CLIAMS:What is claimed is:
1. An optical fiber cable comprising:
a primary portion102, extending longitudinally, comprising
a primary strength member112;
at least one primary buffer tube114, said at least one primary buffer tube 114being arranged around said primary strength member112;
at least one first optical fiber116, said at least one first optical fiber 116being included in said at least one primary buffer tube114; and
a primary outer jacket 118enclosing said primary strength member 112and said at least one primary buffer tube114;
a secondary portion104extending longitudinally, consisting:
a secondary strength member134; and
a secondary outer jacket 136enclosing said secondary strength member134;
a tertiaryportion106extending longitudinally, comprising:
at least one tertiary buffer tube 126;
at least one second optical fiber128, said at least one second optical fiber 128being included in said at least one tertiary buffer tube 126; and ;
a tertiary outer jacket 130enclosing said at least one tertiary buffer tube126, wherein
said secondary portion104and said tertiary portion106lie external to said primary portion102;
said tertiary portion106lies external to said secondary portion 104; and
said secondary portion104and said tertiary portion106are attached with said primary portion102.
2. The optical fiber cable as claimed in claim 1, comprising:
a first web portion108,said first web portion 108 extending longitudinally; and
a second web portion110, said second web portion110 extending longitudinally, wherein
said first web portion 108 attaches said primary portion102 to said tertiary portion106, and
said second web portion 110attachessaidprimary portion 102to saidsecondaryportion104.

3. The optical fiber cable of claim 2, wherein said primary outer jacket118, said secondary outer jacket136, said tertiary outer jacket130, said first web portion108 and said second web portion 110are made of either of:
i. High-Density Polyethylene (HDPE), or
ii. Medium-Density Polyethylene (MDPE).

4. The optical fiber cable of claim 1, wherein said primary strength member 112is made of a fiber reinforced plastic (FRP).

5. The optical fiber cable of claim 1, wherein said secondary strength member 134is made of at least one of a fiber reinforced plastic (FRP) and an aramid reinforced plastic (ARP).

6. The optical fiber cable of claim 1, wherein said at least one primary buffer tube114is made of either of:
i. Polybutylene Terephthalate (PBT), or
ii. Polypropylene, or
iii. Nylon.

7. The optical fiber cable of claim 1, wherein said at least one tertiary buffer tube 126is made of either of:
i. Polybutylene terephthalate (PBT), or
ii. Polypropylene, or
iii. Nylon.

8. The optical fiber cable of claim 1,comprising a layer of water-blocking tape120, said layer of water-blocking tape 120surrounding said at least one primary buffer tube114, said layer of water-blocking tape 120being surrounded by said primary outer jacket118.

9. The optical fiber cable of claim 1, comprising a rip cord122, said rib cord 122being embedded longitudinally in said primary outer jacket118.

10. The optical fiber cable of claim 9, wherein said rip cord 122is made of either of:
i. Polyester, or
ii. Aramid yarn.

11. The optical fiber cable of claim 1,comprising at least one water-swellable yarn124, said at least one water-swellable yarn124 being laid helically around said primary strength member112.

12. The optical fiber cable of claim 11, wherein said at least one water-swellable yarn 124includes a super absorbent polymer (SAP) coated polyester thread.

13. The optical fiber cable of claim 1, comprising at least one water-swellable yarn124, said at least one water-swellable yarn 124being laid longitudinally along said primary strength member112.

14. The optical fiber cable of claim 1,comprising a waterproof jelly filled invoid between said at least one first optical fiber116 and said at least one primary buffer tube114.

15. The optical fiber cable of claim 1, comprising a waterproof jelly filled invoid between said at least one primary buffer tube114and said primary outer jacket118.

16. The optical fiber cable of claim 1, comprising a peripheral strength member132, wherein said peripheral strength member 132surrounds said at least one tertiary buffer tube126.

17. The optical fiber cable of claim 16, wherein said peripheral strength member 132is a layer of either of:
i. glass roving yarns, or
ii. Aramid yarns.

