High-density optical cable

Abstract

A high-density optical cable. The optical cable includes multiple deformable buffer tubes. Each of the multiple deformable buffer tubes includes one or more flexible strips, and each of the one or more flexible strips includes multiple optical fibers. The axial cross-section of the deformable buffer tube including the one or more flexible strips has an irregular shape. An outer sleeve surrounds the multiple deformable buffer tubes. In another example, the optical cable includes multiple deformable buffer tubes and an outer sleeve surrounding the multiple deformable buffer tubes. Each of the multiple deformable buffer tubes includes a single flexible strip, and the single flexible strip includes multiple optical fibers. Each deformable buffer tube also includes an axial cross-section of the deformable buffer tube, which includes a single flexible strip. The axial cross-section has an irregular shape.

Description

[0001] This application is a divisional application of the application filed on June 28, 2019, with application number 201910577250.4 and invention title "High-Density Optical Cable". Technical Field

[0002] This invention generally relates to optical cables, and in certain embodiments to high-density optical cables. Background Technology

[0003] Optical fiber is a glass strand with a very small diameter, capable of transmitting optical signals over extremely long distances at very high speeds, and exhibiting relatively low signal loss compared to standard copper wire networks. Therefore, optical fiber is widely used in long-distance communication and has replaced other technologies such as satellite communication and standard wired communication. Besides long-distance communication, optical fiber is also used in many applications such as medicine, aviation, and computer data servers.

[0004] There is a growing need in many applications for fiber optic cables capable of transmitting high data rates in a minimal space footprint. This demand is evident, for example, in data servers where space is a critical constraint for fiber optics. In particular, data servers are handling increasingly larger volumes of data, necessitating increased connectivity. However, the maximum size of fiber optic cables is limited by the size of the conduits they must pass through. Squeezing conventional fiber optic cables through conduits is not a viable option. This is because while conventional fiber optics can transmit more data than copper wires, they are also more susceptible to damage during installation. The properties of the fiber optic cable within the cable are highly sensitive to bending, buckling, or compressive stress. Excessive compressive stress during manufacturing, installation, or repair can adversely affect the mechanical and optical properties of conventional fiber optics.

[0005] Alternatively, changing the size of the pipes (especially in existing equipment) can be extremely expensive. Summary of the Invention

[0006] According to an embodiment of the present invention, the optical cable includes a plurality of deformable buffer tubes. Each of the plurality of deformable buffer tubes includes a plurality of flexible ribbons, and each flexible ribbon includes a plurality of optical fibers. Each of the plurality of deformable buffer tubes has a non-circular cross-section. An outer jacket surrounds the plurality of deformable buffer tubes.

[0007] According to an optional embodiment of the invention, the optical cable includes a central strength member and a plurality of buffer tubes arranged around the central strength member, wherein each of the plurality of buffer tubes includes a buffer tube jacket surrounding a plurality of flexible strips. The buffer tube jacket includes a first deformable material that can be plastically deformed. Each flexible strip includes a plurality of optical fibers. An outer jacket surrounds the plurality of buffer tubes.

[0008] According to an optional embodiment of the invention, the optical cable includes a rigid strength member and a deformable upper jacket surrounding the rigid strength member. A plurality of buffer tubes are arranged around the rigid strength member. Each of the plurality of buffer tubes includes a plurality of strips, and each strip includes a plurality of optical fibers. Each of the plurality of buffer tubes includes a first compression modulus, and the rigid strength member having the deformable upper jacket includes a second compression modulus. The ratio of the first modulus to the second modulus is approximately 1:1 to 1:20. An outer jacket surrounds the plurality of buffer tubes.

[0009] According to another embodiment, the optical cable includes a plurality of deformable buffer tubes and an outer jacket surrounding the plurality of deformable buffer tubes. Each of the plurality of deformable buffer tubes includes a single flexible strip, and the single flexible strip includes multiple optical fibers. Each deformable buffer tube also includes an axial cross-section of the deformable buffer tube, which includes the single flexible strip. The axial cross-section includes an irregular shape.

[0010] According to another embodiment, the optical cable includes a central strength member, a plurality of buffer tubes arranged around the central strength member, and an outer jacket surrounding the plurality of buffer tubes. Each of the plurality of buffer tubes includes a buffer tube jacket surrounding a single flexible strip. The buffer tube jacket includes a first deformable material that can be plastically deformed. Each single flexible strip includes a plurality of optical fibers and a first longitudinal length. For each single flexible strip, each of the plurality of optical fibers is attached to an adjacent optical fiber of the plurality of optical fibers along a bonding region including a second longitudinal length less than the first longitudinal length.

[0011] According to another embodiment, the optical cable includes a rigid strength member, a deformable upper jacket surrounding the rigid strength member, a plurality of buffer tubes arranged around the rigid strength member, and an outer jacket surrounding the plurality of buffer tubes. Each of the plurality of buffer tubes includes a single strip, and the single strip includes a plurality of optical fibers. Each of the plurality of buffer tubes including corresponding strips includes a first compression modulus. The rigid strength member having the deformable upper jacket includes a second compression modulus. The ratio of the first compression modulus to the second compression modulus is approximately 1:1 to 1:20. Attached Figure Description

[0012] To gain a more complete understanding of the invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0013] Figure 1 A traditional optical cable is shown;

[0014] Figures 2A-2E An optical cable according to an embodiment of the present invention is shown, wherein... Figure 2A A cross-sectional view of the optical cable is shown. Figure 2B A projection diagram of the fiber optic array is shown. Figure 2C It shows Figure 2B The corresponding cross-sectional area of ​​the fiber array shown. Figure 2D A flexible strip formed using an optical fiber array is shown, and Figure 2E A deformable buffer tube formed using multiple flexible strips is shown.

[0015] Figure 3 Another embodiment of the invention is shown, wherein there is no upper jacket surrounding the central strength member;

[0016] Figures 4A to 4B Another embodiment of the invention is shown, which has an additional deformable upper jacket surrounding the central strength member;

[0017] Figure 5A The relationship between the tensile modulus of different upper jacket materials and temperature is shown;

[0018] Figure 5B The shrinkage stress as a function of temperature is shown for different upper jacket materials;

[0019] Figure 5C The compressive modulus is shown based on the slope of the load-deformation curve before the yield point;

[0020] Figure 5D A table summarizing the results after compression testing of the central strength member is shown;

[0021] Figure 5E A table comparing the compression test results from the tested central strength member with those from the buffer tube is shown;

[0022] Figures 6A to 6C An exemplary implementation of an optical cable is shown, wherein Figure 6A The diagram shows the cross-sectional design of the optical cable before compression. Figure 6B The corresponding projection diagram is shown. Figure 6C A cross-sectional view of the compressed optical cable is shown;

[0023] Figures 7A to 7B A specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 7A A cross-sectional view of the optical cable before compression is shown. Figure 7B The corresponding projection diagram is shown;

[0024] Figures 8A to 8B A specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 8A A cross-sectional view of the optical cable before compression is shown. Figure 8B The corresponding projection diagram is shown;

[0025] Figures 9A to 9BA specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 9A A cross-sectional view of the optical cable before compression is shown. Figure 9B The corresponding projection diagram is shown;

[0026] Figures 10A to 10B A specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 10A A cross-sectional view of the optical cable before compression is shown. Figure 10B The corresponding projection diagram is shown;

[0027] Figures 11A to 11B A specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 11A A cross-sectional view of the optical cable before compression is shown. Figure 11B The corresponding projection diagram is shown;

[0028] Figure 12 A general embodiment is shown, illustrating a combination of features described in various embodiments of the invention;

[0029] Figures 13A to 13B This is a table summarizing examples of different optical cable designs according to various embodiments of the present invention;

[0030] Figure 14 A deformable buffer tube formed using a single flexible strip is shown, and it can be used with optical cables according to embodiments of the present invention;

[0031] Figure 15 Another embodiment of the invention is shown, which has an additional deformable upper jacket around a central strength member and includes a plurality of deformable buffer tubes, each formed using a single flexible strip.

