The present invention relates to the technical field of optical fiber
cables, and more particularly to an optical fiber cable with embedded strength members.
BACKGROUND
[0002] Over the last few years, there has been a rapid rise in the development
and usage of networking technology. This is particularly in the field of optical fiber cables and their applications. The optical fiber cables consist of a number of optical fibers. The optical fibers may or may not be enclosed inside buffer tubes. The number of optical fibers constitutes a core of the optical fiber cable. In addition, the core may be surrounded by one or more layers further surrounded by a sheath. The sheath protects the optical fiber cable against any mechanical breakage. Further, the sheath may be embedded with strength members. The strength members provide mechanical strength and stiffness to the optical fiber cable.
[0003] However, the strength members are prone to water penetration. A
number of water droplets may pass through the gap between the embedded strength member and sheath. The passage introduces moisture in the core or the enclosures of the optical fiber cable and reduces optical efficiency of the optical fiber cable. The water penetration reduces the efficiency of the optical fiber cable. Currently, SAP coated ARP is used to prevent water penetration. However, water swellable powders, when exposed to and mixed with water, the surfaces of the cable components that come in contact with

the water swellable agents can become slippery. Also, the situation may induce piston effect in the embedded strength members.
[0004] There are a few patent applications that provide a method to reduce
the penetration of water through the optical fiber cables. In an example, a patent application PL229143B1 discloses a cable consisting of a centrally located plastic tube filled inside with a hydrophobic gel with optical fibers embedded in it. In another example, a patent application RU196630U1 discloses a fiber-optic module with optical fibers in hydrophobic filler. In yet another example, a patent application CN103792630 discloses that hydrophobic particles are filled between the outer sheath and the cable cores as well as between the cable cores and the center reinforcement member. However, the above stated examples provide a solution to prevent water penetration though the core of the optical fiber cable and not through the gap between strength members and sheath..
[0005] In the light of above stated discussion, there is a need of optical fiber
cable having embedded strength members with a coating of hydrophobic layer to prevent ingestion of water.
OBJECT OF THE DISCLOSURE
[0006] A primary object of the present disclosure is to provide optical fiber
cable with embedded strength members coated with a hydrophobic layer.
[0007] Another object of the present disclosure is to enable prevention of
water penetration through the optical fiber cable with embedded strength members.

SUMMARY
[0008] In an aspect, the present disclosure provides an optical fiber cable.
The optical fiber cable includes one or more optical fibers. In addition, the optical fiber cable includes a core. The core encapsulates the one or more optical fibers. The one or more optical fibers are encapsulated by one or more layers. The one or more layers may include one or more buffer tubes, loose tube, tight buffered tube, binder yarns, binder film, binder tape or water blocking tape. Further, the optical fiber cable includes a sheath encapsulating the core. The sheath includes one or more embedded strength members. The one or more embedded strength members is coated with a hydrophobic material.
STATEMENT OF THE DISCLOSURE
[0009] The present disclosure provides an optical fiber cable. The optical
fiber cable includes one or more optical fibers. In addition, the optical fiber cable includes a core. The core encapsulates the one or more optical fibers. The one or more optical fibers are encapsulated by one or more layers. The one or more layers include one or more buffer tubes, loose tube, tight buffered tube, binder yarns, binder film, binder tape or water blocking tape. Further, the optical fiber cable includes a sheath encapsulating the core. The sheath includes one or more embedded strength members. The one or more embedded strength members is coated with a hydrophobic material.
BRIEF DESCRIPTION OF THE FIGURES
[0010] Having thus described the invention in general terms, reference will
now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0011] FIG. 1 illustrates a cross sectional view of an exemplary optical fiber
cable with embedded strength members, in accordance with an aspect of the present disclosure;
[0012] FIG. 2 illustrates a cross sectional view of an exemplary optical fiber
cable with 6 embedded strength members and a core having IBR bundles, in accordance with an aspect of the present disclosure; and
[0013] FIG. 3 illustrates a cross sectional view of an exemplary optical fiber
cable with 2 embedded strength members and a unitube with one or more optical fibers, in accordance with yet another aspect of the present disclosure.
[0014] It should be noted that the accompanying figures are intended to
present illustrations of exemplary aspects 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.