Dated: 6th Day of May, 2015 Signature
Arun Kishore Narasani Patent Agent
,TagSPECI:FIELD OF THE INVENTION
[001] The present invention relates to optical fiber cables. More particularly, the present invention relates to an optical fiber cable which would facilitate convenient overhead installation, and which would facilitate easier distribution of optical fibers with reduced compromise on overall strength and robustness of the cable.
DESCRIPTION OF THE RELATED ART
[002] Optical fiber cables are the backbone of modern communication infrastructure and systems. Our reliance on optical fibers for telecommunications, broadband communication, communication over passive optical networks, and other applications of optical data transmission and reception is growing day by day. Now, optical fiber connectivity is moving closer towards end consumer device by deployment of optical fiber distribution networks such as FTTX (say FTTH, or Fiber-To-The-Home networks, etc.). Due to an unmatched advantage of superior bandwidths over conventional copper wire cables, optical fiber cables are quickly replacing conventional copper wire cable throughout the world.

[003] In optical fiber distribution networks, at times its necessary (and commercially more viable) to provide optical fiber connectivity to subscriber through overhead optical fiber cables (commonly known as aerial optical fiber cables). Since aerial cables are hung and laid overhead, they facilitate easy distribution of optical fibers at subscriber premises in comparison to optical fiber cables which are laid underground. Aerial optical fiber cables which are generally used in distribution networks include multiple hollow tubes (commonly known as buffer tubes or loose tubes). Within one or more of such hollow tubes, one or more optical fibers are laid. Since aerial cables are hung and laid overhead through a series of supporting structures such as poles, they also require additional strengthening members included within themselves. These strengthening members provide robustness against excessive bending and reduce sagging of the cable between successive supports. Popular strengthening members used in aerial cables are either metallic or are made of high strength dielectric such as Fiber Reinforced Plastic (hereinafter referred as FRP). Due to their lighter weight, dielectric strength members are increasingly getting popular over metallic ones.

[004] Though aerial optical fiber cables facilitate easy distribution of optical fibers, they however have some major drawbacks such as:

[005] To provide optical fiber connectivity to a subscriber, optical fiber/s from an overhead/aerial cable is/are to be retrieved from the cable and ‘dropped’ at subscriber premise. To get this done, a considerable portion of the optical fiber jacket and other coverings are to be torn, and a desired subset of optical fibers within the cable is to be unwrapped and pulled out. This is a tedious process and leaves the cable exposed and vulnerable to damages and improper repacking by an irritated on-site technician because a tedious process is never user friendly.

[006] In an area where, multiple optical fiber connectivities are to be provided by dropping optical fibers at different subscriber premises lying in proximity, repeated tearing of the cable at short intervals for accessing and pulling fibers does a serious damage to overall strength and robustness of the cable.

[007] At times, during preparing a branch of the cable by using a joint box, a considerable length of the strength member (or FRP) of the cable has to be cut and removed. Again, though necessary, this process leaves a portion of the cable overall strength and robustness of the cable compromised, and also make installation of such portion of the cable difficult. In fact, additional protective gear is needed to install and protect such portion of the cable.

[008] Further, in gel filled cables, where a gel is used to provide waterproofing or lubrications within cable components, repeated cuts and tear on the cable leads to leakage of filled gel. This eventually degrades the overall performance of the cable.

