Description:FIELD OF INVENTION
[0001] The present disclosure relates to the field of optical fibre cable and, in particular, relates to an optical fibre cable with elongated strength members and manufacturing method thereof. The present application is a divisional application and is based on, and claims priority from an Indian Provisional Application Number 202311032006 filed on 5th May, 2023.
TECHNICAL FIELD
[0002] The present disclosure relates to the field of optical fiber cables and, in particular, relates to an optical fiber cable with metal armoring.

BACKGROUND
[0003] Optical fibers are widely used to transmit information or data in form of light from one place to another. The optical fibers are disposed within the optical fiber cable. The optical fiber cables are widely known in the prior art. In armoured cables, usually, a water blocking tape gets a reverse fold during manufacturing and optical fibers come out of it. If armour tape is right above, the bunches of optical fibers can trap in between two ends of armour tape and can lead to damage in optical fibers. There are various references that disclose different types of optical fiber cables. For example, the reference US6256438B1 discloses fibers enclosed by a metal armour having a water swellable coating on its inner surface. The reference also discloses about use of a separate water swellable layer. The reference US7590322B2 discloses about a water blocking tape over the ribbon stack and an overlapping position. The reference further discloses about a metal armour layer that is positioned above a central tube. The reference EP1170614A1 discloses an electro chrome coated steel (ECCS) tape with an overlap portion of at least 2mm. The ECCS is made up of a water blocking material that is applied over its inner surface. The optical fiber cables of the prior art references remain weaker and thereby the optical fibers are prone to damage.
[0004] In light of the above stated discussion, there is a need for an optical fiber cable with an optimal placement of various layers that provide strength to the optical fiber cable and overcomes the above stated disadvantages of the conventional optical fiber cables.
SUMMARY
[0005] In an aspect of the present disclosure, an optical fiber cable is disclosed. The optical fiber cable has a plurality of optical fibers. The optical fiber cable further has a first layer wrapped around the plurality of optical fibers. The first layer has first and second end portions such that the first end portion overlaps the second end portion to define a first overlap region. The first overlap region has a first predefined width along an axial length of the optical fiber cable. The optical fiber cable further has a second layer that is wrapped around the first layer. The second layer has third and fourth end portions such that the third end portion overlaps the fourth end portion to define a second overlap region. The second overlap region has a second predefined width along the axial length of the optical fiber cable. The first overlap region and the second overlap region are positioned differently at one or more cross-section along the axial length of the optical fiber cable.

BRIEF DESCRIPTION OF DRAWINGS
[0006] Having thus described the disclosure in general terms, reference will now be made to the accompanying figures, where:
[0007] FIG. 1 illustrates a cross-sectional view of an optical fiber cable.
[0008] FIG. 2 illustrates a cross-sectional view of another optical fiber cable.
[0009] FIG. 3 illustrates a perspective view of the optical fiber cable of FIG. 1.
[0010] It should be noted that the accompanying figures are intended to present illustrations of exemplary embodiments of the present disclosure. These figures are not intended to limit the scope of the present disclosure. It should also be noted that accompanying figures are not necessarily drawn to scale.

DEFINITIONS
[0011] The term “optical fiber” as used herein refers to a light guide that provides high-speed data transmission. The optical fiber has one or more glass core regions and a glass cladding region. The light moving through the glass core regions of the optical fiber relies upon the principle of total internal reflection, where the glass core regions have a higher refractive index (n1) than the refractive index (n2) of the glass cladding region of the optical fiber.
[0012] The term “optical fiber cable” as used herein refers to a cable that encloses a plurality of optical fibers.
[0013] The term "single mode fiber” as used herein refers to a single glass fiber strand that may allow transmission of the light. The single mode fiber may feature only transmission mode.
[0014] The term “multi-mode fiber” as used herein refers to an optical fiber that supports propagation of multiple modes.
[0015] The term “single core fiber” as used herein refers to an optical fiber that has single core for transmission of data/light.
[0016] The term “multi-core fiber” as used herein refers to an optical fiber that has multiple cores for transmission of data/light.
[0017] The term “intermittently bonded ribbon (IBR)” as used herein refers to an optical fiber ribbon having a plurality of optical fibers such that the plurality of optical fibers is intermittently bonded to each other by a plurality of bonded portions that are placed along the length of the plurality of optical fibers. The plurality of bonded portions is separated by a plurality of unbonded portions.

DETAILED DESCRIPTION
[0018] The detailed description of the appended drawings is intended as a description of the currently preferred aspects of the present disclosure, and is not intended to represent the only form in which the present disclosure may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different aspects that are intended to be encompassed within the spirit and scope of the present disclosure.
