The present disclosure relates to optical fiber cables, and in particular, relates to a dielectric predictable break load aerial drop cable.
BACKGROUND
[0002] Optical fiber cables have secured an important position in building optical network of modern communication systems across the globe. The optical fiber cables are part of millions of miles of the optical network. From mountain regions to shore lines, from remotest villages to urban environment, engineers have installed the optical fiber cables almost in every region for better internet connectivity and high bandwidth. The optical fiber cables are of various types that may be utilized for various application and one of the various types of the optical fiber cables include aerials cables or overhead cables.
[0003] Typically, the overhead or aerial cables provide an unobtrusive, convenient and cost-effective way for data transmission but also come with drawbacks, such as susceptibility to external hazards like high winds, extreme temperatures, falling tree branches and vehicle accidents.
[0004] Consequently, robust tensile strength i.e., resistance to breakage and a host of other mechanical features are vital, but with this comes another risk. In the event of high-sided vehicle strikes on poles or other support structures, the aerial cables' superior tensile strength (superior tensile strength means the cables don't break at the critical point) causes the poles or other structures to collapse that potentially leads to lengthy and costly repairs to large parts of infrastructure. In extreme cases, injury to personnel and damage to nearby properties may also be possible.
[0005] To solve the aforesaid problem and reduce operators' repair time and cost, there exists a need for a suitable cable. Accordingly, the present disclosure provides a dielectric predictable break load aerial drop cable.

OBJECT OF THE DISCLOSURE
[0006] A primary object of the present disclosure is to provide a dielectric predictable break load aerial drop cable.
[0007] Another object of the present disclosure is to provide the dielectric predictable break load aerial drop cable that breaks at a predefined break load and has a neutral bending performance.
SUMMARY
[0008] In an aspect, the present disclosure discloses a dielectric predictable break load aerial drop cable. The dielectric predictable break load aerial drop cable comprises one or more optical transmission elements, a first layer surrounding the one or more optical transmission elements, a plurality of strength yarns surrounding the first layer and an outer sheath surrounding the plurality of strength yarns. The outer sheath has a plurality of strength members embedded in an equilateral position. The equilateral position has the plurality of strength members arranged in radially equidistant manner and circumferentially equidistant manner, whereby enabling breaking of the dielectric predictable break load aerial drop cable at a predefined break load and having a neutral bending performance. The predefined break load is between 1300 to 2100 N. Each of the plurality of strength members has the plurality of strength yarns held together by epoxy, wherein the plurality of strength members is crushed to crimp the plurality of strength members with a connector, while the dielectric predictable break load aerial drop cable has a crush resistance of 1000 N/100mm (+/-10%). The dielectric predictable break load aerial drop cable has one or more of: a sag less than 2% at a span length of 50-70 meters, the sag of 1.8 m, when the dielectric predictable break load aerial drop cable is loaded with 35-50 kg load along a length at a span of 50-70 m, and a strain less than 0.8 in the one or more optical transmission elements, when the dielectric predictable break load aerial drop cable is loaded with 35-50 kg load along the length at the span of 50-70 m.
[0009] These and other aspects herein will be better appreciated and understood when considered in conjunction with the following description and the

accompanying drawing. It should be understood, however, that the following descriptions are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the invention herein without departing from the spirit thereof.
BRIEF DESCRIPTION OF FIGURE
[0010] The invention is illustrated in the accompanying drawing, throughout which like reference letters indicate corresponding parts in the drawing. The invention herein will be better understood from the following description with reference to the drawing, in which:
[0011] FIG. 1 illustrates a dielectric predictable break load aerial drop cable.
[0012] It should be noted that the accompanying figure is intended to present illustrations of few examples of the present disclosure. The figure is not intended to limit the scope of the present disclosure. It should also be noted that accompanying figure is not necessarily drawn to scale.

