The present disclosure relates to optical fiber cables, and in particular, relates to an optical fiber cable with a different binder pitch.
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 that provide better connectivity and high bandwidth.
[0003] In the optical fiber cables, binding of the optical components such as loose tubes is necessary to hold the optical components properly. FIG. 1 as well a prior art reference "EP2390700" disclose such binding technique, wherein, two binders 104, 106 are contra-helically wound with a same pitch to restrict opening of stranded loose tubes 102.
[0004] However, due to the same pitch of the binders, all overlapping portions of the binders align longitudinally along the length of the optical fiber cables, which drives a risk of the loose tubes bulging out from the positions where there is no overlap between the binders. Therefore, an improved binding technique, thus an improved optical fiber cable is required.
[0005] Any references to methods, apparatus or documents of the prior art are not to be taken as constituting any evidence or admission that they formed, or form part of the common general knowledge.
OBJECT OF THE DISCLOSURE
[0006] A primary object of the present disclosure is to provide an optical fiber cable with at least two binders having different binder pitch.
[0007] Another object of the present disclosure is to prevent bulging issues once binders are wound around loose tubes.

SUMMARY
[0008] Accordingly, an optical fiber cable with at least two binders having different binder pitch (synonymously referred to as "lay-length") is disclosed. The optical fiber cable comprises a plurality of tubes such that each of the plurality of tubes encloses one or more optical transmission elements. The plurality of tubes is stranded around a central strength member in SZ fashion. The optical fiber cable further comprises a first binder and a second binder wound around the plurality of tubes helically, wherein a first lay length of the first binder is different than a second lay length of the second binder. A lay ratio is equal to or more than 1.2, wherein the lay ratio is a ratio of the first lay length of the first binder to the second lay length of the second binder or the lay ratio is a ratio of the second lay length of the second binder to the first lay length of the first binder and a difference between a first stranding angle and a second stranding angle of the first binder and the second binder respectively is greater than or equal to 5 degrees. The first binder is wound in a clockwise direction and the second binder is wound in an anti-clockwise direction. Alternatively, the first binder and the second binder are wound in a same direction. The first binder and the second binder are single-end type binders. Alternatively, the first binder and the second binder are dual-end type binders.
[0009] These and other aspects herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. 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 drawings, throughout which like reference letters indicate corresponding parts in the drawings. The invention herein will be better understood from the following description with reference to the drawings, in which:

[0011] FIG. 1 illustrates a conventional binding technique depicting a same binder pitch.
[0012] FIG. 2 illustrates an example optical fiber cable with different binder pitch.
[0013] FIG. 3 illustrates a binding technique depicting the different binder pitch according to the present disclosure.
[0014] It should be noted that the accompanying figures are intended to present illustrations of few examples of the present disclosure. The figures are not intended to limit the scope of the present disclosure. It should also be noted that accompanying figures are not necessarily drawn to scale.

DETAILED DESCRIPTION
[0015] 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.
[0016] 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.
[0017] The accompanying drawings are used to help easily understand various technical features and it should be understood that the alternatives presented herein are not limited by the accompanying drawings. 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 drawings. 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.
[0018] Now, simultaneous reference is made to FIG. 2 and FIG. 3, in which FIG. 2 illustrates an example optical fiber cable 200 with different binder pitch and FIG. 3 illustrates a binding technique depicting the different binder pitch according to the present disclosure.
[0019] The optical fiber cable 200 may include one or more optical transmission elements 202, a plurality of tubes 204, a central strength member 206, a binder layer 212 and an outer layer 214.
[0020] The one or more optical transmission elements (aka "optical fiber") 202 may be present in form of, but not limited to, a group of loose optical fibers, a group of optical fiber ribbons or a stack of optical fiber ribbons, a group of rollable ribbons, a group of corrugated ribbons, a group of partially/intermittently bonded optical fiber ribbons, a group of flat ribbons. 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.657.A2 category. Alternatively, the optical fiber may be of ITU.T G.657.A1 or G.657.B3 or G.652.D 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.
[0021] The optical fiber may be a bend insensitive fiber that has less degradation in optical properties or less increment in optical attenuation during bending of the optical fiber cable. Thus, the bend insensitive fiber further helps to maintain the optical properties during multiple winding/unwinding operations of the optical fiber cable. The optical fiber may be coloured fiber. The optical fiber may be a single-core optical fiber, a multi-core optical fiber, a single-mode 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-core optical fiber that comprise only a single core.
[0022] The one or more optical transmission elements 202 may be encapsulated in the plurality of tubes 204. That is, each of the plurality of tubes 204 may comprise the one or more optical transmission elements 202. The plurality of tubes 204 may provide mechanical isolation and protection to the one or more optical transmission elements 202 from physical damages. The plurality of tubes 204 may be buffer tubes, loose tubes, tight buffered tubes, flexible tubes, for example. The plurality of tubes 204 may be made up of, but not limited to, PBT (polybutylene terephthalate), polypropylene (PP), polyamide, thermoplastic material or a combination of any of suitable material.
[0023] The plurality of tubes 204 may be stranded around the central strength member 206 in SZ fashion. In SZ stranding, a number of turns are wound in

