The present disclosure relates to the field of optical fibre cable and, in
particular, relates to an armored optical fibre cable.
BACKGROUND
[0002] With the advancement of science and technology, various modern
technologies are being employed for communication purposes. One of the most important modern communication technologies is the optical fiber communication technology using a variety of optical fiber cables. One such type of optical fiber cables is an armored optical fiber cable. These armored optical fiber cables are surrounded by a steel or aluminium jacket which is then covered with a polyethylene jacket to protect it from moisture and abrasion. The armored optical fibre cables may be installed in ducts, or placed in underground enclosures with special protection from dirt and clay intrusion. The armored optical fibre cables face the issue of improper or difficulty of sheath removal because of the bonding between the sheath and steel tape. In order to deal with this issue, there is a need to prevent this bonding in the armored optical fibre cables.
[0003] WO2004083928A1 discloses a fiber optic cable that has one or more
optical fibers, an inner tube surrounding the optical fibers, a strength member, an inner jacket surrounding the inner tube and strength member, and an outer jacket surrounding the inner jacket without being adhered to the inner jacket such that the outer jacket is easily strippable from the inner jacket. The inner jacket is constructed of a flexible, flame resistant material such as braided glass fibers, while the outer jacket may be constructed of a stiffer, flame retardant material such as polyvinyl chloride.

[0004] US2009274426A1 discloses a fiber optic cable that includes at least
one optical fiber and a protective layer generally disposed about the optical fiber. A cable jacket surrounds an outer surface of the protective layer, and a control layer is interposed between a portion of the protective layer and a portion of the cable jacket. The control layer includes one or more apertures extending there through, thereby creating a predetermined bond between the protective layer and the cable jacket. By way of example, the protective layer is an armor layer, buffer tube, or other suitable cable component where a predetermined bond to the cable jacket is desired so the craft can easily remove a portion of the cable jacket. The plurality of apertures can have any suitable size, shape, and/or arrangement for influencing the desired bond strength. A method of manufacturing the fiber optic cable is also disclosed.
[0005] In light of the above-stated discussion, there exists a need for an
unbonded armored optical fibre cable that overcomes the above cited drawbacks of the conventional optical fibre cable.

OBJECT OF THE DISCLOSURE
[0006] A primary object of the present disclosure is to provide an unbonded
armored optical fibre cable.
SUMMARY
[0007] In an aspect, the present disclosure provides an optical fibre cable.
The optical fibre cable includes a plurality of optical fibres. The optical fibre cable includes one or more layers enveloping the plurality of optical fibres. The optical fibre cable includes a metallic layer surrounding the one or more layers. The optical fibre cable includes an outer sheath. The outer sheath has a first melting point. The optical fibre cable includes a separation layer. The separation layer is sandwiched between the metallic layer and the outer sheath. Binding between the metallic layer and the separation layer is defined as metal binding. Binding between the separation layer and the outer sheath is defined as sheath binding. The sheath binding is less than the metal binding.
STATEMENT OF THE DISCLOSURE
[0008] The present disclosure provides an optical fibre cable. The optical
fibre cable includes a plurality of optical fibres. The optical fibre cable includes one or more layers enveloping the plurality of optical fibres. The optical fibre cable includes a metallic layer surrounding the one or more layers. The optical fibre cable includes an outer sheath. The outer sheath has a first melting point. The optical fibre cable includes a separation layer. The separation layer is sandwiched between the metallic layer and the outer sheath. Binding between the metallic layer and the separation layer is defined as metal binding. Binding between the separation layer and the outer sheath is defined as sheath binding. The sheath binding is less than the metal binding.