[0032] Figure 16 Another embodiment of the invention is shown, which has an additional deformable upper jacket surrounding a central strength member and includes a plurality of deformable buffer tubes, each formed using a single flexible strip; and

[0033] Figure 17 Further general embodiments are shown, which include multiple deformable buffer tubes, each formed using a single flexible strip, and combinations of features described in various embodiments of the invention are shown. Detailed Implementation

[0034] The manufacture and use of the currently preferred embodiments are discussed in detail below. However, it should be understood that the present invention provides many applicable inventive concepts that can be implemented in various specific contexts. The specific embodiments discussed are merely illustrative of specific ways of manufacturing and using the invention and do not limit the scope of the invention.

[0035] The invention will be described with reference to exemplary embodiments in the specific context (i.e., optical cable designs with high density per unit cross-sectional area of ​​optical fibers).

[0036] First, we will explain traditional optical cables. Then, we will discuss the use of… Figures 2A to 2E A structural diagram of an optical cable design in one embodiment is shown. Next, we will use... Figures 5A to 5D To illustrate the experimental results that form the basis for selecting materials used in various embodiments of the invention. Then, the experimental results will be used... Figure 3 To Figure 4 and Figure 6 Figure 12 To illustrate other implementations of the structure, Figure 13 will be used to illustrate a table summarizing some implementations of the structure.

[0037] Figure 1 A traditional optical cable is shown.

[0038] like Figure 1 As shown, a conventional optical cable includes a rigid central strength member 20. A conventional upper jacket 30 surrounds the central strength member 20. The outer cover 75 of the optical cable may include multiple layers, such as a water-blocking layer 40, an optional outer strength member 60 that may include steel armor, and an outer jacket 70.

[0039] The optical cable also includes a conventional buffer tube 10, which contains multiple fiber ribbons 15. The conventionally encapsulated ribbons 15 are then stacked and configured into a circular shape in the conventional buffer tube 10.

[0040] The inventors of this application have discovered that a large number of voids or gaps exist within each conventional buffer tube 10. This is because the circular shape of the conventional buffer tube 10 differs from the square shape of the strip 15. Furthermore, the conventional buffer tube 10 is rigid and always maintains a circular shape. On the other hand, the strip 15 is rigid and straight. In addition, the standard strip 15 has a preferred longitudinal bending axis, which prevents the strip from folding on any other axis, thus hindering the high fill rate of the conventional buffer tube. As a result, most of the buffer tube area is filled with voids that would otherwise be used to hold the optical fiber.

[0041] Furthermore, the inventors of this application have discovered that, due to the circular shape of the conventional buffer tube 10, a large portion of the area outside the buffer tube 10 within the optical cable is unused, and this cannot be changed (attributed to the associated stiffness and rigidity of these buffer tubes 10). As a result, the number of buffer tubes that can be placed within the optical cable is limited because the circular shape intersects with other circular shapes along a single line rather than a plane (two cylindrical objects intersect at a line). In other words, a large portion of the space within the outer jacket 70 is empty because the conventional buffer tube 10 is circular, leaving gaps 50 between adjacent buffer tubes or between the conventional buffer tube 10 and the conventional upper jacket 30.

[0042] For example, in Figure 1 In this context, when the outer diameter of the conventional jacket 30 is substantially similar to the diameter of the conventional buffer tube 10, the encapsulation density is mathematically finite. In this example, with six conventional buffer tubes 10 surrounding the conventional jacket 30, the minimum void space per unit area of ​​the optical cable is 22.22%. In other words, at least 22.22% of the optical cable will always be unused empty space. As a result, the number of optical fibers that can be encapsulated per unit cross-sectional area is limited.

[0043] On the other hand, if individual optical fibers are placed directly inside the cable without using a buffer tube, they will have a high encapsulation density. However, when the total number of optical fibers in each cable is large (e.g., hundreds or thousands), such a design makes it more difficult to identify individual optical fibers.

[0044] Therefore, there is a need for fiber optic cables that offer high fiber encapsulation density while maintaining sufficient structural, thermal, and optical performance. For example, when encapsulating a larger number of fibers, the cable must also possess sufficient tensile strength, compressive strength, flexural strength, and resistance to thermal shrinkage while maintaining optical connectivity.

[0045] Embodiments of the present invention avoid the aforementioned problems by providing deformable buffer tubes that allow the buffer tubes to be compressed or squeezed together in a tighter configuration. This is achieved through a combination of the use of flexible strips and a deformable design of the buffer tube jacket. Optionally, embodiments of the present invention also include a deformable upper jacket material surrounding a strength member. Because the gaps between adjacent buffer tubes are filled by deformable buffer tubes, more optical fibers can be encapsulated within the optical cable than could be encapsulated in a conventional optical cable of the same size.

[0046] Figures 2A to 2E An optical cable according to an embodiment of the present invention is shown, wherein... Figure 2A A cross-sectional view of the optical cable is shown. Figure 2B A projection diagram of the fiber optic array is shown. Figure 2C It shows Figure 2B The corresponding cross-sectional area of ​​the fiber array shown. Figure 2D A flexible strip formed using an optical fiber array is shown. Figure 2E A deformable buffer tube formed using multiple flexible strips is shown.

[0047] First refer to Figure 2A In one or more embodiments, the optical cable includes a plurality of deformable buffer tubes 110 formed around a central region. Although Figure 2A (And other figures in this application) show six deformable buffer tubes 110, but this number does not necessarily represent the total number of deformable buffer tubes 110 to be included. Figure 2A (And other figures in this application) do not necessarily represent the shapes of the plurality of deformable buffer tubes 110. In particular, although many deformable buffer tubes 110 are shown as circular objects for practical reasons, many deformable buffer tubes 110 are non-circular or irregularly shaped due to deformation. For example, as Figure 2A As shown, one of the plurality of deformable buffer tubes 110 has a first dimension along the radial direction of the optical cable and a second dimension along a direction perpendicular to that radial direction. Unlike conventional buffer tubes where the first dimension is equal to the second dimension, the second dimension differs from the first dimension (e.g., it may be smaller or larger). In particular, different dimensions can be observed depending on the location where the dimensions of the deformable buffer tube 110 are measured, which differs from the circular dimensions of conventional buffer tubes. In other words, in Figure 2A In the cross-sectional view shown, the deformable buffer tube 110 has been deformed to have a non-circular cross-section.

[0048] In one or more embodiments, the central region includes a central strength member 20 conventionally surrounded by a jacket 30. The central strength member 20 provides mechanical integrity of the optical cable under heavy stress. For example, the optical cable may be subjected to significant strain during installation. The central strength member 20 is a rigid material and is the primary buckling-resistant element in the optical cable. The central strength member 20 resists cable shrinkage at low temperatures and prevents fiber buckling (which would otherwise occur due to the difference in expansion coefficients between the fiber and other plastic optical cable components). The central strength member 20 prevents the optical cable from being compressed and provides the primary clamping points for hardware to connect the optical cable to splices and cabling sheaths.

[0049] The central strength member 20 may be made of a metal element, a glass-reinforced composite rod such as glass-reinforced epoxy resin, an aramid-reinforced composite rod, or a composite rod made of some other high-modulus, low-expansion-coefficient material (such as carbon fiber).

