Intermittently bonded tape having intermittent bonds created with a wet-on-wet process

Abstract

Embodiments of the present disclosure relate to an optical fiber ribbon. The optical fiber ribbon includes a plurality of subunits each including a subunit coating surrounding at least two optical fibers arranged adjacent to each other. The subunit coating is made of a first material. A plurality of bonds are intermittently formed between adjacent subunits of the plurality of subunits. The plurality of bonds are made of a second material. The optical fiber ribbon includes a diffusion zone at an interface between each of the plurality of bonds and the subunit coating of each adjacent subunit. Each diffusion zone has a gradient of the second material in the first material. Further, the intermittent bonds can include one or more saddle surfaces formed by intersecting convex and concave curvatures. A method of forming such an optical fiber ribbon is also disclosed.

Description

[0001] Priority application

[0002] This application claims priority to U.S. Provisional Application No. 63 / 072,429, filed August 31, 2020, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure generally relates to optical fibers, and more specifically to optical fiber ribbons in which optical fibers are intermittently joined together along the length of the ribbon. Background Technology

[0004] A single fiber optic cable can contain many optical fibers (in fact, hundreds), and managing the connections between these fibers can be difficult during the installation of a fiber optic cable network. Therefore, the individual parts of the fiber optic cable (such as individual optical fibers, buffer tubes, or ribbons) can be color-coded for identification purposes when making such connections. Additionally, the fiber optic cable can contain fibers arranged in ribbons to allow multiple fibers to be fused together in a single operation. Arranging the fibers in ribbons allows for a larger cable design compared to loosely containing the fibers within the fiber optic cable. Summary of the Invention

[0005] According to one aspect, embodiments of this disclosure relate to an optical fiber ribbon. The optical fiber ribbon includes a plurality of sub-units, each sub-unit comprising a sub-unit coating surrounding at least two optical fibers arranged adjacent to each other. The sub-unit coatings are made of a first material. A plurality of joints are intermittently formed between adjacent sub-units of the plurality of sub-units. The plurality of joints are made of a second material. The optical fiber ribbon includes a diffusion region at the interface between each of the plurality of joints and the sub-unit coating of each adjacent sub-unit. Each diffusion region has a gradient of the second material in the first material.

[0006] According to another aspect, embodiments of this disclosure relate to a method for preparing an optical fiber ribbon. In this method, a plurality of optical fibers are arranged adjacent to each other along the length of the optical fiber ribbon. A coating made of a first material is applied around at least two optical fibers to create a plurality of sub-units. A bonding portion made of a second material is intermittently applied between adjacent sub-units of the plurality of sub-units. The second material diffuses into the first material, forming a diffusion region of the second material in the first material. The first and second materials are then cured.

[0007] According to another aspect, embodiments of this disclosure relate to an optical fiber ribbon. The optical fiber ribbon includes a plurality of sub-units, each sub-unit having a sub-unit coating of at least two optical fibers arranged adjacent to each other along the longitudinal axis of the optical fiber ribbon. The optical fiber ribbon also includes a plurality of joints intermittently formed between adjacent sub-units of the plurality of sub-units. Each of the plurality of joints has a first end, a second end, and a central region positioned along the longitudinal axis between the first end and the second end. At least one of the first end, the second end, or the central region of each joint includes at least one saddle-shaped surface, the at least one saddle-shaped surface including intersecting convex and concave curvatures.

[0008] Additional features and advantages will be set forth in the following detailed description and will be apparent in part from the description or by practice of the embodiments as described in this written specification and its claims, as well as the accompanying drawings.

[0009] It should be understood that the foregoing general description and the following detailed description are merely exemplary and are intended to provide an overview or framework for understanding the nature and features of the claims. Attached Figure Description

[0010] The accompanying drawings are included to provide further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiments and, together with the description, serve to explain the principles and operation of the various embodiments.

[0011] Figure 1 This is a partial perspective view of an intermittently combined fiber optic ribbon according to an exemplary embodiment;

[0012] Figure 2 A partial cross-sectional view depicting the joint between two fiber subunits of an intermittently coupled fiber ribbon according to another exemplary embodiment;

[0013] Figure 3 A top view depicting an intermittent joint of an optical fiber ribbon according to an exemplary embodiment;

[0014] Figure 4 A saddle-shaped surface at the end of an intermittent joint is depicted according to an exemplary embodiment;

[0015] Figure 5 A cross-sectional view of the intermittent joint along the length of the intermittent joint according to another exemplary embodiment;

[0016] Figures 6A to 6C A cross-sectional view depicting the width of an intermittent joint according to an exemplary embodiment;

