Optical fiber bundle with deformable core element
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SCHLUMBERGER TECH CORP
- Filing Date
- 2025-12-02
- Publication Date
- 2026-06-11
Smart Images
Figure US2025057675_11062026_PF_FP_ABST
Abstract
Description
OPTICAL FIBER BUNDLE WITH DEFORMABLE CORE ELEMENTCROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Application No. 63 / 727,308, titled “OPTICAL FIBER BUNDLE WITH DEFORMABLE CORE TO GAIN STRAIN RELIEF”, filed December 3, 2025, which is hereby incorporated by reference in its entirety.BACKGROUND
[0002] Optical fiber cables used in demanding applications such as downhole monitoring, marine environments, and high-tension deployments face challenges related to mechanical stress management and optical performance preservation. Traditional optical fiber bundle designs typically rely on helical stranding arrangements to provide strain relief when cables are subjected to tensile forces. However, conventional approaches may have limitations when cables experience high working loads as the helical relief mechanism alone may be insufficient to prevent fiber-to-fiber contact and point loading that can degrade optical transmission properties. Enhanced strain relief mechanisms and improved fiber protection methods may provide benefits for optical fiber cables deployed in applications where maintaining optical coupling performance under extreme mechanical conditions is desired.SUMMARY
[0003] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0004] According to an aspect of the present disclosure, an optical fiber bundle is provided. The optical fiber bundle includes a core element having a first hardness. The optical fiber bundle includes a first optical fiber helically stranded about the core element, the first optical fiber having a second hardness greater than the first hardness. The opticalfiber bundle includes a second optical fiber helically stranded about the core element. The core element is configured to deform into a compressed state in response to an axial force or a compressive force acting on the optical fiber bundle to provide strain relief to the first optical fiber and the second optical fiber.
[0005] According to other aspects of the present disclosure, the optical fiber bundle may include one or more of the following features. The first optical fiber may be spaced apart from the second optical fiber about the central core element to define an interstitial space between the first optical fiber and the second optical fiber. In the compressed state, the central core may extend into the interstitial space. The core element may be configured to deform elastically into the compressed state. The first optical fiber and the second optical fiber may contact the core element. The core element may include a metallic wire having a soft polymer coating. The core element may include a twisted yarn. The twisted yarn may be coated with a polymer. The core element may include yarn laid parallel around a wire and a polymer coating. The core element may include a monofilament of a polymeric material. The monofilament may be coated with at least one of EPDM or nitrile.
[0006] According to another aspect of the present disclosure, an optical fiber bundle is provided. The optical fiber bundle includes a core element. The optical fiber bundle includes optical fibers helically stranded around the core element, wherein the core element has a first hardness less than a second hardness of the optical fibers, and the optical fibers are spaced apart about the core element to define interstitial spaces between adjacent optical fibers of the optical fibers. The optical fiber bundle includes a filler material surrounding the optical fibers and filling the interstitial spaces, wherein the filler material has a third hardness less than the second hardness.
[0007] According to other aspects of the present disclosure, the optical fiber bundle may include one or more of the following features. The filler material may include silicon. The core element may include a metallic wire having a soft polymer coating. The core element may include a twisted yarn. The twisted yarn may be coated with a polymer. The core element may include yarn laid parallel around a wire and a polymer coating. The core element may include a monofilament of a polymeric material. The monofilament may be coated with at least one of EPDM or nitrile.
[0008] According to another aspect of the present disclosure, an optical fiber bundle is provided. The optical fiber bundle includes a deformable core element. The optical fiber bundle includes three optical fibers helically stranded around the deformable core element, wherein the deformable core element has a hardness less than a hardness of the three optical fibers. The optical fiber bundle includes three filler elements helically stranded around the deformable core element, wherein each filler element has a hardness less than a hardness of the three optical fibers and each filler element is disposed in a respective interstitial space between radially adjacent optical fibers of the three optical fibers.
[0009] The foregoing general description of the illustrative embodiments and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.BRIEF DESCRIPTION OF FIGURES
[0010] In order to describe the manner in which the above-recited and other features of the disclosure can be obtained, a more particular description will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. For better understanding, the like elements have been designated by like reference numbers throughout the various accompanying figures. While some of the drawings may be schematic or exaggerated representations of concepts, at least some of the drawings may be drawn to scale. Understanding that the drawings depict some example embodiments, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
[0011] FIG. 1 illustrates a well-logging system with a downhole device, according to aspects of the present disclosure;
[0012] FIG. 2 illustrates a perspective cutaway view of a cable with an optical fiber bundle, according to aspects of the present disclosure;
[0013] FIG. 3 A illustrates a cross-sectional view of an optical fiber bundle in an initial state, according to aspects of the present disclosure;
[0014] FIG. 3B illustrates a cross-sectional view of the optical fiber bundle of FIG. 3A in a partially compressed state, according to aspects of the present disclosure;
[0015] FIG. 3C illustrates a cross-sectional view of the optical fiber bundle of FIG. 3A in a fully compressed state, according to aspects of the present disclosure;
[0016] FIG. 4A illustrates a cross-sectional view of an optical fiber bundle in a quad configuration, according to aspects of the present disclosure;
[0017] FIG. 4B illustrates a cross-sectional view of an optical fiber bundle in a hepta configuration, according to aspects of the present disclosure;
[0018] FIG. 5A illustrates a cross-sectional view of an optical fiber bundle with filler elements of equal diameter, according to aspects of the present disclosure;
[0019] FIG. 5B illustrates a cross-sectional view of the optical fiber bundle with filler elements having smaller diameters, according to aspects of the present disclosure;
[0020] FIG. 5C illustrates a cross-sectional view of the optical fiber bundle with filler elements having larger diameters, according to aspects of the present disclosure;
[0021] FIG. 6 illustrates a cross-sectional view of a cable with an optical fiber bundle and filler material, according to aspects of the present disclosure;
[0022] FIG. 7A illustrates a cross-sectional view of a cable with an optical fiber bundle and outer layer, according to aspects of the present disclosure;
[0023] FIG. 7B illustrates a cross-sectional view of the cable with an alternative outer layer configuration, according to aspects of the present disclosure;
[0024] FIG. 8 illustrates a cross-sectional view of a cable with an optical fiber bundle and cladding, according to aspects of the present disclosure;
[0025] FIG. 9A illustrates a cross-sectional view of a hybrid electro-optical conductor with serve wires, according to aspects of the present disclosure;
[0026] FIG. 9B illustrates a cross-sectional view of an alternative hybrid electro- optical conductor configuration, according to aspects of the present disclosure;
[0027] FIG. 10A illustrates a cross-sectional view of a cable assembly in a flat orientation configuration, according to aspects of the present disclosure; and
[0028] FIG. 10B illustrates a cross-sectional view of a cable assembly in a crosspattern configuration, according to aspects of the present disclosure.DETAILED DESCRIPTION
[0029] The following description sets forth exemplary aspects of the present disclosure. It should be recognized, however, that such description is not intended as a limitation on the scope of the present disclosure. Rather, the description also encompasses combinations and modifications to those exemplary aspects described herein.