[0050] Traditionally, the jacket 30 can typically comprise a polymer (such as polypropylene). The jacket 30 can also typically comprise other polymeric materials, such as porous foam polymers (e.g., porous impact-modified nucleated polypropylene (i.e., nucleated ethylene-propylene copolymer)). The upper jacket helps to achieve the appropriate outer diameter of the strength member 20 required for the number and size of the buffer tubes included in the optical cable. The upper jacket around the strength member 20 helps to keep the rigidity of the optical cable within reasonable limits and also reduces the cost of the optical cable. However, the thickness of the upper jacket 30 must be limited to avoid introducing thermal stress (e.g., because polyethylene has a much higher coefficient of thermal expansion than the central strength member 20).

[0051] like Figure 2AAs shown, multiple deformable buffer tubes 110 deform into non-circular shapes that fit within an outer cover 75. The outer cover 75 may include multiple layers, such as an outer jacket 70, a water-blocking layer 40, and an optional outer strength member 60. The outer jacket 70 may include polyurethane, polyethylene, nylon, or other suitable materials. In one embodiment, the outer cover 75 comprises medium-density polyethylene (MDPE) with a nominal jacket thickness of approximately 1 mm to meet fiber optic cable standards (such as Telcordia GR-20, ICEA-640). Flame retardant additives may also be included in the outer cover 75. The water-blocking layer 40 may include water-blocking wires, water-blocking tapes, or other superabsorbent powder-type materials.

[0052] For example, compared to adjacent buffer tubes in a plurality of deformable buffer tubes 110 Figure 1 The adjacent buffer tubes shown are physically in contact with each other over a greater distance. As a result, the amount of voids or gaps 50 within the optical cable is significantly reduced. Figure 2A In the diagram, the amount of voids or gaps 50 is very small relative to the total cross-sectional area because multiple deformable buffer tubes 110 have been adapted to the shape of the optical cable.

[0053] In practice, adjacent deformable buffer tubes 110 can be adapted slightly differently due to the localized stress caused by the outer jacket 75 and other factors such as the materials used. However, in various embodiments, the plurality of deformable buffer tubes 110 undergo plastic (or permanent) and elastic deformation during the formation of the optical cable. The plurality of deformable buffer tubes 110 have a low-stress state due to undergoing plastic deformation (because the energy of the deformation has been absorbed). Alternatively, in some embodiments, the plurality of deformable buffer tubes 110 remain in an elastic state and may have undergone substantially elastic deformation.

[0054] As will be explained in more detail below, in the case of multiple flexible strips 125, a highly compact buffer tube structure can be achieved due to the random distribution of each of the multiple flexible strips 125 in the deformable buffer tube 110. Furthermore, due to the flexibility of the aforementioned multiple flexible strips 125, the deformable buffer tube 110 can be reshaped into a non-circular or irregular shape.

[0055] Figures 2B to 2E The design of the flexible strip and deformable buffer tube 110 is shown, which enables this adaptable design according to an embodiment of the invention.

[0056] Reference Figure 2BAs will be further illustrated in the following figures, each of the plurality of deformable buffer tubes 110 includes a plurality of flexible strips 125. Each of the plurality of flexible strips 125 includes a plurality of optical fibers 150, such as a first optical fiber 151, a second optical fiber 152, a third optical fiber 153, a fourth optical fiber 154, a fifth optical fiber 155, and a sixth optical fiber 156. Although Figure 2B Only six optical fibers are shown, but this does not represent the total number of optical fibers.

[0057] Multiple optical fibers 150 are arranged parallel to each other and connected at the junction region 140. However, as Figure 2B As shown, the bonding region 140 is configured across the flexible strip 125 in such a way that a large surface area of ​​the optical cable is selectively devoid of the bonding material forming the bonding region 140. As a result, the multiple optical fibers 150 maintain a large degree of freedom, and for example, as... Figure 2D As shown, it can be effectively folded or randomly positioned when subjected to external stress.

[0058] In various implementations, the multiple optical fibers 150 can be folded into the following configuration: Figure 2D The densely packaged structure is shown. In one or more embodiments, the folded optical fiber 150 may have a non-circular or irregular shape.

[0059] Figure 2E A deformable buffer tube comprising multiple flexible strips is shown according to an embodiment of the present invention, the deformable buffer tube having been deformed during the formation of the optical cable.

[0060] The flexible band 125 is surrounded by a buffer tube jacket 160. In one or more embodiments, the buffer tube jacket 160 comprises polypropylene. In other embodiments, the buffer tube jacket 160 comprises porous polypropylene, polyethylene, nylon, polyamide, polybutylene terephthalate, a polyolefin copolymer composed of polyethylene and polypropylene, or other materials.

[0061] Additionally, the flexible strip 125 can be dispersed within the gel 170, which allows the flexible strip 125 to move relative to each other. Furthermore, the thickness of the buffer tube jacket 160 is maintained to allow the strip to remain flexible. The lower thickness of the deformable buffer tube 110 ensures that the buffer tube deforms under stress. Specifically, the ratio of the thickness of the buffer tube jacket 160 to the diameter of the deformable buffer tube 110 is maintained in the range of 0.001 to 0.01. The typical diameter of the deformable buffer tube before deformation is between 5 mm and 10 mm, for example, 7.4 mm.

[0062] During the formation of the optical cable, the buffer tube may be subjected to compressive stress. Due to the temperature-dependent decrease in modulus during the jacketing process, the buffer tube may exhibit increased deformation under equal stress. As a result, the flexible strip 125 within the deformable buffer tube 110 can be reconfigured to compensate for or minimize this compressive stress.

[0063] As described above, in various embodiments, the optical cable includes a deformable buffer tube 110. However, some deformation of the deformable buffer tube 110 is caused by the reconfiguration of the flexible strip within the optical cable and therefore does not cause twisting or bending of the optical fiber. Thus, embodiments of the present invention achieve improved encapsulation density without compromising the mechanical or optical properties of the optical cable.

[0064] In the above Figure 1 In the conventional design described herein, flat fiber ribbons are configured as rectangular stacks that are twisted together to maintain their rectangular shape and to average any compressive or tensile stresses on the fiber ribbon stacks spanning different fibers along the length of the cable. However, in the various embodiments described in this application, it is not necessary to twist the ribbons within each deformable buffer tube 110, as maintaining their shape is not required if the ribbons are randomly distributed within the tubes.

[0065] The foldable flexible strip 125 extends longitudinally along each deformable buffer tube 110, allowing each flexible strip 125 to have a random configuration. The subsequent twisting of the multiple deformable buffer tubes 110 (if any) during the formation of the optical cable is sufficient to average the strain on the optical fiber and meet the mechanical and optical standards of the optical fiber cable.

[0066] Despite Figure 2E In this illustration, only four flexible strips 125 are shown within multiple deformable buffer tubes, but in various embodiments, the multiple deformable buffer tubes 110 may include more or even fewer flexible strips 125. For example, in one embodiment, the multiple deformable buffer tubes 110 may include twelve or twenty-four flexible strips 125. Additionally, each flexible strip 125 may include any suitable number of optical fibers 150. In various embodiments, the optical fibers 150 may have a diameter ranging from 100 μm to 300 μm. For example, in one illustration, each flexible strip 125 may include twelve optical fibers. Thus, in this example, each of the multiple deformable buffer tubes 110 includes 144 or 288 optical fibers.