[009] As a partial solution to the above listed drawbacks an optical fiber cable having a ‘Figure-8’ structure is proposed. This type of optical fiber cable includes two longitudinal portions which lie external to each other and are attached to each other along their length. A cross-section of such cables represents numerical ‘8’ wherein two lobes (each lobe representing a longitudinal portion) are attached to each other to look like figure of numerical ‘8’. While one of the longitudinal portions includes an internal strength member, buffer tubes and optical fibers, the other longitudinal portion necessarily includes an additional strength member for providing additional strength to the cable. The strength providing longitudinal portion lies parallel to a longitudinal axis of the cable. Though this type of cable provides additional robustness and facilitates additional gripping of the cable, it fails to address other drawbacks. As an example, for reasons cited above, if within a certain portion of the cable, the internal strength member of the cable has to be removed, the overall strength, robustness of the cable gets compromised.
[0010] In light of the foregoing, there exists an acute need for an optical fiber cable which overcomes the above cited drawbacks of conventionally known aerial distribution cables, and which:
i. would facilitate convenient distribution of optical fibers from the cable with reduced compromise on overall strength and robustness of the cable,
ii. would be better equipped for convenient overhead installation,
iii. would have enhanced robustness, strength and suitability for being laid overhead, and
iv. would be user friendly to an on-site technician for installation and distribution of optical fibers.
OBJECTS OF THE INVENTION
[0011] An object of the present invention is to provide an optical fiber cable that is convenient to install and which facilitates convenient distribution of optical fibers at subscriber premises.
[0012] Another object of the present invention is to provide an optical fiber cable that is convenient to install and which facilitates convenient distribution of optical fibers at subscriber premises with reduced compromise on overall strength and robustness of the cable.
[0013] Yet another object of the present invention is to provide an optical fiber cable which would have enhanced robustness, strength and suitability for being laid overhead.
[0014] Yet another object of the present invention is to provide an optical fiber cable which would be user friendly for an on-site technician for installation and distribution of optical fibers.
[0015] These and other objects of the present invention will be apparent from more detailed description which follows.
SUMMARY
[0016] An embodiment of the present invention provides an improved all-dielectric self-supporting optical fiber cable (referred as ‘ADSS cable’ throughout the text hereinafter). The ADSS cable includes a primary portion, a secondary portion, and a tertiary portion, said primary portion, secondary portion, and tertiary portion extending in a longitudinal direction. The primary portion comprises a primary strength member, at least one primary buffer tube, at least one first optical fiber included in said at least one primary buffer tube, and a primary outer jacket enclosing said primary strength member and said at least one primary buffer tube. The secondary portion consists of a secondary strength member and a secondary outer jacket enclosing the secondary strength member. The tertiary portion comprises at least one tertiary buffer tube, at least one second optical fiber included in said at least one tertiary buffer tube, and a tertiary outer jacket enclosing said at least one tertiary buffer tube. The secondary portion is attached externally to the primary portion in a manner such that the secondary outer jacket is attached with the primary outer jacket, and the tertiary portion is attached externally to the primary portion in a manner such that the tertiary outer jacket is attached with the primary outer jacket. The secondary portion and the primary portion are attached to each other along their lengths. Similarly, the tertiary portion and the primary portion are attached to each other along their lengths.

[0017] In another embodiment of the present invention, the primary portion and the tertiary portion are attached by a first web portion, and the primary portion and the secondary portion are attached by a second web portion. Further in this embodiment, the primary outer jacket, the secondary outer jacket, the tertiary outer jacket, first web portion and the second web portion are made of same material and are integrally formed by using a co-extrusion process.

[0018] In another embodiment of the present invention, a water-blocking tape is disposed under the primary outer jacket. The water-blocking tape surrounds the at least one primary buffer tube.

[0019] In another embodiment of the invention, a rip cord is longitudinally embedded in the primary outer jacket.

[0020] In another embodiment of the invention, a water-swellable yarn is helically wound around the primary strength member.

[0021] In another embodiment of the invention, a waterproof jelly is filled in void between said at least one primary buffer tube and said at least one first optical fiber included in it.

BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The features of the present invention, which are novel, are set forth with particularity in the appended claims. Embodiments of the present invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the scope of the invention, wherein like designations denote like elements, and in which:

[0023] FIG. 1 is a cross-sectional view of an optical fiber cable, in accordance with a first embodiment of the present invention;

[0024] FIG. 2 is a perspective view of the optical fiber cable in accordance with the first embodiment of the present invention;

[0025] FIG. 3 is a perspective view of the optical fiber cable, in accordance with the first embodiment of the present invention, being used for distribution of optical fibers;

[0026] It should be noted that drawings are intended to provide a clear understanding of the present invention may not be necessarily drawn to scale.

DETAILED DESCRIPTION OF EMBODIMENTS
[0027] The invention is described in detail below in connection with the figures for purposes of illustration, only. The invention is defined in the appended claims. Terminology used throughout the specification and claims herein are given their ordinary meanings.

[0028] As used in the specification and claims, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “an article” may include a plurality of articles unless the context clearly dictates otherwise.

[0029] Those with ordinary skill in the art will appreciate that the elements in the Figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the Figures may be exaggerated, relative to other elements, in order to improve the understanding of the present invention.

[0030] There may be additional components described in the foregoing application that are not depicted on one of the described drawings. In the event such a component is described, but not depicted in a drawing, the absence of such a drawing should not be considered as an omission of such design from the specification.

[0031] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.

