3
be bent up to a bending diameter of 30 mm at
the extreme. When FRP rod is bent further
than the allowed 30 mm diameter, the FRP rod decomposes, resulting in loss of tensile
strength of the cable and further contributing to the optical losses and hence efficiency.
[006]
Currently there are optical fibers available that are directed toward a cable design
5
which eliminates or at least minimizes the aforesaid issues with fiber optic cables. US 5630
003 discloses an optical fiber cable has a plural
ity of loose tubes, each containing at least
one optical fiber which is wound to form a loos
e helical configuration. The loose tubes each
contain one or more filamentary members of
superabsorbent material and are arrayed
around a central organizing member and the assembly is surrounded by a strength member
10
forming a jacket. The entire assembly is surrounded by an outer jacket of suitable material,
preferably fire resistant. However, the said invention does not provide desired flexibility
and resistance against termite and rodents.
[007]
Further, in order to avoid premature aging
of the outer jacket of optical fiber cable,
15
US 6,519,396 discloses an ADSS optical cable capable of being used in a high voltage line
and contains at least one optical transmission element surrounded by a protective covering,
at least one tension-proof element, an outer
jacket and several strand-like or string-like
elements completely embedded into the jacket
material, where the strand-like or string-like
elements consist of a polymer with semiconductor characteristics or of a polymer mixture
20
with semiconductor characteristics and where the resistance of the polymers or the polymer
mixture are in the range of 105 Q/m and 109 Q/m, thus, providing high longevity to the
outer jacket. However, this also fails to resolve the issue of flexibility and resistance to
termites and rodents.
25
[008]
Therefore, in order to overcome the aforementioned drawbacks, there exists a need
to provide an improved ADSS optical fiber cable with extreme flexibility and high tensile
strength for protecting the cable in extreme bending during aerial installations of the cables,
further provided with termite and rodent resist
ant properties for allowing the transmission
of data more efficiently.
30
[009]
The present invention overcomes the aforesaid problems and provides an extremely
flexible All Dielectric Self Supporting (AD
SS) optical fiber cable that improves the
4
performance of the network under sharp bending conditions and increases the flexibility of
the cable thereby enabling easy installation and work efficiency along with having termite
and rodent resistant properties.
OBJECT OF THE INVENTION
5
[010]
The primary object of the present invention
is to provide an improved and extremely
flexible All Dielectric Self Supporting (ADSS) optical fiber cable having multiple uses,
especially for short and mid span (up to 150 me
ters) installation in environments requiring
highly flexible cable.
10
[011]
Another object of the invention is to pr
ovide an ADSS optic fiber cable which is
resistant to rodent and termite attacks at its terminating locations.
[012]
Another object of the invention is to provide
an ADSS Cable which is highly flexible
15
with high tensile strength.
[013]
A further object of the invention is to provide a flexible ADSS cable with a Uni-tube
design and a bending diameter approximately
8 times the diameter of ADSS Cable.
20
[014]
Yet another object of the present invention is to provide an improved ADSS cable
that is simple in design, easy to manufacture, variable and cost effective.
[015]
Other objects and advantages of the present invention will become apparent from the
following description taken in connection with the accompanying drawings, illustrations
25
and examples to disclose the aspects of the present invention.
SUMMARY OF THE INVENTION
[016]
The present invention is an improved and flexible All Dielectric Self Supporting
30
(ADSS) optical fiber cable that includes a plur
ality of optical fibers in one central loose
tube, provided with termite and rodent resistan
t properties, for usage in short and medium
span network installation (up to 150 meters).
5
[017]
The present invention is an improved and flexible ADSS cable, comprising a central
loose tube 3 that extends longitudinally and incl
udes at least one single mode or multimode
optical fiber 1, arranged along the length of cable. The said central loose tube 3 is filled
with jelly 2 permeating in the direction of
longitudinal cable axis and is preferably a
5
chemically neutral thixotropic substance, prev
enting water from penetrating into the central
loose tube 3. The central loose tube 3 is surrounded by plurality of strength members 4
extending lengthwise adjacent to said central loose tube 3 positioned such that they are not
stranded around the tube and covers entire pe
riphery. Further, plurality of strengthening
yarns 5 are positioned over the strength members 4. Fiber optic cable 8 also comprises
10