DETAILED DESCRIPTION
[0013] In the following detailed description of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be obvious to a person skilled in the art that the invention may be practiced with or without these specific details. In other instances, well known methods, procedures and components have not been described in details so as not to unnecessarily obscure aspects of the invention.
[0014] Furthermore, it will be clear that the invention is not limited to these alternatives only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art, without parting from the scope of the invention.
[0015] The accompanying drawing is used to help easily understand various technical features and it should be understood that the alternatives presented herein are not limited by the accompanying drawing. As such, the present disclosure should be construed to extend to any alterations, equivalents and substitutes in addition to those which are particularly set out in the accompanying drawing. Although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are generally only used to distinguish one element from another.
[0016] Unlike conventional optical fiber cables, the present disclosure proposes an optical fiber cable, i.e., a dielectric predictable break load aerial drop cable that may break at a predefined break load and has a neutral bending performance. Advantageously, the dielectric predictable break load aerial drop cable is a work safe optical fiber cable with a small diameter and is a lightweight aerial cable. The dielectric predictable break load aerial drop cable is designed for aerial installation with a minimum tensile strength of sufficient for span length up to 55 meters. Further, the dielectric predictable break load aerial drop cable is designed with a breaking load in a range of 1300N-2100N. The breaking load requirement is optimised for maximum installation and operational safety of aerial deployment. The breaking load of 1300N-2100N ensures predicable cable failure, which is below breaking strength of support structures such as wooden pole. In an

event of a high-sided vehicle strike, the cable breaks first without collapsing and breaking the support structures that ensures minimum collateral damage and risk of injury in the event of vehicle strike, therefore significantly improving installation, working and operational safety of the aerial deployment.
[0017] FIG. 1 illustrates a dielectric predictable break load aerial drop cable 100. In general, an aerial drop cable corresponds to a cable that may strung overhead between two fixed points over a span length. The dielectric predictable break load aerial drop cable 100 does not include metal in the cable, hence, may be used near power cables. Further, the dielectric predictable break load aerial drop cable 100 breaks at a predefined load. The predefined load may allow the dielectric predictable break load aerial drop cable 100 to break without bringing down the support structures (i.e., aerial support structures) such as poles etc. in case load is experienced by the dielectric predictable break load aerial drop cable 100. Further, the dielectric predictable break load aerial drop cable 100 may prevent damage to adjacent support structure. That is, in case, if one support structure goes down, then the dielectric predictable break load aerial drop cable 100 may break instead of pulling the support structure down.
[0018] The dielectric predictable break load aerial drop cable 100 may comprise one or more optical transmission elements 102, a first layer 104, a plurality of strength yarns 106, an outer sheath 108 and a plurality of strength members 110.
[0019] The one or more optical transmission elements 102 may be present in form of, but not limited to, a plurality of optical fibers, a group of loose optical fibers, a group of optical fiber ribbons or a stack of optical fiber ribbons, a group of bendable ribbons, a group of corrugated ribbons, a group of intermittently bonded optical fiber ribbons, a plurality of buffer tubes, a plurality of tight buffered optical fibers. Generally, an optical fiber refers to a medium associated with transmission of information over long distances in the form of light pulses. The optical fiber uses light to transmit voice and data communications over long distances when encapsulated in a jacket/sheath. The optical fiber may be of ITU.T G.657A2 category. Alternatively, the optical fiber may be of ITU.T G.657A1 or G.657B3 or