[0032] While the specification concludes with the claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawings, in which like reference numerals are carried forward.

[0033] Construction:
[0034] Reference will now be made in detail to selected embodiment of the present invention in conjunction with accompanying figures. FIG. 1 illustrates a cross-sectional view of an ADSS cable 100prepared in accordance with the first embodiment of the present invention. The cross-section illustrated in FIG. 1 is taken along a plane which is perpendicular to a longitudinal axis of the cable. A perspective view of the ADSS cable 100 is illustrated in FIG. 2. As shown in FIG. 1, the ADSS cable 100 includes a primary portion102, a secondary portion104, and a tertiary portion106.Both, the secondary portion 104and the tertiary portion 106lie external to the primary portion 102.The secondary portion104 and the tertiary portion106 are attached to an outer periphery of the primary portion102. Preferably, the primaryportion102, the secondaryportion104, and the tertiary portions 106 are formed as an integral structure. A first web portion 108 joins the primary portion102 to the tertiary portion106.A second web portion 110joins the primary portion102 to the secondary portion104.It is evident from FIG1 and FIG. 2 that the primary portion102, the secondary portion104, and the tertiary portions 106extend in a longitudinally, and in parallel to each other, to form the ADSS cable 100. Individually, each of the primary portion102, the secondary portion104, and the tertiary portion106have a symmetrical cylindrical structure and, each of the primary portion 102, the secondary portion 104, and the tertiary portion 106 attached to each other in a manner such that longitudinal axis of each of the primary portion 102, the secondary portion 104, and the tertiary portion 106 are coplanar. The secondary portion 104and the primary portion 102are attached to each other along their lengths. Similarly, the tertiary portion 106and the primary portion 102are attached to each other along their lengths.

[0035] The primary portion102 includes a primary strength member112.The primary strength member 112 extends longitudinally and has substantial compressive and tensile strength. The primary strength member 112 provides robustness and strength to ADSS cable 100.Primary buffer tubes114a-114h (hereinafter collectively referred to as primary buffer tubes114) are laid around the primary strength member 112 so as to uniformly surround the primary strength member 112. It should be noted that in this embodiment, as illustrated in FIG. 1, eight primary buffer tubes (114a-114h) are shown. However, based on requirements, the count of the primary buffer tubes114 may be varied without departing from scope and spirit of the present invention. In other embodiments of the invention, the number of optical fibers 116 in each primary buffer tube114 may vary depending on the cable requirements. Next, in the present embodiment as illustrated in FIG. 1, each primary buffer tube114further includes twelve optical fibers 116.It is to be noted that though the present embodiment includes twelve optical fibers116in each of the primary buffer tubes 114, the scope of the present invention does not get limited by the number of optical fibers included in each of the primary buffer tubes 114.In other embodiments of the invention, the number of optical fibers 116 in each primary buffer tube114 may vary depending on the requirements.

[0036] In the present embodiment of the present invention, since the optical fibers 116would be distributed to subscribers, the ‘optical fibers 116’ and term ‘distribution fibers 116’ have been used synonymously and interchangeably.

[0037] Next, in the present embodiment as illustrated in FIG. 1, the primary portion102 further includes a primary outer jacket118 and a layer of water blocking tape 120. While the layer of water blocking tape 120surrounds the primary buffer tubes 114 and the primary strength member 112, the primary outer jacket118surrounds the water blocking tape 120, the primary buffer tubes 114 and the primary strength member 112. The water blocking tape 120is placed underneath the primary outer jacket118. The water blocking tape 120 provides a moisture barrier for the primary portion102, and it protects the primary buffer tubes 114 and the primary strength member 112 from outside moisture. The water blocking tape 120thereby assists in preventing exposure of optical fibers 116 to moisture and contaminants such as Hydroxyl ions (OH- ions).

[0038] The primary portion 102 further includes a rip cord 122. The rip cord 122is embedded the primary outer jacket118.Therip cord 122extends longitudinally along the primary portion 102in the primary outer jacket 118, for facilitating easy stripping or opening of the primary outer jacket 118.Rip cords such as rip cord 112are fairly well known in the art and further description is omitted for the sake of brevity.