[0017] Figure 7 The resin depicting the sub-unit coating being pulled into the saddle-shaped surface at the end of the intermittent joint according to an exemplary embodiment;

[0018] Figure 8 This is a flowchart describing a method for preparing an optical fiber ribbon according to an exemplary embodiment;

[0019] Figure 9 Depicts a discrete coating applicator configured to deposit intermittent joints according to an exemplary embodiment;

[0020] Figure 10 Depicts an intermittent joint deposited between sub-units according to an exemplary embodiment;

[0021] Figure 11 Depicting Figure 10 The cross-section of the intermittent joint;

[0022] Figure 12 and Figure 13 Depicting the fracture of the intermittent joint according to an exemplary embodiment; and

[0023] Figure 14 An optical fiber cable comprising intermittently bonded optical fiber ribbons is depicted according to an exemplary embodiment. Detailed Implementation

[0024] Referring generally to the accompanying drawings, various embodiments of an optical fiber ribbon having intermittent bonding regions between subunits and methods for producing such an optical fiber ribbon are provided. As described herein, the optical fiber ribbon according to this disclosure is flexible, allowing the ribbon to be rolled up, curled, folded, etc., from planar configurations typically associated with optical fiber ribbons to more space-saving configurations. In this way, the ribbon can be carried in cables with smaller diameters, and / or the cables can have a higher fiber density ratio (i.e., the fraction of the cross-sectional area filled with optical fibers relative to the external cross-sectional area of ​​the cable). As described below, the optical fiber ribbon comprises a plurality of optical fiber subunits having two or more optical fibers intermittently bonded together along the length of the optical fiber ribbon. The intermittent bonding regions to which the subunit coatings are applied are not cured in a “wet-on-wet” process, which allows the intermittent bonding material to diffuse into the subunit coatings. The “wet-on-wet” process not only provides a more cohesive connection between the subunits but also improves process efficiency by promoting the “wetting” of the bonding material into the subunit coatings and allowing the intermittent bonding regions and subunit coatings to be bonded in a single step. Each of these exemplary embodiments will now be described in more detail, and these exemplary embodiments are provided in an illustrative manner rather than in a limiting manner. These and other aspects and advantages will be discussed with respect to the embodiments provided herein.

[0025] Figure 1An exemplary embodiment of an optical fiber strip 10 according to this disclosure is depicted. The optical fiber strip 10 includes a plurality of optical fibers 12. In the depicted embodiment, the optical fiber strip 10 includes twelve optical fibers 12. In embodiments, the number of optical fibers 12 included in the optical fiber strip 10 varies from, for example, four to thirty-six. The optical fibers 12 are divided into subunits 14 having two or more optical fibers 12. Figure 1 In the illustrated embodiment, each subunit 14 includes two optical fibers 12. Therefore, for example, in... Figure 1 In this embodiment, the optical fibers 12 are arranged into six sub-units 14. The optical fibers 12 of each sub-unit 14 are coupled to each other along the length of the optical fiber strip 10, but the sub-units 14 are only coupled intermittently along the length of the optical fiber strip 10.

[0026] Figure 1 Intermittent joints 16 are depicted interlacing along the length of subunit 14. The intermittent joints 16 between two adjacent subunits 14 may be spaced, for example, from 10 mm to 1000 mm. As will be discussed more fully below, the intermittent joints 16 are applied in a "wet-on-wet" application process, which results in diffusion of the material of the intermittent joints 16 with the material of the optical fibers 12 connecting the subunits 14. In an embodiment, the fiber ribbon 10 has a first configuration in which the optical fibers 12 are arranged in substantially planar rows, which helps organize the optical fibers 12 for large-scale fusion splicing. Furthermore, as will be described more fully below, the subunits 14 can also be rolled, coiled, or folded into non-planar configurations (e.g., circular or spiral) to save space within the optical fiber cable, particularly a cable with a circular cross-section. The optical fibers 12 of the fiber ribbon 10 can be converted from the first configuration to a second configuration because the subunits 14 are held together intermittently along the length of the optical fiber 10 only by the intermittent joints 16.

[0027] In conventional fiber ribbons, each fiber is bonded to one or more adjacent fibers along the entire length of the ribbon to hold them in a planar configuration. According to this disclosure, however, fiber subunits 14 are intermittently bonded along the length of the fiber ribbon 10, such that the fibers 12 are non-rigidly held in a planar configuration. Between the intermittent bonding portions 16, subunits 14 are not bonded to each other along their length. In this way, the fiber ribbon 10 provides the advantages of ribbon-like fiber organization and large-scale splicing, while also allowing the fiber ribbon 10 to be curled, rolled up, or folded across its width for more compact cable designs.