atleast one ripcords 6 that extend lengthwise along the respective strength members 5.
Finally, the outer jacket 7 surrounds the central loose tube 3, strength members 4 and layer
of strengthening yarns 5.
[018]
In the present invention, the outer sheath or jacket of the ADSS optic fiber cable is
15
induced with specific dopant and additives to make the ADSS Optic Fiber cable resistant to
termite and rodent attacks at its terminat
ing locations when dropped form a pole during
aerial installation of the cable.
BRIEF DESCRIPTION OF THE DRAWING
20
[019]
The present invention may be better unders
tood and its numerous objects, features,
components and advantages are made apparent to those skilled in the art, by referring to the
accompanying drawing, in which:
25
[020]
FIG. 1 illustrates a cross-sectional view of the extremely flexible ADSS Optical Fiber
cable of the present invention.
[021]
FIG. 2 illustrates an isometric view of the flexible ADSS Optical Fiber cable.
30
6
DETAILED DESCRIPTION OF INVENTION
[022]
The particular embodiments of the present invention are described with reference to
the accompanying drawings. The terminology us
ed herein is for the purpose of describing
particular embodiments or aspects only and is
not intended to limit the scope of the present
5
invention. The detailed description is construe
d as a description of the currently preferred
embodiment of the present invention and does not represent the only form in which the
present invention may be practiced. This is to be understood that the same or equivalent
functions may be accomplished, in any order
unless expressly and necessarily limited to a
particular order, by different embodiments that are intended to be encompassed within the
10
scope of the present invention.
[023]
The embodiment is chosen and described to provide the best illustration of the
principles of the invention and its practical app
lication, and to enable one of ordinary skill
in the art to utilize the invention in various embodiments and with various modifications as
15
are suited to the particular use contemplated.
[024]
Furthermore, there is no intention to be bound by any expressed or implied theory
presented in the preceding technical field, background, brief summary or the following
detailed description.
20
[025]
As used herein, the term, “fiber optic cable” refers to network cable that contains
strands of glass fibers inside an insulated casing. They're designed for long distance, very
high-performance data networking and telecommunications.
25
[026]
The term ‘Kevlar
TM
rod’ refers to a synthetic materi
al which is a super strong plastic
that can stop bullets and knives. It is almost
5 times stronger than steel when measured on
an equal weight basis.
[027]
The term ‘Glass Yarn’ refers to a yarn
composed of glass fibers twisted from
30
continuous filament strands or stable fiber silver.
7
[028]
In terrains, when cable runs through a short or medium span network during aerial
installation of the cable, there is extreme bending which leads to bending losses, optical
losses and also tensile strength losses thereby re
ducing the efficiency of data transmission.
[029]
The present invention relates to a flexible All Dielectric Self Supporting (ADSS)
5
optical fiber cable that includes a plurality of optical fibers in one central loose tube, and is
termite and rodent resistant thereby can be used effectively in short and medium span
networks.
[030]
Referring to the drawings, FIG. 1 and 2, the fiber optic cable
8
includes:
10
a)
a central loose tube 3 that extends longitudinally and includes at least one single mode
or multimode optical fiber 1, arranged along the length of cable;
b)
the said central loose tube 3 is filled with jelly 2 permeating in the direction of
longitudinal cable axis and is preferably a chemically neutral thixotropic substance,
15
preventing water from penetrating into the central loose tube 3;
c)
the central loose tube 3 is surrounded by plurality of strength members 4 extending
lengthwise adjacent to said central loose tube 3 positioned such that they are not
stranded around the tube and covers entire periphery;
d)
plurality of strengthening yarns 5 are positioned over the strength members 4;
20
e)
Fiber optic cable 8 also comprises one or mo
re ripcords 6 that extend lengthwise along
the respective strength members 5; and
f)
the outer jacket 7 surrounds the central loose tube 3, strength members 4 and layer of
strengthening yarns 5.
25
[031]
The plurality of optical fibers
1
positioned within the central longitudinally extending
loose tube
3,
upto 48 fibers,
loosely bound or in the form of bundles. In the present
embodiment, plurality of single mode or multimode optical fibers (any grade or variant) is
used which is customizable to a diameter in the range of 6 mm to 8 mm depending on the
number of fibers used and also the span length
of the cable. The optical fiber has an excess
30
length in the range of 0.08% to 0.15% relative to the length of the cable.
8
[032]
The central loose tube
3
extends longitudinally along the fiber optic cable comprising