[0019] Moreover, although the following description contains many specifics for the purposes of illustration, anyone skilled in the art will appreciate that many variations and/or alterations to said details are within the scope of the present technology. Similarly, although many of the features of the present technology are described in terms of each other, or in conjunction with each other, one skilled in the art will appreciate that many of these features can be provided independently of other features. Accordingly, this description of the present technology is set forth without any loss of generality to, and without imposing limitations upon, the present technology.
[0020] FIG. 1 illustrates a cross sectional view of an optical fiber cable 100. The optical fiber cable 100 may be installed through various aerial overhead poles or laid inside various ducts that may be used in different applications. The optical fiber cable 100 may have a plurality of optical fibers 102a-102n (hereinafter collectively referred to and designated as “the optical fibers 102”), a first layer 104, a second layer 106, one or more ripcords 108a-108n (hereinafter collectively referred to and designated as “the ripcords 108”), and a sheath 110. The first layer 104 may have first and second end portions 112, 114. The second layer 106 may have third and fourth end portions 116, 118.
[0021] The optical fibers 102 may be disposed within the optical fiber cable 100. Specifically, the optical fibers 102 may extend up to a length of the optical fiber cable 100. Each optical fiber of the optical fibers 102 may be a cylindrical dielectric waveguide that may facilitate transmission of light along the length of the optical fiber cable 100. Each optical fiber of the optical fibers 102 may have a core (not shown) and a clad layer (not shown) such that the clad layer may surround the core. Specifically, the light may travel through the core of each optical fiber of the optical fibers 102. The clad layer may be adapted to prevent leakage of the light out of each optical fiber of the optical fibers 102. In some preferred aspects of the present disclosure, the core and the clad layer may be made up of a dielectric material.
[0022] In some aspects of the present disclosure, each optical fiber of the optical fibers 102 may be, but not limited to, a single mode fiber, a multi-mode fiber, a single core fiber, and a multi-core fiber. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the optical fiber of the optical fibers 102, without deviating from the scope of the present disclosure.
[0023] In some aspects of the present disclosure, the optical fibers 102 may be in form of including, but not limited to, bunches of ribbons 120a-120n (hereinafter collectively referred to and designated as “the ribbons 120”) and loose fibers. Each ribbon of the bunches of ribbons 120 may be formed by grouping a set of optical fibers of the optical fibers 102. The grouping of the set of optical fibers of the optical fibers 102 may involve adjoining or binding of the set of optical fibers of the optical fibers 102. In some aspects of the present disclosure, the optical fibers 102 may be in form of including, but not limited to, stacks of ribbons, bundles of ribbons, and intermittently bonded ribbon (IBR) bundles. In some aspects of the present disclosure, each ribbon of the ribbons 120 may be an intermittently bonded ribbon (IBR). Each IBR of the IBRs may have a set of optical fibers of the optical fibers 102 such that the set of optical fibers are disposed parallel to each other. The set of optical fibers of the optical fibers 102 may be intermittently bonded by a plurality of bonded portions that may be separated by a plurality of unbonded portions. In some aspects of the present disclosure, each IBR of the IBRs may be placed without any binding element. In some examples, each IBR of the IBRs may be placed with a binding element. In other words, each IBR of the IBRs may be bound by way of one or more binders to form bundles of IBRs. The common materials used as binders in the industry typically include tape, yarns, and other suitable binding materials. In an alternative, the binder may comprise a thin polymeric film or thin polymeric tubes, with a thickness ranging from 0.05mm to 0.3mm. Aspects of the present disclosure are intended to include and/or otherwise cover any form of the optical fiber of the optical fibers 102, without deviating from the scope of the present disclosure.
[0024] The first layer 104 may be wrapped around the optical fibers 102. While wrapping around the optical fibers 102, the first end portion 112 may overlap with the second end portion 114 to define a first overlap region 122. The first overlap region 122 may have a first predefined width (W1) along an axial length of the optical fiber cable 100.
[0025] In some aspects of the present disclosure, the first layer 104 may be, but not limited to, a water blocking tape (WBT) and a mica tape. In some other aspects of the present disclosure, the first layer 104 may be a fire-retardant water blocking tape, a heat barrier tape, a polyester tape, and the like. Additionally, the first layer 104 may comprise other common materials such as aramid yarn, IGFR yarns, polymeric yarns, or combinations thereof. The traditional construction of first layer 106 as WBT is either a woven tape or a non-woven tape coated with a superabsorbent material and has a thickness in range 0.1mm to 1.0mm. Further, in order ensure complete water blocking, additional water-blocking components or absorbent materials are frequently added between the fiber or ribbon bundles, as well as in other positions within the core of the cable 100. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the first layer 104, without deviating from the scope of the present disclosure.