[0030] Optical fiber bundles described herein may be configured with deformable core elements to provide enhanced strain relief capabilities when subjected to tensile and compressive forces. In some embodiments, optical fiber bundles include multiple optical fibers arranged helically around a central core element that may deform under external loading conditions. The deformable core element may fill interstitial spaces between optical fibers when compressed, thereby reducing direct fiber-to-fiber contact and minimizing point loading on individual optical fibers.
[0031] The core element may comprise various materials having different hardness characteristics compared to the optical fibers. In some embodiments, the core element may be softer than the optical fibers, allowing the core element to deform and provide cushioning when the bundle experiences external forces. The deformation of the core element may distribute mechanical stresses more evenly across the optical fiber bundle, which may help maintain optical coupling performance under high-tension conditions.
[0032] Optical fiber bundles with deformable core elements may be particularly suitable for applications involving high tensile loads, such as downhole monitoring systems, marine environments, and other demanding operational conditions. In some embodiments, the optical fiber bundle may be surrounded by filler materials that fill outer interstitial spaces and provide additional protection to the optical fibers. The combination of a deformable core element and protective filler materials may create a robust optical fiber assembly capable of withstanding significant mechanical stresses while maintaining optical transmission properties.
[0033] The helical stranding of optical fibers around the deformable core element may provide dual strain relief mechanisms. In some embodiments, the helical configuration may allow for elongation under tension, while the deformable core element may provide cushioning under compression. This dual approach may enable optical fiber bundles to handle higher working loads compared to conventional fiber bundle designs that rely solely on helical strain relief.
[0034] Referring to FIG. 1, a well-logging system 10 may be employed to deploy optical fiber cables in downhole environments for monitoring and measurement applications. The well-logging system 10 may include a downhole device 12 that may be conveyed through a geological formation 14 via a wellbore 16. In some embodiments, a casing 17 may be disposed within the wellbore 16, and the downhole device 12 may traverse the wellbore 16 within the casing 17.
[0035] The downhole device 12 may be connected to a cable 18 that extends from the surface to the downhole location. The cable 18 may incorporate optical fiber bundles with deformable core elements as described herein to withstand the high tensile and compressive forces encountered in wellbore environments. A logging winch system 20 may manage the deployment and retrieval of the cable 18, and the logging winch system 20 may include a drum 22 for spooling and unspooling the cable 18 during operations.
[0036] An auxiliary power source 24 may provide energy to the logging winch system 20 and the downhole device 12. The downhole device 12 may generate logging measurements 26 that indicate various properties of the wellbore 16 and the geological formation 14, such as pressure, temperature, strain, or vibration. In some embodiments, the logging measurements 26 may be transmitted through optical fibers within the cable 18 to surface equipment for processing and analysis.
[0037] A data processing system 28 may be positioned at the surface to receive and process the logging measurements 26 from the downhole device 12. The data processing system 28 may include a processor 30 that executes instructions for analyzing the received data. A memory 32 may store data and instructions during operation, while a storage 34 may provide long-term data retention capabilities. The data processing system 28 mayprocess the logging measurements 26 to determine properties of the geological formation 14 and conditions within the wellbore 16.
[0038] A display 36 may be connected to the data processing system 28 to provide visualization of the processed logging measurements 26. The display 36 may present well logs or other indications of properties in the geological formation 14 or the wellbore 16 that may otherwise be indiscernible to human operators. In some embodiments, the optical fiber bundles with deformable core elements may maintain optical coupling performance under the high-tension conditions encountered during well-logging operations, thereby enabling reliable transmission of the logging measurements 26 from the downhole device 12 to the surface-based data processing system 28.
[0039] Referring to FIG. 2, a cable 218 may include an optical fiber bundle 240 positioned within the cable 218 to provide optical signal transmission capabilities. FIG. 2 shows a perspective cutaway view that reveals the internal structure and arrangement of components within the cable 218, with the dotted lines indicating internal configuration and positions of the various components. An outer layer 238 may surround the optical fiber bundle 240, and a jacket 248 may encase the outer layer 238 to provide environmental protection for the internal components.
[0040] The optical fiber bundle 240 may comprise a core element 242 located at a generally centralized position within the optical fiber bundle 240 relative to surrounding optical fibers 244a-c. In some embodiments, the core element 242 may have a first hardness that differs from the hardness characteristics of surrounding optical fibers. The optical fiber bundle 240 may include multiple optical fibers arranged in a helical configuration around the core element 242. As shown in FIG. 2, the optical fiber bundle 240 may include a first optical fiber 244a, a second optical fiber 244b, and a third optical fiber 244c that may be helically stranded around the core element 242.
[0041] The first optical fiber 244a and the second optical fiber 244b may have a second hardness that may be greater than the first hardness of the core element 242. In some embodiments, the third optical fiber 244c may also have the second hardness. The helical stranding arrangement may create interstitial spaces between adjacent optical fibers and between the optical fibers and the core element 242. The first optical fiber 244a and thesecond optical fiber 244b may contact the core element 242 when the optical fiber bundle 240 is assembled in the helical configuration.
[0042] The core element 242 may be configured to deform into a compressed state in response to an axial force or a compressive force acting on the optical fiber bundle 240. When such forces are applied to the cable 218, the core element 242 may deform to fill the interstitial spaces between the optical fibers 244a, 244b, 244c. This deformation mechanism may provide strain relief to the first optical fiber 244a and the second optical fiber 244b by reducing direct fiber-to-fiber contact and minimizing point loading on the optical fibers.