G.652D or other suitable category. The ITU.T, stands for International Telecommunication Union-Telecommunication Standardization Sector, is one of the three sectors of the ITU. The ITU is the United Nations specialized agency in the field of telecommunications and is responsible for studying technical, operating and tariff questions and issuing recommendations on them with a view to standardizing telecommunications on a worldwide basis. The optical fiber may have a diameter of 250 microns and a bare optical fiber may have a diameter of 242+/-7 microns. The optical fiber may have a maximum attenuation less than 0.4 dB at 1310nm (nano-meter), or 0.3 dB at 1550nm.
[0020] The optical fiber may be a bend insensitive fiber that has less degradation in optical properties during bending of the optical fiber cable. The optical fibers may be coloured fiber. The optical fiber may be a single mode optical fiber, a multicore optical fiber, a multimode optical fiber or the like. The single mode optical fiber carries only a single mode of light and the multimode optical fiber carries multiple modes of light to propagate. The multicore optical fibers comprise of multiple cores as opposed to the single mode optical fiber and the multimode optical fibers that comprise only a single core.
[0021] Further, the plurality of buffer tubes is an encasement tube used to encapsulate number of optical fibers or an optical fiber ribbon stack. A buffer tube is used in an optical fiber cable to provide mechanical isolation and protection from physical damages. The plurality of buffer tubes includes a plurality of optical transmission elements. Further, an optical fiber ribbon bundle is a group of a plurality of optical fiber ribbons arranged together. The optical fiber ribbon includes a number of optical fibers arranged together using a matrix material. Multiple individual optical fiber ribbons are stacked or grouped into a bundle to form the optical fiber ribbon bundle. Furthermore, an intermittently bonded optical fiber ribbon from the group of intermittently bonded optical fiber ribbons is formed by intermittently bonding the plurality of optical fibers with a special material that imparts a bending and rolling capability along a width of the intermittently bonded optical fiber ribbon.

[0022] Referring to FIG. 1, number of the one or more optical transmission elements 102 may be 4 to 48. The one or more optical transmission elements 102 may be encapsulated by a first layer 104 to form a core of the dielectric predictable break load aerial drop cable 100. The first layer 104 may be a tight buffer. The first layer 104 may be a reduced diameter micro-module that enable fast and easy installation, with reduced risk of kinking and damage of the one or more optical transmission elements 102. That is, the first layer 104 may be kink resistant. In general, kinking implies a discontinuous bend in a cable due to which optical properties of the one or more optical transmission elements 102 degrades. The one or more optical transmission elements 102 encapsulated in the first layer 104 forms a uni-tube design. The first layer 104 consisting of the one or more optical transmission elements 102 may be filled with gel such as, but not limited to, thixotropic compound. The first layer 104 may be made of material such as low-smoke zero-halogen. Alternatively, the first layer 104 may be made of materials such as PBT (polybutylene terephthalate), polypropylene (PP), polyamide, or other polymers, thermoplastic material or a combination of any of suitable material.
[0023] The first layer 104 may have a diameter of 0.9±0.1 mm, which is a reduced diameter. The diameter of the first layer 104 above 0.9±0.1 mm may make the dielectric predictable break load aerial drop cable 100 bulky, whereas the diameter of the first layer 104 below 0.9±0.1 mm may not be suitable for installation.
[0024] The first layer 104 may be surrounded by the plurality of strength yarns 106. In an example, the plurality of strength yarns 106 may be water swellable aramid yarns distributed over and around the first layer 104. In general, an aramid yarn is a high-performance super fiber with high strength and fire-retardant properties. In another example, the plurality of strength yarns 106 may be made from any other suitable material. The plurality of strength yarns 106 may impart strength to the dielectric predictable break load aerial drop cable 100. Further, the plurality of strength yarns 106 may provide cushioning to the dielectric predictable break load aerial drop cable 100. Furthermore, the plurality of strength