[0067] Using embodiments of the present invention, the optical cable can have an optical fiber density of 5.0 optical fibers per square millimeter or greater (fibers / mm²). 2 In one or more embodiments, the fiber density of the optical cable can be 3.5 fibers / mm. 2 Up to 10 optical fibers / mm2 Between, preferably between 3.5 optical fibers / mm 2 Up to 8 optical fibers / mm 2 between.

[0068] Figure 3 Another embodiment of the invention is shown, in which there is no upper jacket surrounding the central strength member.

[0069] In one or more embodiments, the strength member 20 may not include the upper jacket material because the deformable buffer tube 110 provides sufficient encapsulation density and relaxation of its inherent stress. In other respects, this embodiment can be compared with… Figures 2A to 2E The previous implementation described herein is similar.

[0070] In one implementation, such as Figure 3 As shown, the diameter of the strength member 20 can be similar to the size "L" of the deformable buffer tube 110. In other embodiments, the diameter of the strength member 20 can be smaller than the size "L" of the deformable buffer tube 110.

[0071] Figures 4A to 4B A further embodiment of the invention is shown, which has an additional deformable upper jacket surrounding the central strength member.

[0072] In a further embodiment, the upper jacket material surrounding the strength member 20 may also comprise a deformable material. In various embodiments, the upper jacket material is more compressible than the strength member 20, which is designed to be rigid.

[0073] As a result, the optical cable includes a deformable upper jacket 130 that has already deformed during the cable formation process. Depending on the material of the deformable upper jacket 130, the deformation of the deformable upper jacket 130 can be purely elastic or may include plastic deformation. The deformable nature of the upper jacket provides an additional way to compress and encapsulate the optical cable by further improving the contact between the various components. In particular, relative to Figure 2A In this implementation method, the amount of voids or gaps within the optical cable can be further reduced. Additionally, the improved matching of the moduli of the internal components within the optical cable results in a more uniform stress distribution and relatively lower deformation on the more compliant buffer tube.

[0074] Figure 4B An embodiment is shown in which the buffer tube and the deformable upper jacket 130 (jacket material surrounding the strength member 20) undergo deformation during the formation of the optical cable.

[0075] although Figure 4A The ideal design is shown, but in reality, the deformed buffer tube can be similar to... Figure 4B The structure shown. For example, as Figure 4BAs shown, the deformable buffer tube 110 may have a first width W1 along the periphery of the optical cable and a second width W2 toward the central region of the optical cable.

[0076] Similarly, instead of abutting against an adjacent buffer tube along its entire side, each deformable buffer tube 110 physically contacts the adjacent deformable buffer tube 110 at a distance d. In one embodiment, the distance d may be on the same order of magnitude as the first width W1 or the second width W2. In other words, in one embodiment, the distance d may be comparable to the first width W1 or the second width W2. In one embodiment, the distance d may be substantially equal to the first width W1 or the second width W2. In various embodiments, the ratio of the distance d to the first width W1 is approximately 0.2 to approximately 1.5. In one or more embodiments, the ratio of the distance d to the second width W2 is approximately 0.2 to approximately 1.5. In contrast, in Figure 1 In the conventional design shown, adjacent conventional buffer tubes 10 are in contact with each other at a single point or at a very short distance close to the point.

[0077] Figure 5A The relationship between the tensile modulus and temperature for various upper jacket materials is shown.

[0078] Reference Figure 5A The x-axis represents temperature, while the y-axis represents the tensile modulus in MPa. The tensile modulus of a material is the ratio of the tensile stress applied to the material to the resulting elongation (strain). For low deformation, the compressive modulus is equal to the tensile modulus of the material.

[0079] exist Figure 5A In the diagram, the first curve, C1, represents the change in tensile modulus of a traditional jacket material (Conv.UJ.Mat.). An example of such a traditional material could be polypropylene. Figure 5A As shown, the tensile modulus increases significantly as the temperature decreases. In contrast, the second curve C2 represents the change in the tensile modulus of the upper jacket material, which includes a deformable upper jacket material (D.UJ.Mat.). An example of a deformable upper jacket material is a thermoplastic elastomer such as santoprene 201-87.

[0080] The deformable buffer tube 110 has low yield stress and modulus, so it is desirable for the lower modulus of the upper jacket material used in the deformable upper jacket 130 to equalize the compressive stress in the optical cable during compression. If the compressive modulus of the upper jacket material is much higher than that of the deformable buffer tube 110, much higher deformation (strain) of the tube will be observed, resulting in greater stress on the optical fiber housed within it. In contrast, if the compressive modulus of the upper jacket material is similar to that of the deformable buffer tube 110, the deformable buffer tube 110 has reduced strain and the optical fiber housed within it experiences less stress.

[0081] Therefore, the deformable upper jacket material is selected to have low shrinkage, low coefficient of thermal expansion, and low modulus over a wide temperature range. As shown in the figure, in various embodiments, the deformable upper jacket material is selected to have a room temperature modulus below about 700 MPa and a -40°C modulus below about 1 GPa, and a modulus below about 2 × 10⁻⁶ GPa over a temperature range from room temperature to -40°C. -4 The coefficient of thermal expansion is 0.066666.0 ...

[0082] In one illustration represented by the second curve C2, the deformable upper jacket is selected to have a room temperature modulus below approximately 150 MPa and a -40°C modulus below approximately 600 MPa, and a modulus below approximately 1.5 × 10⁻⁶ MPa over a temperature range from room temperature to -40°C. -4 The coefficient of thermal expansion is shown in the figure. In one illustration, thermoplastic vulcanizate 201-87 exhibits a low modulus and a low coefficient of thermal expansion (approximately 1.23 × 10⁻⁶ °C). -4 / ℃). As used herein, the modulus or tensile modulus is determined according to ASTM D638-14 "Standard Test Method for Tensile Properties of Plastics" published by ASTM International, West Conshohocken, PA, 2014.

[0083] Based on experimental data, the deformable upper jacket material containing thermoplastic vulcanizate 201-87 exhibits lower temperature sensitivity compared to conventional upper jacket materials. Even at the lower end of the test range, such as -40°C, the deformable upper jacket material has a compressive modulus of approximately 550 MPa, which is almost six times smaller than that of conventional upper jacket materials.

[0084] Figure 5B The shrinkage stress as a function of temperature is shown for various upper jacket materials. Figure 5BThe shrinkage stress shown is calculated based on thermal expansion coefficient and modulus data, which were determined by DMA analysis of different materials using a TA instrument DMA2980 dynamic mechanical analyzer equipped with liquid nitrogen cooling for operation below room temperature.

[0085] exist Figure 5B In the diagram, curve C3 represents the conventional upper jacket material, and curve C4 represents the deformable upper jacket material. Clearly, compared to the deformable upper jacket material, the conventional upper jacket material causes a substantial increase in shrinkage stress.

[0086] Figure 5A and Figure 5B This indicates that replacing the traditional top jacket material with a deformable top jacket material makes it easier to produce optical cables with better optical and mechanical properties.

[0087] Multiple tests were conducted to determine the feasibility of the applicant's implementation method. Samples containing different upper jacket materials were tested. Figure 5D and Figure 5E The set of experiments shown.