[0043] As further shown in FIG. 2, each optical fiber 244a-c may include a light transmitter 246 to provide optical signal transmission capability. The light transmitter 246 may generate optical signals that may be transmitted through the optical fibers 244a, 244b, 244c within the optical fiber bundle 240. The jacket 248 may form the outermost protective layer of the optical fibers 244a-c, providing mechanical protection during deployment and operation. The hardness of the optical fibers 244a-c referred to herein may refer to a material hardness of the light transmitter 246, a material hardness of the jacket 248, or an average or overall hardness of both the jacket 248 and the light transmitter 246 combined.
[0044] The deformable characteristics of the core element 242 may enable the optical fiber bundle 240 to withstand higher tensile loads compared to conventional fiber bundle designs. In some embodiments, the core element 242 may adapt its shape to conform to available space within the optical fiber bundle 240 when compressive or tensile forces are applied. The helical stranding pattern of the optical fibers 244a, 244b, 244c around the core element 242 may provide both mechanical protection and maintained optical performance under high-tension conditions encountered in applications such as well-logging operations.
[0045] Referring to FIGS. 3A-3C, transverse cross-sectional views of an optical fiber bundle 340 may demonstrate progressive deformation characteristics of a core element 342 under varying loading conditions. The optical fiber bundle 340 may include multiple optical fibers 344 arranged in a helical configuration around the core element 342. In some embodiments, the optical fibers 344 may be positioned at substantially equal angular intervals around the core element 342 to form a triad configuration.
[0046] As shown in FIG. 3 A, the optical fiber bundle 340 may be in an initial state where the core element 342 maintains a substantially circular cross-sectional shape. In some embodiments, the optical fibers 344 may be spaced apart from each other about the core element 342, creating an interstitial space 350 between adjacent optical fibers 344. The interstitial space 350 may also exist between the optical fibers 344 and the core element 342. In the initial state, the core element 342 may retain its original geometry with minimal deformation.
[0047] With continued reference to FIG. 3B, the optical fiber bundle 340 may transition to a partially compressed state when subjected to external compressive or tensile forces. The core element 342 may begin to deform under the compressive forces transmitted through the surrounding optical fibers 344. In some embodiments, the core element 342 may extend into the interstitial space 350 as the core element 342 undergoes initial deformation. The partial deformation of the core element 342 may reduce void spaces between the optical fibers 344 and may begin to provide cushioning effects within the optical fiber bundle 340.
[0048] As further shown in FIG. 3C, the optical fiber bundle 340 may reach a fully compressed state where the core element 342 has deformed substantially to fill the interstitial space 350 between the optical fibers 344. The core element 342 may be configured to deform elastically into the compressed state, allowing the core element 342 to adapt its shape to conform to available space within the optical fiber bundle 340. In some embodiments, the deformed core element 342 may create a thin cushioning layer that prevents direct contact between adjacent optical fibers 344.
[0049] The elastic deformation of the core element 342 may distribute mechanical stresses more evenly across the optical fiber bundle 340 when the bundle experiences external loading. In some embodiments, the core element 342 may substantially fill the interstitial space 350, thereby reducing point loading on individual optical fibers 344. The progressive deformation mechanism illustrated in FIGS. 3A-3C may enable the optical fiber bundle 340 to maintain optical coupling performance while providing enhanced strain relief capabilities under high-tension conditions.
[0050] The deformation characteristics of the core element 342 may depend on the material properties and hardness of the core element 342 relative to the optical fibers 344. In some embodiments, the core element 342 may have a lower hardness than the optical fibers 344, allowing the core element 342 to deform preferentially when compressive forces are applied to the optical fiber bundle 340. The elastic nature of the deformation may allow the core element 342 to return toward its original shape when external forces are reduced or removed.
[0051] The core element may comprise various material compositions that provide different deformability and cushioning characteristics within optical fiber bundles 340. In some embodiments, the selection of core element materials may influence the degree of deformation achievable under compressive and tensile loading conditions. The material properties of the core element 342 may determine how effectively the core element 342 fills interstitial spaces and provides strain relief to surrounding optical fibers 344.
[0052] In some embodiments, the core element 342 may comprise a metallic wire having a soft polymer coating. The metallic wire may be formed from materials such as copper, aluminum, steel, copper cladded aluminum, or nickel coated copper. The metallic wire may provide structural support and dimensional stability to the core element 342 while maintaining sufficient flexibility for deformation under external forces. The soft polymer coating may surround the metallic wire and may provide cushioning properties that enhance the deformability of the core element 342 when compressed by surrounding optical fibers 344.
[0053] The soft polymer coating may comprise materials that have lower hardness characteristics compared to the optical fibers 344, allowing the coated metallic wire to deform preferentially when subjected to compressive forces. In some embodiments, the soft polymer coating may distribute mechanical stresses across the surface of the metallic wire and may provide a compliant interface between the core element 342 and the optical fibers 344. The combination of the metallic wire and soft polymer coating may create a core element 342 that maintains structural integrity while providing enhanced cushioning capabilities.
[0054] Tn some embodiments, the core element 342 may comprise a twisted yarn that may be configured to deform and fill interstitial spaces 350 within the optical fiber bundle 340. The twisted yarn may be formed from various fiber materials that may be twisted together to create a flexible and compressible core element 342. The twisted yarn may have inherent porosity and compressibility characteristics that allow the twisted yarn to deform significantly when subjected to external forces from surrounding optical fibers 344.
[0055] The twisted yarn may be coated with a polymer to modify the surface properties and deformation characteristics of the core element 342. In some embodiments, the polymer coating may enhance the cushioning properties of the twisted yarn and may provide additional protection against mechanical wear during operation. The polymer coating may also improve the compatibility of the twisted yarn with surrounding filler materials and may help maintain the structural integrity of the core element 342 during repeated loading cycles.
[0056] In some embodiments, the core element 342 may comprise yarn laid parallel around a wire and a polymer coating. The yarn may be arranged in parallel strands around a central wire to create a composite core element 342 structure. The parallel yam arrangement may provide enhanced compressibility compared to twisted yarn configurations while maintaining longitudinal strength through the central wire. The polymer coating may encapsulate the yarn and wire assembly, providing a unified core element 342 with controlled deformation characteristics.
[0057] The parallel yarn configuration may allow for controlled compression of the yarn material while the central wire maintains structural continuity along the length of the core element 342. In some embodiments, the polymer coating may bond the parallel yam strands together and may provide a smooth outer surface for the core element 342. The combination of parallel yarn, central wire, and polymer coating may create a core element 342 that balances deformability with structural stability.
