[0001] The present disclosure relates to the field of installation of
pre-ducted optical fiber cable assembly. More particularly, the present disclosure relates to the pre-ducted optical fiber cable assembly for direct buried application.
BACKGROUND
[0002] Optical fiber cables have secured an important position in
building network of modern communication systems across the world. One such type of optical fiber cable is micro optical fiber cable. The micro optical fiber cable is used in micro duct applications and is installed in micro ducts. Typically, the micro optical fiber cable includes sheathing layer and ripcords. Mostly, the sheathing is made of a polymeric material. Typically, the ripcords are positioned inside the sheathing for facilitating access to the core of the micro optical fiber cable. Traditionally, the micro optical fiber cable is laid inside the micro ducts by broadly performing two steps. The two steps involve burying the micro duct inside the ground followed by blowing the cable into the micro duct using a blowing machine. Typically, the micro optical fiber cables are blown into the micro duct while simultaneously pushing it into the micro duct. The micro optical fiber cables are blown into the micro duct by injecting a high volume of compressed air into the duct which flows inside the micro duct at high speed. The high pressure air propels the micro optical fiber cable further inside the micro duct.
[0003] The currently available micro optical fiber cable has certain
limitations. The existing micro optical fiber cable is installed by

performing two different steps. This increases the overall installation time and the cost of installation. There is a need for eliminating the blowing cable step in order to reduce cost and overall time of installation. In addition, the materials used for the sheathing do not provide sufficient mechanical strength. Also, the friction between the duct and these micro optical fiber cables inside the duct is high.
[0004] In light of the foregoing discussion, there exists a need for
an optical fiber cable assembly which overcomes the above cited drawbacks of conventionally known optical fiber cables.
OBJECT OF THE DISCLOSURE
[0005] A primary object of the present disclosure is to provide a
method for underground installation of a pre-ducted optical fiber cable assembly.
[0006] Another object of the present disclosure is to eliminate
blowing and pulling of optical fiber cable inside duct compared to conventional installation of the optical fiber cable and the duct separately.
SUMMARY
[0007] The present disclosure relates to a method for
underground installation of a pre-ducted optical fiber cable assembly. The method includes a first step of drilling a first pilot bore from a second manhole to a first manhole. In addition, the method includes a second step of attaching a second reamer to a

first drill string. Moreover, the method includes a third step of attaching the pre-ducted optical fiber cable assembly to a second reamer. Furthermore, the method includes a fourth step of pulling the pre-ducted optical fiber cable that is spooled over a cable drum placed at vicinity of the first manhole and attached to the first end of the second reamer. Further, the method includes a fifth step of attaching a fourth reamer to the second drill string. Moreover, the method includes a sixth step of attaching the pre-ducted optical fiber cable assembly to the fourth reamer. In addition, the method includes a seventh step of drilling a second pilot bore from a third manhole to the second manhole. Also, the method includes an eighth step of pulling the pre-ducted optical fiber cable assembly installed till a first distance. The pre-ducted optical fiber cable assembly attached to the first end of the fourth reamer is pulled from the second manhole to the third manhole. The second manhole and the first manhole are separated by first distance. The first pilot bore has a first diameter. The first pilot bore is drilled by a first drill string. A first reamer is attached to the first drill string to facilitate the drilling of the first pilot bore. The first drill string is associated with a first horizontal directional drilling machine. The first reamer is detached from the first drill string after completion of the drilling of the first pilot bore. The second reamer is attached at a first end of the first drill string. The pre-ducted optical fiber cable assembly is attached to a first end of the second reamer. The pre-ducted optical fiber cable assembly is pulled from the first manhole to the second manhole. The pre-ducted optical fiber cable assembly is installed for the first distance. The pulling of the pre-ducted optical fiber cable assembly is done by the first horizontal directional drilling machine. The third manhole and the second manhole are separated by a second distance. The second

pilot bore has a second diameter. The second pilot bore is drilled by a second drill string. A third reamer is attached to the second drill string to facilitate the drilling of the second pilot bore. The second drill string is associated a second horizontal directional drilling machine. The second horizontal directional drilling machine is placed at the vicinity of the third manhole. The third reamer is detached from the second drill string after completion of the drilling of the second pilot bore. The fourth reamer is attached at a first end of the second drill string. The pre-ducted optical fiber cable assembly is attached to a first end of the fourth reamer. The pulling of the pre-ducted optical fiber cable assembly is done by the second horizontal directional drilling machine.
[0008] In an embodiment of the present disclosure, the second
reamer is used to expand diameter of the first pilot bore from the first diameter to a third diameter. The first diameter of the first pilot bore is in a range of about 80 millimeters - 100 millimeters. The third diameter of the first pilot bore is in a range of about 120 millimeters - 150 millimeters.
[0009] In an embodiment of the present disclosure, the fourth
reamer is used to expand a diameter of the second pilot bore from the second diameter to a fourth diameter. The second diameter of the second pilot bore is in a range of about 80 millimeters - 100 millimeters. The fourth diameter of the second pilot bore is in a range of about 120 millimeters - 150 millimeters.
[0010] In an embodiment of the present disclosure, the first drill
string includes a first plurality of drill pipes. Each of the first plurality of drill pipes is attached to each other from end to end.

The second drill string includes a second plurality of drill pipes. Each of the second plurality of drill pipes is attached to each other from end to end.
[0011] In an embodiment of the present disclosure, the first pilot
bore and the second pilot bore has a fill factor in a range of about 0.015-0.25.
[0012] In an embodiment of the present disclosure, the pre-
ducted optical fiber cable assembly includes a duct. The duct is made of high density polyethylene material. The high density polyethylene material has a hardness of 60 shore D. The high density polyethylene material has notched izod impact strength of 300 J/m at a temperature of 23 degree Celsius. The duct has a thickness in a range of about 2 millimeters - 4 millimeters.
[0013] In an embodiment of the present disclosure, the first pilot
bore has a depth (Di) in a range of about 1.5 meters - 5 meters.
[0014] In an embodiment of the present disclosure, the second
pilot bore has a depth (D2) in a range of about 1.5 meters - 5 meters.
[0015] In an embodiment of the present disclosure, the first drill
string and the second drill string utilize a drilling fluid to drill the first pilot bore and the second pilot bor. The drilling fluid is water.

STATEMENT OF THE DISCLOSURE
[0016] The present disclosure relates to a method for
underground installation of a pre-ducted optical fiber cable assembly. The method includes a first step of drilling a first pilot bore from a second manhole to a first manhole. In addition, the method includes a second step of attaching a second reamer to a first drill string. Moreover, the method includes a third step of attaching the pre-ducted optical fiber cable assembly to a second reamer. Furthermore, the method includes a fourth step of pulling the pre-ducted optical fiber cable that is spooled over a cable drum placed at vicinity of the first manhole and attached to the first end of the second reamer. Further, the method includes a fifth step of attaching a fourth reamer to the second drill string. Moreover, the method includes a sixth step of attaching the pre-ducted optical fiber cable assembly to the fourth reamer. In addition, the method includes a seventh step of drilling a second pilot bore from a third manhole to the second manhole. Also, the method includes a fourth step of pulling the pre-ducted optical fiber cable assembly installed till a first distance. The pre-ducted optical fiber cable assembly attached to the first end of the fourth reamer is pulled from the second manhole to the third manhole. The second manhole and the first manhole are separated by first distance. The first pilot bore has a first diameter. The first pilot bore is drilled by a first drill string. A first reamer is attached to the first drill string to facilitate the drilling of the first pilot bore. The first drill string is associated with a first horizontal directional drilling machine. The first reamer is detached from the first drill string after completion of the drilling of the first pilot bore. The second reamer is attached at a first end of the first drill string. The pre-ducted optical fiber cable assembly is attached to a first end of the second

reamer. The pre-ducted optical fiber cable assembly is pulled from the first manhole to the second manhole. The pre-ducted optical fiber cable assembly is installed for the first distance. The pulling of the pre-ducted optical fiber cable assembly is done by the first horizontal directional drilling machine. The third manhole and the second manhole are separated by a second distance. The second pilot bore has a second diameter. The second pilot bore is drilled by a second drill string. A third reamer is attached to the second drill string to facilitate the drilling of the second pilot bore. The second drill string is associated a second horizontal directional drilling machine. The second horizontal directional drilling machine is placed at the vicinity of the third manhole. The third reamer is detached from the second drill string after completion of the drilling of the second pilot bore. The fourth reamer is attached at a first end of the second drill string. The pre-ducted optical fiber cable assembly is attached to a first end of the fourth reamer. The pulling of the pre-ducted optical fiber cable assembly is done by the second horizontal directional drilling machine.

BRIEF DESCRIPTION
[0017] Having thus described the disclosure in general terms,
reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
[0018] FIG. 1A, FIG. IB, FIG. 1C and FIG. ID illustrate a
diagram for showing an underground installation of pre-ducted optical fiber cable assembly, in accordance with an embodiment of present disclosure;
[0019] FIG. 2A illustrates a cross sectional view of the pre-
ducted optical fiber cable assembly, in accordance with an embodiment of the present disclosure;
[0020] FIG. 2B illustrates a perspective view of the pre-ducted
optical fiber cable assembly of FIG. 2A, in accordance with an embodiment of the present disclosure;
[0021] FIG. 2C illustrates a cross-sectional view of the pre-
ducted optical fiber cable assembly, in accordance with another embodiment of the present disclosure;
[0022] FIG. 2D illustrates a perspective view of the pre-ducted
optical fiber cable assembly of FIG. 2C, in accordance with another embodiment of the present disclosure;
[0023] FIG. 3A illustrates a cross-sectional view of an
arrangement of grouped optical fiber cable assemblies, in accordance with yet another embodiment of the present disclosure;

[0024] FIG. 3B illustrates a perspective view of the arrangement
of FIG. 3A, in accordance with yet another embodiment of the present disclosure;
[0025] FIG. 3C illustrates a cross-sectional view of an
arrangement of grouped optical fiber cable assemblies, in accordance with yet another embodiment of the present disclosure; and
[0026] FIG. 3D illustrates a perspective view of the arrangement
of FIG. 3C, in accordance with yet another embodiment of the present disclosure.
[0027] 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.
DETAILED DESCRIPTION
[0028] Reference will now be made in detail to selected
embodiments of the present disclosure in conjunction with accompanying figures. The embodiments described herein are not intended to limit the scope of the disclosure, and the present disclosure should not be construed as limited to the embodiments 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 embodiments 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.
[0029] 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.
[0030] FIG. 1A and FIG. IB illustrate a diagram 100 for
showing an underground installation of a pre-ducted optical fiber cable assembly, in accordance with an embodiment of present disclosure. The diagram 100 is shown for explanation of a method of installing the pre-ducted optical fiber cable assembly 114 inside ground. The pre-ducted optical fiber cable assembly 114 is installed for the underground applications in urban and rural areas without disrupting activities taking place in the area. The method utilizes one or more horizontal direct drilling machines for installing the pre-ducted optical fiber cable assembly 114 underground. In an embodiment of the present disclosure, the method is used for installing the pre-ducted optical fiber cable assembly 114 for at least 2 kilometers. In another embodiment of the present disclosure, the method may be used for installing the pre-ducted optical fiber cable assembly 114 for any suitable
[0031] The diagram 100 of FIG. 1A includes a cable drum 102,
a first horizontal directional drilling machine 104, a first manhole 108, a second manhole 110, a pre-ducted optical fiber cable