[0088] Figure 5D and Figure 5E The experiments shown in the table were conducted on an optical cable containing 1728 optical fibers with six buffer tubes, one of which was a gel-filled dummy tube. The buffer tubes surrounded a glass-reinforced polymer core forming strength member 20. Compression tests were performed on the individual upper jacket central strength member and the individual deformable buffer tubes. Compression tests were conducted in an Instron 5567 (SNC5456) testing machine, where the samples were fixed between two four-inch parallel plates. Tests were performed using a strain rate of 0.05 inches / minute and an ambient temperature of 22°C. The compressive modulus was determined by… Figure 5C The slope of the load-deformation curve preceding the yield point is shown, where the triangles represent the yield points of three different samples or specimens. The obtained modulus (the slope of the load relative to the deformation) can be further normalized by the length of the specimen under compression to obtain the modulus in MPa or lbf / in. 2 The compression modulus is expressed in units of 1. Figure 5D and Figure 5E The results shown are the original values ​​before this length normalization. The test procedures described herein are for illustrative purposes only and should not be considered the only way to test the compressive modulus. It should be further noted that different experimental setups (e.g., using a two-inch parallel plate instead of a four-inch parallel plate) will result in different modulus values, although the results are expected to be qualitatively and relatively similar.

[0089] Figure 5DA table summarizing the compression test results from the tested central strength member is shown.

[0090] First, such as Figure 5D As shown, compression tests were performed on the central strength member with the upper jacket under different conditions, with variations in the upper jacket material. In particular, compression tests were performed by de-processing the completed optical cable to form individual components (such as individual buffer tubes or individual strength members encapsulated using the upper jacket material).

[0091] In the table shown, the upper jacket diameter is the outer diameter of the upper jacket material, while the SM diameter is the diameter of the central strength member 20, which in this case comprises a glass-reinforced polymer.

[0092] The second and third columns show the test results using a jacketed material on solid polypropylene. These samples have a very high compressive modulus, approximately 40,000 lbf / in, which is the modulus normalized over the length of each sample (note that modulus is typically expressed in lbf / in). 2 (or expressed in MPa). For columns four through six, the upper jacket material comprises foamed polypropylene. The foam content varies between 45%, 35%, and 40%, while keeping other parameters constant. The use of a foamed polypropylene upper jacket causes a twofold reduction in compressive modulus (reduced to half).

[0093] Column 7 shows test results using deformable overlay materials such as thermoplastic elastomers (e.g., thermoplastic vulcanizate 201-87CCT). The deformable overlay material further reduced the compression modulus to approximately 15,000 lbf / in. Compared to solid polypropylene overlays, thermoplastic elastomers resulted in a compression modulus reduction of greater than 60%. Similarly, compared to foamed polypropylene overlays, thermoplastic elastomers resulted in a compression modulus reduction of greater than 20%.

[0094] Figure 5E A table is shown comparing the compression test results from the test central strength member with those from the buffer tube.

[0095] Figure 5E The fourth column summarizes the data from... Figure 5DThe results show that the deformable upper jacket material has a compressive modulus of approximately 15,000 lbf / in. In comparison, the second and third columns show the compression test results for the individual deformable buffer tubes. The second column shows the results before the deformable buffer tube was deformed, i.e., before it was placed inside the optical cable and compressed. The third column, in contrast, shows the results after the compressed buffer tube was formed inside the optical cable and thus represents the actual product. The deformed buffer tube exhibits a slightly higher compressive modulus, but there is no significant difference compared to the undeformed buffer tube. More importantly, however, the compressive modulus of the deformable buffer tube is much smaller than that of the deformable upper jacket material.

[0096] In various embodiments, the deformable upper jacket material is selected in such a way that it has a compressive modulus similar to that of the buffer tube. In one or more embodiments, the deformable upper jacket material is selected such that the ratio of the compressive modulus of the buffer tube to the compressive modulus of the deformable upper jacket material is less than 1:20, or in one embodiment, the ratio is between 1:1 and 1:20.

[0097] In this exemplary embodiment, the ratio of the compressive modulus of the buffer tube to the compressive modulus of the deformable upper jacket material is approximately 1:18. In comparison, this ratio increases to 1:25 for foamed polypropylene upper jackets and to 1:45 for solid polypropylene upper jackets.

[0098] Figure 6 to Figure 12 Specific embodiments of various designs for optical cables according to various embodiments of the present invention are described.

[0099] Figures 6A to 6C An example implementation of the optical cable is shown, wherein Figure 6A The diagram shows the cross-sectional design of the optical cable before compression. Figure 6B The corresponding projection diagram is shown. Figure 6C A cross-sectional view of the compressed optical cable is shown. Figures 6A to 6B The design configuration is shown and the final shape is not represented, as will be stated above. The circular cross-section shown here is provided for ease of explanation.

[0100] Reference Figures 6A to 6B The optical cable includes an outer cover 75 within which six deformable buffer tubes 110 (labeled herein as 110R, 110B, 110W, 110BK, 110O, and 110G) are concentrically arranged around a rigid strength member 20. The strength member 20 is clamped by a deformable upper jacket 130. The outer layers of the deformable buffer tubes 110R, 110B, 110W, 110BK, 110O, and 110G can be colored (e.g., red, blue, white, black, orange, green, etc.) for identification.

[0101] Figure 6C The compressed version is shown. Figure 6A The fiber optic cable in the middle. Although Figure 6C The cross-section includes some gaps 50, but the deformable buffer tube 110 attempts to relative to Figure 6A Significant deformation has already occurred when the area occupied by gap 50 is reduced. In various implementations, the actual amount of deformation will depend on both external and internal factors. Examples of external factors include the amount of compression applied to the buffer tube (e.g., Figure 6A (The arrows in the text), the time of applying compression, the temperature at which compression is applied, etc., while examples of internal factors include the material and thickness of the buffer tube jacket, the flexibility of the flexible strip inside the buffer tube, and the stacking configuration of the flexible strip.

[0102] exist Figures 6A to 6C In one example of the optical cable shown, the cable diameter is 24.7 mm and includes six buffer tubes, each holding 288 optical fibers, each with a diameter of 250 μm. Therefore, Figures 6A to 6C The optical cable in the cable consists of 1728 optical fibers and has a fill percentage of approximately 78%, which is the ratio of the conduit diameter to the cable's outer diameter. Therefore, Figure 6C The fiber optic cable can easily pass through a 1.25-inch conduit.

[0103] Figures 7A to 7B A specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 7A A cross-sectional view of the optical cable before compression is shown. Figure 7B The corresponding projection diagram is shown. (Compared to...) Figures 6A to 6B Same, Figures 7A to 7B The design configuration is shown but the final shape is not represented.

[0104] Figures 7A to 7B An alternative design is shown in which deformable buffer tubes 110 are arranged in multiple concentric paths around a central strength member 20. Additionally, after the first row of deformable buffer tubes 110 is arranged, a support layer 175 can be introduced to reinforce the first row of deformable buffer tubes 110. The support layer 175 may contain a material with sufficient properties for reinforcing the buffer tubes surrounded by the support layer 175, and the support layer 175 is also deformable, so that the support layer 175 can be compressed or deformed. Examples of materials for the support layer 175 include polypropylene, polyethylene, nylon, polyurethane, etc.

[0105] Another set of deformable buffer tubes 110 are arranged around the support layer 175. The outer cover 75 is arranged around the multiple rows of deformable buffer tubes 110 and includes the outer sheath of the optical cable.

[0106] and Figures 6A to 6C The difference lies in Figures 7A to 7BThe subsequent cross-sectional view of the optical cable after deformation is not shown. However, the individual buffer tube deforms in a similar manner to that described in the foregoing embodiments.

[0107] exist Figures 7A to 7B In one example of the implementation, the optical cable has a diameter of 37.4 mm and five buffer tubes in the first row and eleven buffer tubes in the second row. Each buffer tube holds 432 optical fibers, each with a diameter of 200 μm. Therefore, Figures 7A to 7B The optical cable in the cable consists of 6912 optical fibers, with a fill percentage of approximately 74%, which is the ratio of the conduit diameter to the cable's outer diameter. Therefore, Figures 7A to 7B The fiber optic cable can easily pass through a two-inch pipe, and even through a 1.5-inch pipe.