DETAILED DESCRIPTION
[0015] In the following description, for purposes of explanation, numerous
specific details are set forth in order to provide a thorough understanding of the present technology. It will be apparent, however, to one skilled in the art that the present technology can be practiced without these specific details. In other instances, structures and devices are shown in block diagram form only in order to avoid obscuring the present technology.
[0016] Reference in this specification to "one aspect" or "an aspect" means
that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect of the present technology. The appearance of the phrase "in one aspect" in various places in the specification are not necessarily all referring to the same aspect, nor are separate or alternative aspects mutually exclusive of other aspects. Moreover, various features are described which may be exhibited by some aspects and not by others. Similarly, various requirements are described which may be requirements for some aspects but not other aspects.
[0017] 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. Although the following description provides an optical fiber cable, the shown cable construction method can be applied to any cable with loose tube and sheath.

[0018] It should be noted that the terms "first", "second", and the like, herein
do not denote any order, ranking, quantity, or importance, but rather are used to distinguish one element from another. Further, the terms "a" and "an" herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.
[0019] FIG. 1 illustrates a cross sectional view of an exemplary optical fiber
cable 100, in accordance with an aspect of the present disclosure. The optical fiber cable 100 is used for telecommunication applications, data centers and the like. The optical fiber cable includes a core and a sheath 108. The sheath 108 encapsulates the core. The core encapsulates one or more optical fibers 102. The one or more optical fibers 102 are encapsulated by one or more layers.
[0020] Further, the optical fiber cable 100 includes one or more embedded
strength members 110. The one or more embedded strength members 110 are coated with a hydrophobic material. In an aspect, the optical fiber cable 100 further includes one or more buffer tubes 104, a first layer 106, a plurality of water swellable yarns 112 and a ripcord 114. In general, an optical fiber cable includes a plurality of fibers and carries information in the form of data between two places using light technology. The optical fiber cable 100 is a cable used for carrying light over long distances. Furthermore, the optical fiber cable 100 may simply be used to transmit optical signals (which may carry sensor data or communication data).
[0021] FIG. 2 illustrates a cross sectional view of an exemplary optical fiber
cable 200, in accordance with another aspect of the present disclosure. The optical fiber cable 200 includes a plurality of bundles of optical fibers 202, the first layer 106, the sheath 108 and the one or more embedded strength

members 110 (references made to FIG.l). In addition, the optical fiber cable 200 includes the one or more water swellable yarns 112 and the ripcord 114. In an aspect, the optical fiber cable 200 includes a core having IBR bundles 202. In another aspect, the core of the optical fiber cable 200 may or may not include the IBR bundles.
[0022] In an aspect of the present disclosure, each bundle of the plurality of
bundles 202 includes at least one intermittently bonded ribbon. The intermittently bonded ribbon includes the one or more optical fibers 102. The one or more optical fibers 102 are bonded intermittently with a matrix material to form the intermittently bonded ribbon. In an aspect of the present disclosure, number of the plurality of bundles 202 in the optical fibre cable 200 is 6. In another aspect of the present disclosure, number of the plurality of bundles 202 in the optical fibre cable 200 may be more or less than 6. In an aspect of the present disclosure, each of the plurality of bundles 202 includes binders for binding multiple IBR bundles.
[0023] FIG. 3 illustrates a cross sectional view of an exemplary optical fiber
cable 300, in accordance with yet another aspect of the present disclosure. The optical fiber cable 300 includes the one or more optical fibers 102, a unitube 304, the first layer 106, the sheath 108 and the one or more embedded strength members 110 (references made to FIG. 1). In addition, the optical fiber cable 300 includes the one or more water swellable yarns 112 and the ripcord 114. In an aspect, the unitube 304 includes the one or more optical fiber ribbons 102.
[0024] The one or more optical fibers 102 extend longitudinally along a
length of the optical fiber cable 100. The one or more optical fibers 102 is a fiber used for transmitting information as light pulses from one end to another. In addition, each of the one or more optical fibers 102 is a thin