assembly 114, a first pilot bore 116, a first drill string 118 and a first reamer 120. Moreover, the diagram 100 of FIG. IB includes the cable drum 102, the first horizontal directional drilling machine 104, the first manhole 108, the second manhole 110, the pre-ducted optical fiber cable assembly 114, the first pilot bore 116, the first drill string 118 and a second reamer 122. In addition, the diagram 100 of FIG. 1C includes the cable drum 102, the first horizontal directional drilling machine 104, the first manhole 108, the second manhole 110, a third manhole 112, the pre-ducted optical fiber cable assembly 114, a second horizontal directional drilling machine 106, a second pilot bore 128, a second drill string 130 and a third reamer 132. Further, the diagram 100 of FIG. ID includes the cable drum 102, the first horizontal directional drilling machine 104, the first manhole 108, the second manhole 110, the third manhole 112, the pre-ducted optical fiber cable assembly 114, the second horizontal directional drilling machine 106, the second pilot bore 128, the second drill string 130 and a fourth reamer 134.
[0032] The cable drum 102 includes the pre-ducted optical fiber
cable assembly 114 that is spooled over the cable drum 102. In an embodiment of the present disclosure, the cable drum 102 is made of suitable material. In an example, the suitable material includes wood, plywood, steel, plastic and the like. The cable drum 102 is positioned in a vicinity of the first manhole 108. The second manhole 110 and the first manhole 108 are separated by first distance. In an embodiment of the present disclosure, the first distance is in a range of about 50 meters - 200 meters. The second manhole 110 and the third manhole 112 are separated by a second distance. In an embodiment of the present disclosure, the second distance is in a range of about 50 meters - 200 meters. Further, the

second manhole 110 is at a distance of 200 meters from the third manhole 112.
[0033] In an embodiment of the present disclosure, the plurality
of pilot bores includes the first pilot bore 116 and the second pilot bore 128. Moreover, the first pilot bore 116 is drilled from the second manhole 110 to the first manhole 108. The first pilot bore 116 has a first diameter. In an embodiment of the present disclosure, the first diameter of the first pilot bore 116 is around 80 millimeters. Further, the second pilot bore 128 is drilled from the third manhole 112 to the second manhole 110. The second pilot bore 128 has a second diameter. In an embodiment of the present disclosure, the second diameter of the second pilot bore 128 is around 80 millimeters. Each of the plurality of pilot holes is horizontally drilled and continues underground across the manholes 108-112. Moreover, the plurality of pilot bores is drilled using the one or more horizontal directional drilling machines 104-106. In an embodiment to the present disclosure, the first pilot bore 116 and the second pilot bore 128 has a fill factor in a range of about 0.015 - 0.25. The fill factor of the first pilot bore 116 is defined as ratio of cross sectional area of bore (the first pilot bore 116) to the cross sectional area of the pre-ducted optical fiber cable assembly 114. Similarly, the fill factor of the second pilot bore 128 is defined as ratio of cross sectional area of bore (the second pilot bore 128) to the cross sectional area of the pre-ducted optical fiber cable assembly 114. In an embodiment of the present disclosure, the first pilot bore 116 is characterized by depth Di and the second pilot bore 128 is characterized by depth D2. In an embodiment of the present disclosure, the first pilot bore 116 has a depth Di in a range of about 1.5 meters - 5 meters. In an embodiment of the

present disclosure, the second pilot bore 128 has a depth D2 in a range of about 1.5 meters - 5 meters.
[0034] In addition, the one or more horizontal directional drilling
machines 104-106 are direct drilling machines used for underground installation of any suitable cable assembly. In an embodiment of the present disclosure, the one or more horizontal directional drilling machines 104-106 are used for underground installation of pre-ducted optical fiber cable assembly 114. Moreover, the one or more horizontal directional drilling machine 104-106 includes the first horizontal directional drilling machine 104 and the second horizontal directional drilling machine 106. Further, the first horizontal directional drilling machine 104 include a plurality of components. Furthermore, the plurality of components includes a first plurality of drill pipes, the first reamer 120 and the like. Each of the first plurality of drill pipes is attached to each other from end to end. Moreover, the first plurality of drill pipes are connected together to form the first drill string 118. The first drill sting 118 is used for drilling inside the ground from one point to another. Also, the second horizontal directional drilling machine 106 includes a plurality of components. Further, the plurality of components includes a second plurality of drill pipes, the third reamer 132 and the like. Each of the second plurality of drill pipes is attached to each other from end to end. Furthermore, the second plurality of drill pipes are connected together to form the second drill string 130. Moreover, the first plurality of drill pipes and the second plurality of drill pipes have male threading on one side and female threading on the other side. In an embodiment of the present disclosure, each of the first plurality of drill pipes and second plurality of drill pipes is a hollow pipe made from heat-
Page 14 / 41

treated-high-carbon steel. In an embodiment of the present disclosure, the first drill string 118 and the second drill string 130 utilize a drilling fluid to drill the first pilot bore 116 and the second pilot bore 128. The drilling fluid is water. The drilling fluid is used while drilling the bores to provide wet surface to make drilling easy.
[0035] The first reamer 120 is attached to the first drill string 118
to facilitate the drilling of the first pilot bore 116. The first reamer 120 is attached at a first end 124 of the first drill string 118. The first reamer 120 is detached from the first end 124 of the first drill string 118 after completion of the drilling of the first pilot bore 116. The first reamer 120 is a reamer with a small diameter or size. In an embodiment of the present disclosure, the first pilot bore 116 is drilled across the second manhole 110 to the first manhole 108. The second manhole 110 acts as an entry point for the first drill sting 118 and the first manhole 108 acts as an exit point for the first drill string 118. The first pilot bore 116 drilling starts from the second manhole 110 and continues underground to the first manhole 108. The first pilot bore 116 is drilled by the first drill string 118. Further, the first drill string 118 is associated with the first horizontal directional drilling machine 104.
[0036] Further, the second reamer 122 is attached to the first drill
string 118. The second reamer 122 is attached at the first end 124 of the first drill string 118. The second reamer 122 has a larger diameter than the first reamer 120. Further, the second reamer 122 is used for enlarging the first pilot bore 116. In an embodiment of the present disclosure, the second reamer 122 is used to expand diameter of the first pilot bore 116 from the first diameter to a third
Page 15 / 41

diameter. The first diameter of the first pilot bore 116 is in a range of about 80 millimeters - 100 millimeters. The third diameter of the first pilot bore 116 is in a range of about 120 millimeters - 150 millimeters. Further, the pre-ducted optical fiber cable assembly 114 is attached to the second reamer 122. The pre-ducted optical fiber cable assembly 114 is attached to a first end 126 of the second reamer 122. Accordingly, the pre-ducted optical fiber cable assembly 114 attached to the first end 126 of the second reamer 122 is pulled by the first horizontal directional drilling machine 104. Furthermore, the pulling of the pre-ducted optical fiber cable assembly 114 starts from the second manhole 110 by the first horizontal directional drilling machine 104. The pre-ducted optical fiber cable assembly 114 is installed for the first distance between the first manhole 108 and the second manhole 110. In an embodiment of the present disclosure, the pre-ducted optical fiber cable assembly 114 is installed for a distance of about 200 meters.
[0037] The third reamer 132 is attached to the second drill string
130 to facilitate the drilling of the second pilot bore 128. The third reamer 132 is attached at a first end 136 of the second drill string 130. The third reamer 132 is detached from the first end 136 of the second drill string 130 after completion of the drilling of the second pilot bore 128. The third reamer 132 is a reamer with a small diameter or size. In an embodiment of the present disclosure, the third reamer 132 and the first reamer 120 are same. In an embodiment of the present disclosure, the first pilot bore 116 and the second pilot bore 128 are drilled using same reamer (the first reamer 120). The second pilot bore 128 is drilled across the third manhole 112 to the second manhole 110. The third manhole 112 acts as an entry point for the second drill sting 130 and the second
Page 16 / 41

manhole 110 acts as an exit point for the second drill string 130. The second pilot bore 128 drilling starts from the third manhole 112 and continues underground to the second manhole 110. The second pilot bore 128 is drilled by the second drill string 130. Further, the second drill string 130 is associated with the second horizontal directional drilling machine 106.
[0038] Further, the fourth reamer 134 is attached to the second
drill string 130. The fourth reamer 134 is attached at the first end 136 of the second drill string 130. The fourth reamer 134 has a larger diameter than the third reamer 132. In addition, the pre-ducted optical fiber cable assembly 114 is attached to the fourth reamer 134. The pre-ducted optical fiber cable assembly 114 is attached to a first end 138 of the fourth reamer 134. Furthermore, the fourth reamer 134 is used for enlarging the second pilot bore 128. In an embodiment of the present disclosure, the fourth reamer 134 is used to expand a diameter of the second pilot bore 128 from the second diameter to a fourth diameter. The second diameter of the second pilot bore 128 is in a range of about 80 millimeters -100 millimeters. The fourth diameter of the second pilot bore 128 is in a range of about 120 millimeters - 150 millimeters. In an embodiment of the present disclosure, the second reamer 122 and the fourth reamer 134 are same. In an embodiment of the present disclosure, the first pilot bore 116 and the second pilot bore 128 are enlarged using the same reamer (the second reamer 122).
[0001] Further, the pre-ducted optical fiber cable assembly 114
installed till the first distance and attached to the first end 138 of the fourth reamer 134 is pulled by the second horizontal directional drilling machine 106. Furthermore, the pulling of the pre-ducted
Page 17 / 41

optical fiber cable assembly 114 starts from the second manhole 110 by the second horizontal directional drilling machine 106. In an embodiment of the present disclosure, the pre-ducted optical fiber cable assembly 114 is installed for a distance of about 400 meters. In an embodiment of the present disclosure, there may be more number of manholes and the cable assembly may be installed for more distance depending upon need.
[0039] In an embodiment of the present disclosure, the first
horizontal directional drilling machine 104 and the second horizontal directional drilling machine 106 are same. In another embodiment of the present disclosure, the first horizontal directional drilling machine 104 and the second horizontal directional drilling machine 106 are different.
[0040] FIG. 2A illustrates a cross sectional view of a pre-ducted
optical fiber cable assembly 114, in accordance with an embodiment of the present disclosure. The pre-ducted optical fiber cable assembly 114 includes an optical fiber cable 200 and a duct 212. The optical fiber cable 200 is a micro optical fiber cable. The micro optical fiber cable is used for installation in third layer. In addition, the optical fiber cable 200 is used for underground installations. Moreover, the optical fiber cable 200 is used for direct buried applications. The optical fiber cable 200 can be directly buried inside the ground without blowing the optical fiber cable 200. In an embodiment of the present disclosure, the optical fiber cable 200 is a 192F micro optical fiber cable. In addition, 192F corresponds to 192 optical fibers.
[0041] The optical fiber cable 200 is made of a plurality of layers
(mentioned below in the patent application). The plurality of layers
Page 18 / 41

encloses one or more buffer tubes. Each of the one or more buffer tubes is a loose buffer tube. Each buffer tube of the one or more buffer tubes encloses a plurality of optical fibers. In an embodiment of the present disclosure, the plurality of optical fibers is loosely held inside the one or more buffer tubes. In an embodiment of the present disclosure, each of the one or more buffer tubes has a small diameter (mentioned below in the provisional patent application).
[0042] Going further, the optical fiber cable 200 includes a
central strength member 202, one or more buffer tubes 204a-204h, a first layer 206, a second layer 208 (as seen in FIG. 2A in conjunction with the perspective view of the optical fiber cable 200 provided in FIG. 2B). In addition, the optical fiber cable 200 includes one or more water swellable yarns and one or more ripcords. Further, the optical fiber cable 200 is enclosed by a duct 212. The duct 212 allows direct installation of the optical fiber cable 200 without the need of blowing the optical fiber cable 200. The optical fiber cable 200 is used to transmit optical signals (which may carry sensor data or communication data).
[0043] Further, the central strength member 202 lies
substantially along a longitudinal axis of the optical fiber cable 200. In addition, the central strength member 202 is coated with a layer of polyethylene. In an embodiment of the present disclosure, the central strength member 202 may be coated with any suitable material. In an embodiment of the present disclosure, the central strength member 202 has a circular cross-section. The central strength member 202 is made of a composite material having a polymer matrix. In an embodiment of the present disclosure, the composite material is flexible fiber reinforced plastic. In another
Page 19 / 41