the plurality of optical fiber. The loose tube
3
is filled with a jelly
2
which is a chemical
neutral thixotropic substance that prevents wate
r from penetrating into the central loose tube
and permeating in the direction of longitudinal cable axis.
5
[033]
Further, the central loose tube
3
of the cable is made of
Polyamide, Polypropylene,
Poly Butylene Terephthalate (PBTP) and othe
r suitable materials, preferably of Poly
Butylene Terephthalate (PBTP) having dimensio
nal stability, high stiffness and hardness
and thereby protecting the optical fibers.
10
[034]
The central loose tube
3
is surrounded by plurality of strength members
4
extending
lengthwise adjacent to central loose tube 3 and positioned in such a way that they are not
stranded around the tube and covers the entire periphery of the tube. The strength members
4
are generally disposed around the central loose tube
3
and extend longitudinally along the
tube
3
. The strength members
4
are formed of Kevlar
TM
rods. Further, at least one water
15
swellable yarns is also positioned around the central loose tube
3
and/or with strengthening
yarns, in the range of 1 to 24. The water swellable yarns are formed of non-woven, spun
bonded cellulosic fiber impregnated with superabsorbent hydrophilic material.
[035]
Kevlar
TM
rod is basically a plastic element with increased flexibility and durability
20
and comparatively acts as a very good strengthening material due to its increased flexibility
and tensile strength retaining properties. The Kevlar
TM
rod has a bending diameter of 15
times its own diameter. The Kevlar
TM
rod
4
of diameter in the range of 0.4 mm to 1.2 mm,
preferably 0.5 mm diameter is used in the fi
ber optic cable of the present invention. For
example- a 0.5 mm diameter Kevlar
TM
rod used yields a bending diameter up to 7.5 mm
25
ensuring a superior flexibility. When the Kevlar
TM
rod is bend beyond the bending diameter
of 7.5 mm it decomposes, however, retainin
g 90% of its tensile strength and hence
contributing to the overall tensile strength of the ADSS Optic Fiber cable besides the
flexibility property. The plural
ity of strength members (Kevlar
TM
Rods) in the fiber optic
cable of the present invention is in the range of 8 to 32.
30
[036]
An additional layer of plurality of strengthening yarns
5
is positioned over the
strength member
4
(Kevlar
TM
rods). Strengthening yarns
5
are preferably E-Glass yarn or
9
impregnated Glass fiber
reinforcement and are disposed longitudinally along the axis such
that they entirely cover the layer of strength members
4
. The layering of strengthening yarn
5
over the Kevlar
TM
rods adds second level of flexibility to the cable and compensates for
the required tensile strength when it is bend beyond its recommended bending diameter. It
also acts as a second level resistance against r
odents as well. In the optical fiber cable of
5
present invention, the plurality of strengthening yarns are in the range of 2 to 48.
[037]
The fiber optic cable
8
comprises at least one or more ripcords
6
that extend
lengthwise along the strength member
4
(Kevlar
TM
rods). By pulling ripcord
6
in both
radially outward and longitudinal directions, the ripcords
6
are separated from the outer
10
jacket to expose the central loose tube
3
. The ripcords
6
are positioned symmetrically along
the cable axis.
[038]
The outer sheath
7
of the ADSS Optical Fiber cable is surrounding the central loose
tube
3
; strength member
4
and layer of strengthening yarns
5
. The outer jacket
7
is made
15
up of Polyolefin or copolymers of several ol
efins like High Density Polyethylene (HDPE),
Medium Density Polyethylene (MDPE), Low
Density Polyethylene(LDPE), Low Linear
Density Polyethylene(LLPDE), however, preferably Polyethylene is used.
[039]
In the Outer Sheath
7,
specific dopants and additives are added before extrusion to
20
induce termite and rodent resist
ant properties. Thus, during aerial installation of the ADSS
Optical fiber cable in short and medium span networks, the cable is protected from possible
termite and rodent attacks at its terminating
end due to its rodent and termite resistant
properties of the outer sheath of the cable.
25
[040]
The extremely flexible ADSS Optical Fiber Cable according to the present invention
is a complete metal free construc
tion for operating range of at least -40° C to +70° C.
[041]
The optical fiber cable with all the said features achieves a bending diameter of
approximately 8 times of its diameter.
30
10
[042]
Although the embodiments herein are described with various specific embodiments,
it will be obvious for a person skilled in the
art to practice the invention with modifications.
However, all such modifications are deemed to be within the scope of the claims.
[043]
It is also to be understood that the following claims are intended to cover all of the
5
generic and specific features of the embodiment
s described herein and all the statements of
the scope of the embodiments which as a matter of language might be said to fall there
between