[0039] In the present embodiment, in addition to water blocking tape 120, water swellable yarns 124 are also laid helically around the primary strength member 112 to provide moisture absorbent features to the ADSS cable 100.Water swellable yarns 124provide additional capability to the cable for preventing exposure of optical fibers 116to contaminants such as Hydroxyl ions (OH- ions). Water swellable yarns 124 facilitate soaking up of accidental water ingression if any, inside the primary portion102 (such as through cuts in the ADSS cable100).In an another embodiment of the present invention, instead of helically winding the water swellable yarns 124 around the primary strength member 112, the water swellable yarns 124could be laid in parallel to primary strength member 112.

[0040] Further, in the first embodiment if the present invention, a waterproof jelly (or gel) is filled in void between the primary buffer tubes114 and their corresponding optical fibers 116(which are included within respective primary buffer tubes 114). Similarly, the waterproof jelly is also filled in void between the primary buffer tubes114 and the primary outer jacket 102.The waterproof jelly acts as filler and facilitates water proofing within the ADSS cable 100.It is to be noted that in another embodiment of the present invention, the jelly can be altogether replaced by a suitable waterproofing material, such as water swellable yarns.

[0041] Further, as illustrated in FIG. 1 and FIG. 2, the tertiaryportion106 includes a tertiary buffer tube 126.The tertiary buffer tube 126 is dry and does not include a waterproof jelly. The tertiary buffer tube 126is laid longitudinally within the tertiary portion, and includes one or more optical fibers 128.The optical fibers 128 would be used as drop fibers for connecting subscriber premises from the distribution fibers 116in an optical fiber distribution network (for example an FTTX network). Though, in the first embodiment of the present invention, the tertiary buffer tube 126 includes 12 optical fibers, scope of the present invention does not get limited by the number of optical fibers 128 included in the in the tertiary buffer tube 126. In other embodiments of the invention count of optical fibers 128 may vary depending on the requirements. Similarly, though, the first embodiment of the present invention, only one tertiary buffer tube 126 is included in the tertiary portion 106, scope of the present invention does not get limited by the number of tertiary buffer tube 126 included in the in the tertiary portion 106. In other embodiments of the invention count of tertiary buffer tube 126 may vary depending on the requirements.

[0042] Further, in the first embodiment of the present invention, as illustrated in FIG. 1, the tertiary buffer tube 126 is encapsulated in a tertiary outer jacket 130.The tertiary outer jacket 130 is attached to the primary outer jacket 118through web portion 108.Further, a peripheral strength member 132 is provided between the tertiary outer jacket 130 and the tertiary buffer tube 126.The peripheral strength member 132is a layer of a ramid yarns which surrounds the tertiary buffer tube 126. Peripheral strength member 132provides additional mechanical strength to the tertiaryportion106.

[0043] It is to be noted that in some embodiments of the present invention, a separate rip cord may be provided in the tertiary outer jacket 130 for facilitating stripping of the tertiary portion106 and exposing the drop fibers 128 during the drop operation. In addition, water swellable yarns may also be provided underneath the tertiary outer jacket 130 to provide additional moisture barrier and to prevent water ingression inside the tertiary portion106.Such water swellable yarns may either be helically wound around the tertiary buffer tube 126 or may be laid longitudinally along the tertiary buffer tube 126.

[0044] Further, as illustrated in FIG. 1 and FIG. 2, in the first embodiment of the present invention, the secondary portion104 consists of a secondary strength member 134 which is surrounded by a secondary outer jacket 136.The secondary strength member 134, along with the primary strength member 112, provides the necessary mechanical strength to the ADSS cable 100.The secondary outer jacket 136 is attached to the primary outer jacket 118 by way of the web portion 110. In addition to providing additional strength and robustness to ADSS cable 100, the secondary portion104 can also be used by clamps of cable supporting means (for example clamps on poles on which the cable would be hanging) to grip the ADSS cable 100.Advantageously, if the ADSS cable 100is clamped with the help of secondary portion104, the entire primary portion102and the tertiary portion 106would be freely available for conveniently facilitating retrieval and distribution of optical fibers.

[0045] In the first embodiment of the present invention as described above, the Primary outer jacket 118, the secondary outer jacket 136,the tertiary outer jacket 130, the web portion 108 and the web portion 110are made of High density poly-ethylene (HDPE),however, based on requirements and suitability, in other embodiments of the present invention, other materials such a medium density poly-ethylene(MDPE) can also be used. Further, in the first embodiment of the present invention, the Primary outer jacket 118, the secondary outer jacket 136, the tertiary outer jacket 130, the web portion 108 and the web portion 110form an integral part of the ADSS cable 100.