embodiment of the present disclosure, the central strength member 202 may not be coated.
[0044] The fiber reinforced plastic is a composite material
having a polymer matrix reinforced with glass fibers. Examples of the fiber reinforced plastics include glass fibers, carbon fibers, aramid fibers, basalt fibers and the like. In an embodiment of the present disclosure, the central strength member 202 is made of any suitable material. Moreover, the central strength member 202 provides physical strength to the optical fiber cable 200 and resists over bending of the optical fiber cable 200. The central strength member 202 provides tensile strength to the optical fiber cable 200. The tensile strength corresponds to a resistance shown by the optical fiber cable 200 against buckling.
[0045] The central strength member 202 is characterized by a
diameter measured substantially across the cross section and from the longitudinal axis of the optical fiber cable 200. In an embodiment of the present disclosure, the central strength member 202 has a diameter of about 2.60 millimeters. In another embodiment of the present disclosure, the central strength member 202 has a diameter in a range of 2.60 millimeters ± 0.05 millimeter. In an embodiment of the present disclosure, the diameter of the central strength member 202 may vary. Also, the central strength member 202 prevents buckling of the optical fiber cable 200. In an embodiment of the present disclosure, the optical fiber cable 200 may not include the central strength member 202.
[0046] Further, the optical fiber cable 200 includes the one or
more buffer tubes 204a-204h. The one or more buffer tubes 204a-204h is stranded around the central strength member 202 to form a
Page 20 / 41

stranded core. In an embodiment of the present disclosure, the central strength member 202 is surrounded by the one or more buffer tubes 204a-204h. In an embodiment of the present disclosure, the one or more buffer tubes 204a-204h is S-Z stranded around the central strength member 202. Each of the one or more buffer tubes 204a-204h is wound around the central strength member 202 in sections with a first direction of winding in an S-shape alternating with the sections with a second direction of winding in a Z-shape. In an embodiment of the present disclosure, the first direction is a clockwise direction and the second direction is an anticlockwise direction. The binding is performed to retain lay length of the stranded plurality of sleeves and uniform stress distribution along length of the optical fiber cable 200. The S-Z fashion of stranding is a form of stranding of the one or more buffer tubes 204a-204h. In addition, the S-Z stranding allows uniform distribution of the stress across all the one or more buffer tubes 204a-204h. The S-Z stranding may have any number of turns between the S-shape and the Z-shape. In an embodiment of the present disclosure, the S-Z stranding may have 4-7 turns between the S-shape and the Z -shape.
[0047] The SZ stranding of the one or more buffer tubes 204a-
204h is performed in order to maintain a uniform lay length, mid-spanning and achieve higher production speeds and longer lengths of cable as compared to Helical stranding. In general, the lay length is a longitudinal distance along length of the central strength member 202 required for one buffer tube to go all the way around the central strength member 202 to complete one rotation. In another embodiment of the present disclosure, the one or more buffer tubes 204a-204h are helically stranded around the central
Page 21 / 41

strength member 202.
[0048] The cross section of each of the one or more buffer tubes
204a-204h is circular in shape. In an embodiment of the present disclosure, the cross section of each of the one or more buffer tubes 204a-204h may be of any suitable shape. In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-204h has a uniform structure and dimensions. In an embodiment of the present disclosure, number of the one or more buffer tubes 204a-204h is 8. In another embodiment of the present disclosure, the number of the one or more buffer tubes 204a-204h may vary.
[0049] Each of the one or more buffer tubes 204a-204h has a
thickness. In an embodiment of the present disclosure, the thickness of each of the one or more buffer tubes 204a-204h is equal. In an embodiment of the present disclosure, the thickness of each of the one or more buffer tubes 204a-204h is about 0.20 millimeter. In another embodiment of the present disclosure, the thickness of each of the one or more buffer tubes 204a-204h is in a range of 0.20 millimeter ± 0.025 millimeter. In yet another embodiment of the present disclosure, the thickness of each of the one or more buffer tubes 204a-204h may vary.
[0050] Furthermore, each of the one or more buffer tubes 204a-
204h has an inner diameter and an outer diameter. In an embodiment of the present disclosure, the inner diameter of each of the one or more buffer tubes 204a-204h is about 1.25 millimeters. In another embodiment of the present disclosure, the inner diameter of each of the one or more buffer tubes 204a-204h is in a range of 1.25 millimeters ± 0.05 millimeter. In yet another embodiment of the present disclosure, the inner diameter of each of the one or
Page 22 / 41

more buffer tubes 204a-204h may vary.
[0051] In an embodiment of the present disclosure, the outer
diameter of each of the one or more buffer tubes 204a-204h is about 1.65 millimeters. In another embodiment of the present disclosure, the outer diameter of each of the one or more buffer tubes 204a-204h is in a range of 1.65 millimeters ± 0.05 millimeter. In yet another embodiment of the present disclosure, the outer diameter of each of the one or more buffer tubes 204a-204h may vary. Further, each of the one or more buffer tubes 204a-204h is a micro loose tube.
[0052] Going further, each of the one or more buffer tubes 204a-
204h encloses a plurality of optical fibers 218. In addition, each of the one or more buffer tubes 204a-204h encloses 24 optical fibers. In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-204h may enclose more or less number of optical fibers. In an example, the total number of optical fibers 218 in the optical fiber cable 200 is 288. Each of the one or more buffer tubes 204a-204h is a tube for encapsulating the plurality of optical fibers. The one or more buffer tubes 204a-204h provides support and protection to each of the plurality of optical fibers 218 against crush, bend and stretch. In addition, the one or more buffer tubes 204a-204h protects the plurality of optical fibers 218 and prevents ingression of water inside the stranded core of the optical fiber cable 200.
[0053] Further, the one or more buffer tubes 204a-204h provides
mechanical isolation, physical damage protection and identification of each of the plurality of optical fibers 218. In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-
Page 23 / 41

204h is colored. In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-204h has a different color. In addition, total number of colors available for coloring the buffer tubes is 12. The coloring is done for identification of each of the one or more buffer tubes 204a-204h. The colors include blue, orange, green, brown, gray, white, red, black, yellow, violet, pink and aqua. In an embodiment of the present disclosure, the one or more buffer tubes 204a-204h is made from a material selected from a group. The group consists of polybutylene terephthalate and nylon. In another embodiment of the present disclosure, the one or more buffer tubes 204a-204h may be made of any other suitable material.
[0054] In an embodiment of the present disclosure, each of the
one or more buffer tubes 204a-204h is filled with a gel. In an embodiment of the present disclosure, the gel is a thixotropic gel. In an embodiment of the present disclosure, the thixotropic gel prevents ingression of water inside each of the one or more buffer tubes 204a-204h. In another embodiment of the present disclosure, the one or more buffer tubes 204a-204h may not be filled with the gel.
[0055] Further, each of the plurality of optical fibers 218 is a
fiber used for transmitting information as light pulses from one end to another. In addition, each of the plurality of optical fibers 218 is a thin strand of glass capable of transmitting optical signals. Also, each of the plurality of optical fibers 218 is configured to transmit large amounts of information over long distances with relatively low attenuation. Further, each of the plurality of optical fibers 218 includes a core region and a cladding region. The core region is an
Page 24 / 41