[0108] Figures 8A to 8B A specific design of an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 8A A cross-sectional view of the optical cable before compression is shown. Figure 8B The corresponding projection diagram is shown. Again, Figures 8A to 8B The design configuration is shown but the final shape is not represented.

[0109] exist Figures 8A to 8B In this embodiment, the deformable upper sleeve 130 surrounds the central reinforcing member 20. In various embodiments, the thickness of the deformable upper sleeve 130 may differ from the diameter of the reinforcing member 20. For example, in the illustrated embodiment, the thickness of the deformable upper sleeve 130 is greater than the diameter of the reinforcing member 20. However, in other embodiments, the thickness of the deformable upper sleeve 130 may be the same as the diameter of the reinforcing member 20. In one embodiment, the thickness of the deformable upper sleeve 130 may be similar to the diameter of the reinforcing member 20. Eight buffer tubes are arranged around the outer periphery of the deformable upper sleeve 130. Figures 8A to 8B In one example of the implementation, the optical cable has a diameter of 38.8 mm and eight buffer tubes. Each buffer tube holds 864 optical fibers, each with a diameter of 200 μm. Therefore, Figures 8A to 8B The optical cable in the cable consists of 6912 optical fibers, with a fill percentage of approximately 76%, which is the ratio of the conduit diameter to the cable's outer diameter. Therefore, Figures 8A to 8B The fiber optic cable can easily pass through a two-inch conduit, and even through a 1.5-inch conduit.

[0110] exist Figures 8A to 8B The subsequent cross-sectional view of the optical cable after deformation is not shown. However, the deformation of the individual buffer tube is similar to that described in detail in the foregoing embodiments.

[0111] Figures 9A to 9BA specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 9A A cross-sectional view of the optical cable before compression is shown. Figure 9B The corresponding projection diagram is shown. As mentioned earlier, Figures 9A to 9B The design configuration is shown but the final shape is not represented.

[0112] In this embodiment, the optical cable is designed to be similar to Figures 7A to 7B The embodiments described above are different because they do not include an upper jacket around the central strength member and also include two rows of buffer tubes around the central region. However, in this embodiment, a smaller number of buffer tubes are arranged in the first row. Instead Figures 7A to 7B Five buffer tubes are configured in the middle, and in this embodiment, three buffer tubes are configured in the first row.

[0113] However, unlike the aforementioned embodiments, this embodiment also includes additional strength members 25 placed around the strength member 20. The additional strength members 25 are separated from the strength member 20 by deformable buffer tubes 110 in the first row. In one embodiment, the number of additional strength members 25 is the same as the number of deformable buffer tubes 110 in the first row. The additional strength members 25 provide additional rigidity to the optical cable to support a larger number of buffer tubes. In particular, the additional strength members 25, together with the strength member 20, make better use of space because they are at least twice the diameter of the deformable buffer tubes 110.

[0114] As a result, Figures 9A to 9B In this embodiment, three deformable buffer tubes 110 are arranged in the first row and surrounded by a support layer 175. The other nine deformable buffer tubes 110 are arranged around the support layer 175. Figures 9A to 9B In one example of the implementation, the optical cable diameter is 39.4 mm. Each buffer tube accommodates 576 optical fibers, each with a diameter of 200 μm. Therefore, Figures 9A to 9B The optical cable in the cable consists of 6912 optical fibers, with a fill percentage of approximately 78%, which is the ratio of the conduit diameter to the cable's outer diameter. Therefore, Figures 9A to 9B The fiber optic cable can easily pass through a two-inch conduit.

[0115] exist Figures 9A to 9B The subsequent cross-sectional view of the optical cable after deformation is not shown. However, the deformation of the individual buffer tube is similar to that described in detail in the foregoing embodiments.

[0116] Figures 10A to 10B A specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 10A A cross-sectional view of the optical cable before compression is shown. Figure 10B The corresponding projection diagram is shown. As mentioned earlier, Figures 10A to 10BThe design configuration is shown but the final shape is not represented.

[0117] This embodiment incorporates features of the aforementioned embodiments illustrated in Figures 7 to 9. For example, this embodiment includes, for instance... Figure 8A The deformable upper sleeve 130 surrounding the strength member 20 is described in the text. Similar to... Figure 7A In one embodiment, a first row of deformable buffer tubes 110 is arranged around a deformable upper jacket 130. The first row of deformable buffer tubes 110 includes nine buffer tubes enclosed within a support layer 175. A second row of deformable buffer tubes 110, including fifteen buffer tubes, is arranged around the support layer 175.

[0118] As a result, Figures 10A to 10B In the example of the implementation method, the optical cable diameter is 40.5 mm. Each buffer tube accommodates 288 optical fibers, each with a diameter of 200 μm. Therefore, Figures 10A to 10B The cable contains 6912 optical fibers, with a fill percentage of approximately 80%, which is the ratio of the conduit diameter to the cable's outer diameter. Therefore, Figures 10A to 10B The fiber optic cable can easily pass through a two-inch conduit.

[0119] exist Figures 10A to 10B The subsequent cross-sectional view of the optical cable after deformation is not shown. However, the deformation of the individual buffer tube is similar to that described in detail in the foregoing embodiments.

[0120] Figures 11A to 11B A specific design for an optical cable according to an alternative embodiment of the present invention is shown, wherein... Figure 11A A cross-sectional view of the optical cable before compression is shown. Figure 11B The corresponding projection diagram is shown. As mentioned earlier, Figures 11A to 11B The design configuration is shown but the final shape is not represented.

[0121] This implementation method is similar to Figures 9A to 9B This is because it includes additional strength members 25 disposed between the deformable buffer tubes 110. Adjacent additional strength members 25 are separated from each other by a deformable buffer tube 110 and from the strength members 20. In one embodiment, the number of additional strength members 25 is the same as the number of deformable buffer tubes 110 in the first row.

[0122] Again, as Figures 9A to 9B In some embodiments, no additional upper sleeve is used around the strength member 20 or the additional strength member 25. However, in some embodiments, a deformable upper sleeve material may be used to sleeve either or both of these strength members.

[0123] exist Figures 11A to 11BThe subsequent cross-sectional view of the optical cable after deformation is not shown. However, the deformation of the individual buffer tube is similar to that described in detail in the foregoing embodiments.

[0124] As a result, Figures 11A to 11B In one example of the implementation, the optical cable has a diameter of 26.8 mm. Each buffer tube accommodates 864 optical fibers, each with a diameter of 200 μm. Therefore, Figures 11A to 11B The optical cable in the cable consists of 3456 optical fibers, with a fill percentage of approximately 70%, which is the ratio of the conduit diameter to the cable's outer diameter. Therefore, Figures 11A to 11B The fiber optic cable can easily pass through a 1.5-inch conduit.

[0125] Figure 12 A general embodiment is shown, which illustrates a combination of features described in various embodiments of the invention. Figure 12 The subsequent cross-sectional view of the optical cable after deformation is not shown. However, the deformation of the individual buffer tube is similar to that described in detail in the foregoing embodiments.

[0126] like Figure 12 As shown, the optical cable may include multiple rows of deformable buffer tubes 110 arranged around the central strength member 20. Additionally, as... Figure 12 As shown, the central strength member may include a deformable upper jacket 130 surrounding the central strength member. For clarity, not all elements such as the buffer tubes 110 are shown. A first row of deformable buffer tubes surrounds the central strength member 20. Alternatively, the optical cable may include multiple rows of buffer tubes arranged after the first row. In the illustration, two rows of deformable buffer tubes 110 are arranged around the first row. Any row may include additional strength members 25. For example, in the illustration, the second and third rows include additional strength members 25. In an alternative embodiment, the first row may also include additional strength members 25. Additionally, the dimensions of the additional strength members 25 may differ from the dimensions of other additional strength members 25 in other rows that include the central strength member 20. Furthermore, some or all of the additional strength members 25 may include a deformable upper jacket 130 surrounding them.