yarns 106 or other water swelling elements may prevent water/moisture ingression inside the first layer 104 longitudinally.
[0025] The plurality of strength yarns 106 may be surrounded by the outer sheath 108. The outer sheath 108 may be referred to as a jacket or a sheath. The outer sheath 108 may be extruded over the plurality of strength members 110. Usually, sheathing (extrusion) is done at a high temperature (more than 100°C). The sheathing is a process of squeezing a sheathing material through a funnel of a die as the core runs through center. The sheathing material for the outer sheath 108 may include, but not limited to, polyvinylchloride, polyethylene (such as High Density Poly Ethylene (HDPE), Medium Density Poly Ethylene, and Low Density Poly Ethylene), polyurethane, thermoplastic rubber/elastomer, thermoplastic chlorinated polyethylene, thermoset polyolefins or combination thereof. Preferably, the outer sheath 108 may be formed using Ultra-violet (UV) stabilised black polyethylene.
[0026] The outer sheath 108 may have a nominal thickness of 1.5 mm (millimeter) as below the nominal thickness of 1.5 mm, the outer sheath 108 may become mechanically weak and beyond the nominal thickness of 1.5 mm, a bulky cable may be produced that may not be suitable for installation.
[0027] The outer sheath 108 may have the plurality of strength members 110 embedded in an equilateral position. The equilateral position may have the plurality of strength members 110 arranged in radially equidistant manner and circumferentially equidistant manner. In an example, number of the plurality of strength members 110 may be 3. In such a case, an angle formed by placement of 3 strength members 110 may be 120 degrees. Alternatively, number of the plurality of strength members 110 may vary. In such a case, the angle may also vary. The plurality of strength members 110 may provide predictable break load and excellent crush protection/resistance performance. The crush resistance is an ability of a cable to withstand and/or recover from the effects of a compressive force.
[0028] Each of the plurality of strength members 110 may be embedded at same radius. Alternatively, each of the plurality of strength members 110 may be embedded at different radius. Each of the plurality of strength members 110 may

have same dimension. Alternatively, each of the plurality of strength members 110 may have different dimension. The plurality of strength members may be made of, but not limited to, FRP (Fiber Reinforced Plastic), ARP (Aramid Reinforced Plastic) or any other suitable dielectric/strength material. The plurality of strength members 110 may have a round shape, a flat shape or any other suitable shape. The plurality of strength members 110 may enable the dielectric predictable break load aerial drop cable 100 to be used nearby a high voltage cable as the plurality of strength members 110 is prone to lightning strikes and electromagnetic effects from a nearby high voltage line. The dielectric predictable break load aerial drop cable 100 may be suitable for use under 11 kV (kiloVolt) power cables. The plurality of strength members 110 may be coated with EAA (Ethylene Acrylic Acid) or EVA (Ethylene-Vinyl Acetate) coating for better adhesion with the outer sheath 108.
[0029] Each of the plurality of strength members may have the plurality of strength yarns 106 held together by an epoxy. The epoxy is a material that hardens (brittle) on cooling. Any other suitable material in place of epoxy may be used. The plurality of strength members 110 may be crushed to crimp the plurality of strength members 110 with a connector, while the dielectric predictable break load aerial drop cable 100 may have a crush resistance of 1000 N/100mm (+/-10%), where crushing may be performed to break the epoxy. That is, due to the proposed arrangement and properties, maintaining a crush resistance and crimping with the connector may simultaneously be possible as the plurality of strength members 110 provides crush resistance and crushing the plurality of strength members 110 allows the plurality of strength yarns 106 to be crimped i.e., connected/joined easily and appropriately with the connector. The crush resistance is an ability of a cable to withstand and/or recover from the effects of a compressive force.
[0030] The plurality of strength members 110 may protect the dielectric predictable break load aerial drop cable 100 from buckling. Buckling corresponds to a sudden change in shape i.e., deformation of a cable under a load.
[0031] The abovementioned arrangement and properties may enable breaking of the dielectric predictable break load aerial drop cable 100 at a predefined break load and having a neutral bending performance. The neutral