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 218. In addition, the cladding region surrounds the core region.
[0056] Each of the plurality of optical fibers 218 has a diameter
of about 200 microns. In another embodiment of the present disclosure, each of the plurality of optical fibers 218 has a diameter in a range of 200 microns ± 5 microns. In yet another embodiment of the present disclosure, the diameter of each of the plurality of optical fibers 218 may vary. In an embodiment of the present disclosure, each of the plurality of optical fibers 218 is a single mode fiber. In another embodiment of the present disclosure, each of the plurality of optical fibers 218 is a multimode fiber.
[0057] In an embodiment of the present disclosure, number of
the plurality of optical fibers 218 in each of the one or more buffer tubes 204a-204h is 24. In another embodiment of the present disclosure, the number of the plurality of optical fibers 218 in each of the one or more buffer tubes 204a-204h is more or less than 24. In an embodiment of the present disclosure, the number of the plurality of optical fibers 218 in each buffer tube may vary depending upon the cable requirements. Accordingly, a total number of the plurality of optical fibers 218 in the optical fiber cable 200 is 192 (24*8). In an embodiment of the present disclosure, the total number of the plurality of optical fibers 218 may be more or less than 192 depending upon the number of buffer tubes and the optical fibers in each buffer tube.
[0058] In an embodiment of the present disclosure, each of the
plurality of optical fibers 218 is a colored optical fiber. In an
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embodiment of the present disclosure, each of the plurality of optical fibers 218 has a different color. In another embodiment of the present disclosure, the total number of colors available for coloring the optical fibers is 12. The coloring is done for identification of each of the plurality of optical fibers 218. The colors include blue, orange, green, brown, gray, white, red, black, yellow, violet, pink and aqua. In an embodiment of the present disclosure, the color repeats when the number of the plurality of optical fibers 218 exceed more than 12. In an embodiment of the present disclosure, a number of optical fibers 218 with same color in each of the one or more buffer tubes 204a-204h are 2.
[0059] Going further, the optical fiber cable 200 includes the
first layer 206. The first layer 206 surrounds the one or more buffer tubes 204a-204h. The first layer 206 includes one or more yarns. In addition, the first layer acts as a binding element for the one or more buffer tubes 204a-204h. In an embodiment of the present disclosure, each of the one or more yarns is a binder yarn. In an embodiment of the present disclosure, the binder yarn is made of aramid. In another embodiment of the present disclosure, the binder yarn is made of any other suitable material. Each of the one or more yarns is a yarn thread. In an embodiment of the present disclosure, a number of the one or more yarns are 2. In another embodiment of the present disclosure, the number of the one or more yarns may vary.
[0060] In an embodiment of the present disclosure, the binder
yarn facilitates absorption of water and moisture. In addition, each of the one or more yarns prevents ingression of the water inside the optical fiber cable 200. In addition, the first layer 206 binds the stranded one or more buffer tubes 204a-204h to prevent opening up
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of the stranded one or more buffer tubes 204a-204h. In an embodiment of the present disclosure, the first layer 206 provides retention of the lay length of the one or more buffer tubes 204a-204h. In an embodiment of the present disclosure, the first layer 206 acts as a strengthening element for the one or more buffer tubes 204a-204h
[0061] Further, the optical fiber cable 200 includes the second
layer 208. The second layer 208 surrounds the first layer 206. In an embodiment of the present disclosure, the second layer 208 is made of a material. The material is selected from a group. The group consists of polyamide and polypropylene. The material for the second layer 208 has high melting point than the material of the duct 212. Further, the second layer 208 is an outer jacket of the optical fiber cable 200. Also, the second layer 208 provides protection to the optical fiber cable 200.
[0062] The second layer 208 is characterized by a thickness. In
an embodiment of the present disclosure, the second layer 208 has a thickness of about 0.45 millimeter. In another embodiment of the present disclosure, the second layer 208 has the thickness in the range of 0.40 millimeter - 0.80 millimeter. In yet another embodiment of the present disclosure, the thickness of the second layer 208 may vary. In an embodiment of the present disclosure, the second layer 208 is black in color. In another embodiment of the present disclosure, the second layer 208 may be of any color. In addition, the second layer 208 is a sheathing layer. The second layer 208 protects the optical fiber cable 200 against the crush, the bend and tensile stress along the length of the optical fiber cable 200. In an embodiment of the present disclosure, the second layer 208 is enclosed by an anti-rodent masterbatch added during the
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extrusion process.
[0063] Going further, the optical fiber cable 200 includes the one
or more water swellable yarns. In an embodiment of the present disclosure, the optical fiber cable 200 includes a water swellable yarn 214. In another embodiment of the present disclosure, number of the water swellable yarns are 5. In yet another embodiment of the present disclosure, the number of the one or more water swellable yarns may vary. Further, the one or more water swellable yarns are positioned over the central strength member 202 and over the stranded core of the optical fiber cable 200. The one or more water swellable yarns prevent ingression of water in the stranded core of the optical fiber cable 200.
[0064] Further, the optical fiber cable 200 includes the one or
more ripcords. In an embodiment of the present disclosure, the optical fiber cable 200 includes a ripcord 216. In another embodiment of the present disclosure, a number of the one or more ripcords are 1. In yet another embodiment of the present disclosure, the number of the one or more ripcords may vary. In an embodiment of the present disclosure, the one or more ripcords are embedded in the first layer 206. The one or more ripcords lie substantially along the longitudinal axis of the optical fiber cable 200. The one or more ripcords facilitate stripping of the second layer 208.
[0065] In an embodiment of the present disclosure, the one or
more ripcords are made of a material selected from a group. The material includes a polyester material and aramid fibers material. In another embodiment of the present disclosure, the one or more ripcords are made of any suitable material. In an embodiment of
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the present disclosure, each of the one or more ripcords has a circular cross-section. Further, the optical fiber cable 200 has a diameter of about 6.80 millimeters. In an embodiment of the present disclosure, the optical fiber cable 200 has the diameter in a range of 6.6 millimeters - 7.5 millimeters. In another embodiment of the present disclosure, the diameter of the optical fiber cable 200 may vary. In an embodiment of the present disclosure, the optical fiber cable 200 has a core diameter of about 5.90 millimeters. Moreover, the optical fiber cable 200 has a weight of about 129 kilograms per kilometer. In an embodiment of the present disclosure, the optical fiber cable 200 has a weight in a range of 129 kilograms per kilometer ± 5 percent.
[0066] Going further, the optical fiber cable 200 is enclosed by
the duct 212. The optical fiber cable 200 and the duct 212 are substantially positioned along the longitudinal axis of the optical fiber cable 200. Also, the optical fiber cable 200 and the duct 212 are separated by a first pre-defined separation. The predefined separation is such that fill factor of the optical fiber cable 200 is around 50%. The fill factor is ratio of cross section of cable diameter to cross section of the inner diameter of the duct 212. The first pre-defined separation corresponds to a free space 210.
[0067] The duct 212 does not stick with the second layer 208 of
the optical fiber cable 200. In addition, the non-sticking of the duct 212 is due to the material from which the second layer 208 is made. Moreover, the temperature of the duct 212 is tightly controlled during manufacturing to ensure that the duct 212 does not stick with the optical fiber cable 200. Further, the duct 212 allows direct installation of the optical fiber cable 200 without the need for blowing the optical fiber cable 200. In addition, the duct 212 is
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ultraviolet proof.
[0068] The duct 212 is characterized by a thickness. In an
embodiment of the present disclosure, the thickness of the duct 212 is about 2 millimeters. In another embodiment of the present disclosure, the thickness of the duct 212 is in a range of 2 millimeters - 4 millimeters. In yet another embodiment of the present disclosure, the thickness of the duct 212 may vary.
[0069] Furthermore, the duct 212 has an inner diameter and an
outer diameter. In an embodiment of the present disclosure, the inner diameter of the duct 212 is about 10.8 millimeters. In another embodiment of the present disclosure, the inner diameter of the duct 212 is in a range of 10.60 millimeters - 11.5 millimeters. In yet another embodiment of the present disclosure, the inner diameter of the duct 212 may vary. In an embodiment of the present disclosure, the duct 212 is made of high density polyethylene material. In an embodiment of the present disclosure, the high density polyethylene material has a hardness of 60 shore D. The Shore D hardness is a standard test for measuring hardness of material based on depth of penetration of a specific indenter. In an embodiment of the present disclosure, the high density polyethylene material has notched izod impact strength of 300 J/m at a temperature of 23 degree Celsius. The izod impact strength is used for measuring the impact resistance of materials. In addition, the impact strength corresponds to a capability of a material to withstand suddenly applied load.
[0070] In an embodiment of the present disclosure, the outer
diameter of the duct 212 is about 14.8 millimeters. In another embodiment of the present disclosure, the outer diameter of the
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duct 212 is in a range of 14.4 millimeters - 15.5 millimeters. In yet another embodiment of the present disclosure, the outer diameter of the duct 212 may vary. Further, the duct 212 is a micro duct. In an embodiment of the present disclosure, the duct 212 can be applied over any type of cable design. In an embodiment of the present disclosure, the duct 212 can be extruded around any type of optical fiber cable which needs to be blown into a duct.
[0071] In an embodiment of the present disclosure, the second
layer 208 is enclosed by a fourth layer 220 when the duct 212 is made of at least one of low density polyethylene, medium density polyethylene and high density polyethylene (as shown in FIG. 2C and FIG. 2D). The fourth layer 220 is a thin layer. In an embodiment of the present disclosure, the fourth layer 220 is made of a material selected from a group. The group consists of polyamide or polypropylene. In an embodiment of the present disclosure, the fourth layer 220 has a thickness in a range of 0.3 mm - 0.5 mm. In another embodiment of the present disclosure, the optical fiber cable 200 may not include the fourth layer w20. In an embodiment of the present disclosure, the fourth layer 220 is provided to avoid sticking of the second layer 208 made of polyethylene material with the polyethylene duct (the duct 212).
[0072] In an embodiment of the present disclosure, the duct 212
is enclosed by an armoring layer for providing additional ruggedness. In addition, the armoring layer is made of a material selected from a group. The group consists of steel tape, aramid yarns, glass yarns, fiber reinforced plastic, steel wire and the like. In an embodiment of the present disclosure, the armoring layer may be made of any other suitable material. In another embodiment of the present disclosure, the third layer may not be enclosed by the
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armoring layer.
[0073] FIG. 3A illustrates a cross-sectional view of an
arrangement 300 of grouped optical fiber cable assemblies, in accordance with yet another embodiment of the present disclosure. The arrangement 300 an optical fiber cable 302 and an optical fiber cable 320. The optical fiber cable 302 and the optical fiber cable 320 is similar to the optical fiber cable 200 of FIG. 2A. In an embodiment of the present disclosure, the arrangement 200 is applicable for any type of optical fiber cable design. The optical fiber cable 302 includes a central strength member 304, one or more buffer tubes 306a-306h, a first layer 308 and a second layer 310 (as seen in FIG. 3A in conjunction with the perspective view of the arrangement 300 provided in FIG. 3B). In addition, the optical fiber cable 302 includes a plurality of optical fibers 340. Further, the optical fiber cable 320 includes central strength member 322, one or more buffer tubes 324a-324h, a first layer 326 and a second layer 328. In addition, the optical fiber cable 320 includes a plurality of optical fibers 342.
[0074] The optical fiber cable 302 and the optical fiber cable 320
includes one or more water swellable yarns and one or more ripcords. In an embodiment of the present disclosure, the optical fiber cable 302 includes a water swellable yarn 316 and the optical fiber cable 320 includes a water swellable yarn 334. In an embodiment of the present disclosure, the optical fiber cable 302 includes a ripcord 318 and the optical fiber cable 320 includes a ripcord 336. Further, the optical fiber cable 302 is enclosed by a third layer. The third layer is a duct 314. In addition, the optical fiber cable 320 is enclosed by a third layer. The third layer is a
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duct 332. The third layer 314 and the third layer 332 allows direct installation of the optical fiber cable 302 and the optical fiber cable 320 without the need of blowing the optical fiber cable 302 and the optical fiber cable 320 (as previously mentioned above in the detailed description of the FIG. 2A).
[0075] Further, the combination of the optical fiber cable 302
enclosed by the duct 314 and the optical fiber cable 320 enclosed by the duct 332 is enclosed by a fourth layer 338. In an embodiment of the present disclosure, the fourth layer 338 is an additional duct layer. The fourth layer 338 is made of a material selected from a group. The group consists of polyamide, low density polyethylene, medium density polyethylene and high density polyethylene and polypropylene. The fourth layer 338 holds the grouped optical fiber cables with corresponding third layers together. In an embodiment of the present disclosure, the optical fiber cable 302 and the optical fiber cable 320 is jacketed together by the fourth layer 338. In an embodiment of the present disclosure, the fourth layer 338 has a thickness in a range of 1.5 mm - 2.0 mm.
[0076] In an embodiment of the present disclosure, the fourth
layer 338 may be used for jacketing multiple combinations of optical fiber cables with corresponding third layers together. In an example, the fourth layer 338 may jacket 3 combinations of the optical fiber cables with corresponding third layers together. In another example, the fourth layer 338 may jacket 4 combinations of the optical fiber cables with corresponding third layers together. In yet another example, the fourth layer 338 may jacket 5 combinations of the optical fiber cables with corresponding third layers together. In an embodiment of the present disclosure, the
Page 33 / 41

fourth layer 338 is flat shaped. In another embodiment of the present disclosure, the fourth layer 338 is triangle shaped. In yet another embodiment of the present disclosure, the fourth layer 338 is square shaped. In yet another embodiment of the present disclosure, the fourth layer 338 is hexagonal shaped. In an embodiment of the present disclosure, the shape of the fourth layer 338 is based on a number of the grouped optical fiber cables with corresponding third layers.
[0077] In an embodiment of the present disclosure, the duct 314
may not enclose any optical fiber cable and the duct 332 encloses the optical fiber cable 320 to facilitate blowing of a new cable. In another embodiment of the present disclosure, the duct 314 and the duct 332 include pre-installed optical fiber cables. In yet another embodiment of the present disclosure, an optical fiber cable with same fiber capacity or a higher fiber capacity as compared to the optical fiber cable 302 can be blown by de-blowing the existing cable 302.
[0078] In an embodiment of the present disclosure, the second
layer 310 is enclosed by a fifth layer 344 and the second layer 328 is enclosed by a fifth layer 346 when the duct 314 and the duct 332 are made of at least one of low density polyethylene, medium density polyethylene and high density polyethylene (as shown in FIG. 3C and FIG. 3D). The fifth layer 344 of the optical fiber cable 302 and the fifth layer 346 of the optical fiber cable 320 are similar to the fourth layer 220 of the optical fiber cable 200. The fifth layer 344 and the fifth layer 346 is a thin layer. In an embodiment of the present disclosure, the fifth layer 344 and the fifth layer 346 are made of a material selected from a group. The
Page 34 / 41

group consists of polyamide or polypropylene. In an embodiment of the present disclosure, the fifth layer 344 and the fifth layer 346 have a thickness in a range of 0.3 mm - 0.5 mm. In another embodiment of the present disclosure, the arrangement 300 may not include the fifth layer 344 and the fifth layer 346. In an embodiment of the present disclosure, the fifth layer 344 and the fifth layer 346 are provided to avoid sticking of the second layer 310 and the second layer 328 made of polyethylene material with the polyethylene duct.

CLAIMS

1.A method for underground installation of a pre-ducted optical fiber cable assembly (114), the method comprising:

drilling a first pilot bore (116) from a second manhole (110) to a first manhole (108), wherein the second manhole (110) and the first manhole (108) are separated by first distance, wherein the first pilot bore (116) has a first diameter, wherein the first pilot bore (116) is drilled by a first drill string (118), wherein a first reamer (120) is attached to the first drill string (118) to facilitate the drilling of the first pilot bore (116), wherein the first drill string (118) is associated with a first horizontal directional drilling machine (104), wherein the first reamer (120) is detached from the first drill string (118) after completion of the drilling of the first pilot bore (116);

attaching a second reamer (122) to the first drill string (118), wherein the second reamer (122) is attached at a first end (124) of the first drill string(118);

attaching the pre-ducted optical fiber cable assembly (114) to the second reamer (122), wherein the pre-ducted optical fiber cable assembly (114) is attached to a first end (126) of the second reamer (122);

pulling the pre-ducted optical fiber cable assembly (114) that is spooled over a cable drum (102) placed in vicinity of the first manhole (108) and attached to the first end (126) of the second reamer (122), wherein the pre-ducted optical fiber cable assembly (114) is pulled from the first manhole (108) to the second manhole (110), wherein the pre-ducted optical fiber cable assembly (114) is installed for the first distance, wherein the pulling of the pre-ducted optical fiber cable assembly (114) is done by the first horizontal directional drilling machine (104);

drilling a second pilot bore (128) from a third manhole (112) to the second manhole (110), wherein the third manhole (112) and the second manhole (110) are separated by a second distance, wherein the second pilot bore (128) has a second diameter, wherein the second pilot bore (128) is drilled by a second drill string (130), wherein a third reamer (132) is attached to the second drill string (130) to facilitate the drilling of the second pilot bore (128), wherein the second drill string (130) is associated with a second horizontal directional drilling machine (106), wherein the second horizontal directional drilling machine (106) is placed in vicinity of the third manhole (112), wherein the third reamer (132) is detached from the second drill string (130) after completion of the drilling of the second pilot bore (128);

attaching a fourth reamer (134) to the second drill string (130), wherein the fourth reamer (134) is attached at a first end (136) of the second drill string(130);

attaching the pre-ducted optical fiber cable assembly (114) to the fourth reamer (134), wherein the pre-ducted optical fiber cable assembly (114) is attached to a first end (138) of the fourth reamer (134); and

pulling the pre-ducted optical fiber cable assembly (114) installed till the first distance, wherein the pre-ducted optical fiber cable assembly (114) attached to the first end (138) of the fourth reamer (134) is pulled from the second manhole (110) to the third manhole (112), wherein the pulling of the pre-ducted optical fiber cable assembly (114) is done by the second horizontal directional drilling machine (106).