[0028] Figure 2 The cross-section of the intermittent joint 16 between subunits 14 is depicted. Figure 2As can be seen in the cross-section, each optical fiber 12 includes a core 18 disposed substantially at the center of the fiber 12. Surrounding the core 18 is a cladding 20. Optical signals propagate along the core 18 via internal reflections from the cladding 20. In an embodiment, the cladding 20 is surrounded by a primary coating 22, which may in turn be surrounded by a secondary coating 24. The primary coating 22 and the secondary coating 24 protect the core 18 and the cladding 20. Additionally, in an embodiment, the secondary coating 24 is surrounded by a color layer 26. The color layer 26 can be used to arrange the optical fibers 12 in a color-coded pattern. For example, a convention for color-coding the optical fibers 12 is to arrange them according to the following color sequence: blue, orange, green, brown, stone gray, white, red, black, yellow, purple, rose, and light green (relative to...). Figure 1 (The orientation is from top left to bottom right). In embodiments containing more than twelve optical fibers 12, the color pattern may repeat. Color coding of the optical fibers 12 in this way helps in organization and identification of specific optical fibers 12 during connection or splicing.

[0029] exist Figure 2 As can be seen, the optical fibers 12 of each subunit 14 are connected by a subunit coating 28. The subunit coatings 28 connect the optical fibers 12 of each subunit 14 along their length. In an embodiment, the optical fibers 12 in each subunit 14 can contact or separate a space not exceeding one and a half times the diameter of the optical fibers 12 within the strip 10. Additionally, in an embodiment, the gap between adjacent subunits 14 can be from 5 μm to 100 μm. At various intervals along the length of the fiber strip 10, intermittent joints 16 are provided in the gaps between adjacent subunits 14. The intermittent joints 16 are applied before the subunit coating 28 is cured, and the intermittent joints 16 and the subunit coating 28 are cured together. Therefore, when the intermittent joint material 16 is applied to the fiber strip 10, both the intermittent joint material 16 and the subunit coating 28 material are wet, i.e., uncured. Figure 2 As shown, this "wet-on-wet" application produces the material of the intermittent joint 16 into the diffusion region 30 of the material of the sub-unit coating 28, and vice versa.

[0030] Outside the diffusion region 30, the material of the intermittent bonding portion 16 has a first characteristic, and the material of the sub-unit coating 28 has a second characteristic. Within the diffusion region 30, there exists a gradient between the first and second characteristics. In an embodiment, the gradient of characteristics includes at least one of color, Young's modulus, surface friction, ultimate tear strength, or elongation at break. Therefore, for example, the material of the intermittent bonding portion 16 may have a first Young's modulus, and the material of the sub-unit coating 28 may have a second Young's modulus greater than the first Young's modulus. In the diffusion region 30, the Young's modulus decreases from the second Young's modulus in the region of the sub-unit coating 28 just outside the diffusion region 30 to the first Young's modulus 30 in the region of the intermittent bonding portion 16 just outside the diffusion region. In an embodiment, the gradient of characteristics in the diffusion region 30 may be linear, exponential, geometric, etc. In an embodiment, the diffusion region 30 has a thickness of 2 μm to 50 μm, particularly 5 μm to 15 μm.

[0031] In embodiments, the formation of the diffusion region 30 is facilitated by using a miscible resin for both the intermittent bonding portion 16 material and the sub-unit coating 28 material. By using a miscible resin, the material of the intermittent bonding portion 16 will more easily mix with the material of the sub-unit coating 28. Additionally, besides miscibility, a relatively thick diffusion region 30 can be produced using other material properties (such as reduced coating viscosity) to facilitate the mixing of the intermittent bonding portion 16 and the sub-unit coating 28 materials. In embodiments, the resin of the intermittent bonding portion 16 may be immiscible with, but at least insoluble in, the resin of the sub-unit coating 28, and in some embodiments, the resin of the intermittent bonding portion 16 is at least slightly soluble in the resin of the sub-unit coating 28. In embodiments, the diffusion region 30 may also be characterized as providing a region of molecular entanglement between the material of the intermittent bonding portion 16 and the material of the sub-unit coating 28; for example, the diffusion region 30 may provide an interface between the intermittent bonding portion 16 and the sub-unit coating 28 in which mechanical bonding occurs, for example, due to micromechanical surface fluctuations of the intermittent bonding portion 16 and the sub-unit coating 28.