[0046] In another embodiment of the present invention, for providing additional strength to the ADSS cable 100, one or more additional dielectric strength members (made of FRP, and the like) which would extend longitudinally along the primary strength member 112(not shown in figures) may be provided within the primary portion 102.

[0047] Materials and dimensions:
[0048] The following description lists dimensions and composition material of various components used for ADSS cable 100as described in the first embodiment of the present invention. It should be noted that the materials and dimensions included herein do not restrict the scope of the present invention in any way. Various alternative materials known in the art can be used and the dimensions may vary depending on requirements, design parameters and other constraints, if any.

[0049] In the first embodiment illustrated in FIG. 1, the total span of ADSS cable 100is about 17.2±0.5millimeters.

[0050] Further, primary outer jacket 118 has an outer diameter of about 9.2±0.3 millimeters and an inner diameter of about 7.4 millimeters. The tertiary outer jacket 130 has an outer diameter of about 4.0 ±0.3 millimeters and an inner diameter of about 2.5 millimeters. The secondary outer jacket 136 has an outer diameter of about 4.0 ±0.3 millimeters and an inner diameter of about 2.5 millimeters.

[0051] The cross-sections of web portions 108 and 110(as shown in FIG. 1) have a width of about 1±0.3 millimeter.

[0052] As mentioned above, the Primary outer jacket 118, the secondary outer jacket 136, the tertiary outer jacket 130, the web portion 108 and the web portion 110 are made of High Density Poly-Ethylene (HDPE), however, based on requirements and suitability, other materials such a medium density poly-ethylene (MDPE) and other jacketing material known in the prior-art can also be used.

[0053] The primary strength member 112 is made of a fiber reinforced plastic (FRP), however, in other embodiments of present invention, aramid reinforced plastic (ARP) can be used as an alternate material. The primary strength member 112has a diameter of about 3.2millimeters. The secondary strength member 134 is also made of fiber reinforced plastic (FRP), however, in other embodiments of present invention, aramid reinforced plastic (ARP) can be used as an alternate material. The secondary strength member 134has a diameter of about 2.5 millimeters.

[0054] The primary buffer tubes114a-h are made of polybutylene terephthalate (PBT), however, in other embodiments of present invention, polypropylene or nylon can be used as an alternate material. The primary buffer tubes 114a-h have an outer diameter of about 1.85 millimeters and an inner diameter of about 1.4 millimeters.
[0055] The tertiary buffer tube 126 is made of polybutylene terephthalate (PBT), however, in other embodiments of present invention, polypropylene or nylon can be used as an alternate material. The tertiary buffer tube 126has an outer diameter of about 2.4 millimeters and an inner diameter of about 1.7 millimeters.

[0056] The distribution fibers 116 and the optical fibers 128are standard ITU-T G.652D silica optical fibers, and each has a diameter of about 250 microns. However, other embodiments of present invention may include optical fiber of other ITU-T categories (example, sub-categories of ITU-T G.657 or ITU-T G.655 may be used).

[0057] The layer of water-blocking tape120 includes a super absorbent polymer (SAP) tape and has thickness of about 0.15 millimeters.

[0058] The rip cord 122 is made of polyester (however, in other embodiments of the present invention, aramid yarns can be used as an alternate material). The rip cord 122 has a circular-cross-section and has a diameter of about 0.4 millimeters. The water-swellable yarn 124 includes a super absorbent polymer (SAP) coated polyester thread, and has a diameter of about 150 microns. The peripheral strength member 132 is made of glass roving yarn (however, in other embodiments of the present invention, aramid yarns can be used as an alternate material). The peripheral strength member 132 has a thickness of about 0.3 millimeters.

[0059] Installation and Usage advantages:
[0060] In the conventional optical fiber cables, when the fibers from an optical fiber cable are required to be ‘dropped’ at the customer premise, the buffer tube that enclose the optical fibers has to be cut for accessing the fibers to be dropped. This process is referred to as a ‘mid span’ cut. Frequent mid span cuts result in reduction of the mechanical strength and robustness of the optical fiber cable. In certain cases, even portions of strength member/s in the conventional cables are to be cut. Cutting of portions of strength member/swith in the cable also reduces strength and robustness of the optical fiber cable drastically.