BRIEF DESCRIPTION OF THE FIGURES
[0009] 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:
[0010] FIG. 1 illustrates an optical fibre cable, in accordance with an aspect
of the present disclosure;
[0011] FIG. 2 illustrates a separation layer of the optical fibre cable of the
FIG. 1, in accordance with an aspect of the present disclosure;
[0012] FIG. 3 illustrates a close view of the separation layer inside the
optical fibre cable of the FIG. 1, in accordance with an aspect of the present disclosure;
[0013] FIG. 4 illustrates a cross-sectional view of an intermittently bonded
ribbon cable, in accordance with another aspect of the present disclosure; and
[0014] FIG. 5 illustrates a cross-sectional view of a unitube optical fiber
cable, in accordance with yet another aspect of the present disclosure.
[0015] 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
[0016] Reference in this specification to "one aspecf'aspectmeans 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 no other aspects.
[0017] Reference will now be made in detail to selected aspects of the
present disclosure in conjunction with accompanying figures. The aspects described herein are not intended to limit the scope of the disclosure, and the present disclosure should not be construed as limited to the aspects described. This disclosure may be embodied in different forms without departing from the scope and spirit of the disclosure. It should be understood that the accompanying figures are intended and provided to illustrate aspects of the disclosure described below and are not necessarily drawn to scale. In the drawings, like numbers refer to like elements throughout, and thicknesses and dimensions of some components may be exaggerated for providing better clarity and ease of understanding.
[0018] 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.
[0019] 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.
[0020] FIG. 1 illustrates an optical fibre cable 100, in accordance with an
aspect of the present disclosure. FIG. 2 illustrates a separation layer 110 of the optical fibre cable 100 of the FIG. 1, in accordance with an aspect of the present disclosure. FIG. 3 illustrates a close view 300 of the separation layer 110 inside the optical fibre cable 100 of the FIG. 1. FIG. 4, illustrates a cross-sectional view of an intermittently bonded ribbon cable 400, in accordance with another aspect of the present disclosure. FIG. 5, illustrates a cross-sectional view of a unitube optical fiber cable 500, in accordance with yet another aspect of the present disclosure.
[0021] The optical fibre cable 100 includes a plurality of optical fibres 102,
one or more retaining elements 104, a blocking layer 106, a metallic layer 108, the separation layer 110, and an outer sheath 112. In addition, the optical fibre cable 100 includes a central strength member 114 surrounded by a polyethylene up coating layer 116.
[0022] The plurality of optical fibres 102 are placed inside a core of the
optical fibre cable 100. In general, core is the inner most part of the optical fibre cable. The plurality of optical fibres 102 are surrounded by the one or more retaining elements 104. The one or more retaining elements 104 envelops the one or more optical fibres 102. The one or more retaining elements 104 corresponds to at least one of tight buffer units, single buffer

tube, a plurality of buffer tubes, binder element, water blocking tape, aramid yarns. Further, the one or more retaining elements 104 is surrounded by the metallic layer 108. The plurality of optical fibers 102 may be in the form of plurality of intermittently bonded ribbons 402, as shown in FIG. 4.
[0023] The metallic layer 108 surrounds the one or more retaining elements
104. The metallic layer 108 surrounds the blocking layer 106 in case of presence of the blocking layer 106. The metallic layer 108 has a tensile strength of more than 350 mega Pascals. The tensile strength of the metallic layer 108 may vary. The metallic layer '108 has a breaking elongation of more than 20 percent. The breaking elongation of the metallic layer 108 may vary. The metallic layer 108 is surrounded by a separation layer 110. The separation layer is applied around the metallic layer 108 with an overlap of at least 10% of width of the film. The separation layer is a dual layer thin film that prevents bonding between the outer sheath 112 and the metallic layer 108. In an example, the metallic layer 108 is one of a steel tape, a corrugated steel tape and an ECCS (Electro Chrome coated Steel) tape. The separation layer is made of a combination of polyethylene and polyethylene terephthalate layers. In addition, the outer sheath 112 prevents the optical fibre cable 100 from external pressures and environmental conditions. The environmental conditions include but may not be limited to rainfall, sunlight, wind, and snowfall. The outer sheath 112 has a first melting point.
[0024] The optical fibre cable 100 includes the separation layer 110. The
separation layer 110 is sandwiched between the metallic layer 108 and the outer sheath 112. Binding between the metallic layer 108 and the separation layer 110 is defined as metal binding. In addition, binding between the separation layer 110 and the outer sheath 112 is defined as sheath binding. The metal binding is less than the sheath binding. The sheath binding is more

than 70% of total binding. Further, the metal binding is less than 20% of total binding.
[0025] The sheath binding may be calculated as:
Sheath binding = Internal surface area of the outer sheath sticking to the separation layer * 100 / Total internal surface area of the outer sheath
[0026] The metal binding may be calculated as:
Metal binding = Internal surface area of the separation layer sticking to the inner layer * 100 / Total internal surface area of the separation layer
[0027] The separation layer 110 includes a first separation layer Fl and a
second separation layer F2 (as shown in FIG. 2). The first separation layer Fl and the second separation layer F2 are bonded together using an adhesive. The first separation layer Fl is made of polyolefin material e.g. polyethylene. The second separation layer F2 is made of polyester material e.g. polyethylene terephthalate. The first separation layer Fl is placed in contact the outer sheath 112 and the second separation layer F2 is placed in contact the metallic layer 108. The first separation layer Fl and the second separation layer F2 allows easy removal or stripping of the outer sheath 112.
[0028] The first separation layer Fl corresponds to at least a first portion of
the separation layer 110. The first separation layer Fl binds to the outer sheath 112. The first portion of the separation layer 110 has a melting point within the tolerance range of around 10% of the first melting point. The tolerance range of around 10% allows the first separation layer Fl to get partially melted during extrusion of the outer sheath 112 and binds with the outer sheath 112. The second separation layer F2 corresponds to a second portion of the separation layer 110. The second portion of the separation layer 110 has a melting point of at least 50% greater than the first melting point.