strand of glass or plastic capable of transmitting optical signals. Also, the one or more optical fibers 102 are configured to transmit large amounts of information over long distances with relatively low attenuation. Further, each of the one or more optical fibers 102 includes a core region and a cladding region. The core region is an inner part of an optical fiber and the cladding section is an outer part of the optical fiber. Moreover, the core region is defined by a central longitudinal axis of each of the one or more optical fibers 102. In addition, the cladding region surrounds the core region.
[0025] The core region and the cladding region are formed along the central
longitudinal axis of each of the one or more optical fibers 102. Moreover, the core region and the cladding region are formed during the manufacturing stage of each of the one or more optical fibers 102. The core region has a refractive index which is greater than a refractive index of the cladding region. In an aspect, the core region has a higher refractive index than the cladding region.
[0026] Each of the one or more optical fibers 102 has a diameter in the range
of 140-250 microns. In another aspect, the diameter of each of the one or more optical fibers 102 may vary. In an aspect, each of the one or more optical fibers 102 is a single mode fiber. In another aspect, each of the one or more optical fibers 102 is a multimode fiber. In an aspect, the one or more optical fibers 102 is at least one of loose fibers, flat ribbon, corrugated ribbon and intermittently bonded ribbon. In general, a ribbon of fibers is made by placing a plurality of optical fibers parallel and joining the adjacent fibers partially or entirely with a matrix material.
[0027] In an aspect, the optical fiber cable 100 includes the one or more
buffer tubes 104. Each of the one or more buffer tubes 104 encloses the one or more optical fibers 102. In an example, each of the one or more buffer tubes 104 encloses 12 optical fibers. The one or more buffer tubes 104 may

enclose any number of optical fibers. . Each of the one or more buffer tubes 104 is a tube for encapsulating the one or more optical fibers 102. The one or more buffer tubes 104 provide support and protection to each of the one or more optical fibers 102 against crush, bend and stretch. In addition, the one or more buffer tubes 104 protect the one or more optical fibers 102 and prevent ingression of water inside. In an aspect, the one or more optical fibers 102 may be placed inside the one or more buffer tubes 104 (as shown in FIG. 1). In another aspect, the one or more fibers 102 may be bundled together using binder yarns, binder film, binder tape, water blocking tape to be placed inside the core of the optical fiber cable 100. In an example, the one or more buffer tubes 104 may be a bundle of a plurality of IBRs wound by one or more binders.
[0028] Further, the one or more buffer tubes 104 provide mechanical
isolation, physical damage protection and identification of each of the one or more optical fibers 102. In an aspect, the one or more buffer tubes 104 provide a single layer core construction.
[0029] The optical fiber cable 100 includes the one or more layers. In an
aspect, the one or more layers include the first layer 106. However, the one or more layers may include more number of layers. In an aspect, the one or more layers include a single buffer tube that is a unitube surrounding the one or more optical fibers 102 (as shown in FIG. 3). In an aspect, the first layer 106 is made of binder yarns. The binder yarn is used for binding of the core of the optical fiber cable 100. In an aspect of the present disclosure, the binder yarn is a polyester yarn. In another aspect of the present disclosure, the binder yarn is made of any other suitable material. The optical fiber cable 100 may include more layers in addition or in place of the first layer 106.

[0030] The optical fiber cable 100 includes the sheath 108. The sheath 108
surrounds the core. In an aspect, the sheath 108 surrounds the first layer 106. In an aspect, the sheath 108 is a high density polyethylene (HDPE) jacket. In another aspect, the sheath 108 may be made using any other suitable materials such as PE, MDPE, LDPE, PVC or LSZH. The sheath 108 is characterized by a thickness of at least 0.5 mm). In an aspect, the thickness of the sheath 108 may vary. In an aspect, the sheath 108 is black in color. In another aspect, the sheath 108 may be of any color. The sheath 108 interacts directly with ambient environment. In addition, the sheath 108 is a jacketing layer. The sheath 108 protects the optical fiber cable 100 against crush, bend and tensile stress along the length of the optical fiber cable 100.
[0031] The one or more embedded strength members 110 are embedded in
the sheath 108 of the optical fiber cable 100. In an aspect, the one or more embedded strength members 110 lies substantially along a longitudinal axis of the optical fiber cable 100. In another aspect, the one or more embedded strength members 110 may not lie along the longitudinal axis. In addition, the one or more embedded strength members 110 provide tensile strength and stiffness to the optical fiber cable 100.
[0032] In an aspect, the one or more embedded strength members 110 are
made of a material selected from a group. The group consists of fiber reinforced plastic, aramid reinforced plastic, steel wire or any other desired material. Further, the one or more embedded strength members 110 are characterized by a diameter. In an aspect, the one or more embedded strength members 110 has a diameter of about at least 0.5 mm. In another aspect, the diameter of the one or more embedded strength members 110 may vary. In an aspect, number of the one or more embedded strength members 110 are 2. In another aspect, the number of the one or more embedded strength members 110 may be more than 2.