[0058] In some embodiments, the core element 342 may comprise a monofilament of a polymeric material that may provide uniform deformation characteristics throughout the length of the optical fiber bundle 340. The polymeric monofilament may be formed from materials that have controlled hardness and elasticity properties suitable for cushioningapplications. The monofilament structure may provide consistent cross-sectional properties and may deform uniformly when subjected to compressive forces from surrounding optical fibers 344.
[0059] The monofilament may be coated with at least one of EPDM or nitrile to enhance the cushioning and deformation properties of the core element 342. EPDM (ethylene propylene diene monomer) may provide excellent elasticity and compression set resistance, allowing the coated monofilament to recover its shape after deformation. Nitrile coatings may provide enhanced chemical resistance and may maintain flexibility across a wide temperature range. In some embodiments, the EPDM or nitrile coating may increase the effective diameter of the monofilament and may provide additional cushioning material that may be compressed into interstitial spaces 350.
[0060] The selection of core element 342 material composition may be tailored to specific application requirements, including the expected loading conditions, operating environment, and desired strain relief characteristics. In some embodiments, softer core element 342 materials may provide greater deformability and cushioning capabilities, while harder materials may provide enhanced structural support and dimensional stability. The material properties of the core element 342 may be balanced with the requirements for optical fiber 344 protection and bundle performance under various loading scenarios.
[0061] The optical fibers 344 used in the optical fiber bundles 340 may comprise various fiber types selected based on the transmission requirements and operational characteristics of the specific application. In some embodiments, the optical fibers 344 may include single mode fibers (SMF) that may support a single propagation mode and may provide low dispersion characteristics for long-distance signal transmission. The optical fibers 344 may alternatively include multiple mode fibers (MMF) that may support multiple propagation modes and may be suitable for shorter distance applications or applications requiring higher optical power handling capabilities. In some embodiments, the optical fiber bundles 340 may incorporate a combination of both SMF and MMF within the same bundle assembly, allowing for diverse optical transmission capabilities within a single cable structure.
[0062] The optical fibers 344 may be provided with protective polymer coatings that may enhance the mechanical durability and environmental resistance of the fibers during handling and operation. In some embodiments, the optical fibers 344 may have acrylate coatings that may provide flexibility and protection against mechanical damage while maintaining optical transmission properties. The optical fibers 344 may alternatively be coated with silicon materials that may offer enhanced temperature resistance and chemical compatibility with surrounding filler materials within the optical fiber bundle 340.
[0063] In some embodiments, the optical fibers 344 may be coated with polyimide materials that may provide enhanced thermal stability and mechanical strength for high- temperature applications or demanding operational environments. The optical fibers 344 may also be coated with fluoropolymers such as PFA (perfluoroalkoxy) or Tefzel that may provide superior chemical resistance and low friction characteristics. The selection of protective polymer coatings may be tailored to the specific environmental conditions and mechanical stresses expected during deployment and operation of the optical fiber bundles 340, with different coating materials providing varying degrees of protection against temperature extremes, chemical exposure, and mechanical wear.
[0064] FIGS. 4A-4B show transverse cross-sectional views of optical fiber bundles configured in alternative arrangements that accommodate different numbers of optical fibers while maintaining the deformable core element structure. The multi-fiber configurations may provide enhanced optical transmission capabilities and may offer different mechanical characteristics compared to triad arrangements. In some embodiments, the selection of fiber bundle configuration may depend on the specific transmission requirements and mechanical loading conditions of the intended application.
[0065] As shown in FIG. 4A, an optical fiber bundle 440a may be arranged in a quad configuration that includes four optical fibers 444 positioned around a core element 442a. The optical fibers 444 may be helically stranded around the core element 442a at substantially equal angular intervals, creating a symmetrical arrangement with approximately 90-degree spacing between adjacent optical fibers 444. The core element 442a may be positioned at the center of the optical fiber bundle 440a and may provide deformable characteristics similar to those described for other core element configurations.
[0066] The quad configuration of the optical fiber bundle 440a may create interstitial spaces between adjacent optical fibers 444 and between the optical fibers 444 and the core element 442a. In some embodiments, the core element 442a may be configured to deform into these interstitial spaces when the optical fiber bundle 440a is subjected to compressive or tensile forces. The four optical fibers 444 may contact the core element 442a when the optical fiber bundle 440a is assembled, and the helical stranding arrangement may distribute mechanical stresses across the core element 442a during loading conditions.
[0067] With continued reference to FIG. 4B, an optical fiber bundle 440b may be configured in a hepta formation that includes six optical fibers 444 arranged around a core element 442b. The optical fibers 444 may be helically stranded around the core element 442b at substantially equal angular intervals, creating a hexagonal arrangement with approximately 60-degree spacing between adjacent optical fibers 444. The core element 442b may be positioned at the central location within the optical fiber bundle 440b and may provide deformable cushioning capabilities when the bundle experiences external forces.
[0068] The hepta configuration of the optical fiber bundle 440b may accommodate a greater number of optical fibers 444 within a single bundle assembly compared to triad or quad configurations. In some embodiments, the six optical fibers 444 may create a more densely packed arrangement around the core element 442b, which may result in smaller interstitial spaces between adjacent optical fibers 444. The core element 442b may be configured to deform and fill these interstitial spaces when compressive forces are applied to the optical fiber bundle 440b.
[0069] The helical stranding of the optical fibers 444 around the core element 442a in the quad configuration and around the core element 442b in the hepta configuration may provide strain relief mechanisms similar to those achieved in triad arrangements. In some embodiments, the increased number of optical fibers 444 in the quad and hepta configurations may distribute mechanical loads across a greater number of contact points with the respective core elements 442a, 442b. The deformable characteristics of the core elements 442a, 442b may enable these multi-fiber configurations to maintain opticalcoupling performance while accommodating the mechanical stresses associated with higher fiber counts within the bundle assemblies.
[0070] FIGS. 5A-5C show transverse cross-sectsional views of optical fiber bundles that may incorporate filler elements in combination with optical fibers to create hepta configurations that provide enhanced mechanical properties and strain distribution characteristics. The hepta configurations may include both optical fibers and filler elements helically stranded around a deformable core element, with the filler elements positioned to occupy interstitial spaces between adjacent optical fibers. In some embodiments, the filler elements may have different diameter relationships relative to the optical fibers, allowing for customized mechanical and optical performance characteristics within the bundle assembly.