[0061] The present invention provides a solution to this problem. FIG. 3 shows a perspective view of ADSS cable 100 when being used for distribution of optical fibers. Optical fibers 128 from the ADSS cable 100 are used for being dropped at various subscriber premises. It is to be noted that current illustration is based on an exemplary requirement that all twelve optical fibers 128are to be dropped at various subscriber premises. To achieve this, as illustrated in FIG. 3, a mid-span cut 302 is made in the ADSS cable 100 (as illustrated, cut is also made on optical fibers 128 and optical fibers 116).In the following step, twelve optical fibers 116 from one of the primary buffer tubes114a-h are spliced with optical fibers 128. As shown in FIG. 3, each of the illustrated twelve optical fibers 116is spliced with one of the optical fibers 128.Thereafter, based on requirement, free ends of all twelve spliced optical fibers 128 are dropped at various subscriber premises.

[0062] In this way, the optical fibers 116 from the primary outer portion102 are only required to be accessed once after every twelve drops, and instead of cutting and opening the primary outer jacket 118at twelve different locations, only a single cut is required for facilitating drops (and if needed, the tertiary lobe 106may be cut open at different locations). This is a primary advantage of the first embodiment of the present invention over conventional optical fiber cables, in which, there would have been multiple cuts at different locations in the cable jacket, each corresponding to a drop. Apart from having lesser number of cuts, the first embodiment of the present invention also offers other additional advantages. Lesser number of cuts in primary outer jacket 118ensures that mechanical strength and robustness of the ADSS cable 100 are not reduced by much. Further, reduced number of cuts in primary outer jacket 118 also ensures reduced sag when the ADSS cable 100 is hung between supports. Moreover, it is to be noted that during the process of accessing and providing optical fibers 116, the primary strength member 112 remains intact. Additionally, presence of secondary lobe 104 (along with secondary strength member134)further strengthens robustness of ADSS cable100, and ensures that any reduction in robustness of the ADSS cable 100caused due to cuts in primary outer jacket 118is further reduced. Still further, presence of the secondary strength member 134 offers additional advantages. The secondary strength member 134may be is used for anchoring ADSS cable 100 at clamps of supporting structures (for example, poles). Such a provision leaves the entire primary outer portion 102, available for being used freely for accessing optical fibers 116. Still further, based on requirements, portion/s of the secondary strength member 134may be cut to provide convenient closure/termination/joints of ADSS cable 100 in closures designed for conventional cables (such as joint boxes, distribution boxes, etc.). The ADSS cable 100 is easy to install and drop at the subscriber premises, as the primary strength member 112 is not required to be cut. Since the tertiary buffer tubes of the present invention have dry interstices, the installation process is less messy and problems arising due to leakage of filler gel/jelly are prevented.

[0063] ADSS cable 100 was made in an ordinary optical fiber cable production set-up which is conventionally well known. The primary buffer tubes 114were laid and arranged around the primary strength member 112 using commonly known ‘SZ stranding’ process. The primary strength member 112, SZ stranded primary buffer tubes 114a-h (along with optical fibers 116 included in them),the tertiary buffer tube 126 (along with optical fibers 128 included in it), the secondary strength member 134, and other components (as described above)were simultaneously passed in a covering unit in a manner such that they get covered with an HDPE cover and that an integral structure of ADSS cable 100 having Primary outer jacket 118,secondary outer jacket 136, tertiary outer jacket 130, web portion 108 and web portion 110is obtained.

[0064] The present invention has been described and illustrated with the help of accompanying drawings which are not intended to limit the scope of the present invention. It is obvious to the persons skilled in the art to incorporate obvious modifications in the embodiments of the invention without deviating from the scope of the present invention. Accordingly, such modifications are intended to be included in the scope of the present invention. In other words, embodiments of the present invention which arise from incorporating obvious modifications in embodiments of the present invention are also fully covered under scope of the present invention. It is to be noted that the scope of the present invention is not limited by dimensional values or material composition of its components. In other words, all embodiments of the optical fiber cable which are in accordance with the present invention are fully covered by the scope claims of the present invention. The present invention is restricted with the following claims.