[0032] Because the material of the intermittent joint 16 is mixed or entangled with the material of the subunit coating 28, significant bond / cohesive strength is provided at the location of the intermittent joint 16. During the separation of the optical fiber 12 or the subunit 14, any damage will occur either within the material (depending on the cross-sectional area and cohesive strength of the material) or at the interface between the subunit coating 28 and the color layer 26.

[0033] The diffusion region 30 distinguishes the currently disclosed intermittently bonded fiber ribbon 10 from other fiber ribbons utilizing a "wet-on-dry" deposition technique. In this technique, the coating with the bonding material is at least partially or completely cured. In this way, the "wet" bonding material does not have the opportunity to diffuse into or mix with the "dry" coating material to create a diffusion region with a gradient of properties between those of the bonding material and those of the coating material.

[0034] Furthermore, using the currently disclosed "wet-on-wet" process, the shape of the intermittent joint 16 also distinguishes the fiber ribbon 10 from other conventional fiber ribbons. Now refer to... Figure 3 A top view of the intermittent joint 16 between subunits 14 is shown. The intermittent joint 16 has a generally rhomboid profile, wherein the narrow first end 32 of the intermittent joint 16 widens to its maximum width in the central region 34 of the intermittent joint 16 and narrows again at the second end 36. Additionally, the surface of the intermittent joint 16 includes a plurality of saddle-shaped surfaces 38. As used herein, a "saddle-shaped surface" refers to a surface having intersecting convex and concave curvatures. In this case, the saddle-shaped surface may include at least one point ("saddle point") where the slopes in the orthogonal directions are all zero, for example, relative minimum and relative maximum values ​​intersect at a cross axis. In an embodiment, the intermittent joint 16 includes saddle-shaped surfaces 38 located at the first end 32, the second end 36, or both the first end 32 and the second end 36. Figure 4 As can be seen in the detailed diagram, the first end 32 has a concave curvature, wherein the edge portion 33 adjacent to the optical fiber 12 extends through the middle portion 35. However, in Figure 5 In the longitudinal sectional view, it can be seen that the middle portion 35 extends through the first (upper) surface 40 and the second (lower) surface 42 to define a convex curvature. Therefore, in contrast to the intersecting concave curvature (which would define a bowl shape) and the intersecting convex curvature (which would define a dome shape), the first end portion 32 defines a saddle-shaped surface 38. In the embodiment, the second end portion 36 defines the saddle-shaped surface 38 in the same manner as the first end portion 32, and... Figure 4 The depiction of the first end 32 can also be considered to apply to the second end 36.

[0035] from Figure 5As can be seen from the longitudinal cross-sectional view shown, the first surface 40 and the second surface 42 define a varying thickness along the length of the intermittent joint 16. Specifically, the thickness T1 at the edge portion 33 increases as it moves from the first end 32 toward the central region 34, and decreases as it moves from the central region 34 toward the second end 36. Similarly, the thickness T2 in the intermediate portion 35 increases as it moves from the first end 32 toward the central region 34, and decreases as it moves from the central region 34 toward the second end 36. In this way, the first surface 40 and the second surface 42 each define a convex curvature extending longitudinally along the length of the intermittent joint 16. However, as... Figures 6A to 6C As shown in the transverse cross-section, the first surface 40 and the second surface 42 also define a concave curvature that extends laterally across the width of the intermittent joint 16.

[0036] First refer to Figure 6A The image depicts a transverse cross-section taken near the first end 32. It can be seen that the edge portion 33 adjacent to the optical fiber 12 on the first surface 40 is higher than the middle portion 35, and the edge portion 33 adjacent to the optical fiber 12 on the second surface 42 is lower than the middle portion 35. Figure 6B Depicts the transverse cross-sections taken at 34 points in the central region. (and) Figure 6A In comparison, the thickness T2 of the intermittent joint 16 is... Figure 6B The cross-section is increased to further demonstrate the longitudinal convex curvature (thickness T1 will also increase, but for clarity, only one thickness is shown). Additionally, in Figure 6B In the middle, the edge portions 33 adjacent to the optical fiber 12 are respectively higher than the middle portion 35 of the first surface 40 and lower than the middle portion 35 of the second surface 42. Therefore, the transverse cross-section shows the concave curvature across the width of the intermittent joint 16. Figure 6C The image depicts a transverse cross-section taken near the second end 36. Similarly, it can be seen that the edge portion 33 adjacent to the optical fiber 12 is higher than the middle portion 35 of the first surface 40 and lower than the middle portion 35 of the second surface 42.