Claims:WE CLAIM:

1) An All Dielectric Self Supporting (ADSS) optical fiber cable 8, comprising:

a central loose tube 3 with one or more optical fiber 1 extending longitudinally along the length of cable;
a jelly 2 filled in the said central loose tube 3 in the direction of longitudinal cable axis;
plurality of strength members 4 surrounding the central loose tube 3 by extending lengthwise adjacent to said central loose tube 3;
plurality of strengthening yarns 5 positioned over the strength members 4;
atleast one ripcord 6 extended lengthwise along the respective strength members 5; and
outer jacket 7 surrounding the central loose tube 3, strength members 4 and layer of strengthening yarns 5.

2) The ADSS optical fiber cable 8 as claimed in claim 1, wherein said plurality of strength members 4 are formed of KevlarTM rods and are in the range of 8 to 32 in the cable.

3) The ADSS optical fiber cable 8 as claimed in claim 2, wherein said KevlarTM rods 4 is in diameter range of 0.4 mm to 1.2 mm.

4) The ADSS optical fiber cable 8 as claimed in claim 1, wherein said plurality of strengthening yarns 5 are preferably E-Glass yarn or impregnated Glass fiber reinforcement are in the range of 2 to 48 in the cable.

5) The ADSS optical fiber cable 8 as claimed in claim 1, wherein said loose tube 3 of said cable 8 is made up of a material selected from the group consisting Polyamide, Polypropylene, Poly Butylene Terephthalate (PBTP) and comprising one or more single or multimode optical fiber 1 in the range of 1 to 48 fibers.

6) The ADSS optical fiber cable 8 as claimed in claim 1, wherein said outer jacket or sheath 7 of said cable 8 is made up of material selected from the group consisting of Polyolefin or copolymers of olefins such as High Density Polyethylene (HDPE), Medium Density Polyethylene (MDPE), Low Density Polyethylene (LDPE), Low Linear Density Polyethylene (LLPDE).

7) The ADSS optical fiber cable 8 as claimed in claim 1, wherein at least one water swellable yarns is also positioned around the central loose tube 3 and/or with strengthening yarns 5 and is in the range of 1 to 24 in the cable.

8) The ADSS optical fiber cable 8 as claimed in claim 7, wherein the water swellable yarns are formed of non-woven, spun bonded cellulosic fiber impregnated with superabsorbent hydrophilic material.

9) The ADSS optical fiber cable 8 as claimed in claim 1, wherein bending diameter of the cable is approximately 8 times the diameter of said cable 8.

10) The ADSS optical fiber cable 8 as claimed in claim 1, wherein specific dopants and additives are added in the outer sheath 7 of said cable 8 before extrusion to induce rodent and termite resistant properties.

Dated this 30th day of June, 2017
RANA, Vikrant (PA-248)
S.S. Rana & Co.
Attorneys for the Applicant
AKSH OPTIFIBRE LIMITED
, Description:FIELD OF THE INVENTION

[001] The present invention relates to the field of fiber optic cables, particularly an improved and extremely flexible All Dielectric Self Supporting (ADSS) optical fiber cable with termite and rodent resistant properties for usage in short and medium span networks.

BACKGROUND OF THE INVENTION

[002] Optical fibers are very small diameter glass strands which are capable of transmitting an optical signal over great distances, at high speeds, and with relatively low signal loss as compared to standard wire or cable (including wire cable) networks. Many applications of optical fibers require the individual fibers to be placed into groupings, such as in fiber optic cables.

[003] Fiber Optic Cables have been in use in the field of telecom infrastructure for transmission of data by short, medium and long span networks for a long period of time. These are cables containing one or more optical fibers and provide fast transfer speeds, large bandwidth and hence find use in data transfer all over the world. Fiber Optical cables provide the fastest data transfer rates as compared to any of the data transmission medium.