[0026] The second layer 106 may be wrapped around the first layer 104. While wrapping around the first layer 104, the third end portion 116 may overlap with the fourth end portion 118 to define a second overlap region 124. The second overlap region 124 may have a second predefined width (W2) along the axial length of the optical fiber cable 100. Specifically, the first overlap region 122 and the second overlap region 124 may be positioned differently at one or more cross-section along the axial length of the optical fiber cable 100. In other words, the first overlap region 122 and the second overlap region 124 may not co-exist or overlap at any cross section along the axial length of the optical fiber cable 100. Specifically, the first overlap region 122 and the second overlap region 124 may be spaced apart within an angular range at one or more cross-section along the axial length of the optical fiber cable 100.
[0027] In some aspects of the present disclosure, the second layer 106 may be a metallic tape. In some other aspects of the present disclosure, the second layer 106 may be, but not limited to, a metal armor and an electrolytic chrome-coated steel (ECCS) tape. Additionally, the armor layer 106 may also comprise of other common elements such as aluminum tape, spiral interlocking steel, or spiral interlocking aluminum. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the second layer 106, without deviating from the scope of the present disclosure.
[0028] In some aspects of the present disclosure, the first and second overlap regions 122 and 124 have first and second centers 126 and 128, respectively such that an angle between (i) a plane joining the first center 126 with a center 130 of the optical fiber cable 100 and (ii) a plane joining the second center 128 with the center 130 of the optical fiber cable 100 may be restricted by an angle of 180 Degrees (180o) with a tolerance value of 45 Degrees (45o). In other words, the angle between the first and second centers 126 and 128 may be restricted to 1800 + 45o. The angle of 180o + 45o between the first and second centers 126 and 128 may prevent the optical fibers 102 to come out from the optical fiber cable 100. Further, during manufacturing or handling of the optical fibers 102, the optical fibers 102 may come out of the first layer 104, however, by virtue of the angle of 1800 + 45o between the first and second centers 126 and 128, the optical fibers 102 may not get trapped inside the overlap region 124 of the second layer 106. This may prevent physical damage of the optical fibers 102.
[0029] In some aspects of the present disclosure, (i) the plane joining the first center 126 with the center 130 of the optical fiber cable 100 and (ii) the plane joining the second center 128 with the center 130 of the optical fiber cable 100 may be restricted by an angle of 90 Degrees (90o) with a tolerance value of 45 Degrees (45o). In other words, the angle between the first and second centers 126 and 128 may be restricted to 90o + 45o. The angle of 90o + 45o between the first and second centers 126 and 128 may prevent the optical fibers 102 to come out from the optical fiber cable 100. Further, during manufacturing or handling of the optical fibers 102, the optical fibers 102 may come out of the first layer 104, however, by virtue of the angle of 90o + 45o between the first and second centers 126 and 128, the optical fibers 102 may not get trapped inside the overlap region 124 of the second layer 106. This may prevent physical damage of the optical fibers 102.
[0030] In some aspects of the present disclosure, (i) the plane joining the first center 126 with the center 130 of the optical fiber cable 100 and (ii) the plane joining the second center 128 with the center 130 of the optical fiber cable 100 may be restricted by an angle of 270 Degrees (270o) with a tolerance value of 45 Degrees (45o). In other words, the angle between the first and second centers 126 and 128 may be restricted to 270o + 45o. The angle of 270o + 45o between the first and second centers 126 and 128 may prevent the optical fibers 102 to come out from the optical fiber cable 100. Further, during manufacturing or handling of the optical fibers 102, the optical fibers 102 may come out of the first layer 104, however, by virtue of the angle of 270o + 45o between the first and second centers 126 and 128, the optical fibers 102 may not get trapped inside the overlap region 124 of the second layer 106. This may prevent physical damage of the optical fibers 102.
[0031] In some aspects of the present disclosure, the ripcords 108 may be positioned between the first and second layers 104 and 106. The ripcords 108 may be adapted to facilitate tearing of the sheath 110 and the second layer 106. Specifically, the ripcords 108 may be adapted to facilitate tearing of the sheath 110 and the second layer 106 to access the optical fibers 102.
[0032] In some aspects of the present disclosure the one or more ripcords 108a-108n may be positioned between the first overlap region 122 and the second overlap region 124 at any cross-section along the axial length of the optical fiber cable 100.