[0071] As shown in FIG. 5A, an optical fiber bundle 540a may be configured with a core element 542 positioned at the center of the bundle assembly. The optical fiber bundle 540a may include three optical fibers 544 helically stranded around the core element 542, with the optical fibers 544 positioned at substantially equal angular intervals around the core element 542. In some embodiments, the optical fiber bundle 540a may also include three filler elements, including filler element 552a, a filler element 552b, and a filler element 552c that may be helically stranded around the core element 542.
[0072] The filler elements 552a, 552b, 552c may be positioned in respective interstitial spaces between radially adjacent optical fibers 544, creating an alternating arrangement of optical fibers 544 and filler elements around the core element 542. In some embodiments, each filler element 552a, 552b, 552c may be disposed in a respective interstitial space between radially adjacent optical fibers of the three optical fibers 544. The filler elements 552a, 552b, 552c in the optical fiber bundle 540a may have diameters substantially equal to the diameters of the optical fibers 544, creating a symmetrical hepta configuration with uniform spacing between adjacent elements.
[0073] With continued reference to FIG. 5B, an optical fiber bundle 540b may demonstrate an alternative hepta configuration where the filler elements have different diameter characteristics compared to the optical fibers 544. The optical fiber bundle 540b may include the core element 542 positioned at the center, with three optical fibers 544helically stranded around the core element 542. The optical fiber bundle 540b may also include the filler elements 552a, 552b, 552c helically stranded around the core element 542 and positioned in interstitial spaces between the optical fibers 544.
[0074] In the configuration shown in FIG. 5B, the filler elements 552a, 552b, 552c may have diameters smaller than the diameters of the optical fibers 544. The smaller diameter filler elements may occupy the interstitial spaces between adjacent optical fibers 544 while providing different mechanical characteristics compared to equal-diameter configurations. In some embodiments, the smaller filler elements 552a, 552b, 552c may allow for greater deformation of the core element 542 into the interstitial spaces when the optical fiber bundle 540b is subjected to compressive forces.
[0075] As further shown in FIG. 5C, an optical fiber bundle 540c may incorporate filler elements having diameters greater than the diameters of the optical fibers 544. The optical fiber bundle 540c may include the core element 542 at the center, with three optical fibers 544 helically stranded around the core element 542. The filler elements 552a, 552b, 552c may be helically stranded around the core element 542 and may be positioned in the interstitial spaces between adjacent optical fibers 544.
[0076] The larger diameter filler elements 552a, 552b, 552c in the optical fiber bundle 540c may provide enhanced mechanical support and may influence the overall bundle geometry compared to smaller or equal diameter configurations. In some embodiments, the larger filler elements 552a, 552b, 552c may create a more robust bundle structure that may distribute mechanical loads across a greater cross-sectional area. The larger diameter filler elements may also influence the deformation characteristics of the core element 542 by providing different constraint conditions when the optical fiber bundle 540c is subjected to external forces.
[0077] The filler elements 552a, 552b, 552c in the various hepta configurations may comprise materials that have hardness characteristics less than the hardness of the optical fibers 544. In some embodiments, the filler elements may be formed from materials similar to those described for core elements, including metallic wires with soft polymer coatings, twisted yams, polymer monofilaments, or other deformable materials. The selection of filler element materials may influence the overall mechanical behavior of the optical fiberbundles 540a, 540b, 540c and may provide additional cushioning capabilities beyond those provided by the core element 542 alone.
[0078] The core element 542 in the hepta configurations may have a hardness less than the hardness of the three optical fibers 544, allowing the core element 542 to deform preferentially when the optical fiber bundles 540a, 540b, 540c are subjected to compressive or tensile forces. In some embodiments, the combination of the deformable core element 542 and the softer filler elements 552a, 552b, 552c may provide enhanced strain relief capabilities compared to configurations that rely solely on core element deformation. The multiple deformable elements within the hepta configurations may distribute mechanical stresses more effectively and may provide improved protection for the optical fibers 544 under various loading conditions.
[0079] Referring to the transverse cross-sectional view in FIG. 6, a cable 618 may incorporate an optical fiber bundle 640 that demonstrates the application of filler materials to enhance the mechanical properties and protection characteristics of helically stranded optical fiber assemblies. The cable 618 may include the optical fiber bundle 640 positioned within the cable structure to provide optical signal transmission capabilities while maintaining structural integrity under various loading conditions. The optical fiber bundle 640 may comprise a core element 642 positioned at the center of the bundle assembly, with multiple optical fibers 644 arranged helically around the core element 642 in a stranded configuration.
[0080] The optical fibers 644 may be spaced apart about the core element 642 to define interstitial spaces 650 between adjacent optical fibers 644 of the optical fibers 644. In some embodiments, the interstitial spaces 650 may also exist between the optical fibers 644 and the core element 642, creating void areas within the helically stranded assembly. The core element 642 may have a first hardness less than a second hardness of the optical fibers 644, allowing the core element 642 to deform preferentially when the optical fiber bundle 640 is subjected to compressive or tensile forces.
[0081] A filler material 654 may surround the optical fibers 644 and may fill the interstitial spaces 650 within the optical fiber bundle 640. The filler material 654 may have a third hardness less than the second hardness of the optical fibers 644, providingcushioning characteristics that complement the deformable properties of the core element 642. In some embodiments, the fdler material 654 may comprise silicon that may be applied to the helically stranded assembly through a liquid silicon application process. The stranded fiber assembly may be passed through liquid silicon to fill the outer interstitial spaces 650, ensuring that the filler material 654 penetrates into void areas between the optical fibers 644 and around the periphery of the bundle assembly. The filler material 654 may be present and surround any other fiber optic bundle configuration described herein and shown in other figures.
[0082] The liquid silicon may be cured using thermal or other curing techniques to transform the filler material 654 from a liquid state to a solid protective layer that encapsulates the optical fiber bundle 640. In some embodiments, thermal curing may involve heating the silicon-coated assembly to a predetermined temperature for a specified duration to achieve complete polymerization and solidification of the filler material 654. The cured filler material 654 may form a unified protective structure around the optical fibers 644 that maintains the helical stranding arrangement while providing mechanical protection and strain relief capabilities. The combination of the deformable core element 642 and the silicon filler material 654 may create a robust optical fiber bundle 640 capable of withstanding significant mechanical stresses while preserving optical transmission properties during operation.