[0127] Figures 13A to 13B This is a table summarizing exemplary embodiments of different optical cable designs according to various embodiments of the present invention.

[0128] like Figures 13A to 13B The table shows various specific designs. The fiber optic cable diameter refers to the outer diameter of the fiber optic cable, while the conduit size refers to the size of the conduit through which the fiber optic cable can pass. Subsequent columns follow the design configuration of the buffer tubes within the fiber optic cable. For example, the total number of buffer tubes is the total number of buffer tubes within the fiber optic cable, while the number of rows of buffer tubes indicates the number of concentric configurations of the buffer tubes. For example, Figure 7AIt features two rows (two concentric configurations of buffer tubes). The first row of buffer tubes is the one directly surrounding or adjacent to the central strength member. The use of the upper jacket surrounding the central strength member is summarized as either affirmative (yes) or negative (no). In various designs that include an additional strength member, the size of the additional strength member can be larger than or approximately the same as the size of the central strength member. As previously stated, the fill percentage (%) is the ratio of the tube diameter to the outer diameter of the optical cable.

[0129] like Figure 13A and Figure 13B As shown, using embodiments of the present invention, a fill percentage of approximately 70% to approximately 80% is obtained. Similarly, the number of optical fibers per unit area of ​​each optical cable can reach up to 6.3 fibers / mm. 2 Optionally, the number of optical fibers per unit area of ​​each optical cable can reach 3.5 fibers / mm. 2 Up to 6.5 optical fibers / mm 2 The changes between them.

[0130] Figure 14 A deformable buffer tube formed using a single flexible strip is shown, and it can be used with optical cables according to embodiments of the present invention. For example, Figure 14 The deformable buffer tube in this embodiment can replace the deformable buffer tube of any other optical cable implementation, such as... Figures 2A to 2E , Figure 3 , Figures 4A to 4B , Figure 12 Optical cables, etc.

[0131] Reference Figure 14 The deformable buffer tube 1410 includes a single flexible strip 140, which can be as described above. That is, the flexible strip 140 can include any suitable number of optical fibers. For example, as shown, the flexible strip 140 can include a first optical fiber 151, a second optical fiber 152, a third optical fiber 153, a fourth optical fiber 154, a fifth optical fiber 155, and a sixth optical fiber 156. A possible advantage of including a single flexible strip in each deformable buffer tube of the optical cable is that it facilitates easier identification of individual optical fibers within the cable.

[0132] The flexible band 140 is surrounded by a buffer tube clamp 1460, which can be any of the other specific embodiments of buffer tube clamps described herein, such as... Figure 2E The buffer tube clamp 1460 is used in the buffer tube. Additionally, the buffer tube clamp 1460 may be smaller than the buffer tube clamp used to surround the multiple flexible strips. Alternatively, compared to an embodiment with multiple flexible strips in each buffer tube clamp, the number of optical fibers in the flexible strips may be increased, and the size of the buffer tube clamp 1460 may be larger than or the same as the size of the buffer tube clamp surrounding the multiple flexible strips.

[0133] As described above, any of the optical cables described herein can be implemented using a deformable buffer tube that surrounds only a single flexible strip. Figures 15 to 17 Specifically, multiple optical cables are shown, each comprising multiple deformable buffer tubes, each buffer tube surrounding a single flexible strip. Similar labeled elements may be those previously described.

[0134] Figure 15 Another embodiment of the invention is shown, which has an additional deformable upper jacket surrounding a central strength member and includes a plurality of deformable buffer tubes, each formed using a single flexible strip. For example, Figure 15 The optical cable in the text can be a specific implementation of other optical cable implementations, such as... Figure 4B The optical cable in the middle. (Refer to...) Figure 15 The optical cable comprises multiple deformable buffer tubes 1410, each surrounding a single flexible strip. Although six deformable buffer tubes are shown, any suitable number is possible.

[0135] Figure 16 Another embodiment of the invention is shown, which has an additional deformable upper jacket surrounding a central strength member and includes a plurality of deformable buffer tubes, each formed using a single flexible strip. For example, Figure 16 The optical cable in the text can be a specific implementation of other optical cable implementation methods, such as... Figure 4B The optical cable in the middle.

[0136] Reference Figure 16 The optical cable includes multiple deformable buffer tubes 1410, each surrounding a single flexible strip. For example, including a single flexible strip in each deformable buffer tube can advantageously allow one or more dimensions of the deformable buffer tube 1410 to be reduced relative to the dimensions of other components of the optical cable, such as the central strength member 20. Therefore, the diameter of the optical cable can be further reduced.

[0137] Each deformable buffer tube 1410 can have a peripheral width W3, an inner width W4, and a physical contact distance d2, respectively, similar to the first width W1, the second width W2, and the distance d described above. Comparatively, the peripheral width W3 and the inner width W4 can be relatively small, while increasing the number of deformable buffer tubes in the optical cable. For example, as... Figure 16 As shown, the optical cable includes nine deformable buffer tubes, but it is also possible to have a larger or smaller number of deformable buffer tubes, each surrounding a single flexible strip.

[0138] Because the size of each deformable buffer tube 1410 is reduced relative to the central strength member 20, the ratio of the physical contact distance d2 to the peripheral width W3 and the internal width W4 can be advantageously increased relative to other embodiments. Compared to the peripheral width W3 and internal width W4, which can be reduced relative to the first width W1 and the second width W2, the physical contact distance d2 can be equal to or greater than the distance d in other embodiments.

[0139] Figure 17 Another general embodiment is shown, which includes a plurality of deformable buffer tubes, each formed using a single flexible strip, and illustrates a combination of features illustrative in various embodiments of the invention. For example, Figure 17 The optical cable in the text can be a specific implementation of optical cables in other ways, such as... Figure 12 The fiber optic cable in the system. Specifically, Figure 17 The optical cable includes multiple rows of deformable buffer tubes, each of which 1410 surrounds a single flexible strip. Figure 12 The subsequent cross-sectional view of the optical cable after deformation is not shown. However, the deformation of the individual buffer tube is similar to that described in detail in the foregoing embodiments.

[0140] Exemplary embodiments of the present invention are summarized herein. Other embodiments can be understood from the entire specification and technical solutions submitted herein.

[0141] Example 1: The optical cable includes multiple deformable buffer tubes. Each of the multiple deformable buffer tubes includes multiple flexible strips, and each flexible strip includes multiple optical fibers. Each of the multiple deformable buffer tubes has a non-circular cross-section. An outer jacket surrounds the multiple deformable buffer tubes.

[0142] Example 2: The optical cable of Example 1, wherein each of the plurality of deformable buffer tubes is configured to deform in any direction.

[0143] Example 3: An optical cable according to one of Examples 1 or 2, wherein a plurality of flexible strips are surrounded by a first deformable material, the first deformable material forming part of the outer surface of each of a plurality of buffer tubes.

[0144] Example 4: An optical cable of one of Examples 1 to 3, wherein the first deformable material surrounding a plurality of flexible strips includes polypropylene, polyethylene, nylon, polyamide, polybutylene terephthalate, or a polyolefin copolymer comprising polyethylene and polypropylene.

