wire 48 (not shown) to prevent the non-tight-buffered optical fibers 44 from tangling with the strength member 46. Figure 6 The optical fiber cable 40 uses a structure between optical fibers 44, although non-tight-buffered optical fibers 44 may also include a tight-buffered layer. The optical fiber cable 40 may also include a tear line 54 to facilitate the removal of the cable sheath 50. Figure 6 The optical fiber cable 40 in the middle has a general circular cross-section and can be used as an interconnecting optical cable.

[0069] Traditional fiber optic ribbon interconnects typically exhibit preferential bending characteristics due to the planar arrangement of fibers within the fiber ribbon. Therefore, conventional eight-fiber ribbon interconnects can be difficult to bend and store, especially in confined spaces such as connector trays. Since fiber optic cable 40 has a generally circular cross-section, it typically does not exhibit preferential bending characteristics, making it easier to bend and route in connector trays.

[0070] In one embodiment, Figure 6 The fiber optic cable 40 includes a cable sheath 50, typically surrounding three-terminal 2450 denier aramid yarn. The aramid yarn is twisted around a bundle 42 containing eight single-mode optical fibers 44, which are secured by binding wires 48 (not shown). The cable diameter is approximately 3 mm or less. However, other configurations can be used, and the cable diameter can be greater than 3 mm. For example, the cable sheath 50 typically surrounds four-terminal 2450 denier aramid yarn, which is twisted around a bundle 42 containing twelve multimode optical fibers 44, secured by binding wires 48 (not shown). The cable diameter is approximately 3-4 mm. However, the cable diameter can also be greater than 3-4 mm.

[0071] Figure 7 Another embodiment of the present invention is shown: an optical fiber cable 40'. Figure 7 The fiber optic cable 40' in the middle includes multiple Figure 6 The optical fibers 40 are twisted together to form a branch optical cable. The optical fiber cable 40' includes a first layer with three optical fibers 40 twisted in a helical direction, and a second layer with nine optical fibers 40 twisted in a counter-helical direction around the first layer, and is externally covered by an optical cable sheath 50. Embodiments of the optical fiber cable 40' may also include, for example, a separator layer 52 (such as a waterproof tape), a central member, a tear line, and / or other suitable optical cable assemblies.

[0072] Figure 8 An optical fiber cable 40 according to another embodiment of the present invention is shown. Figure 8The fiber optic cable 40 includes at least one unsheathed bundle 42 containing unbuffered optical fibers 44 and wrapped with binding wire 48. However, the optical fibers 44 can also be tightly sheathed, or other binding elements can be used. The bundles 42 are twisted together, but can also be untwisted. More specifically, the fiber optic cable 40 includes a first layer with three bundles 42 twisted in a helical direction, and a second layer with nine bundles 42 twisted in a counter-helical direction around the first layer. A separator layer 52 surrounds the bundles 42 of the fiber optic cable 40 and is constituted by a flexible sheath. The flexible sheath typically has a smooth inner surface for contacting the bundles 42 and / or optical fibers 44. For example, a CPID interlocking sheath from Eastern Wire & Conduit in Ontario, Canada, can be used, but other suitable sheath materials can also be used. The flexible sheath also provides bend control for the fiber optic cable 40, reducing optical attenuation by preventing small bending radii. The cable sheath 50 surrounds... Figure 8 The sheath separator layer 52 in the middle, but Figure 8 The embodiments can also be practiced without the optical cable sheath 50.

[0073] Figure 8 The fiber optic cable 40 in this embodiment does not yet include a bundle or cable sheath within the separator layer 52; however, some embodiments may include a bundle sheath. Higher fiber density can be achieved within the sheath separator layer 52 by removing the sheaths of individual bundles 42 and / or the sheaths of stranded bundles 42 within the sheath separator layer 52.

[0074] Figure 8 Embodiments of the optical fiber cable 40 may include, for example, a central member, a tear line, a waterproof tape wrapped around the bundle, and / or other suitable optical cable components.

[0075] This invention employs a dry cable design, eliminating the need for grease filling and avoiding problems such as grease dripping at high temperatures, operational chaos, and time-consuming grease removal. Craftsmen can directly manipulate the optical fibers, improving operational efficiency. The fiber bundle is fixed by binding elements, eliminating the need for traditional protective sleeves or buffer tubes. Furthermore, the optimized cable structure significantly reduces the cable diameter, allowing for more optical fibers within the same size, thus increasing fiber density and meeting the demands of outdoor communication for miniaturized and high-density optical cables. Separation elements prevent adhesion between the cable sheath and the fiber bundle or fibers, allowing relative movement of the fibers when the cable is bent or folded, ensuring stable optical signal transmission and reducing optical attenuation. Identifiers on the optical fibers and fiber bundle facilitate identification by craftsmen, improving construction and maintenance convenience. A variety of materials are available for the cable sheath and components, and can be designed to have flame-retardant and UV-resistant properties, making it suitable for complex outdoor environments.

[0076] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A high-density outdoor optical fiber communication cable, characterized in that, The fiber optic cable (40) includes multiple fiber bundles (42), each fiber bundle (42) including multiple non-tightly packed fibers (44) and a bonding element. The bonding element holds multiple non-tightly wrapped optical fibers (44) within the fiber bundle (42); A separation layer contacts a portion of the fiber bundle (42); An outer sheath (50) of an optical cable contacts at least a portion of a separation layer (52), wherein the separation layer (52) inhibits adhesion between the fiber bundle (42) and the outer sheath (50); The optical fiber cable (40) does not contain grease or greasy substances that come into contact with the optical fiber bundle (42), which are used to fill the gaps in the cable to prevent water from flowing through it.

2. The high-density outdoor optical fiber communication cable according to claim 1, characterized in that, The bonding element is configured as one or more of the following: bonding wire, bonding yarn, film, and tape.

3. The high-density outdoor optical fiber communication cable according to claim 1, characterized in that, The optical fiber cable (40) contains 144 non-tightly wrapped optical fibers (44) and the diameter of the cable is less than 10 mm.

4. The high-density outdoor optical fiber communication cable according to claim 1, characterized in that, The plurality of non-tightly covered optical fibers (44) further include a tightly covered layer, and the optical fiber cable (40) comprises 144 tightly covered optical fibers (44) with a diameter of less than 20 mm.

5. A high-density outdoor optical fiber communication cable according to claim 1, characterized in that, The bonding element is a bonding wire that surrounds the plurality of non-tightly covered optical fibers (44).

6. The high-density outdoor optical fiber communication cable according to claim 1, characterized in that, The separation layer (52) is configured as one or more of the following: glass fiber yarn, aramid yarn, sheath layer, water-swellable tape, film and flexible shell.

7. A high-density outdoor optical fiber communication cable according to claim 1, characterized in that, The separation layer (52) has tensile strength properties.

8. A high-density outdoor optical fiber communication cable according to claim 1, characterized in that, At least one of the fiber bundles (42) is wrapped around the central strength member (46).

9. A high-density outdoor optical fiber communication cable according to claim 1, characterized in that, The optical fiber cable (40) is part of a branch cable.

10. A high-density outdoor optical fiber communication cable according to claim 1, characterized in that, The plurality of the non-tightly clad optical fibers (44) further include a tightly clad layer.

Images