2. The method as recited in claim 1, wherein the second reamer (122) is used to expand diameter of the first pilot bore (116) from the first diameter to a third diameter, wherein the first diameter of the first pilot bore (116) is in a range of about 80 millimeters – 100 millimeters and wherein the third diameter of the first pilot bore (116) is in a range of about 120 millimeters – 150 millimeters.

3. The method as recited in claim 1, wherein the fourth reamer (134) is used to expand a diameter of the second pilot bore (128) from the second diameter to a fourth diameter, wherein the second diameter of the second pilot bore (128) is in a range of about 80 millimeters – 100 millimeters and wherein the fourth diameter of the second pilot bore (128) is in a range of about 120 millimeters – 150 millimeters.

4. The method as recited in claim 1, wherein the first drill string (118) comprises a first plurality of drill pipes, wherein each of the first plurality of drill pipes is attached to each other from end to end, wherein the second drill string (130) comprises a second plurality of drill pipes, wherein each of the second plurality of drill pipes is attached to each other from end to end.

5. The method as recited in claim 1, wherein the first pilot bore (116) and the second pilot bore (128) have a fill factor in a range of about 0.015 – 0.25.

6. The method as recited in claim 1, wherein the pre-ducted optical fiber cable assembly (114) comprises a duct (212), wherein the duct (212) is made of high density polyethylene material, wherein the high density polyethylene material has a hardness of 60 shore D, wherein the high density polyethylene material has a notched izod impact strength of 300 J/m at a temperature of 23 degree Celsius and wherein the duct (212) has a thickness in a range of about 2 millimeters – 4 millimeters.

7. The method as recited in claim 1, wherein the first pilot bore (116) has a depth (D1) in a range of about 1.5 meters – 5 meters.

8. The method as recited in claim 1, wherein the second pilot bore (128) has a depth (D2) in a range of about 1.5 meters – 5 meters.

9. The method as recited in claim 1, wherein the first drill string (118) and the second drill string (130) utilize a drilling fluid to drill the first pilot bore (116) and the second pilot bore (128) and wherein the drilling fluid is water.
, Description:TECHNICAL FIELD

[0001] The present disclosure relates to the field of installation of pre-ducted optical fiber cable assembly. More particularly, the present disclosure relates to the pre-ducted optical fiber cable assembly for direct buried application.

BACKGROUND

[0002] Optical fiber cables have secured an important position in building network of modern communication systems across the world. One such type of optical fiber cable is micro optical fiber cable. The micro optical fiber cable is used in micro duct applications and is installed in micro ducts. Typically, the micro optical fiber cable includes sheathing layer and ripcords. Mostly, the sheathing is made of a polymeric material. Typically, the ripcords are positioned inside the sheathing for facilitating access to the core of the micro optical fiber cable. Traditionally, the micro optical fiber cable is laid inside the micro ducts by broadly performing two steps. The two steps involve burying the micro duct inside the ground followed by blowing the cable into the micro duct using a blowing machine. Typically, the micro optical fiber cables are blown into the micro duct while simultaneously pushing it into the micro duct. The micro optical fiber cables are blown into the micro duct by injecting a high volume of compressed air into the duct which flows inside the micro duct at high speed. The high pressure air propels the micro optical fiber cable further inside the micro duct.

[0003] The currently available micro optical fiber cable has certain limitations. The existing micro optical fiber cable is installed by performing two different steps. This increases the overall installation time and the cost of installation. There is a need for eliminating the blowing cable step in order to reduce cost and overall time of installation. In addition, the materials used for the sheathing do not provide sufficient mechanical strength. Also, the friction between the duct and these micro optical fiber cables inside the duct is high.

[0004] In light of the foregoing discussion, there exists a need for an optical fiber cable assembly which overcomes the above cited drawbacks of conventionally known optical fiber cables.

OBJECT OF THE DISCLOSURE

[0005] A primary object of the present disclosure is to provide a method for underground installation of a pre-ducted optical fiber cable assembly.

[0006] Another object of the present disclosure is to eliminate blowing and pulling of optical fiber cable inside duct compared to conventional installation of the optical fiber cable and the duct separately.

SUMMARY

[0007] The present disclosure relates to a method for underground installation of a pre-ducted optical fiber cable assembly. The method includes a first step of drilling a first pilot bore from a second manhole to a first manhole. In addition, the method includes a second step of attaching a second reamer to a first drill string. Moreover, the method includes a third step of attaching the pre-ducted optical fiber cable assembly to a second reamer. Furthermore, the method includes a fourth step of pulling the pre-ducted optical fiber cable that is spooled over a cable drum placed at vicinity of the first manhole and attached to the first end of the second reamer. Further, the method includes a fifth step of attaching a fourth reamer to the second drill string. Moreover, the method includes a sixth step of attaching the pre-ducted optical fiber cable assembly to the fourth reamer. In addition, the method includes a seventh step of drilling a second pilot bore from a third manhole to the second manhole. Also, the method includes an eighth step of pulling the pre-ducted optical fiber cable assembly installed till a first distance. The pre-ducted optical fiber cable assembly attached to the first end of the fourth reamer is pulled from the second manhole to the third manhole. The second manhole and the first manhole are separated by first distance. The first pilot bore has a first diameter. The first pilot bore is drilled by a first drill string. A first reamer is attached to the first drill string to facilitate the drilling of the first pilot bore. The first drill string is associated with a first horizontal directional drilling machine. The first reamer is detached from the first drill string after completion of the drilling of the first pilot bore. The second reamer is attached at a first end of the first drill string. The pre-ducted optical fiber cable assembly is attached to a first end of the second reamer. The pre-ducted optical fiber cable assembly is pulled from the first manhole to the second manhole. The pre-ducted optical fiber cable assembly is installed for the first distance. The pulling of the pre-ducted optical fiber cable assembly is done by the first horizontal directional drilling machine. The third manhole and the second manhole are separated by a second distance. The second pilot bore has a second diameter. The second pilot bore is drilled by a second drill string. A third reamer is attached to the second drill string to facilitate the drilling of the second pilot bore. The second drill string is associated a second horizontal directional drilling machine. The second horizontal directional drilling machine is placed at the vicinity of the third manhole. The third reamer is detached from the second drill string after completion of the drilling of the second pilot bore. The fourth reamer is attached at a first end of the second drill string. The pre-ducted optical fiber cable assembly is attached to a first end of the fourth reamer. The pulling of the pre-ducted optical fiber cable assembly is done by the second horizontal directional drilling machine.

[0008] In an embodiment of the present disclosure, the second reamer is used to expand diameter of the first pilot bore from the first diameter to a third diameter. The first diameter of the first pilot bore is in a range of about 80 millimeters – 100 millimeters. The third diameter of the first pilot bore is in a range of about 120 millimeters – 150 millimeters.

[0009] In an embodiment of the present disclosure, the fourth reamer is used to expand a diameter of the second pilot bore from the second diameter to a fourth diameter. The second diameter of the second pilot bore is in a range of about 80 millimeters – 100 millimeters. The fourth diameter of the second pilot bore is in a range of about 120 millimeters – 150 millimeters.

[0010] In an embodiment of the present disclosure, the first drill string includes a first plurality of drill pipes. Each of the first plurality of drill pipes is attached to each other from end to end. The second drill string includes a second plurality of drill pipes. Each of the second plurality of drill pipes is attached to each other from end to end.

[0011] In an embodiment of the present disclosure, the first pilot bore and the second pilot bore has a fill factor in a range of about 0.015 – 0.25.

[0012] In an embodiment of the present disclosure, the pre-ducted optical fiber cable assembly includes a duct. The duct is made of high density polyethylene material. The high density polyethylene material has a hardness of 60 shore D. The high density polyethylene material has notched izod impact strength of 300 J/m at a temperature of 23 degree Celsius. The duct has a thickness in a range of about 2 millimeters – 4 millimeters.

[0013] In an embodiment of the present disclosure, the first pilot bore has a depth (D1) in a range of about 1.5 meters – 5 meters.

[0014] In an embodiment of the present disclosure, the second pilot bore has a depth (D2) in a range of about 1.5 meters – 5 meters.

[0015] In an embodiment of the present disclosure, the first drill string and the second drill string utilize a drilling fluid to drill the first pilot bore and the second pilot bor. The drilling fluid is water.

STATEMENT OF THE DISCLOSURE
[0016] The present disclosure relates to a method for underground installation of a pre-ducted optical fiber cable assembly. The method includes a first step of drilling a first pilot bore from a second manhole to a first manhole. In addition, the method includes a second step of attaching a second reamer to a first drill string. Moreover, the method includes a third step of attaching the pre-ducted optical fiber cable assembly to a second reamer. Furthermore, the method includes a fourth step of pulling the pre-ducted optical fiber cable that is spooled over a cable drum placed at vicinity of the first manhole and attached to the first end of the second reamer. Further, the method includes a fifth step of attaching a fourth reamer to the second drill string. Moreover, the method includes a sixth step of attaching the pre-ducted optical fiber cable assembly to the fourth reamer. In addition, the method includes a seventh step of drilling a second pilot bore from a third manhole to the second manhole. Also, the method includes a fourth step of pulling the pre-ducted optical fiber cable assembly installed till a first distance. The pre-ducted optical fiber cable assembly attached to the first end of the fourth reamer is pulled from the second manhole to the third manhole. The second manhole and the first manhole are separated by first distance. The first pilot bore has a first diameter. The first pilot bore is drilled by a first drill string. A first reamer is attached to the first drill string to facilitate the drilling of the first pilot bore. The first drill string is associated with a first horizontal directional drilling machine. The first reamer is detached from the first drill string after completion of the drilling of the first pilot bore. The second reamer is attached at a first end of the first drill string. The pre-ducted optical fiber cable assembly is attached to a first end of the second reamer. The pre-ducted optical fiber cable assembly is pulled from the first manhole to the second manhole. The pre-ducted optical fiber cable assembly is installed for the first distance. The pulling of the pre-ducted optical fiber cable assembly is done by the first horizontal directional drilling machine. The third manhole and the second manhole are separated by a second distance. The second pilot bore has a second diameter. The second pilot bore is drilled by a second drill string. A third reamer is attached to the second drill string to facilitate the drilling of the second pilot bore. The second drill string is associated a second horizontal directional drilling machine. The second horizontal directional drilling machine is placed at the vicinity of the third manhole. The third reamer is detached from the second drill string after completion of the drilling of the second pilot bore. The fourth reamer is attached at a first end of the second drill string. The pre-ducted optical fiber cable assembly is attached to a first end of the fourth reamer. The pulling of the pre-ducted optical fiber cable assembly is done by the second horizontal directional drilling machine.

BRIEF DESCRIPTION

[0017] Having thus described the disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0018] FIG. 1A, FIG. 1B, FIG. 1C and FIG. 1D illustrate a diagram for showing an underground installation of pre-ducted optical fiber cable assembly, in accordance with an embodiment of present disclosure;

[0019] FIG. 2A illustrates a cross sectional view of the pre-ducted optical fiber cable assembly, in accordance with an embodiment of the present disclosure;

[0020] FIG. 2B illustrates a perspective view of the pre-ducted optical fiber cable assembly of FIG. 2A, in accordance with an embodiment of the present disclosure;

[0021] FIG. 2C illustrates a cross-sectional view of the pre-ducted optical fiber cable assembly, in accordance with another embodiment of the present disclosure;

[0022] FIG. 2D illustrates a perspective view of the pre-ducted optical fiber cable assembly of FIG. 2C, in accordance with another embodiment of the present disclosure;

[0023] FIG. 3A illustrates a cross-sectional view of an arrangement of grouped optical fiber cable assemblies, in accordance with yet another embodiment of the present disclosure;

[0024] FIG. 3B illustrates a perspective view of the arrangement of FIG. 3A, in accordance with yet another embodiment of the present disclosure;

[0025] FIG. 3C illustrates a cross-sectional view of an arrangement of grouped optical fiber cable assemblies, in accordance with yet another embodiment of the present disclosure; and

[0026] FIG. 3D illustrates a perspective view of the arrangement of FIG. 3C, in accordance with yet another embodiment of the present disclosure.