[0033] The one or more embedded strength members 110 are coated with a
hydrophobic material. The hydrophobic material prevents water ingression through the gaps between the one or more embedded strength members 110 and the sheath 108.
[0034] The water penetrates through the one or more embedded strength
members 110 due to a capillary action and an external pressure head. In an aspect, the sheath 108 with coated strength members 110 is capable of passing a water penetration test performed at lm water-head applied to a 3 metre of cable sample kept for at least 24 hours. In another aspect, the water penetration test may be performed at different parameters.
[0035] The capillary action is dominant over the pressure water head due to
small pore size of the one or more embedded strength members 110. The dominant capillary action causes water penetration through the gap between the one or more strength members 110 and sheath 108. In an aspect, the capillary action is reduced by coating the hydrophobic layer over the one or more embedded strength members 110. The hydrophobic layer reduces the capillary action and the water penetration length.
[0036] In general, the hydrophobic materials are non-polar in nature and
have affinity for hydrocarbons. Affinity is the electronic property of chemical species to form chemical compounds. The affinity to hydrocarbons further improves the bonding of the one or more embedded strength members 110 with a polyethylene (hydrocarbon) and reduces the penetration of water. In addition, the hydrophobic layer improves adhesion between the one or more embedded strength members 110 and the sheath 108. Further, the hydrophobic layer includes a number of hydrophobic materials. In an example, the hydrophobic materials include at least one of fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE),

perfluoroalkoxy (PFA), terapolymer (EFEP) and the like. EFEP is a terapolymer composed of three materials - ethylene, tetrafluroethylene and hexafluoropropyl ene.
[0037] In an aspect, the thickness of coating of the hydrophobic layer is in a
range of 20-100 microns. A thickness of below 20 microns makes the one or more embedded strength members 110 difficult to coat and maintain uniformity. In addition, a thickness of above 100 microns makes the coating thick and requires high thickness of sheath for the one or more embedded strength members 110. In an aspect, the one or more embedded strength members 110 may be aramid reinforced plastic (ARP), fiber reinforced plastic (FRP), glass reinforced plastic (GRP) and other suitable material.
[0038] In an aspect, the contact angle between water and the coated one or
more embedded strength members 110 is equal to or more than 100 degrees. In another aspect, the contact angle between water and the coated one or more embedded strength member 110 may be of any other value. In general, a contact angle is formed when a drop of liquid is placed on a material surface and the drop forms a dome shape on the surface. In addition, the contact angle refers to the angle formed between the surface and the line tangent to the edge of the drop of the water. As the drop of water spreads across a surface and the dome becomes flatter, correspondingly the contact angle becomes smaller. In an aspect, the hydrophobic materials have a contact angle greater than 90 degrees. The hydrophobicity increases with the increase in contact angle.
[0039] In an aspect, the one or more embedded strength members 110 are
coated with the hydrophobic material by extrusion, wiping or brushing, spraying or passing through liquid resin. The hydrophobic material is coated by extruding the hydrophobic material. In general, extruding includes

pushing any material through a die of the desired cross section to create objects. In addition, the hydrophobic material is coated by dipping the hydrophobic material in a liquid resin when the hydrophobic material is in dispersion form.
[0040] In an aspect, the pulling force between the one or more embedded
strength members 110 and the sheath 108 is greater than 0.1 N/mm2. In
addition, the pulling is performed by fixing one end of a 1 metre cable sample and pulling the one or more embedded strength members 110 from the another open end.
[0041] In an aspect, the hydrophobic material may be obtained by surface
modification of a hydrophilic material using one of acetylation, metal oxide treatment, sol-gel process, modification with chlorosilanes and grafting of polymers. In addition, the hydrophobic material is obtained by micro emulsion, layer by layer deposition, plasma treatment and nanotechnology.
[0042] In general, acetylation is an organic esterification reaction with acetic
acid. The acetylation process introduces an acetyl functional group into a chemical compound. In addition, the metal oxide treatment includes the treatment of the hydrophilic material with metal oxide polymer in nanocomposite form. Further, the sol-gel process is a method for producing solid materials from small molecules. Furthermore, the modification with chlorosilanes includes reaction of silicon powder with methyl chloride gas through direct synthesis. Moreover, grafting is a process in which monomers are covalently bonded and polymerized as side chains onto the main polymer chain.