[0083] Referring to FIGS. 7A-7B, which show various transverse cross-section views of optical fiber bundles including additional protective outer layers that enhance the mechanical durability and environmental resistance of silicon-coated assemblies. The protective outer layers may serve multiple functions including maintaining structural integrity, preserving bundle geometry, and providing enhanced protection against external mechanical forces and environmental conditions. In some embodiments, the selection of protective outer layer materials and configurations may be tailored to specific application requirements and operational environments.
[0084] As shown in FIG. 7A, a cable 718a may include an optical fiber bundle 740a that may be surrounded by a filler material 754 and enclosed within an outer layer 756. The optical fiber bundle 740a may include multiple optical fibers helically stranded around adeformable core element, with the filler material 754 filling outer interstitial spaces between the optical fibers to provide cushioning and protection. The outer layer 756 may include a polymer layer that may be extruded over the silicon-coated optical fiber bundle 740a to create a unified protective structure. In some embodiments, the extruded polymer layer may be formed from materials such as Tefzel, PFA (perfluoroalkoxy), or PEEK (polyetheretherketone) that may provide enhanced chemical resistance, temperature stability, and mechanical durability for demanding operational environments.
[0085] The outer layer 756 may be configured with either a smooth outer surface or a profiled outer surface depending on the specific application requirements and mechanical interface considerations. In some embodiments, a smooth outer surface may provide reduced friction characteristics and may facilitate cable deployment through conduits or other confined spaces. Alternatively, the outer layer 756 may be formed with a profiled outer surface that may include ridges, grooves, or other surface features that may enhance mechanical interlocking with surrounding cable components or may provide improved grip characteristics during handling operations. The outer layer 756 may also include a tape made of fluoropolymer, PEEK, or polyamide that may be wrapped helically around the optical fiber bundle 740a using a mechanical tape head to create a protective covering that maintains bundle integrity while providing flexibility for cable bending and manipulation.
[0086] With continued reference to FIG. 7B, a cable 718b may demonstrate an alternative protective configuration that incorporates shaped metallic elements for enhanced mechanical protection. The cable 718b may include an optical fiber bundle 740b that may be surrounded by the filler material 754 and enclosed within an outer layer 758. In some embodiments, the optical fiber bundle 740b may be enclosed within multiple shaped metal wires such as copper halves or other shaped metallic elements that may provide enhanced mechanical protection and electrical conductivity characteristics. The shaped metal wires may be configured to form a tubular profile that houses the optical fiber bundle 740b while providing structural support and protection against external compressive forces.
[0087] The outer layer 758 in the cable 718b may encapsulate the shaped metallic elements and may provide additional environmental protection for the enclosed opticalfiber bundle 740b. In some embodiments, the shaped metal wires may be formed from materials such as copper, copper alloys, aluminum, or steel that may provide both mechanical protection and electrical conductivity capabilities. The combination of shaped metallic elements and the outer layer 758 may create a robust cable structure that may withstand significant mechanical stresses while maintaining optical transmission properties and providing electrical functionality when required for hybrid electro-optical applications.
[0088] Referring to FIG. 8, a transverse cross-section view of a cable 818 is shown, may incorporate metallic cladding configurations that provide enhanced mechanical protection and electrical conductivity characteristics for optical fiber bundle assemblies. The cable 818 may include an optical fiber bundle 840 positioned at the center of the cable structure, with the optical fiber bundle 840 comprising multiple optical fibers helically stranded around a deformable core element. An outer layer 856 may surround the optical fiber bundle 840 and may provide a protective coating that encases the bundle assembly while maintaining optical coupling performance.
[0089] A cladding 860 may be applied over the outer layer 856 to form a metallic protective shell around the optical fiber bundle 840. The cladding 860 may be in contact with the outer layer 856 to ensure optical coupling and structural integrity of the cable 818 assembly. In some embodiments, the cladding 860 may be drawn over the outer layer 856 using conventional metal forming processes that create intimate contact between the metallic cladding 860 and the underlying outer layer 856. The contact between the cladding 860 and the outer layer 856 may distribute external mechanical forces across the optical fiber bundle 840 while maintaining the helical stranding arrangement of the optical fibers within the bundle.
[0090] The cladding 860 may be formed from various metallic materials selected based on the specific mechanical, electrical, and environmental requirements of the intended application. In some embodiments, the cladding 860 may comprise copper that may provide excellent electrical conductivity and corrosion resistance characteristics. The cladding 860 may alternatively be formed from aluminum that may offer reduced weight and enhanced corrosion resistance in certain environments. In some embodiments, thecladding 860 may comprise stainless steel that may provide superior mechanical strength and chemical resistance for demanding operational conditions.
[0091] For applications requiring enhanced performance under extreme environmental conditions, the cladding 860 may be formed from specialized alloy materials. In some embodiments, the cladding 860 may comprise Inconel 625 or Inconel 825 that may provide exceptional corrosion resistance and mechanical strength at elevated temperatures. The cladding 860 may also be formed from 27-7MO alloy material that may offer superior stress corrosion cracking resistance and mechanical properties for high-stress applications. The selection of metallic cladding material may be tailored to the specific operational environment and mechanical loading conditions expected during deployment and operation of the cable 818, with the cladding 860 providing both mechanical protection for the optical fiber bundle 840 and electrical functionality when required for coupled optical conductor applications.
[0092] Referring to the transverse cross-sectional views ofFIGS. 9A-9B, coupled electro-optical conductor configurations may incorporate serve wire layers that provide both electrical conductivity and mechanical support for optical fiber bundle assemblies. The coupled electro-optical conductors may enable hybrid cable designs that combine optical signal transmission capabilities with electrical power delivery or signal transmission functions. In some embodiments, the serve wire configurations may be applied over silicon-coated optical fiber bundles to create integrated assemblies that maintain optical coupling performance while providing enhanced mechanical protection and electrical functionality.
[0093] As shown in FIG. 9A, a cable 918a may include an optical fiber bundle 940 positioned at the center of the cable assembly. The optical fiber bundle 940 may comprise multiple optical fibers helically stranded around a deformable core element, with the optical fibers encapsulated by filler material as described in other configurations. Serve wires 962 may be helically wound around the optical fiber bundle 940 to create a served layer that provides both mechanical support and electrical conductivity. An outer layer 956 may encapsulate the optical fiber bundle 940, and a cladding 960 may form the outermost protective layer of the cable 918a, with the serve wires 962 between the outer layer 956and the cladding 960. The serve wires 962 may be made of copper that may provide excellent electrical conductivity characteristics, or the serve wires 962 may comprise aluminum that may offer reduced weight while maintaining adequate electrical performance. In some embodiments, the serve wires 962 may be formed from copper cladded aluminum that may combine the conductivity benefits of copper with the weight advantages of aluminum, or the serve wires 962 may comprise nickel coated aluminum that may provide enhanced corrosion resistance and electrical properties.