[0027] 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.

DETAILED DESCRIPTION

[0028] Reference will now be made in detail to selected embodiments of the present disclosure in conjunction with accompanying figures. The embodiments described herein are not intended to limit the scope of the disclosure, and the present disclosure should not be construed as limited to the embodiments 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 embodiments 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.

[0029] 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.

[0030] FIG. 1A and FIG. 1B illustrate a diagram 100 for showing an underground installation of a pre-ducted optical fiber cable assembly, in accordance with an embodiment of present disclosure. The diagram 100 is shown for explanation of a method of installing the pre-ducted optical fiber cable assembly 114 inside ground. The pre-ducted optical fiber cable assembly 114 is installed for the underground applications in urban and rural areas without disrupting activities taking place in the area. The method utilizes one or more horizontal direct drilling machines for installing the pre-ducted optical fiber cable assembly 114 underground. In an embodiment of the present disclosure, the method is used for installing the pre-ducted optical fiber cable assembly 114 for at least 2 kilometers. In another embodiment of the present disclosure, the method may be used for installing the pre-ducted optical fiber cable assembly 114 for any suitable

[0031] The diagram 100 of FIG. 1A includes a cable drum 102, a first horizontal directional drilling machine 104, a first manhole 108, a second manhole 110, a pre-ducted optical fiber cable assembly 114, a first pilot bore 116, a first drill string 118 and a first reamer 120. Moreover, the diagram 100 of FIG. 1B includes the cable drum 102, the first horizontal directional drilling machine 104, the first manhole 108, the second manhole 110, the pre-ducted optical fiber cable assembly 114, the first pilot bore 116, the first drill string 118 and a second reamer 122. In addition, the diagram 100 of FIG. 1C includes the cable drum 102, the first horizontal directional drilling machine 104, the first manhole 108, the second manhole 110, a third manhole 112, the pre-ducted optical fiber cable assembly 114, a second horizontal directional drilling machine 106, a second pilot bore 128, a second drill string 130 and a third reamer 132. Further, the diagram 100 of FIG. 1D includes the cable drum 102, the first horizontal directional drilling machine 104, the first manhole 108, the second manhole 110, the third manhole 112, the pre-ducted optical fiber cable assembly 114, the second horizontal directional drilling machine 106, the second pilot bore 128, the second drill string 130 and a fourth reamer 134.

[0032] The cable drum 102 includes the pre-ducted optical fiber cable assembly 114 that is spooled over the cable drum 102. In an embodiment of the present disclosure, the cable drum 102 is made of suitable material. In an example, the suitable material includes wood, plywood, steel, plastic and the like. The cable drum 102 is positioned in a vicinity of the first manhole 108. The second manhole 110 and the first manhole 108 are separated by first distance. In an embodiment of the present disclosure, the first distance is in a range of about 50 meters – 200 meters. The second manhole 110 and the third manhole 112 are separated by a second distance. In an embodiment of the present disclosure, the second distance is in a range of about 50 meters – 200 meters. Further, the second manhole 110 is at a distance of 200 meters from the third manhole 112.

[0033] In an embodiment of the present disclosure, the plurality of pilot bores includes the first pilot bore 116 and the second pilot bore 128. Moreover, the first pilot bore 116 is drilled from the second manhole 110 to the first manhole 108. The first pilot bore 116 has a first diameter. In an embodiment of the present disclosure, the first diameter of the first pilot bore 116 is around 80 millimeters. Further, the second pilot bore 128 is drilled from the third manhole 112 to the second manhole 110. The second pilot bore 128 has a second diameter. In an embodiment of the present disclosure, the second diameter of the second pilot bore 128 is around 80 millimeters. Each of the plurality of pilot holes is horizontally drilled and continues underground across the manholes 108-112. Moreover, the plurality of pilot bores is drilled using the one or more horizontal directional drilling machines 104-106. In an embodiment to the present disclosure, the first pilot bore 116 and the second pilot bore 128 has a fill factor in a range of about 0.015 – 0.25. The fill factor of the first pilot bore 116 is defined as ratio of cross sectional area of bore (the first pilot bore 116) to the cross sectional area of the pre-ducted optical fiber cable assembly 114. Similarly, the fill factor of the second pilot bore 128 is defined as ratio of cross sectional area of bore (the second pilot bore 128) to the cross sectional area of the pre-ducted optical fiber cable assembly 114. In an embodiment of the present disclosure, the first pilot bore 116 is characterized by depth D1 and the second pilot bore 128 is characterized by depth D2. In an embodiment of the present disclosure, the first pilot bore 116 has a depth D1 in a range of about 1.5 meters – 5 meters. In an embodiment of the present disclosure, the second pilot bore 128 has a depth D2 in a range of about 1.5 meters – 5 meters.

[0034] In addition, the one or more horizontal directional drilling machines 104-106 are direct drilling machines used for underground installation of any suitable cable assembly. In an embodiment of the present disclosure, the one or more horizontal directional drilling machines 104-106 are used for underground installation of pre-ducted optical fiber cable assembly 114. Moreover, the one or more horizontal directional drilling machine 104-106 includes the first horizontal directional drilling machine 104 and the second horizontal directional drilling machine 106. Further, the first horizontal directional drilling machine 104 include a plurality of components. Furthermore, the plurality of components includes a first plurality of drill pipes, the first reamer 120 and the like. Each of the first plurality of drill pipes is attached to each other from end to end. Moreover, the first plurality of drill pipes are connected together to form the first drill string 118. The first drill sting 118 is used for drilling inside the ground from one point to another. Also, the second horizontal directional drilling machine 106 includes a plurality of components. Further, the plurality of components includes a second plurality of drill pipes, the third reamer 132 and the like. Each of the second plurality of drill pipes is attached to each other from end to end. Furthermore, the second plurality of drill pipes are connected together to form the second drill string 130. Moreover, the first plurality of drill pipes and the second plurality of drill pipes have male threading on one side and female threading on the other side. In an embodiment of the present disclosure, each of the first plurality of drill pipes and second plurality of drill pipes is a hollow pipe made from heat-treated-high-carbon steel. In an embodiment of the present disclosure, the first drill string 118 and the second drill string 130 utilize a drilling fluid to drill the first pilot bore 116 and the second pilot bore 128. The drilling fluid is water. The drilling fluid is used while drilling the bores to provide wet surface to make drilling easy.

[0035] The first reamer 120 is attached to the first drill string 118 to facilitate the drilling of the first pilot bore 116. The first reamer 120 is attached at a first end 124 of the first drill string 118. The first reamer 120 is detached from the first end 124 of the first drill string 118 after completion of the drilling of the first pilot bore 116. The first reamer 120 is a reamer with a small diameter or size. In an embodiment of the present disclosure, the first pilot bore 116 is drilled across the second manhole 110 to the first manhole 108. The second manhole 110 acts as an entry point for the first drill sting 118 and the first manhole 108 acts as an exit point for the first drill string 118. The first pilot bore 116 drilling starts from the second manhole 110 and continues underground to the first manhole 108. The first pilot bore 116 is drilled by the first drill string 118. Further, the first drill string 118 is associated with the first horizontal directional drilling machine 104.

[0036] Further, the second reamer 122 is attached to the first drill string 118. The second reamer 122 is attached at the first end 124 of the first drill string 118. The second reamer 122 has a larger diameter than the first reamer 120. Further, the second reamer 122 is used for enlarging the first pilot bore 116. In an embodiment of the present disclosure, the second reamer 122 is used to expand diameter of the first pilot bore 116 from the first diameter to a third diameter. The first diameter of the first pilot bore 116 is in a range of about 80 millimeters – 100 millimeters. The third diameter of the first pilot bore 116 is in a range of about 120 millimeters – 150 millimeters. Further, the pre-ducted optical fiber cable assembly 114 is attached to the second reamer 122. The pre-ducted optical fiber cable assembly 114 is attached to a first end 126 of the second reamer 122. Accordingly, the pre-ducted optical fiber cable assembly 114 attached to the first end 126 of the second reamer 122 is pulled by the first horizontal directional drilling machine 104. Furthermore, the pulling of the pre-ducted optical fiber cable assembly 114 starts from the second manhole 110 by the first horizontal directional drilling machine 104. The pre-ducted optical fiber cable assembly 114 is installed for the first distance between the first manhole 108 and the second manhole 110. In an embodiment of the present disclosure, the pre-ducted optical fiber cable assembly 114 is installed for a distance of about 200 meters.

[0037] The third reamer 132 is attached to the second drill string 130 to facilitate the drilling of the second pilot bore 128. The third reamer 132 is attached at a first end 136 of the second drill string 130. The third reamer 132 is detached from the first end 136 of the second drill string 130 after completion of the drilling of the second pilot bore 128. The third reamer 132 is a reamer with a small diameter or size. In an embodiment of the present disclosure, the third reamer 132 and the first reamer 120 are same. In an embodiment of the present disclosure, the first pilot bore 116 and the second pilot bore 128 are drilled using same reamer (the first reamer 120). The second pilot bore 128 is drilled across the third manhole 112 to the second manhole 110. The third manhole 112 acts as an entry point for the second drill sting 130 and the second manhole 110 acts as an exit point for the second drill string 130. The second pilot bore 128 drilling starts from the third manhole 112 and continues underground to the second manhole 110. The second pilot bore 128 is drilled by the second drill string 130. Further, the second drill string 130 is associated with the second horizontal directional drilling machine 106.

[0038] Further, the fourth reamer 134 is attached to the second drill string 130. The fourth reamer 134 is attached at the first end 136 of the second drill string 130. The fourth reamer 134 has a larger diameter than the third reamer 132. In addition, the pre-ducted optical fiber cable assembly 114 is attached to the fourth reamer 134. The pre-ducted optical fiber cable assembly 114 is attached to a first end 138 of the fourth reamer 134. Furthermore, the fourth reamer 134 is used for enlarging the second pilot bore 128. In an embodiment of the present disclosure, the fourth reamer 134 is used to expand a diameter of the second pilot bore 128 from the second diameter to a fourth diameter. The second diameter of the second pilot bore 128 is in a range of about 80 millimeters – 100 millimeters. The fourth diameter of the second pilot bore 128 is in a range of about 120 millimeters – 150 millimeters. In an embodiment of the present disclosure, the second reamer 122 and the fourth reamer 134 are same. In an embodiment of the present disclosure, the first pilot bore 116 and the second pilot bore 128 are enlarged using the same reamer (the second reamer 122).

[0001] Further, the pre-ducted optical fiber cable assembly 114 installed till the first distance and attached to the first end 138 of the fourth reamer 134 is pulled by the second horizontal directional drilling machine 106. Furthermore, the pulling of the pre-ducted optical fiber cable assembly 114 starts from the second manhole 110 by the second horizontal directional drilling machine 106. In an embodiment of the present disclosure, the pre-ducted optical fiber cable assembly 114 is installed for a distance of about 400 meters. In an embodiment of the present disclosure, there may be more number of manholes and the cable assembly may be installed for more distance depending upon need.

[0039] In an embodiment of the present disclosure, the first horizontal directional drilling machine 104 and the second horizontal directional drilling machine 106 are same. In another embodiment of the present disclosure, the first horizontal directional drilling machine 104 and the second horizontal directional drilling machine 106 are different.