[0043] The hydrophobic material may be obtained through the micro
emulsion. In general, micro emulsions are clear, thermodynamically stable, isotropic liquid mixtures of oil, water, surfactant and cosurfactant. In addition, the layer by layer deposition is a thin film fabrication technique. The films are formed by depositing alternating layers of oppositely charged materials with wash steps in between. Further, the plasma treatment includes increasing the wettability of any polymer. Furthermore, the nanotechnology is the understanding and control of matter at the nanoscale, at dimensions approximately 1 to 100 nanometres.
[0044] In an aspect, the coating of the one or more embedded strength
members 110 is applicable to IBR based optical fiber cables. In another aspect, the coating of the one or more strength members 110 may be applicable to any other cable with embedded strength members.
[0045] In an aspect, the optical fiber cable 100 may or may not include the
plurality of water swellable yarns 112. The plurality of water swellable yarns 112 may be positioned between the one or more buffer tubes 104. The plurality of water swellable yarns 112 prevents ingression of water in the stranded core of the optical fiber cable 100. In an aspect, the number of the plurality of water swellable yarns 112 is 2. In another aspect, the number of the plurality of water swellable yarns 112 may vary.
[0046] The optical fiber cable 100 may include at least one of the central
strength member (not shown in FIG.l). Moreover, the central strength member is made of a fiber reinforced plastic. The fiber reinforced plastic is a composite material made of a polymer matrix reinforced with glass fibers. Examples of the fiber reinforced plastic include glass fiber, carbon fiber, aramid fiber and the like. In an aspect, the central strength member is made of any suitable material.

[0047] The optical fiber cable 100 may or may not include the ripcord 114.
In an aspect, the optical fiber cable 100 may include more ripcords. In an aspect, the ripcord 114 is placed inside the sheath 108. The ripcord 114 lies substantially along the longitudinal axis of the optical fiber cable 100. In an aspect, the ripcord 114 facilitates stripping of the sheath 108. In an aspect, the ripcord 114 is made of a polyester material. In another aspect, the ripcord 114 is made of any suitable material. In an aspect, the ripcord 114 has circular cross-section. In an aspect, a number of the ripcord 114 is 1. In another aspect, the number of the ripcord 114 may vary.
[0048] The foregoing descriptions of specific aspects of the present
technology have been presented for purposes 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 aspects 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 aspects 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.
[0049] While several possible aspects 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 aspect should not be limited by any of the above-described exemplary aspects.

CLAIMS

What is claimed is:

1. An optical fiber cable (100) comprising:
one or more optical fibers (102);
a core, wherein the core encloses the one or more optical fibers (102) encapsulated by one or more layers; and
a sheath (108) encapsulating the core, wherein the sheath (108) comprising one or more embedded strength members (110), wherein the one or more embedded strength members (110) is coated with a hydrophobic material.
2. The optical fiber cable (100) as recited in claim 1, wherein the hydrophobic material is one of perfluoroalkoxy (PFA), flurorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE) and terapolymer (EFEP).
3. The optical fiber cable (100) as recited in claim 1, wherein the sheath (108) is capable of passing a water penetration test, wherein a lm water-head is applied to a 3 metre cable sample kept for at least 24 hours.
4. The optical fiber cable (100) as recited in claim 1, wherein a contact angle between water and the one or more coated embedded strength member (110) is equal to or more than 100 degrees.

5. The optical fiber cable (100) as recited in claim 1, wherein a thickness of the hydrophobic material coating is in a range of 20 microns to 100 microns.
6. The optical fiber cable (100) as recited in claim 1, wherein the one or more embedded strength members (110) are coated with the hydrophobic material by extrusion, vapour spray or passing through the liquid resin.
7. The optical fiber cable (100) as recited in claim 1, wherein a pulling force between the one or more embedded strength members (110) and the sheath (108) is greater than 0.1 N/mm2 and wherein pulling is performed by fixing one end of a lm cable sample and pulling the one or more embedded strength member (110) from another open end.
8. The optical fiber cable (100) as recited in claim 1, wherein the one or more embedded strength members (110) are coated with the hydrophobic material obtained by surface modification of a hydrophilic material using one of acetylation, metal oxide treatment, sol-gel process, modification with chlorosilanes, grafting of polymers, micro-emulsion, layer by layer deposition, plasma treatment and nanotechnology.
9. The optical fiber cable (100) as recited in claim 1, wherein the one or more optical fibers (102) is encapsulated by at least one of a buffer tube, loose tube, tight buffered tube, binder yarns, binder film, binder tape, water blocking tape.