[0094] With continued reference to FIG. 9B, a cable 918b may demonstrate an alternative coupled electro-optical conductor construction that incorporates shaped metallic elements in combination with serve wire layers. The cable 918b may include the optical fiber bundle 940 assembled within an outer layer 956 and multiple shaped metallic wires 958 that form a larger central structure around the optical fiber bundle 940. The serve wires 962 may be applied over the shaped metallic wire assembly to hold the shaped wires together and maintain the structural integrity of the cable 918b. The cladding 960 may form over the served assembly as the outermost protective layer. The shaped metallic wires may be made of copper, aluminum, or copper cladded aluminum and may provide both structural support and electrical conductivity for the optical fiber bundle 940.
[0095] The serve wires 962 in both cable configurations may hold the respective assemblies together while distributing mechanical loads across the optical fiber bundle 940 and any associated shaped metallic elements. The cladding 960 may provide protection from external forces and may maintain optical coupling by ensuring intimate contact between the cladding 960 and the underlying layers. In some embodiments, the cladding 960 may be drawn over the served assemblies using conventional metal forming processes that create unified cable structures capable of withstanding significant tensile and compressive forces while preserving both optical transmission properties and electrical functionality. The combination of serve wires 962 and cladding 960 may enable the cables 918a, 918b to function as hybrid electro-optical conductors suitable for applications requiring both optical signal transmission and electrical power delivery or signal transmission capabilities.
[0096] Referring to further cross-sectional views of the embodiments shown in FIGS. 10A and 10B, cable assemblies may be configured to accommodate multiple optical fiber cables in organized arrangements that provide enhanced mechanical support and functionality for permanent monitoring applications. The cable assemblies may incorporate various conductor arrangements combined with structural support elements and power delivery components to create integrated cable systems suitable for demanding operational environments. In some embodiments, the cable assemblies may utilize the coupled optical conductors and coupled electro-optical conductors described in previous configurations to provide both optical signal transmission and electrical functionality within unified cable structures.
[0097] As shown in FIG. 10A, a cable assembly 1064a may be configured in a flat pack arrangement that positions multiple cables 1018 in a side-by-side orientation. The cables 1018 may comprise any combination of the optical fiber bundle configurations described herein, including coupled optical conductors or coupled electro-optical conductors that provide optical signal transmission capabilities. The cable assembly 1064a may include strength members 1066 positioned on opposite sides of the cables 1018 to provide structural support and load distribution for the cable assembly 1064a. In some embodiments, the strength members 1066 may be positioned on the left and right sides of the flat pack arrangement, creating a symmetrical configuration that distributes tensile loads across the cable assembly 1064a during deployment and operation.
[0098] A filler material 1054 may surround the cables 1018 and the strength members 1066 within the cable assembly 1064a, filling interstitial spaces between the components and providing mechanical support for the flat pack arrangement. A jacket 1068 may encapsulate the entire cable assembly 1064a, providing an outer protective layer around the cables 1018, and the strength members 1066. In some embodiments, the jacket 1068 may comprise a polymer jacket that may be reinforced with carbon or man-made fibers to enhance the mechanical strength and durability of the cable assembly 1064a for permanent monitoring applications.
[0099] With continued reference to FIG. 10B, a cable assembly 1064b may demonstrate an alternative arrangement that positions the cables 1018 in a cross-patternconfiguration. The cable assembly 1064b may include four cables 1018 arranged with two cables positioned horizontally and two cables positioned vertically, creating a symmetrical cross-pattern that distributes the cables 1018 throughout the circular cross-section of the cable assembly 1064b. Power delivery members 1070 may be positioned at comer locations between the cables 1018, providing electrical power delivery capabilities within the cable assembly 1064b. In some embodiments, the power delivery members 1070 may comprise copper wires that may provide excellent electrical conductivity for power transmission applications, enabling the cable assembly 1064b to support both optical signal transmission through the cables 1018 and electrical power delivery through the power delivery members 1070.
[0100] The filler material 1054 may surround the cables 1018 and the power delivery members 1070 within the cable assembly 1064b, filling spaces between the components and providing structural support for the cross-pattern arrangement. The jacket 1068 may encapsulate the cables 1018 and the filler material 1054 may encapsulate the jacket 1068, creating a circular cable structure that provides environmental protection and mechanical support for the enclosed components. The cable assembly 1064b shown in FIG. 10B may include the strength members 1066 and / or power delivery members 1070 in any number other than two and two, as shown. For example, the cable assembly 1064b may include one, three, or four power delivery members 1070 and / or one, two, or four strength members 1066 arranged in comers as shown. The strength members 1066 in both cable assembly configurations may be formed from galvanized improved plow steel (GIPS) that may provide high tensile strength and corrosion resistance for demanding operational environments. In some embodiments, the strength members 1066 may comprise alloy wires for improved corrosion resistance, including materials such as MP35N, 27-7MO, orHC265 that may offer enhanced performance under extreme environmental conditions. The strength members 1066 may alternatively comprise alloy cladded GIPS wires that may combine the strength characteristics of GIPS with the corrosion resistance properties of specialized alloy materials, providing optimized performance for specific application requirements.
[0101] The optical fiber bundles and cable configurations described herein may be incorporated into various cable construction styles to accommodate different deploymentrequirements and operational environments. In some embodiments, the coupled optical conductors and coupled electro-optical conductors may be utilized in conventional cable configurations that provide standard mechanical and electrical characteristics for wireline applications. The cable assemblies may alternatively be constructed in TuffLINE configurations that may offer enhanced mechanical durability and protection for demanding operational conditions. In some embodiments, the cable assemblies may be configured in StreamLINE arrangements that may provide optimized deployment characteristics and reduced drag during cable installation and retrieval operations.
[0102] The cable construction styles may accommodate mono conductor configurations that incorporate single optical fiber bundles with deformable core elements for applications requiring single-channel optical signal transmission. In some embodiments, coaxial cable configurations may be employed that position optical fiber bundles within coaxial conductor arrangements to provide both optical signal transmission and electrical functionality within unified cable structures. The cable assemblies may also be configured in hepta style arrangements that incorporate seven conductor positions, with optical fiber bundles positioned in center element locations or helical element positions depending on the specific transmission requirements and mechanical loading considerations of the intended application.