[0033] In some aspects of the present disclosure, the first predefined width (W1) may be in a range between 5 millimeters (mm) and 10 mm. Specifically, the first predefined width (W1) may be preferably kept in the range between 5 millimeters (mm) and 10 mm, as the first predefined width (W1) being lesser than 5 mm may produce the first overlap region 122 of a smaller width, which may cause the optical fibers 102 to come out from the first overlap region 122. The first predefined width (W1) being greater than 10 mm, may require additional material to be placed in the optical fiber cable 100, which may leave low space for the optical fibers 102.
[0034] In some aspects of the present disclosure, the second predefined width (W2) may be in a range between 2 mm and 6 mm. Specifically, the second predefined width (W2) may be preferably kept in the range between 2 mm and 6 mm, as the second predefined width (W2) being lesser than 2 mm, may produce the second overlap region 124 of a smaller width, which may add difficulty in manufacturing the optical fiber cable 100. The second predefined width (W2) being greater than 6 mm, may require additional material to be placed in the optical fiber cable 100, which may leave low space for the optical fibers 102.
[0035] In some aspects of the present disclosure, material of the sheath 110 may be, but not limited to, polyethylene, low-smoke zero-halogen (LSZH), polyvinyl chloride (PVC), thermoplastic polyurethane (TPU), and the like. Aspects of the present disclosure are intended to include and/or otherwise cover any type of known and later developed materials, without deviating from the scope of the present disclosure.
[0036] In some aspects of the present disclosure, the first layer 104 and the second layer 106 are at least partially in contact with each other along the axial length of the optical fiber cable 100.
[0037] FIG. 2 illustrates a cross sectional view of another optical fiber cable 200. The optical fiber cable 200 may be substantially similar to the optical fiber cable 100, in terms of structural and functional aspects and the like elements of the optical fiber cable 100 are referenced with like numerals in the optical fiber cable 200. However, the optical fiber cable 200 is provided with a plurality of strength members 202a-202n (hereinafter collectively referred to and designated as “the strength members 202”) that are embedded in the sheath 110. Partial embedding or fully embedding are the only two alternatives for the strength members 202. Further, it is industry practice to coat the strength member 202a-202n, which is embedded in the sheath 110, with a non-abrasive or adhesive material to ensure it sticks securely to the sheath without deteriorating. Additionally, superabsorbent material may be coated to prevent water leakage and protect the integrity of the cable. In an embodiment, strength members may be positioned in the central core of the cable 100. The strength members 202 may provide the required tensile strength and stiffness to the optical fiber cable 200. Each strength member of the strength members 202 may be made up of a material, having but not limited to, a reinforced aramid yarn, a reinforced glass yarn, and steel. The commonly available strength members (202) comprise of steel wires, aramid reinforced plastic (ARP), fiber reinforced plastic (FRP), glass reinforced plastic (GRP), aramid yarn, and impregnated glass fiber reinforcement (IGFR) yarn. Aspects of the present disclosure are intended to include and/or otherwise cover any type of material for each strength member of the strength members 202, without deviating from the scope of the present disclosure.
[0038] Further, in the optical fiber cable 200, the plane joining the first center 126 with the center 130 of the optical fiber cable 100 and (ii) the plane joining the second center 128 with the center 130 of the optical fiber cable 100 may be restricted by an angle of 90 Degrees (90o) with a tolerance value of 45 Degrees (45o). In other words, the angle between the first and second centers 126 and 128 may be restricted to 900 + 45o. The angle of 90o + 45o between the first and second centers 126 and 128 may prevent the optical fibers 102 to come out from the optical fiber cable 100. Further, during manufacturing or handling of the optical fibers 102, the optical fibers 102 may come out of the first layer 104, however, by virtue of the angle of 900 + 45o between the first and second centers 126 and 128, the optical fibers 102 may not get trapped inside the second overlap region 124 of the second layer 106. This may prevent physical damage of the optical fibers 102.
[0039] In some aspects of the present disclosure, the first predefined width (W1) may be in a range between 5 millimeters (mm) and 10 mm. Specifically, the first predefined width (W1) may be preferably kept in the range between 5 mm and 10 mm, as the first predefined width (W1) being lesser than 5 mm, may produce the first overlap region 122 of a smaller width, which may cause the optical fibers 102 to come out from the first overlap region 122. The first predefined width (W1) being greater than 10 mm, may require additional material to be placed in the optical fiber cable 100, which may leave low space for the optical fibers 102.
[0040] In some aspects of the present disclosure, the second predefined width (W2) may be in a range between 2 mm and 6 mm. Specifically, the second predefined width (W2) may be preferably kept in the range between 2 mm and 6 mm, as the second predefined width (W2) being lesser than 2 mm, may produce the second overlap region 124 of a smaller width, which may add difficulty in manufacturing the optical fiber cable 100. The second predefined width (W2) being greater than 6 mm, may require additional material to be placed in the optical fiber cable 100, which may leave low space for the optical fibers 102.