[0037] Therefore, in an embodiment, the intermittent joint 16 can be described as having a variable lateral thickness, wherein the maximum lateral thickness is located at the edge portion 33 adjacent to the optical fiber 12 of the subunit 14, and the minimum lateral thickness is located at the middle portion 35 near the midpoint between the optical fibers 12 of the subunit 14. Additionally, in an embodiment, the intermittent joint 16 can be described as having a variable longitudinal thickness, wherein the minimum longitudinal thickness is located at the longitudinal ends 32, 36 of the intermittent joint 16, and the maximum longitudinal thickness is located near the midpoint in the central region 34 between the longitudinal ends 32, 36 of the intermittent joint 16. Furthermore, the variable thickness profile of the intermittent joint 16 can be described as a thin / thick / thin profile, wherein the surfaces 40, 42 will be concave at each point around the plane bisecting the intermittent joint 16 in the longitudinal (i.e., longitudinal) direction.

[0038] Additionally, in the implementation method and referenced Figure 5 The intermittent joint 16 can be described as having a maximum longitudinal length L1 at the edge portion 33 near the sub-unit of the optical fiber 12, and a minimum longitudinal length L2 at the middle portion 35 between the edge portions 33. Additionally, in the embodiment and referring to... Figure 3 The intermittent joint 16 can be described as having a minimum lateral width at the longitudinal ends 32, 36 of the intermittent joint 16 and a maximum lateral width in the central region 34 between the longitudinal ends 32, 36 of the longitudinal joint 16.

[0039] Due to the wet-on-wet application process, the material of the sub-unit coating 28 is drawn into the intermittent joint 16 at the ends 32 and 36, such as Figure 7 As shown. Specifically, in addition to the diffusion zone 30 generated at the interface between the intermittent joint 16 and the sub-unit coating 28, the sub-unit coating 28 is also drawn into the gaps between the sub-units 28, improving mixing at the saddle-shaped surface 38 at the ends 32, 36. This mixing... Figure 7 The diagram is illustrated by using dots with a first weight in the intermittent joint 16 and the sub-unit coating 28 material, and using dots with a heavier weight in the area where the sub-unit coating 28 material is pulled into the intermittent joint 16 material.

[0040] Figure 8 A process flow diagram of a method 100 for fabricating an optical fiber ribbon 10 according to this disclosure is shown. In a first step 110, optical fibers 12 are arranged adjacent to each other. The optical fibers 12 may be arranged in a planar manner to process and deposit the subunit coating 28 and the intermittent joint 16. In a second step 120, the optical fibers 12 are moved by a continuous applicator that applies material for the subunit coating 28. The material for the subunit coating 28 is applied in such a way that at least two sets of optical fibers 12 are connected to the optical fiber subunits 14.

[0041] In this embodiment, the material used for coating 16 is a curable formulation (e.g., a UV-curable formulation) comprising one or more urethane acrylate oligomers, one or more epoxy acrylate oligomers, one or more acrylate monomers, one or more photoinitiators, antioxidants, and / or other typical processing additives. Additionally, in this embodiment, the material used for subunit coating 28 has a Young's modulus of 25 MPa to 1300 MPa, an elongation at break of 10% to 200%, a specific gravity of 0.9 to 1.2, a tensile strength of 10 MPa to 40 MPa, and / or a viscosity in the range of 100 cP to 8000 cP at 25°C. Furthermore, in this embodiment, the material used for intermittent bonding portion 16 has a glass transition temperature of 30°C to 100°C.

[0042] The sub-unit coating 28 is applied in a continuous manner to provide a longitudinally continuous coating 28 for two (or more) optical fibers 12 in the sub-unit 14. (Reference) Figure 2 It can be seen that the sub-unit coating 28 has a variable thickness around the optical fiber 12. In this embodiment, the sub-unit coating 28 is designed to have a minimum thickness T ranging from 2 μm to 20 μm. 28 (like Figure 2 The sub-unit coating 28 is applied in the manner shown. Minimum thickness T 28 The location is approximately around or near the fiber 12, and the location is orthogonal to the plane defined by the adjacent fiber 12 of the sub-unit 14.