The melting point of at least 50% greater than the first melting point of the outer sheath 112 prevents melting and binding of the second separation layer F2 with the outer sheath 112. The second separation layer F2 does not bind to the metallic layer 108. The second separation layer F2 has a melting point of at least 250°C.
[0029] The separation layer 110 has a thickness of more than 20 microns.
The thickness of the separation layer 110 may vary. The first separation layer Fl has a thickness in range of about 10-30 microns. The thickness of the first separation layer Fl may vary. The second separation layer F2 has a thickness in range of about 8-30 microns. The thickness of the second separation layer F2 may vary. The separation layer 110 is wrapped with overlapping ends over the entire length of the optical fibre cable 100. Demonstration of overlapping of the separation layer 110 along longitudinal directions of the optical fibre cable 100 is shown in FIG. 3. The overlapping between two ends of the separation layer 110 is minimum 10% of width of the separation layer 110. In an example, if width of the separation layer 110 is 32 millimeters for the optical fibre cable 100 having 144 optical fibres along with cable diameter of about 14.5 millimeters, the minimum overlap would be 3.2 millimeters. The overlapping completely eliminates chances of bonding between the metallic layer 108 and the outer sheath 112 around ends of the film.
[0030] The optical fibre cable 100 may include the central strength member
114. The central strength member 114 may or may not be surrounded by polyethylene up-coating layer 116. The optical fibre cable 100 may not include the central strength member 114.
[0031] The optical fibre cable 100 is an unbonded armored cable. In general,
the armored optical fibre cable provides extra protection without sacrificing flexibility or functionality within fiber networks, featuring more robust and

reliable when encountered with rodents, moisture, and the like. The optical fibre cable 100 is manufactured by a process. The process includes a first step of paying off the core of the optical fibre cable 100. The core includes the plurality of optical fibres 102. The core of the optical fibre cable 100 may be tubeless, unitube, multitube or inner sheath core. The core may be surrounded by the blocking layer 106 before applying the metallic layer 108. The blocking layer 106 corresponds to at least one of water blocking tape, aramid yarns, water swellable yarns or any other suitable layer.
[0032] The method includes a second step of wrapping the metallic layer 108
around the blocking layer 106 of the optical fiber cable 100. The method includes a third step of wrapping the separation layer 110 around the metallic layer 108. The method includes a forth step of extruding the outer sheath 112 surrounding the separation layer 110. The separation layer 110 substantially binds with the outer sheath 112 and remains substantially un-bonded with the metallic layer 108. The separation layer 110 binds with the outer sheath 112 during extrusion. The separation layer 110 comes out bonded with the outer sheath 112 when the outer sheath 112 is ripped during installation. So, there is no need to remove the separation layer 110 separately. On removal of the outer sheath 112, the separation layer 110 is also removed along with the outer sheath 112. The method is not limited to the above mentioned steps.
[0033] FIG. 4 illustrates an intermittently bonded ribbon cable 400, in
accordance with another aspect of the present disclosure. The intermittently bonded ribbon cable 400 includes a plurality of intermittently bonded ribbons 402, the one or more layers 104, the blocking layer 106, the metallic layer 108, the separation layer 110, and the outer sheath 112.
[0034] In an aspect of the present disclosure, each of the one or more layers
104 includes the plurality of intermittently bonded ribbons 402. In an aspect of the present disclosure, number of the one or more layers 104 may vary. In

another aspect of the present disclosure, number of the plurality of intermittently bonded ribbons 402 of each of the one or more layers 104 may vary. In an aspect of the present disclosure, the plurality of intermittently bonded ribbons 402 includes the plurality of optical fibres 102. In an aspect of the present disclosure, number of the plurality of optical fibres 102 in each of the plurality of intermittently bonded ribbons 402 is 12. In another aspect of the present disclosure, number of the plurality of optical fibres 102 may vary.
[0035] FIG. 5 illustrates a cross-sectional view of a unitube optical fiber
cable 500, in accordance with yet another aspect of the present disclosure. The unitube optical fiber cable 500 includes the plurality of optical fibers 102, the one or more layers 104, the blocking layer 106, a metallic layer 108 and the separation layer 110. The unitube optical fiber cable 500 includes the outer sheath 112 and a gel 502. The one or more layers 104 includes a unitube or a single buffer tube which encloses the plurality of optical fibers 102.
[0036] The plurality of optical fibers 102 is positioned inside a core of the
unitube optical fiber cable 500. In addition, the plurality of optical fibers 102 lies substantially along a longitudinal axis of the unitube optical fiber cable 500 inside the one or more layers 104. Each of the plurality of optical fibers 102 is a fiber used for transmitting information as light pulses from one end to another. In addition, each of the plurality of optical fibers 102 is a thin strand of glass capable of transmitting optical signals. Also, each of the plurality of optical fibers 102 is configured to transmit large amounts of information over long distances with relatively low attenuation. Further, each of the plurality of 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 plurality of optical fibers 102. In addition, the cladding region surrounds the core region.