[0145] Example 5: An optical cable according to one of Examples 1 to 4, wherein multiple flexible strips are arranged within a gel material.

[0146] Example 6: An optical cable of one of Examples 1 to 5, wherein the shape or size of each of the plurality of deformable buffer tubes is different from the shape or size of all the other deformable buffer tubes in the plurality of deformable buffer tubes.

[0147] Example 7: An optical cable according to one of Examples 1 to 6, which further includes a first rigid strength member disposed within an outer jacket.

[0148] Example 8: An optical cable according to one of Examples 1 to 7, wherein a rigid strength member is arranged in a central region surrounded by a plurality of deformable buffer tubes.

[0149] Example 9: An optical cable according to one of Examples 1 to 8, further comprising a plurality of rigid additional strength members disposed between a plurality of deformable buffer tubes, wherein the plurality of additional rigid strength members are arranged around a first rigid strength member.

[0150] Example 10: An optical cable according to one of Examples 1 to 9, wherein the first rigid strength member is surrounded by a second deformable material.

[0151] Example 11: An optical cable according to one of Examples 1 to 10, wherein the second deformable material comprises a material with a modulus of less than 1 GPa at -40°C.

[0152] Example 12: An optical cable according to one of Examples 1 to 11, wherein the second deformable material comprises a material with a modulus between 50 MPa and 600 MPa in a temperature range between -40°C and 20°C.

[0153] Example 13: An optical cable according to one of Examples 1 to 12, wherein the compressive modulus of the second deformable material is less than the compressive modulus of the first deformable material surrounding the plurality of flexible strips.

[0154] Example 14: An optical cable according to one of Examples 1 to 3 and 5 to 13, wherein the first deformable material comprises polypropylene and the second deformable material comprises thermoplastic vulcanizate 201-87.

[0155] Example 15: The optical cable includes a central strength member and a plurality of buffer tubes arranged around the central strength member, wherein each of the plurality of buffer tubes includes a buffer tube jacket surrounding a plurality of flexible strips. The buffer tube jacket includes a first deformable material that can be plastically deformed. Each flexible strip includes a plurality of optical fibers. An outer jacket surrounds the plurality of buffer tubes.

[0156] Example 16: The optical cable of Example 15, wherein multiple buffer tubes are arranged in multiple concentric rows around a central strength member.

[0157] Example 17: An optical cable according to one of Examples 15 or 16, further comprising additional strength members disposed in one of a plurality of concentric rows.

[0158] Example 18: An optical cable according to one of Examples 15 to 17, which further includes a second deformable material surrounding the strength member.

[0159] Example 19: An optical cable according to one of Examples 15 to 18, which further includes a second deformable material surrounding an additional strength member.

[0160] Example 20: An optical cable according to one of Examples 15 to 19, wherein the first deformable material comprises polypropylene.

[0161] Example 21: An optical cable according to one of Examples 15 to 20, wherein the thickness of the first deformable material is in a ratio of approximately 0.1 to 1 to the cross-sectional width of one of the plurality of buffer tubes.

[0162] Example 22: The optical cable includes a rigid strength member and a deformable upper jacket surrounding the rigid strength member. Multiple buffer tubes are arranged around the rigid strength member. Each of the multiple buffer tubes includes multiple strips, and each strip includes multiple optical fibers. Each of the multiple buffer tubes has a first compression modulus, and the rigid strength member with the deformable upper jacket has a second compression modulus. The ratio of the first modulus to the second modulus is approximately 1:1 to 1:20. An outer jacket surrounds the multiple buffer tubes.

[0163] Example 23: The optical cable of Example 22, wherein the deformable upper jacket comprises a polypropylene-based thermoplastic elastomer.

[0164] Example 24: An optical cable according to one of Examples 22 or 23, wherein the deformable upper jacket comprises a material with a modulus of less than 1000 MPa at -40°C.

[0165] Example 25: An optical cable according to one of Examples 22 to 24, wherein the deformable upper jacket comprises a material having a modulus between 50 MPa and 600 MPa in a temperature range of -40°C to 20°C.

[0166] Although the invention has been described with reference to illustrative embodiments, this specification is not intended to be limited in meaning. Various variations and combinations of the illustrative embodiments, as well as other embodiments of the invention, will become apparent to those skilled in the art from this specification. Therefore, the appended claims are intended to cover any such variations or embodiments.

Claims

1. An optical cable comprising: Multiple deformable buffer tubes, wherein each of the multiple deformable buffer tubes includes One or more flexible strips, each flexible strip comprising multiple optical fibers, and The axial cross-section of the deformable buffer tube comprising the one or more flexible strips, wherein the axial cross-section includes an irregular shape; and An outer jacket surrounds the plurality of deformable buffer tubes. Each of the one or more flexible strips comprises multiple optical fibers and a first longitudinal length along the length direction of the corresponding flexible strip. Wherein, for each of the one or more flexible strips, each of the plurality of optical fibers is attached to an adjacent optical fiber along a bonding region, the bonding region comprising a second longitudinal length along the length direction, the second longitudinal length being less than the first longitudinal length. Each deformable buffer tube includes a buffer tube jacket, and the buffer tube jacket includes a deformable first deformable material. The optical cable also includes a central strength member and a second deformable material surrounding the central strength member, and The second deformable material includes a modulus of less than 1 GPa at -40°C, a modulus of less than 700 MPa at room temperature, and a coefficient of thermal expansion of less than 2 × 10⁻⁶ in the temperature range of room temperature to -40°C. -4 Materials at / ℃.

2. The optical cable according to claim 1, characterized in that, The first deformable material includes polypropylene.

3. The optical cable according to claim 1, characterized in that, The plurality of deformable buffer tubes are arranged in multiple concentric rows around the central strength member.

4. The optical cable according to claim 3, characterized in that, The optical cable also includes additional strength members disposed in one of the plurality of concentric rows.

5. The optical cable according to claim 4, characterized in that, It also includes a second deformable material surrounding the additional strength member.

6. The optical cable according to claim 1, characterized in that, The thickness of the buffer tube jacket is in the ratio of 0.1 to 1 to the cross-sectional width of one of the plurality of deformable buffer tubes.

7. The optical cable according to claim 1, characterized in that, The one or more flexible strips include a single flexible strip, such that each of the plurality of deformable buffer tubes contains exactly one of the single flexible strips.

8. An optical cable comprising: Rigid strength components; A deformable upper jacket surrounds the rigid strength member; A plurality of buffer tubes are arranged around the rigid strength member, each of the plurality of buffer tubes including one or more flexible strips, each of the one or more flexible strips including multiple optical fibers, wherein each of the plurality of buffer tubes including the corresponding strips includes a first compression modulus, and the rigid strength member having the deformable upper jacket includes a second compression modulus, the ratio of the first compression modulus to the second compression modulus being 1:1 to 1:20; and An outer jacket surrounds the plurality of buffer tubes. The deformable upper jacket includes a modulus of less than 1 GPa at -40°C, a modulus of less than 700 MPa at room temperature, and a coefficient of thermal expansion of less than 2 × 10⁻⁶ in the temperature range from room temperature to -40°C. -4 Materials at / ℃.

9. The optical cable according to claim 8, characterized in that, The deformable upper jacket comprises a polypropylene-based thermoplastic elastomer.

10. The optical cable according to claim 8, characterized in that, The deformable upper jacket comprises a material with a modulus between 50 MPa and 600 MPa in a temperature range of -40ºC to 20ºC.

11. The optical cable according to claim 8, characterized in that, The one or more flexible strips include a single flexible strip, such that each of the plurality of deformable buffer tubes contains exactly one of the single flexible strips.

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