[0103] The optical fiber bundles with deformable core elements may be particularly suited for high tension applications where safe working loads exceed 10,000 Ibf. In some embodiments, the combination of helical stranding and collapsible core elements may provide dual strain relief mechanisms that enable the optical fiber bundles to withstand significantly higher tensile loads compared to conventional fiber bundle designs that rely solely on helical strain relief. The deformable core elements may compress and fill interstitial spaces when subjected to high tension conditions, thereby distributing mechanical stresses more effectively across the optical fiber bundle and reducing point loading on individual optical fibers.
[0104] The enhanced strain relief capabilities of the optical fiber bundles with collapsible cores may make these configurations particularly suitable for temporary and permanent monitoring applications in oil wells and other demanding operationalenvironments. Tn some embodiments, the optical fiber bundles may be deployed in downhole monitoring systems where cables experience extreme tensile forces, high pressures, and temperature variations during installation and operation. The deformable core elements may maintain optical coupling performance under these challenging conditions while providing the mechanical durability required for reliable long-term monitoring applications in energy, telecommunications, marine, geothermal, and oil and gas industries where coupled fiber performance under high tension conditions may be of paramount importance.
[0105] The embodiments of devices and systems have been primarily described with reference to wellbore operations such as well-logging systems and applications; the devices described herein may be used in applications other than wellbore logging and other wellbore applications. In other embodiments, devices according to the present disclosure may be used outside a wellbore or other downhole environment used for the exploration or production of natural resources. For instance, devices of the present disclosure may be used in a borehole used for placement of utility lines. Accordingly, the terms “wellbore,” “borehole” and the like should not be interpreted to limit tools, systems, assemblies, or methods of the present disclosure to any particular industry, field, or environment.
[0106] One or more specific embodiments of the present disclosure are described herein. These described embodiments are examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, not all features of an actual embodiment may be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous embodiment-specific decisions will be made to achieve the developers’ specific goals, such as compliance with system-related and business-related constraints, which may vary from one embodiment to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
[0107] Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excludingthe existence of additional embodiments that also incorporate the recited features. For example, any element described in relation to an embodiment herein may be combinable with any element of any other embodiment described herein. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about” or “approximately” the stated value, as would be appreciated by one of ordinary skill in the art encompassed by embodiments of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable manufacturing or production process, and may include values that are within 5%, within 1%, within 0.1%, or within 0.01% of a stated value.
[0108] A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made to embodiments disclosed herein without departing from the spirit and scope of the present disclosure. Equivalent constructions, including functional “means-plus-function” clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words ‘means for’ appear together with an associated function. Each addition, deletion, and modification to the embodiments that falls within the meaning and scope of the claims is to be embraced by the claims.
[0109] The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that is within standard manufacturing or process tolerances, or which still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount that is within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount. Further, it should be understood that any directions or reference frames in the preceding description are merely relative directions ormovements. For example, any references to “up” and “down” or “above” or “below” are merely descriptive of the relative position or movement of the related elements.
[0110] The present disclosure may be embodied in other specific forms without departing from its spirit or characteristics. The described embodiments are to be considered as illustrative and not restrictive. The scope of the disclosure is, therefore, indicated by the appended claims rather than by the foregoing description. Changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims
CLAIMS1. An optical fiber bundle comprising: a core element having a first hardness; a first optical fiber helically stranded about the core element, the first optical fiber having a second hardness greater than the first hardness; and a second optical fiber helically stranded about the core element; wherein the core element is configured to deform into a compressed state in response to an axial force or a compressive force acting on the optical fiber bundle to provide strain relief to the first optical fiber and the second optical fiber.
2. The optical fiber bundle of claim 1, wherein the first optical fiber is spaced apart from the second optical fiber about the core element to define an interstitial space between the first optical fiber and the second optical fiber.
3. The optical fiber bundle of claim 2, wherein in the compressed state, the core element extends into the interstitial space.
4. The optical fiber bundle of claim 3, wherein the core element is configured to deform elastically into the compressed state.
5. The optical fiber bundle of claim 1, wherein the first optical fiber and the second optical fiber contact the core element.
6. The optical fiber bundle of claim 1, wherein the core element comprises a metallic wire having a soft polymer coating.
7. The optical fiber bundle of claim 1, wherein the core element comprises a twisted yarn.
8. The optical fiber bundle of claim 7, wherein the twisted yarn is coated with a polymer.
9. The optical fiber bundle of claim 1, wherein the core element comprises yarn laid parallel around a wire and a polymer coating.
10. The optical fiber bundle of claim 1, wherein the core element comprises a monofilament of a polymeric material.
11. The optical fiber bundle of claim 10, wherein the monofilament is coated with at least one of EPDM or nitrile.
12. An optical fiber bundle comprising: a core element; optical fibers helically stranded around the core element, wherein: the core element has a first hardness less than a second hardness of the optical fibers; and the optical fibers are spaced apart about the core element to define interstitial spaces between adjacent optical fibers of the optical fibers; and a filler material surrounding the optical fibers and filling the interstitial spaces, wherein the filler material has a third hardness less than the second hardness.
13. The optical fiber bundle of claim 12, wherein the filler material comprises silicon.
14. The optical fiber bundle of claim 12, wherein the core element comprises a metallic wire having a soft polymer coating.
15. The optical fiber bundle of claim 12, wherein the core element comprises a twisted yarn.
16. The optical fiber bundle of claim 15, wherein the twisted yarn is coated with a polymer.
17. The optical fiber bundle of claim 12, wherein the core element comprises yarn laid parallel around a wire and a polymer coating.
18. The optical fiber bundle of claim 12, wherein the core element comprises a monofilament of a polymeric material.
19. The optical fiber bundle of claim 18, wherein the monofilament is coated with at least one of EPDM or nitrile.
20. An optical fiber bundle comprising: a deformable core element; three optical fibers helically stranded around the deformable core element, wherein the deformable core element has a first hardness less than a second hardness of the three optical fibers; and three filler elements helically stranded around the deformable core element, wherein each filler element has a third hardness less than the second hardness of the three optical fibers and each filler element is disposed in a respective interstitial space between radially adjacent optical fibers of the three optical fibers.