[0037] In an aspect of the present disclosure, each of the plurality of optical
fibers 102 has a diameter of about 250 microns. In yet another aspect of the present disclosure, the diameter of the plurality of optical fibers 102 is in a range of 200 microns or less. In yet another aspect of the present disclosure, the diameter of the plurality of optical fibers 102 may vary. In an aspect of the present disclosure, each of the plurality of optical fibers 102 is a single mode fiber. In another aspect of the present disclosure, each of the plurality of optical fibers 102 is a multimode fiber.
The unitube optical fiber cable 500 includes the gel 502. The gel 502 is filled
inside the core of the one or more layers 104 and around the plurality of
optical fibers 102. The gel 502 is a thixotropic gel. The thixotropic gel
prevents ingression of water inside the core of the unitube optical fiber cable
500. In an aspect of the present disclosure, the gel 502 may be replaced by
any other type of water blocking elements.
[0038] The foregoing descriptions of pre-defined 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.

WE CLAIMS:

What is claimed is:
1. An optical fibre cable (100) comprising:
a plurality of optical fibres (102);
one or more layers (104) enveloping the plurality of optical fibres (102);
a metallic layer (108) surrounding the one or more layers (104);
an outer sheath (112), wherein the outer sheath has a first melting point; and
a separation layer (110), wherein the separation layer is sandwiched between the metallic layer (108) and the outer sheath (112), wherein binding between the metallic layer (108) and the separation layer (110) is defined as metal binding, wherein binding between the separation layer (110) and the outer sheath (112) is defined as sheath binding, wherein the metal binding is less than the sheath binding.
2. The optical fibre cable (100) as claimed in claim 1, wherein the sheath binding is more than 70% of total binding.
3. The optical fibre cable (100) as claimed in claim 1, wherein the metal binding is less than 20% of total binding.
4. The optical fibre cable (100) as claimed in claim 1, wherein the one or more layers (104) corresponds to at least one of tight buffer units, central buffer

tube, a plurality of buffer tubes, binder element, water blocking tape, aramid yarns.
5. The optical fibre cable (100) as claimed in claim 1, further comprising a central strength member (114).
6. The optical fibre cable (100) as claimed in claim 1, wherein at least a first portion of the separation layer (110) has a melting point within the tolerance range of around 10% of the first melting point, and wherein at least a second portion of the separation layer (110) has a melting point of at least 50% greater than the first melting point.
7. The optical fibre cable (100) as claimed in claim 1, wherein the separation layer (110) comprises a first separation layer (Fl) corresponding to at least a first portion of the separation layer (110), wherein the first separation layer (Fl) binds to the outer sheath (112).
8. The optical fibre cable (100) as claimed in claim 7, wherein the first separation layer (Fl) and the outer sheath (112) has a melting point of less than 150°C.
9. The optical fibre cable (100) as claimed in claim 1, wherein the separation layer (110) comprises a second separation layer (F2) corresponding to a second portion of the separation layer, wherein the second separation layer (F2) does not bind to the metallic layer.
10. The optical fibre cable (100) as claimed in claim 9, wherein the second separation layer (F2) has a melting point of at least 250°C.
11. The optical fibre cable (100) as claimed in claim 1, wherein the separation layer (110) comprises a first separation layer (Fl) and a second separation layer

(F2), wherein the first separation layer (Fl) and the second separation layer (F2) are bonded together.
12. The optical fibre cable (100) as claimed in claim 1, wherein the separation layer (110) has a thickness of more than 20 microns.
13. The optical fibre cable (100) as claimed in claim 1, wherein the separation layer (110) comprises a first separation layer (Fl) and a second separation layer (F2), wherein the first separation layer (Fl) has a thickness in range of about 10-30 microns, wherein the second separation layer (F2) has a thickness in range of about 8-30 microns.
14. The optical fibre cable (100) as claimed in claim 1, wherein the metallic layer (108) is surrounded by a film, wherein the film is applied around the metallic layer (108) with an overlap of at least 10% of width of the film.
15. A method of manufacturing an optical fibre cable (100), the method comprising:
paying off a core comprising a plurality of optical fibres (102);
wrapping a metallic layer (108) around the plurality of optical fibres (102);
wrapping a separation layer (110) around the metallic layer (108); and
extruding an outer sheath (112) surrounding the separation layer (HO),

wherein the separation layer (110) substantially binds with the outer sheath (112) and remains substantially un-bonded with the metallic layer (108).