bending performance may correspond to no preferential bending, which may imply bending of the dielectric predictable break load aerial drop cable 100 with equal ease in all directions. The predefined break load may be between 1300 N (Newton) to 2100 N. That implies, the load to break off the cable shall be not less than 1300 N and not more than 2100 N.
[0032] The dielectric predictable break load aerial drop cable 100 may be characterized by sag. The sag may correspond to increment in downward hanging of the dielectric predictable break load aerial drop cable 100 over a period of time. The dielectric predictable break load aerial drop cable 100 may have the sag of less than 2% at the span length of 50-70 m (meters). Preferably, the dielectric predictable break load aerial drop cable 100 may have the sag of less than 1% at the span length of 55m. The span length may correspond to a distance between the support structures such as wooden poles. Further, the dielectric predictable break load aerial drop cable 100 may have 1.8 m sag, when the dielectric predictable break load aerial drop cable 100 may be loaded with 35-50 kg load along a length at a span of 50-70 m i.e., along the span length of 50-70 m. Furthermore, the dielectric predictable break load aerial drop cable 100 may have strain less than 0.8 in the one or more optical transmission elements 102 when the dielectric predictable break load aerial drop cable 100 may be loaded with 35-50 kg load along the span length of 50-70 m.
[0033] The dielectric predictable break load aerial drop cable (or cable) 100 may be characterized by a cable diameter, a cable length and a cable weight. The cable diameter may be 4.3+/-0.3mm, the cable length may be 500m+/-5% or 1000m+/-5% and the cable weight 15+/-5% kg/km. Alternatively, the cable diameter, the cable length and the cable weight may vary.
[0034] The dielectric predictable break load aerial drop cable (or cable) 100 may be compliant with IEC 60794-1-2 standard, where the dielectric predictable break load aerial drop cable 100 may be characterized by an installation tension of about 150N, a maximum allowable tensile strength 500 N, a bend diameter of 12D, an impact resistance of 5nm and torsion of +/-360 degrees. The installation tension corresponds to tension experienced by the cable due to a pull

during installation of the cable. Further, the tensile strength referred to as an ability of the cable to resist a force that tends to pull it apart. Further, the bend diameter may be a minimum diameter one can bend the cable without damaging it, or shortening its life or kinking it. Further, the impact resistance is an ability of the cable to withstand an impact. Furthermore, the torsion may be an ability of the cable to withstand turns and twists as the cable usually encounters torsional forces.
[0035] Advantageously, the dielectric predictable break load aerial drop cable 100 may be suited for use in transport networks. The compact micro-module construction with fiber counts ranging from 4 to 48 fibers may offer a versatile and compact construction with benefits of quick fiber preparation ready for installation. The dielectric predictable break load aerial drop cable 100 may be manufactured in such a way that it has fast and easy midspan access. The dielectric predictable break load aerial drop cable 100 may be Ultra-violet (UV) protected and may comply to latest issue of various standards such as IEC.60794 series (International Electrotechnical Commission), EN 60794, ANSI/ICEA (American National Standards Institute/Insulated Cable Engineers Association) S-87-640, RoHS (Reduction of Hazardous Substances) compliant, Telcordia GR-20, ITU-T Recommendations and British telecom.
[0036] Advantageously, the dielectric predictable break load aerial drop cable 100 may be suitable to be used as a 55m short span aerial cable to deliver fibre to remote locations or drop to customer or business premises in FTTx (Fiber-to-the-x) applications. The dielectric predictable break load aerial drop cable 100 may reduce the complexity of network maintenance and upgrade and may improve end user experience. The dielectric predictable break load aerial drop cable 100 may be suitable for FTTH (Fiber-to-the-home) roll out and a range of light weight drop type design/construction cables for installation in fibre network in overhead and underground environments.
[0037] It will be apparent to those skilled in the art that other alternatives of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered

presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific aspect, method, and examples herein. The invention should therefore not be limited by the above described alternative, method, and examples, but by all aspects and methods within the scope of the invention. It is intended that the specification and examples be considered as exemplary, with the true scope of the invention being indicated by the claims.
[0038] Conditional language used herein, such as, among others, "can," "may," "might," "may," "e.g.," and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain alternatives include, while other alternatives do not include, certain features, elements and/or steps. Thus, such conditional language is not generally intended to imply that features, elements and/or steps are in any way required for one or more alternatives or that one or more alternatives necessarily include logic for deciding, with or without other input or prompting, whether these features, elements and/or steps are included or are to be performed in any particular alternative. The terms "comprising," "including," "having," and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term "or" is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list.
[0039] Disjunctive language such as the phrase "at least one of X, Y, Z," unless specifically stated otherwise, is otherwise understood with the context as used in general to present that an item, term, etc., may be either X, Y, or Z, or any combination thereof (e.g., X, Y, and/or Z). Thus, such disjunctive language is not generally intended to, and should not, imply that certain alternatives require at least one of X, at least one of Y, or at least one of Z to each be present.
[0040] While the detailed description has shown, described, and pointed out novel features as applied to various alternatives, it can be understood that various omissions, substitutions, and changes in the form and details of the devices