[0040] FIG. 2A illustrates a cross sectional view of a pre-ducted optical fiber cable assembly 114, in accordance with an embodiment of the present disclosure. The pre-ducted optical fiber cable assembly 114 includes an optical fiber cable 200 and a duct 212. The optical fiber cable 200 is a micro optical fiber cable. The micro optical fiber cable is used for installation in third layer. In addition, the optical fiber cable 200 is used for underground installations. Moreover, the optical fiber cable 200 is used for direct buried applications. The optical fiber cable 200 can be directly buried inside the ground without blowing the optical fiber cable 200. In an embodiment of the present disclosure, the optical fiber cable 200 is a 192F micro optical fiber cable. In addition, 192F corresponds to 192 optical fibers.

[0041] The optical fiber cable 200 is made of a plurality of layers (mentioned below in the patent application). The plurality of layers encloses one or more buffer tubes. Each of the one or more buffer tubes is a loose buffer tube. Each buffer tube of the one or more buffer tubes encloses a plurality of optical fibers. In an embodiment of the present disclosure, the plurality of optical fibers is loosely held inside the one or more buffer tubes. In an embodiment of the present disclosure, each of the one or more buffer tubes has a small diameter (mentioned below in the provisional patent application).

[0042] Going further, the optical fiber cable 200 includes a central strength member 202, one or more buffer tubes 204a-204h, a first layer 206, a second layer 208 (as seen in FIG. 2A in conjunction with the perspective view of the optical fiber cable 200 provided in FIG. 2B). In addition, the optical fiber cable 200 includes one or more water swellable yarns and one or more ripcords. Further, the optical fiber cable 200 is enclosed by a duct 212. The duct 212 allows direct installation of the optical fiber cable 200 without the need of blowing the optical fiber cable 200. The optical fiber cable 200 is used to transmit optical signals (which may carry sensor data or communication data).

[0043] Further, the central strength member 202 lies substantially along a longitudinal axis of the optical fiber cable 200. In addition, the central strength member 202 is coated with a layer of polyethylene. In an embodiment of the present disclosure, the central strength member 202 may be coated with any suitable material. In an embodiment of the present disclosure, the central strength member 202 has a circular cross-section. The central strength member 202 is made of a composite material having a polymer matrix. In an embodiment of the present disclosure, the composite material is flexible fiber reinforced plastic. In another embodiment of the present disclosure, the central strength member 202 may not be coated.

[0044] The fiber reinforced plastic is a composite material having a polymer matrix reinforced with glass fibers. Examples of the fiber reinforced plastics include glass fibers, carbon fibers, aramid fibers, basalt fibers and the like. In an embodiment of the present disclosure, the central strength member 202 is made of any suitable material. Moreover, the central strength member 202 provides physical strength to the optical fiber cable 200 and resists over bending of the optical fiber cable 200. The central strength member 202 provides tensile strength to the optical fiber cable 200. The tensile strength corresponds to a resistance shown by the optical fiber cable 200 against buckling.

[0045] The central strength member 202 is characterized by a diameter measured substantially across the cross section and from the longitudinal axis of the optical fiber cable 200. In an embodiment of the present disclosure, the central strength member 202 has a diameter of about 2.60 millimeters. In another embodiment of the present disclosure, the central strength member 202 has a diameter in a range of 2.60 millimeters ± 0.05 millimeter. In an embodiment of the present disclosure, the diameter of the central strength member 202 may vary. Also, the central strength member 202 prevents buckling of the optical fiber cable 200. In an embodiment of the present disclosure, the optical fiber cable 200 may not include the central strength member 202.

[0046] Further, the optical fiber cable 200 includes the one or more buffer tubes 204a-204h. The one or more buffer tubes 204a-204h is stranded around the central strength member 202 to form a stranded core. In an embodiment of the present disclosure, the central strength member 202 is surrounded by the one or more buffer tubes 204a-204h. In an embodiment of the present disclosure, the one or more buffer tubes 204a-204h is S-Z stranded around the central strength member 202. Each of the one or more buffer tubes 204a-204h is wound around the central strength member 202 in sections with a first direction of winding in an S-shape alternating with the sections with a second direction of winding in a Z-shape. In an embodiment of the present disclosure, the first direction is a clockwise direction and the second direction is an anticlockwise direction. The binding is performed to retain lay length of the stranded plurality of sleeves and uniform stress distribution along length of the optical fiber cable 200. The S-Z fashion of stranding is a form of stranding of the one or more buffer tubes 204a-204h. In addition, the S-Z stranding allows uniform distribution of the stress across all the one or more buffer tubes 204a-204h. The S-Z stranding may have any number of turns between the S-shape and the Z-shape. In an embodiment of the present disclosure, the S-Z stranding may have 4-7 turns between the S-shape and the Z –shape.

[0047] The SZ stranding of the one or more buffer tubes 204a-204h is performed in order to maintain a uniform lay length, mid-spanning and achieve higher production speeds and longer lengths of cable as compared to Helical stranding. In general, the lay length is a longitudinal distance along length of the central strength member 202 required for one buffer tube to go all the way around the central strength member 202 to complete one rotation. In another embodiment of the present disclosure, the one or more buffer tubes 204a-204h are helically stranded around the central strength member 202.

[0048] The cross section of each of the one or more buffer tubes 204a-204h is circular in shape. In an embodiment of the present disclosure, the cross section of each of the one or more buffer tubes 204a-204h may be of any suitable shape. In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-204h has a uniform structure and dimensions. In an embodiment of the present disclosure, number of the one or more buffer tubes 204a-204h is 8. In another embodiment of the present disclosure, the number of the one or more buffer tubes 204a-204h may vary.

[0049] Each of the one or more buffer tubes 204a-204h has a thickness. In an embodiment of the present disclosure, the thickness of each of the one or more buffer tubes 204a-204h is equal. In an embodiment of the present disclosure, the thickness of each of the one or more buffer tubes 204a-204h is about 0.20 millimeter. In another embodiment of the present disclosure, the thickness of each of the one or more buffer tubes 204a-204h is in a range of 0.20 millimeter ± 0.025 millimeter. In yet another embodiment of the present disclosure, the thickness of each of the one or more buffer tubes 204a-204h may vary.

[0050] Furthermore, each of the one or more buffer tubes 204a-204h has an inner diameter and an outer diameter. In an embodiment of the present disclosure, the inner diameter of each of the one or more buffer tubes 204a-204h is about 1.25 millimeters. In another embodiment of the present disclosure, the inner diameter of each of the one or more buffer tubes 204a-204h is in a range of 1.25 millimeters ± 0.05 millimeter. In yet another embodiment of the present disclosure, the inner diameter of each of the one or more buffer tubes 204a-204h may vary.

[0051] In an embodiment of the present disclosure, the outer diameter of each of the one or more buffer tubes 204a-204h is about 1.65 millimeters. In another embodiment of the present disclosure, the outer diameter of each of the one or more buffer tubes 204a-204h is in a range of 1.65 millimeters ± 0.05 millimeter. In yet another embodiment of the present disclosure, the outer diameter of each of the one or more buffer tubes 204a-204h may vary. Further, each of the one or more buffer tubes 204a-204h is a micro loose tube.

[0052] Going further, each of the one or more buffer tubes 204a-204h encloses a plurality of optical fibers 218. In addition, each of the one or more buffer tubes 204a-204h encloses 24 optical fibers. In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-204h may enclose more or less number of optical fibers. In an example, the total number of optical fibers 218 in the optical fiber cable 200 is 288. Each of the one or more buffer tubes 204a-204h is a tube for encapsulating the plurality of optical fibers. The one or more buffer tubes 204a-204h provides support and protection to each of the plurality of optical fibers 218 against crush, bend and stretch. In addition, the one or more buffer tubes 204a-204h protects the plurality of optical fibers 218 and prevents ingression of water inside the stranded core of the optical fiber cable 200.

[0053] Further, the one or more buffer tubes 204a-204h provides mechanical isolation, physical damage protection and identification of each of the plurality of optical fibers 218. In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-204h is colored. In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-204h has a different color. In addition, total number of colors available for coloring the buffer tubes is 12. The coloring is done for identification of each of the one or more buffer tubes 204a-204h. The colors include blue, orange, green, brown, gray, white, red, black, yellow, violet, pink and aqua. In an embodiment of the present disclosure, the one or more buffer tubes 204a-204h is made from a material selected from a group. The group consists of polybutylene terephthalate and nylon. In another embodiment of the present disclosure, the one or more buffer tubes 204a-204h may be made of any other suitable material.

[0054] In an embodiment of the present disclosure, each of the one or more buffer tubes 204a-204h is filled with a gel. In an embodiment of the present disclosure, the gel is a thixotropic gel. In an embodiment of the present disclosure, the thixotropic gel prevents ingression of water inside each of the one or more buffer tubes 204a-204h. In another embodiment of the present disclosure, the one or more buffer tubes 204a-204h may not be filled with the gel.

[0055] Further, each of the plurality of optical fibers 218 is a fiber used for transmitting information as light pulses from one end to another. In addition, each of the plurality of optical fibers 218 is a thin strand of glass capable of transmitting optical signals. Also, each of the plurality of optical fibers 218 is configured to transmit large amounts of information over long distances with relatively low attenuation. Further, each of the plurality of optical fibers 218 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 218. In addition, the cladding region surrounds the core region.

[0056] Each of the plurality of optical fibers 218 has a diameter of about 200 microns. In another embodiment of the present disclosure, each of the plurality of optical fibers 218 has a diameter in a range of 200 microns ± 5 microns. In yet another embodiment of the present disclosure, the diameter of each of the plurality of optical fibers 218 may vary. In an embodiment of the present disclosure, each of the plurality of optical fibers 218 is a single mode fiber. In another embodiment of the present disclosure, each of the plurality of optical fibers 218 is a multimode fiber.

[0057] In an embodiment of the present disclosure, number of the plurality of optical fibers 218 in each of the one or more buffer tubes 204a-204h is 24. In another embodiment of the present disclosure, the number of the plurality of optical fibers 218 in each of the one or more buffer tubes 204a-204h is more or less than 24. In an embodiment of the present disclosure, the number of the plurality of optical fibers 218 in each buffer tube may vary depending upon the cable requirements. Accordingly, a total number of the plurality of optical fibers 218 in the optical fiber cable 200 is 192 (24*8). In an embodiment of the present disclosure, the total number of the plurality of optical fibers 218 may be more or less than 192 depending upon the number of buffer tubes and the optical fibers in each buffer tube.

[0058] In an embodiment of the present disclosure, each of the plurality of optical fibers 218 is a colored optical fiber. In an embodiment of the present disclosure, each of the plurality of optical fibers 218 has a different color. In another embodiment of the present disclosure, the total number of colors available for coloring the optical fibers is 12. The coloring is done for identification of each of the plurality of optical fibers 218. The colors include blue, orange, green, brown, gray, white, red, black, yellow, violet, pink and aqua. In an embodiment of the present disclosure, the color repeats when the number of the plurality of optical fibers 218 exceed more than 12. In an embodiment of the present disclosure, a number of optical fibers 218 with same color in each of the one or more buffer tubes 204a-204h are 2.

[0059] Going further, the optical fiber cable 200 includes the first layer 206. The first layer 206 surrounds the one or more buffer tubes 204a-204h. The first layer 206 includes one or more yarns. In addition, the first layer acts as a binding element for the one or more buffer tubes 204a-204h. In an embodiment of the present disclosure, each of the one or more yarns is a binder yarn. In an embodiment of the present disclosure, the binder yarn is made of aramid. In another embodiment of the present disclosure, the binder yarn is made of any other suitable material. Each of the one or more yarns is a yarn thread. In an embodiment of the present disclosure, a number of the one or more yarns are 2. In another embodiment of the present disclosure, the number of the one or more yarns may vary.

[0060] In an embodiment of the present disclosure, the binder yarn facilitates absorption of water and moisture. In addition, each of the one or more yarns prevents ingression of the water inside the optical fiber cable 200. In addition, the first layer 206 binds the stranded one or more buffer tubes 204a-204h to prevent opening up of the stranded one or more buffer tubes 204a-204h. In an embodiment of the present disclosure, the first layer 206 provides retention of the lay length of the one or more buffer tubes 204a-204h. In an embodiment of the present disclosure, the first layer 206 acts as a strengthening element for the one or more buffer tubes 204a-204h.