[0043] Before curing the sub-unit coating 28, intermittent bonding portions 16 are deposited between the sub-units 14 in a third step 130. In an embodiment, the material for the intermittent bonding portions 16 is applied dropwise. Specifically, the intermittent bonding portions 16 can be deposited using a discrete coating applicator, which sprays droplets of liquid material for the intermittent bonding portions 16 onto the uncured and still wet sub-unit coating 28. As described above, the sub-units 14 are spaced apart such that a gap of 5 μm to 100 μm is provided between the sub-units 14, and the intermittent bonding portions 16 bridge the gaps between the sub-units 14. The shape of the intermittent bonding portions 16 can be affected by the viscosity of the deposited material; for example, lower viscosity can improve mixing and increase the thickness of the diffusion zone, and also cause the droplets to diffuse more. Therefore, in an embodiment, the discrete coating applicator can be operated in conjunction with a heating element to adjust the viscosity to affect the shape of the intermittent bonding portions 16. Additionally, the discrete coating applicator can be adjusted to change the droplet volume to increase or decrease the length or width of the intermittent bonding portions 16. In an implementation, for example when the fiber optic ribbon 10 is installed, the volume, length, and / or width of the manipulating intermittent joint 16 can affect the tear strength required for splitting the intermittent joint 16.

[0044] Figure 9 One embodiment of a discrete coating applicator 44 is depicted. The applicator 44 includes a nozzle 46 having an orifice 48 through which droplets 50 of material for intermittent joints 16 are ejected. The droplets 50 can be ejected using a plunger actuated by a controller. In this embodiment, the applicator 44 is movable across the width of a strip 10 to deposit each intermittent joint 16. In other embodiments, multiple applicators 44 may be provided to deposit droplets 50 between specific subunits 14. For example, a fiber strip 10 having twelve optical fibers 12 would have six subunits 14 with five gaps between them, which are filled with droplets 50 to form intermittent joints 16. Thus, five applicators 44 may be provided across the width of the fiber strip 10 to deposit the intermittent joints 16. In practice, the optical fibers 12 will move along a processing line, and one or more applicators 44 will be located at stations on the processing line. Thus, one or more applicators 44 will apply droplets 50 onto the moving optical fibers 12.

[0045] In this embodiment, the material of the intermittent joint 16 is a curable formulation (e.g., a UV-curable formulation) comprising one or more urethane acrylate oligomers, one or more epoxy acrylate oligomers, one or more acrylate monomers, one or more photoinitiators, antioxidants, and / or other typical processing additives. Additionally, in this embodiment, the material for the intermittent joint 16 has a Young's modulus of 25 MPa to 1300 MPa, an elongation at break of 100% to 500%, preferably 100% to 200%, a specific gravity of 0.9 to 1.2, a tensile strength of 10 MPa to 40 MPa, and / or a viscosity in the range of 100 cP to 8000 cP at 25°C. Furthermore, in this embodiment, the material for the intermittent joint 16 has a glass transition temperature of 20°C to 100°C.

[0046] Return to Figure 8 In the fourth step 140, the sub-unit coating 28 and the intermittent bonding portion 16 are cured together. In embodiments, curing may involve applying various forms of radiation, such as ultraviolet (UV) light, visible light, and infrared (IR) radiation. Alternatively, curing may involve applying heat or water vapor. Similar to the applicator 44, the optical fiber 12 will move generally along the processing line, and therefore, curing occurs in a chamber at another station on the processing line, for example, downstream of the applicator 44 station.

[0047] Figure 10 An intermittent joint 16 between adjacent subunits 14 of the optical fiber ribbon 10 prepared using the method 100 described above is depicted. A saddle-shaped surface 38 can be seen at the ends 32 and 36 of the intermittent joint 16. Furthermore, in... Figure 10As can be seen, the sub-unit coating 28 is pulled into the ends 32 and 36 of the intermittent joint 16 at the saddle-shaped surface 38. Figure 11 Describing the cross Figure 10 The width of subunit 14 shown is the cross section. Figure 11 The outline of the intermittent joint 16 is shown, wherein the thickness decreases at the midpoint of the intermittent joint 16 between the sub-units 14 compared to the thickness of the adjacent sub-units 14. Additionally, Figure 11 Depict the diffusion zone 30 between the sub-unit coating 28 and the intermittent joint 16.

[0048] Figure 12 and Figure 13 Depict the different fractures of the intermittent joint 16 when it is pulled apart. Figure 12 The cohesive failure of the intermittent joint 16 is described. That is, the failure point is located within the intermittent joint 16 itself, rather than at the interface between the subunit coating 28 and the intermittent joint 16. In an embodiment, as measured by a T-peel test, cohesive failure of the intermittent joint 16 occurs under a force of 0.2 gf to 75 gf, preferably 1 gf to 35 gf, in which the ends of adjacent subunits 14 are pulled in opposite directions until the intermittent joint 16 breaks (see, for example, Method G5 for ribbon tear (separability) in IEC 60794-1-23:2019). As described above, the intermittent joint 16 allows the subunit 14 to operate like the fiber ribbon 10, while also providing the fiber density advantages of loose-tube fiber. When the fiber 12 is installed, the subunit 14 may need to be separated to properly route the fiber. Therefore, the breakage of the intermittent joint 16 is incorporated into the design of the intermittent joint 16. Furthermore, as mentioned above, the length and / or width of the intermittent joint can be manipulated to provide greater or lower fracture strength. Additionally, the material of the intermittent joint 16 and / or the sub-unit coating 28 can be manipulated to provide the desired fracture strength. In that respect, Figure 13 The diagram depicts bond failure, where the intermittent joint 16 separates from the subunit 14. In reality, considering the diffusion zone 30 where the materials of the subunit coating 28 and the intermittent joint 16 are mixed, the cracking is likely due to a combination of bond and cohesive failure.