or algorithms illustrated can be made without departing from the scope of the disclosure. As can be recognized, certain alternatives described herein can be embodied within a form that does not provide all of the features and benefits set forth herein, as some features can be used or practiced separately from others.

CLAIMS
We Claim:

1. A dielectric predictable break load aerial drop cable (100) comprising:
one or more optical transmission elements (102);
a first layer (104) surrounding the one or more optical transmission elements (102);
a plurality of strength yarns (106) surrounding the first layer (104);
an outer sheath (108) surrounding the plurality of strength yarns (106), wherein the outer sheath (108) has a plurality of strength members (110) embedded in an equilateral position, wherein the equilateral position has the plurality of strength members (110) arranged in radially equidistant manner and circumferentially equidistant manner,
whereby enabling breaking of the dielectric predictable break load aerial drop cable (100) at a predefined break load and having a neutral bending performance.
2. The dielectric predictable break load aerial drop cable (100) as claimed in claim 1, wherein each of the plurality of strength members (110) has the plurality of strength yarns (106) held together by epoxy, wherein the plurality of strength members (110) is crushed to crimp the plurality of strength members with a connector, while the dielectric predictable break load aerial drop cable (100) has a crush resistance of 1000 N/lOOmm (+/-10%).
3. The dielectric predictable break load aerial drop cable (100) as claimed in claim 1, wherein the predefined break load is between 1300 to 2100 N.
4. The dielectric predictable break load aerial drop cable (100) as claimed in claim 1 has one or more of:

a sag less than 2% at a span length of 50-70 meters;
the sag of 1.8 m, when the dielectric predictable break load aerial drop cable (100) is loaded with 35-50 kg load along a length at a span of 50-70 m; and
a strain less than 0.8 in the one or more optical transmission elements (102), when the dielectric predictable break load aerial drop cable (100) is loaded with 35-50 kg load along the length at the span of 50-70 m.
A dielectric predictable break load aerial drop cable (100) comprising:
one or more optical transmission elements (102);
a first layer (104) surrounding the one or more optical transmission elements (102);
a plurality of strength yarns (106) surrounding the first layer (104);
an outer sheath (108) surrounding the plurality of strength yarns (106), wherein a plurality of strength members (110) is embedded in the outer sheath (108), wherein each of the plurality of strength members (110) has the plurality of strength yarns (106) held together by epoxy, wherein the plurality of strength members (110) is crushed to crimp the plurality of strength members with a connector, while the dielectric predictable break load aerial drop cable (100) has a crush resistance of 1000 N/lOOmm (+/-10%).
The dielectric predictable break load aerial drop cable (100) as claimed in claim 5, wherein the plurality of strength members (110) is embedded in the outer sheath (108) in an equilateral position, wherein the equilateral position has the plurality of strength members (110) arranged in radially equidistant manner and circumferentially equidistant manner enabling a neutral bending performance.
The dielectric predictable break load aerial drop cable (100) as claimed in claim 5 breaks at a predefined break load between 1300 to 2100 N.

8. The dielectric predictable break load aerial drop cable (100) as claimed in claim 5 has one or more of:
a sag less than 2% at a span length of 50-70 meters;
the sag of 1.8 m, when the dielectric predictable break load aerial drop cable (100) is loaded with 35-50 kg load along a length at a span of 50-70 m; and
a strain less than 0.8 in the one or more optical transmission elements (102), when the dielectric predictable break load aerial drop cable (100) is loaded with 35-50 kg load along the length at the span of 50-70 m.