[004] Presently, there are numerous ADSS optic fiber cables available wherein Fiber Reinforced Plastic (FRP) rods are used as the central strengthening material. During installation of aerial Optical Fiber cables, certain terrains with short and medium span length require sharp bends for Aerial installation. In such areas, increased flexibility is required in the fiber optic cable. Further, while dropping the cable from pole to the dropping/terminating point, there is very high possibility of Termite and Rodents, which may cause serious damage to the cable. Therefore, there is requirement of an ADSS fiber optic cable to have Termite and Rodent resistant properties.

[005] Moreover, there exists a limited flexibility in these cables and occurrence of loss of tensile strength due to over bending of the FRP rod. The bending diameter of a typical FRP rod is 25 times its own diameter. A FRP rod of 1.2 mm diameter used as an embedded strength member in an Optical Fiber cable suffer decomposition. The FRP in this cable can be bent up to a bending diameter of 30 mm at the extreme. When FRP rod is bent further than the allowed 30 mm diameter, the FRP rod decomposes, resulting in loss of tensile strength of the cable and further contributing to the optical losses and hence efficiency.

[006] Currently there are optical fibers available that are directed toward a cable design which eliminates or at least minimizes the aforesaid issues with fiber optic cables. US 5630 003 discloses an optical fiber cable has a plurality of loose tubes, each containing at least one optical fiber which is wound to form a loose helical configuration. The loose tubes each contain one or more filamentary members of superabsorbent material and are arrayed around a central organizing member and the assembly is surrounded by a strength member forming a jacket. The entire assembly is surrounded by an outer jacket of suitable material, preferably fire resistant. However, the said invention does not provide desired flexibility and resistance against termite and rodents.

[007] Further, in order to avoid premature aging of the outer jacket of optical fiber cable, US 6,519,396 discloses an ADSS optical cable capable of being used in a high voltage line and contains at least one optical transmission element surrounded by a protective covering, at least one tension-proof element, an outer jacket and several strand-like or string-like elements completely embedded into the jacket material, where the strand-like or string-like elements consist of a polymer with semiconductor characteristics or of a polymer mixture with semiconductor characteristics and where the resistance of the polymers or the polymer mixture are in the range of 105 Q/m and 109 Q/m, thus, providing high longevity to the outer jacket. However, this also fails to resolve the issue of flexibility and resistance to termites and rodents.

[008] Therefore, in order to overcome the aforementioned drawbacks, there exists a need to provide an improved ADSS optical fiber cable with extreme flexibility and high tensile strength for protecting the cable in extreme bending during aerial installations of the cables, further provided with termite and rodent resistant properties for allowing the transmission of data more efficiently.

[009] The present invention overcomes the aforesaid problems and provides an extremely flexible All Dielectric Self Supporting (ADSS) optical fiber cable that improves the performance of the network under sharp bending conditions and increases the flexibility of the cable thereby enabling easy installation and work efficiency along with having termite and rodent resistant properties.

OBJECT OF THE INVENTION

[010] The primary object of the present invention is to provide an improved and extremely flexible All Dielectric Self Supporting (ADSS) optical fiber cable having multiple uses, especially for short and mid span (up to 150 meters) installation in environments requiring highly flexible cable.

[011] Another object of the invention is to provide an ADSS optic fiber cable which is resistant to rodent and termite attacks at its terminating locations.

[012] Another object of the invention is to provide an ADSS Cable which is highly flexible with high tensile strength.

[013] A further object of the invention is to provide a flexible ADSS cable with a Uni-tube design and a bending diameter approximately 8 times the diameter of ADSS Cable.

[014] Yet another object of the present invention is to provide an improved ADSS cable that is simple in design, easy to manufacture, variable and cost effective.

[015] Other objects and advantages of the present invention will become apparent from the following description taken in connection with the accompanying drawings, illustrations and examples to disclose the aspects of the present invention.

SUMMARY OF THE INVENTION

[016] The present invention is an improved and flexible All Dielectric Self Supporting (ADSS) optical fiber cable that includes a plurality of optical fibers in one central loose tube, provided with termite and rodent resistant properties, for usage in short and medium span network installation (up to 150 meters).