[0049] As mentioned above, the intermittently combined fiber optic strips 10 allow for smaller cable diameters and / or higher fill ratios. Figure 14 An exemplary embodiment of an optical fiber cable or buffer tube 50 comprising intermittently bonded optical fiber ribbons 10 is depicted. The optical fiber cable 50 has a cable sheath 52 with an inner surface 54 and an outer surface 56. The inner surface 54 defines a central hole 58 containing the optical fiber ribbons 10. The central hole 58 has a diameter that is the inner diameter ID of the cable sheath 52. Figure 14As shown, the central hole 58 is also filled with a filler material 60, which may be, for example, a strength component (such as aramid, cotton, basalt and / or glass yarn), a water-blocking gel or powder and / or a flame-retardant material.

[0050] Typically, the inner diameter of the cable sheath must be at least as large as the width of the fiber optic ribbon in a planar configuration to accommodate the entire ribbon. However, this means that a large portion of the internal space of the fiber optic sheath is left unfilled. According to this disclosure, a smaller cable diameter and / or a higher fiber density ratio can be achieved by reducing the maximum cross-sectional dimension of the fiber optic ribbon 10. In particular, the inner diameter ID of the cable 50 can be smaller by winding, coiling, or folding the fiber optic ribbon 10 into, for example, a circular or spiral shape, thus providing a smaller and more densely packed cable design overall. Nevertheless, the fiber optic ribbon 10 can still be removed from the fiber optic cable 50, flattened into a planar configuration, and then easily spliced ​​at scale like a conventional fiber optic ribbon. For simplicity, a single fiber optic ribbon 10 is shown in the fiber optic cable 50. However, in other embodiments, the fiber optic cable 50 may contain dozens or hundreds of fiber optic ribbons 10. Additionally, such fiber optic ribbons 10 may be arranged in one or more buffer tubes within the central hole 58 of the cable sheath 52.

[0051] Unless otherwise expressly stated, no method described herein is intended to be construed as requiring its steps to be performed in a particular order. Therefore, no particular order is intended to be inferred unless a method claim actually describes the order in which the steps are to be followed or unless otherwise specified in the claims or description that the steps will be limited to a particular order. Furthermore, as used herein, the article “a” is intended to include one or more components or elements, and is not intended to be construed as referring to only one.

[0052] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations, and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to those skilled in the art, the disclosed embodiments should be interpreted as encompassing all contents within the scope of the appended claims and their equivalents.

Claims

1. An optical fiber ribbon, comprising: Multiple sub-units, each of the multiple sub-units including at least two optical fibers arranged adjacent to each other and a sub-unit coating surrounding the at least two optical fibers, the sub-unit coating comprising a first material; Multiple joints are intermittently formed between adjacent sub-units of the multiple sub-units, and the multiple joints contain a second material; as well as A diffusion region, the diffusion region being located at the interface between each of the plurality of joints and the coating of each adjacent subunit; In the diffusion region, the second material diffuses into the first material.

2. The fiber ribbon as claimed in claim 1, wherein each diffusion region has a thickness of 2 μm to 50 μm.

3. The optical fiber ribbon of claim 1, wherein the second material comprises at least one of the following: a Young's modulus of 25 MPa to 1300 MPa, an elongation at break of 100% to 200%, a specific gravity of 0.9 to 1.2, a tensile strength of 10 MPa to 40 MPa, a viscosity in the range of 100 cP to 8000 cP at 25°C, or a glass transition temperature of 20°C to 100°C.

4. The optical fiber ribbon of claim 1, wherein the first material comprises a Young's modulus of 25 MPa to 1300 MPa and an elongation at break of 10% to 200%. 、 At least one of the following: a specific gravity of 0.9 to 1.2, a tensile strength of 10 MPa to 40 MPa, a viscosity of 100 cP to 8000 cP at 25°C, or a glass transition temperature of 30°C to 100°C.