[0041] FIG. 3 illustrates a perspective view of the optical fiber cable 100 of FIG. 1. For sake of brevity, not all the elements or components of the optical fiber cable 100 are shown in FIG. 3. However, FIG. 3 clearly shows the first overlap region 122 of the first layer 104 and the second overlap region 124 of the second layer 106. Specifically, FIG. 3 shows that the first overlap region 122 is disposed diametrically opposite to the second overlap region 124. In other words, FIG. 3 shows that the angle between (i) the plane joining the first center 126 with the center 130 of the optical fiber cable 100 and (ii) the plane joining the second center 128 with the center 130 of the optical fiber cable 100 may be restricted to 1800 + 45o. The angle of 180o + 45o between the first and second centers 126 and 128 may prevent the optical fibers 102 to come out from the optical fiber cable 100. Further, during manufacturing or handling of the optical fibers 102, the optical fibers 102 may come out of the first layer 104, however, by virtue of the angle of 180o + 45o between the first and second centers 126 and 128, the optical fibers 102 may not get trapped inside the overlap region 124 of the second layer 106. This may prevent physical damage of the optical fibers 102.
[0042] Thus, the optical fiber cables 100 and 200 may advantageously have a reduced diameter. By virtue of relative positioning of the first overlap region 122 with respect to the second overlap region 124, the optical fibers 102 may be protected from any kind of physical damage. Further, by virtue of relative positioning of the first overlap region 122 with respect to the second overlap region 124, the optical fibers 102 may not get trapped in the second layer 106, if by any chance the optical fibers 102 comes out from the first layer 104.
[0043] The foregoing descriptions of specific embodiments of the present technology have been presented for purpose of illustration and description. They are not intended to be exhaustive or to limit the present technology to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present technology and its practical application, to thereby enable others skilled in the art to best utilize the present technology and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present technology.
[0044] While several possible embodiments of the invention have been described above and illustrated in some cases, it should be interpreted and understood as to have been presented only by way of illustration and example, but not by limitation. Thus, the breadth and scope of a preferred embodiment should not be limited by any of the above-described exemplary embodiments. , Claims:Claims
We Claim(s):
1. An optical fiber cable (100) comprising:
a. a central core comprising a plurality of bundles (120) enclosing a plurality of optical fibers (106);
b. an armor layer (102) enclosing the central core;
c. a first layer (104) located between the armor layer (106) and the central core; and
d. an outer cable jacket (110).
2. The optical fiber cable (100) as claimed in claim 1, wherein said bundle has wall thickness in the range of 0.05 mm to 0.3 mm.
3. The optical fiber cable (100) as claimed in claim 1, wherein the plurality of optical fibers (102) in at least a bundle (120) are arranged in the form of intermittently bonded ribbons (IBRs).
4. The optical fiber cable (100) as claimed in claim 1, wherein the armor layer (106) is selected from the group comprising of corrugated steel tape, aluminum tape, spiral interlocking steel, and spiral interlocking aluminum.
5. The optical fiber cable (100) as claimed in claim 1, wherein the first layer (104) material is selected from the group comprising of barrier tape, water blocking tape, polyester tape, aramid yarn, IGFR yarns, polymeric yarns, and combinations thereof.
6. The optical fiber cable (100) as claimed in claim 1, wherein the first layer (104) is restrictively wrapped around the plurality of bundles (120).
7. The optical fiber cable (100) as claimed in claim 1, wherein the first layer (104) has a thickness in range 0.1-1 mm.
8. The optical fiber cable (100) as claimed in claim 1, comprising at least a strength
member (202) partially or fully embedded in the outer cable jacket (110).
9. The optical fiber cable (100) as claimed in claim 1, comprising at least a strength
member (202) located in the central core.
10. The optical fiber cable (100) as claimed in claims 8-9, wherein at least a strength member (202) is coated with any one or more of non-abrasive material, adhesive material, water absorbent material, and combinations thereof.
11. The optical fiber cable (100) as claimed in claim 10, wherein the strength member (202) is selected from the group comprising of steel wires, aramid reinforced plastic (ARP), fiber reinforced plastic (FRP), glass reinforced plastic (GRP), aramid yarn, and impregnated glass fiber reinforcement (IGFR).
12. The optical fiber cable (100) as claimed in claim 1, comprising at least a water-absorbent material enclosed within the plurality of bundles, or additionally between the plurality of bundles.