[017] The present invention is an improved and flexible ADSS cable, comprising a central loose tube 3 that extends longitudinally and includes at least one single mode or multimode optical fiber 1, arranged along the length of cable. The said central loose tube 3 is filled with jelly 2 permeating in the direction of longitudinal cable axis and is preferably a chemically neutral thixotropic substance, preventing water from penetrating into the central loose tube 3. The central loose tube 3 is surrounded by plurality of strength members 4 extending lengthwise adjacent to said central loose tube 3 positioned such that they are not stranded around the tube and covers entire periphery. Further, plurality of strengthening yarns 5 are positioned over the strength members 4. Fiber optic cable 8 also comprises atleast one ripcords 6 that extend lengthwise along the respective strength members 5. Finally, the outer jacket 7 surrounds the central loose tube 3, strength members 4 and layer of strengthening yarns 5.

[018] In the present invention, the outer sheath or jacket of the ADSS optic fiber cable is induced with specific dopant and additives to make the ADSS Optic Fiber cable resistant to termite and rodent attacks at its terminating locations when dropped form a pole during aerial installation of the cable.

BRIEF DESCRIPTION OF THE DRAWING

[019] The present invention may be better understood and its numerous objects, features, components and advantages are made apparent to those skilled in the art, by referring to the accompanying drawing, in which:

[020] FIG. 1 illustrates a cross-sectional view of the extremely flexible ADSS Optical Fiber cable of the present invention.

[021] FIG. 2 illustrates an isometric view of the flexible ADSS Optical Fiber cable.

DETAILED DESCRIPTION OF INVENTION

[022] The particular embodiments of the present invention are described with reference to the accompanying drawings. The terminology used herein is for the purpose of describing particular embodiments or aspects only and is not intended to limit the scope of the present invention. The detailed description is construed as a description of the currently preferred embodiment of the present invention and does not represent the only form in which the present invention may be practiced. This is to be understood that the same or equivalent functions may be accomplished, in any order unless expressly and necessarily limited to a particular order, by different embodiments that are intended to be encompassed within the scope of the present invention.

[023] The embodiment is chosen and described to provide the best illustration of the principles of the invention and its practical application, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated.

[024] Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.

[025] As used herein, the term, “fiber optic cable” refers to network cable that contains strands of glass fibers inside an insulated casing. They're designed for long distance, very high-performance data networking and telecommunications.

[026] The term ‘KevlarTM rod’ refers to a synthetic material which is a super strong plastic that can stop bullets and knives. It is almost 5 times stronger than steel when measured on an equal weight basis.

[027] The term ‘Glass Yarn’ refers to a yarn composed of glass fibers twisted from continuous filament strands or stable fiber silver.

[028] In terrains, when cable runs through a short or medium span network during aerial installation of the cable, there is extreme bending which leads to bending losses, optical losses and also tensile strength losses thereby reducing the efficiency of data transmission.

[029] The present invention relates to a flexible All Dielectric Self Supporting (ADSS) optical fiber cable that includes a plurality of optical fibers in one central loose tube, and is termite and rodent resistant thereby can be used effectively in short and medium span networks.

[030] Referring to the drawings, FIG. 1 and 2, the fiber optic cable 8 includes:

a) a central loose tube 3 that extends longitudinally and includes at least one single mode or multimode optical fiber 1, arranged along the length of cable;
b) the said central loose tube 3 is filled with jelly 2 permeating in the direction of longitudinal cable axis and is preferably a chemically neutral thixotropic substance, preventing water from penetrating into the central loose tube 3;
c) the central loose tube 3 is surrounded by plurality of strength members 4 extending lengthwise adjacent to said central loose tube 3 positioned such that they are not stranded around the tube and covers entire periphery;
d) plurality of strengthening yarns 5 are positioned over the strength members 4;
e) Fiber optic cable 8 also comprises one or more ripcords 6 that extend lengthwise along the respective strength members 5; and
f) the outer jacket 7 surrounds the central loose tube 3, strength members 4 and layer of strengthening yarns 5.

[031] The plurality of optical fibers 1 positioned within the central longitudinally extending loose tube 3, upto 48 fibers, loosely bound or in the form of bundles. In the present embodiment, plurality of single mode or multimode optical fibers (any grade or variant) is used which is customizable to a diameter in the range of 6 mm to 8 mm depending on the number of fibers used and also the span length of the cable. The optical fiber has an excess length in the range of 0.08% to 0.15% relative to the length of the cable.