5. The optical fiber ribbon of claim 1, wherein the first material is miscible with the second material.

6. The optical fiber ribbon of claim 1, wherein each of the plurality of joints includes at least one saddle-shaped surface.

7. The fiber optic ribbon of claim 6, wherein each joint includes a first end, a second end, and a central region disposed between the first end and the second end, and wherein the at least one saddle-shaped surface includes a first saddle-shaped surface located at the first end of the joint.

8. The fiber ribbon of claim 7, wherein the sub-unit coating is drawn into the first saddle-shaped surface.

9. The optical fiber ribbon of claim 7, wherein the at least one saddle-shaped surface includes a second saddle-shaped surface located at the second end of the joint or at the central region of the joint.

10. The fiber ribbon of claim 1, wherein each of the plurality of joints breaks under a force of 0.2 gf to 75 gf, as measured by a T-peel test.

11. The optical fiber ribbon of claim 1, wherein the first material comprises a first property and the second material comprises a second property and wherein the diffusion region comprises a gradient between the first property and the second property.

12. A method for preparing optical fiber ribbon, comprising: Multiple optical fibers are arranged so that they are adjacent to each other along the length of the fiber band; A coating containing a first material is applied around a group consisting of at least two optical fibers to produce multiple sub-units; A bonding portion containing a second material is intermittently applied between adjacent sub-units of the plurality of sub-units, wherein the second material diffuses into the first material, creating a diffusion region of the second material in the first material; The first material and the second material are cured.

13. The method of claim 12, wherein the step of intermittently applying the bonding portion further comprises depositing droplets of the second material between adjacent sub-units of the plurality of sub-units.

14. The method of claim 12, wherein the second material is miscible with the first material.

15. The method of claim 12, wherein the diffusion region has a thickness of 2 µm to 50 µm.

16. The method of claim 12, wherein the first material comprises a first property and the second material comprises a second property and wherein the diffusion region comprises a gradient between the first property and the second property.

17. The method of claim 16, wherein the first characteristic and the second characteristic each include at least one of color, Young's modulus, surface friction, ultimate tear strength, or elongation at break.

18. The method of claim 12, wherein each of the joints comprises at least one saddle-shaped surface, and wherein the step of intermittently applying the joints pulls the first material of the coating into the saddle-shaped surface.

19. An optical fiber ribbon, comprising: Multiple sub-units, each of the multiple sub-units comprising at least two optical fibers arranged adjacent to each other along the longitudinal axis of the optical fiber strip and a sub-unit coating surrounding the at least two optical fibers; as well as Multiple joints are formed intermittently between adjacent sub-units of the multiple sub-units; Each of the plurality of joints includes a first end, a second end, and a central region positioned along a longitudinal axis between the first end and the second end; and At least one of the first end, the second end, or the central region of each joint includes at least one saddle-shaped surface, the at least one saddle-shaped surface including intersecting convex curvature and concave curvature. The sub-unit coating comprises a first material, each of the plurality of joints comprises a second material, and the fiber ribbon further includes a diffusion region at the interface between each of the plurality of joints and the sub-unit coating of the adjacent sub-unit in the plurality of sub-units. In the diffusion region, the second material diffuses into the first material.

20. The fiber ribbon of claim 19, wherein each joint includes a variable lateral thickness between adjacent subunits, and wherein the maximum lateral thickness is located in the fiber adjacent to the subunit, and the minimum lateral thickness is located near the midpoint between adjacent subunits.

21. The fiber optic ribbon of claim 20, wherein each joint includes a variable longitudinal thickness between the first end and the second end, and wherein the minimum longitudinal thickness is located at at least one of the first end or the second end, and the maximum longitudinal thickness is located near the central region.

22. The fiber optic ribbon of claim 19, wherein each joint includes a maximum longitudinal length between the first end and the second end near the edge portion of the subunit and a minimum longitudinal length near the midpoint between the edge portions.

23. The fiber optic ribbon of claim 22, wherein each joint includes a minimum lateral width at at least one of the first end or the second end and a maximum lateral width at the central region.

24. The optical fiber ribbon of claim 19, wherein the first material comprises a first property and the second material comprises a second property and wherein the diffusion region comprises a gradient between the first property and the second property.

25. The fiber ribbon of claim 19, wherein the at least one saddle-shaped surface includes a first saddle-shaped surface at the first end, and wherein the sub-unit coating is drawn into the first saddle-shaped surface.

26. The fiber ribbon of claim 19, wherein the diffusion region has a thickness of 2 µm to 50 µm.

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