[0061] Further, the optical fiber cable 200 includes the second layer 208. The second layer 208 surrounds the first layer 206. In an embodiment of the present disclosure, the second layer 208 is made of a material. The material is selected from a group. The group consists of polyamide and polypropylene. The material for the second layer 208 has high melting point than the material of the duct 212. Further, the second layer 208 is an outer jacket of the optical fiber cable 200. Also, the second layer 208 provides protection to the optical fiber cable 200.

[0062] The second layer 208 is characterized by a thickness. In an embodiment of the present disclosure, the second layer 208 has a thickness of about 0.45 millimeter. In another embodiment of the present disclosure, the second layer 208 has the thickness in the range of 0.40 millimeter – 0.80 millimeter. In yet another embodiment of the present disclosure, the thickness of the second layer 208 may vary. In an embodiment of the present disclosure, the second layer 208 is black in color. In another embodiment of the present disclosure, the second layer 208 may be of any color. In addition, the second layer 208 is a sheathing layer. The second layer 208 protects the optical fiber cable 200 against the crush, the bend and tensile stress along the length of the optical fiber cable 200. In an embodiment of the present disclosure, the second layer 208 is enclosed by an anti-rodent masterbatch added during the extrusion process.

[0063] Going further, the optical fiber cable 200 includes the one or more water swellable yarns. In an embodiment of the present disclosure, the optical fiber cable 200 includes a water swellable yarn 214. In another embodiment of the present disclosure, number of the water swellable yarns are 5. In yet another embodiment of the present disclosure, the number of the one or more water swellable yarns may vary. Further, the one or more water swellable yarns are positioned over the central strength member 202 and over the stranded core of the optical fiber cable 200. The one or more water swellable yarns prevent ingression of water in the stranded core of the optical fiber cable 200.

[0064] Further, the optical fiber cable 200 includes the one or more ripcords. In an embodiment of the present disclosure, the optical fiber cable 200 includes a ripcord 216. In another embodiment of the present disclosure, a number of the one or more ripcords are 1. In yet another embodiment of the present disclosure, the number of the one or more ripcords may vary. In an embodiment of the present disclosure, the one or more ripcords are embedded in the first layer 206. The one or more ripcords lie substantially along the longitudinal axis of the optical fiber cable 200. The one or more ripcords facilitate stripping of the second layer 208.

[0065] In an embodiment of the present disclosure, the one or more ripcords are made of a material selected from a group. The material includes a polyester material and aramid fibers material. In another embodiment of the present disclosure, the one or more ripcords are made of any suitable material. In an embodiment of the present disclosure, each of the one or more ripcords has a circular cross-section. Further, the optical fiber cable 200 has a diameter of about 6.80 millimeters. In an embodiment of the present disclosure, the optical fiber cable 200 has the diameter in a range of 6.6 millimeters - 7.5 millimeters. In another embodiment of the present disclosure, the diameter of the optical fiber cable 200 may vary. In an embodiment of the present disclosure, the optical fiber cable 200 has a core diameter of about 5.90 millimeters. Moreover, the optical fiber cable 200 has a weight of about 129 kilograms per kilometer. In an embodiment of the present disclosure, the optical fiber cable 200 has a weight in a range of 129 kilograms per kilometer ± 5 percent.

[0066] Going further, the optical fiber cable 200 is enclosed by the duct 212. The optical fiber cable 200 and the duct 212 are substantially positioned along the longitudinal axis of the optical fiber cable 200. Also, the optical fiber cable 200 and the duct 212 are separated by a first pre-defined separation. The predefined separation is such that fill factor of the optical fiber cable 200 is around 50%. The fill factor is ratio of cross section of cable diameter to cross section of the inner diameter of the duct 212. The first pre-defined separation corresponds to a free space 210.

[0067] The duct 212 does not stick with the second layer 208 of the optical fiber cable 200. In addition, the non-sticking of the duct 212 is due to the material from which the second layer 208 is made. Moreover, the temperature of the duct 212 is tightly controlled during manufacturing to ensure that the duct 212 does not stick with the optical fiber cable 200. Further, the duct 212 allows direct installation of the optical fiber cable 200 without the need for blowing the optical fiber cable 200. In addition, the duct 212 is ultraviolet proof.

[0068] The duct 212 is characterized by a thickness. In an embodiment of the present disclosure, the thickness of the duct 212 is about 2 millimeters. In another embodiment of the present disclosure, the thickness of the duct 212 is in a range of 2 millimeters - 4 millimeters. In yet another embodiment of the present disclosure, the thickness of the duct 212 may vary.

[0069] Furthermore, the duct 212 has an inner diameter and an outer diameter. In an embodiment of the present disclosure, the inner diameter of the duct 212 is about 10.8 millimeters. In another embodiment of the present disclosure, the inner diameter of the duct 212 is in a range of 10.60 millimeters - 11.5 millimeters. In yet another embodiment of the present disclosure, the inner diameter of the duct 212 may vary. In an embodiment of the present disclosure, the duct 212 is made of high density polyethylene material. In an embodiment of the present disclosure, the high density polyethylene material has a hardness of 60 shore D. The Shore D hardness is a standard test for measuring hardness of material based on depth of penetration of a specific indenter. In an embodiment of the present disclosure, the high density polyethylene material has notched izod impact strength of 300 J/m at a temperature of 23 degree Celsius. The izod impact strength is used for measuring the impact resistance of materials. In addition, the impact strength corresponds to a capability of a material to withstand suddenly applied load.

[0070] In an embodiment of the present disclosure, the outer diameter of the duct 212 is about 14.8 millimeters. In another embodiment of the present disclosure, the outer diameter of the duct 212 is in a range of 14.4 millimeters - 15.5 millimeters. In yet another embodiment of the present disclosure, the outer diameter of the duct 212 may vary. Further, the duct 212 is a micro duct. In an embodiment of the present disclosure, the duct 212 can be applied over any type of cable design. In an embodiment of the present disclosure, the duct 212 can be extruded around any type of optical fiber cable which needs to be blown into a duct.

[0071] In an embodiment of the present disclosure, the second layer 208 is enclosed by a fourth layer 220 when the duct 212 is made of at least one of low density polyethylene, medium density polyethylene and high density polyethylene (as shown in FIG. 2C and FIG. 2D). The fourth layer 220 is a thin layer. In an embodiment of the present disclosure, the fourth layer 220 is made of a material selected from a group. The group consists of polyamide or polypropylene. In an embodiment of the present disclosure, the fourth layer 220 has a thickness in a range of 0.3 mm – 0.5 mm. In another embodiment of the present disclosure, the optical fiber cable 200 may not include the fourth layer w20. In an embodiment of the present disclosure, the fourth layer 220 is provided to avoid sticking of the second layer 208 made of polyethylene material with the polyethylene duct (the duct 212).

[0072] In an embodiment of the present disclosure, the duct 212 is enclosed by an armoring layer for providing additional ruggedness. In addition, the armoring layer is made of a material selected from a group. The group consists of steel tape, aramid yarns, glass yarns, fiber reinforced plastic, steel wire and the like. In an embodiment of the present disclosure, the armoring layer may be made of any other suitable material. In another embodiment of the present disclosure, the third layer may not be enclosed by the armoring layer.

[0073] FIG. 3A illustrates a cross-sectional view of an arrangement 300 of grouped optical fiber cable assemblies, in accordance with yet another embodiment of the present disclosure. The arrangement 300 an optical fiber cable 302 and an optical fiber cable 320. The optical fiber cable 302 and the optical fiber cable 320 is similar to the optical fiber cable 200 of FIG. 2A. In an embodiment of the present disclosure, the arrangement 200 is applicable for any type of optical fiber cable design. The optical fiber cable 302 includes a central strength member 304, one or more buffer tubes 306a-306h, a first layer 308 and a second layer 310 (as seen in FIG. 3A in conjunction with the perspective view of the arrangement 300 provided in FIG. 3B). In addition, the optical fiber cable 302 includes a plurality of optical fibers 340. Further, the optical fiber cable 320 includes central strength member 322, one or more buffer tubes 324a-324h, a first layer 326 and a second layer 328. In addition, the optical fiber cable 320 includes a plurality of optical fibers 342.

[0074] The optical fiber cable 302 and the optical fiber cable 320 includes one or more water swellable yarns and one or more ripcords. In an embodiment of the present disclosure, the optical fiber cable 302 includes a water swellable yarn 316 and the optical fiber cable 320 includes a water swellable yarn 334. In an embodiment of the present disclosure, the optical fiber cable 302 includes a ripcord 318 and the optical fiber cable 320 includes a ripcord 336. Further, the optical fiber cable 302 is enclosed by a third layer. The third layer is a duct 314. In addition, the optical fiber cable 320 is enclosed by a third layer. The third layer is a duct 332. The third layer 314 and the third layer 332 allows direct installation of the optical fiber cable 302 and the optical fiber cable 320 without the need of blowing the optical fiber cable 302 and the optical fiber cable 320 (as previously mentioned above in the detailed description of the FIG. 2A).

[0075] Further, the combination of the optical fiber cable 302 enclosed by the duct 314 and the optical fiber cable 320 enclosed by the duct 332 is enclosed by a fourth layer 338. In an embodiment of the present disclosure, the fourth layer 338 is an additional duct layer. The fourth layer 338 is made of a material selected from a group. The group consists of polyamide, low density polyethylene, medium density polyethylene and high density polyethylene and polypropylene. The fourth layer 338 holds the grouped optical fiber cables with corresponding third layers together. In an embodiment of the present disclosure, the optical fiber cable 302 and the optical fiber cable 320 is jacketed together by the fourth layer 338. In an embodiment of the present disclosure, the fourth layer 338 has a thickness in a range of 1.5 mm – 2.0 mm.

[0076] In an embodiment of the present disclosure, the fourth layer 338 may be used for jacketing multiple combinations of optical fiber cables with corresponding third layers together. In an example, the fourth layer 338 may jacket 3 combinations of the optical fiber cables with corresponding third layers together. In another example, the fourth layer 338 may jacket 4 combinations of the optical fiber cables with corresponding third layers together. In yet another example, the fourth layer 338 may jacket 5 combinations of the optical fiber cables with corresponding third layers together. In an embodiment of the present disclosure, the fourth layer 338 is flat shaped. In another embodiment of the present disclosure, the fourth layer 338 is triangle shaped. In yet another embodiment of the present disclosure, the fourth layer 338 is square shaped. In yet another embodiment of the present disclosure, the fourth layer 338 is hexagonal shaped. In an embodiment of the present disclosure, the shape of the fourth layer 338 is based on a number of the grouped optical fiber cables with corresponding third layers.

[0077] In an embodiment of the present disclosure, the duct 314 may not enclose any optical fiber cable and the duct 332 encloses the optical fiber cable 320 to facilitate blowing of a new cable. In another embodiment of the present disclosure, the duct 314 and the duct 332 include pre-installed optical fiber cables. In yet another embodiment of the present disclosure, an optical fiber cable with same fiber capacity or a higher fiber capacity as compared to the optical fiber cable 302 can be blown by de-blowing the existing cable 302.

[0078] In an embodiment of the present disclosure, the second layer 310 is enclosed by a fifth layer 344 and the second layer 328 is enclosed by a fifth layer 346 when the duct 314 and the duct 332 are made of at least one of low density polyethylene, medium density polyethylene and high density polyethylene (as shown in FIG. 3C and FIG. 3D). The fifth layer 344 of the optical fiber cable 302 and the fifth layer 346 of the optical fiber cable 320 are similar to the fourth layer 220 of the optical fiber cable 200. The fifth layer 344 and the fifth layer 346 is a thin layer. In an embodiment of the present disclosure, the fifth layer 344 and the fifth layer 346 are made of a material selected from a group. The group consists of polyamide or polypropylene. In an embodiment of the present disclosure, the fifth layer 344 and the fifth layer 346 have a thickness in a range of 0.3 mm – 0.5 mm. In another embodiment of the present disclosure, the arrangement 300 may not include the fifth layer 344 and the fifth layer 346. In an embodiment of the present disclosure, the fifth layer 344 and the fifth layer 346 are provided to avoid sticking of the second layer 310 and the second layer 328 made of polyethylene material with the polyethylene duct.