[032] The central loose tube 3 extends longitudinally along the fiber optic cable comprising the plurality of optical fiber. The loose tube 3 is filled with a jelly 2 which is a chemical neutral thixotropic substance that prevents water from penetrating into the central loose tube and permeating in the direction of longitudinal cable axis.

[033] Further, the central loose tube 3 of the cable is made of Polyamide, Polypropylene, Poly Butylene Terephthalate (PBTP) and other suitable materials, preferably of Poly Butylene Terephthalate (PBTP) having dimensional stability, high stiffness and hardness and thereby protecting the optical fibers.

[034] The central loose tube 3 is surrounded by plurality of strength members 4 extending lengthwise adjacent to central loose tube 3 and positioned in such a way that they are not stranded around the tube and covers the entire periphery of the tube. The strength members 4 are generally disposed around the central loose tube 3 and extend longitudinally along the tube 3. The strength members 4 are formed of KevlarTM rods. Further, at least one water swellable yarns is also positioned around the central loose tube 3 and/or with strengthening yarns, in the range of 1 to 24. The water swellable yarns are formed of non-woven, spun bonded cellulosic fiber impregnated with superabsorbent hydrophilic material.

[035] KevlarTM rod is basically a plastic element with increased flexibility and durability and comparatively acts as a very good strengthening material due to its increased flexibility and tensile strength retaining properties. The KevlarTM rod has a bending diameter of 15 times its own diameter. The KevlarTM rod 4 of diameter in the range of 0.4 mm to 1.2 mm, preferably 0.5 mm diameter is used in the fiber optic cable of the present invention. For example- a 0.5 mm diameter KevlarTM rod used yields a bending diameter up to 7.5 mm ensuring a superior flexibility. When the KevlarTM rod is bend beyond the bending diameter of 7.5 mm it decomposes, however, retaining 90% of its tensile strength and hence contributing to the overall tensile strength of the ADSS Optic Fiber cable besides the flexibility property. The plurality of strength members (KevlarTM Rods) in the fiber optic cable of the present invention is in the range of 8 to 32.

[036] An additional layer of plurality of strengthening yarns 5 is positioned over the strength member 4 (KevlarTM rods). Strengthening yarns 5 are preferably E-Glass yarn or impregnated Glass fiber reinforcement and are disposed longitudinally along the axis such that they entirely cover the layer of strength members 4. The layering of strengthening yarn 5 over the KevlarTM rods adds second level of flexibility to the cable and compensates for the required tensile strength when it is bend beyond its recommended bending diameter. It also acts as a second level resistance against rodents as well. In the optical fiber cable of present invention, the plurality of strengthening yarns are in the range of 2 to 48.

[037] The fiber optic cable 8 comprises at least one or more ripcords 6 that extend lengthwise along the strength member 4 (KevlarTM rods). By pulling ripcord 6 in both radially outward and longitudinal directions, the ripcords 6 are separated from the outer jacket to expose the central loose tube 3. The ripcords 6 are positioned symmetrically along the cable axis.

[038] The outer sheath 7 of the ADSS Optical Fiber cable is surrounding the central loose tube 3; strength member 4 and layer of strengthening yarns 5. The outer jacket 7 is made up of Polyolefin or copolymers of several olefins like High Density Polyethylene (HDPE), Medium Density Polyethylene (MDPE), Low Density Polyethylene(LDPE), Low Linear Density Polyethylene(LLPDE), however, preferably Polyethylene is used.

[039] In the Outer Sheath 7, specific dopants and additives are added before extrusion to induce termite and rodent resistant properties. Thus, during aerial installation of the ADSS Optical fiber cable in short and medium span networks, the cable is protected from possible termite and rodent attacks at its terminating end due to its rodent and termite resistant properties of the outer sheath of the cable.

[040] The extremely flexible ADSS Optical Fiber Cable according to the present invention is a complete metal free construction for operating range of at least -40° C to +70° C.

[041] The optical fiber cable with all the said features achieves a bending diameter of approximately 8 times of its diameter.

[042] Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be within the scope of the claims.

[043] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the embodiments described herein and all the statements of the scope of the embodiments which as a matter of language might be said to fall there between.