S direction and then a number of turns in Z direction throughout the length. The central strength member 206 may provide mechanical strength and stiffness to the optical fiber cable 200. The central strength member 206 may provide enhanced 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. The central strength member 206 may be made of, but not limited to, FRP (Fiber Reinforced Plastic), ARP (Aramid Reinforced Plastic) or any other suitable dielectric/strength material. The central strength member 206 may have a round shape, a flat shape or any other suitable shape. Alternatively, the plurality of tubes 204 may be stranded around each other.
[0024] The plurality of tubes 204 may be encapsulated by the binder layer 212. The binder layer 212 may be formed by a pair of binders, i.e., a first binder 208 and a second binder 210 as shown in FIG. 3. The first binder 208 and the second binder 210 may be wound around the plurality of tubes 204 helically such that a first lay length of the first binder 208 is different than a second lay length of the second binder 210 and a lay ratio is equal to or more than 1.2, wherein the lay ratio is a ratio of the first lay length (LI) to the second lay length (L2) or a ratio of the second lay length to the first lay length. For example, if the first binder 208 has the first lay length (LI) as 50mm and the second binder 210 has the second lay length (L2) as 35mm, then the lay ratio will be 1.4. In an implementation, the first binder 208 may be wound in a clockwise direction and the second binder 210 may be wound in an anti-clockwise direction. In an alternative implementation, the first binder 208 may be wound in an anti-clockwise direction and the second binder 210 may be wound in a clockwise direction. In an alternative implementation, the first binder 208 and the second binder 210 may be wound in a same direction. In an alternative implementation, for a tubeless optical fiber cable, the first binder 208 and the second binder 210 may be wound around one or more bundles of optical transmission elements 202. The first binder 208 and the second binder 210 may be coloured and/or coated with a water swellable material and/or a fire retardant material.
[0025] The first binder 208 and the second binder 210 may be defined by a first stranding angle and a second stranding angle, wherein a difference between the

first stranding angle and the second stranding angle is greater than or equal to ±5
degrees. A stranding angle (a) may be given as a = tan_1( ); wherein L is a lay
length and R is a stranding radius. For example, LI = 50mm, L2 = 35mm, R = 4mm, then ai = tan_1(50/2* n * 4) and 012 = tan_1(35/2* n * 4). Accordingly, ai - 012 = 9 degrees.
[0026] Generally, the stranding angle is an angle between a stranding element i.e., binders and cross-section of the optical fiber cable 200, the stranding radius R is a distance between a longitudinal cable axis and middle of the stranding element and the lay length refers to a distance required to complete one revolution of the stranding element around a diameter of a bundle of the plurality of tubes 204.
[0027] The first binder 208 and the second binder 210 may be single-end type binders. Alternatively, the first binder 208 and the second binder 210 may be dual-end type binders. Alternatively, the first binder 208 and the second binder 210 may be a combination of a single-end type binder and a dual-end type binder. Typically, in a single-end type binder, all filaments of a binder are assembled together in a single group, whereas, in a dual-end type binder, the filaments of the binder are assembled in two groups, having substantially equal number of filaments in each group.
[0028] In an aspect, the plurality of tubes 204 may be arranged in one or more layers, wherein each layer is wound by the pair of binders having aforesaid parameters and characteristics.
[0029] The binder layer 212 may be surrounded by the outer layer 214. The outer layer 214 may be a jacket or a sheath. Usually, sheathing (extrusion) is done at a high temperature (preferably more than 100°C). The sheathing is a process of squeezing a molten sheathing material through a funnel of a die as the core runs through the center. The sheathing material for the sheath 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 or combination thereof.

[0030] Advantageously, due to different binder pitch or lay lengths, radial position of overlapping portions (216a, 216b, 216c, 216d, 216e, 216f, 216g, 216h, 216i), as shown in FIG. 3, of the pair of binders along the length varies, which provides a better hold on the stranded plurality of tubes 204 and avoids bulging issues, thereby facilitating easy handling. Further, one lay-length can be kept bigger in the optical fiber cable 200, i.e., lesser amount of binder is required, which reduces the cost.
[0031] It may be noted that the optical fiber cable 200 may contain one or more elements depending upon requirement and implementation. Non-limiting examples of the one or more elements are binders, water blocking tape, fire retardant tape, metal tape, rip cords, water swellable yarns, water blocking gel, strength yarns, dielectric armouring, ECCS (Electro Chrome Coated Steel) tape etc. Although FIG. 2 and FIG. 3 show various elements of the optical fiber cable 200 but it is to be understood that other alternatives are not limited thereon. In other implementations, the optical fiber cable 200 may include less or more number of elements/components. Further, the labels or names of the elements/components are used only for illustrative purpose and do not limit the scope of the present disclosure. The shape and size of the various elements in the optical fiber cable 200 do not limit the scope of the present disclosure.
[0032] 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.

[0033] 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.
[0034] 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.
[0035] 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. An optical fiber cable (200), comprising:
a plurality of tubes (204) such that each of the plurality of tubes (204) encloses one or more optical transmission elements (202); and
a first binder (208) and a second binder (210) wound around the plurality of tubes (204), wherein a first lay length of the first binder (208) is different than a second lay length of the second binder (210).
2. The optical fiber cable (200) as claimed in claim 1, wherein a lay ratio is equal to or more than 1.2, wherein the lay ratio is a ratio of the first lay length of the first binder (208) to the second lay length of the second binder (210).
3. The optical fiber cable (200) as claimed in claim 1, wherein a lay ratio is equal to or more than 1.2, wherein the lay ratio is a ratio of the second lay length of the second binder (210) to the first lay length of the first binder (208).
4. The optical fiber cable (200) as claimed in claim 1, wherein the plurality of tubes (204) is arranged in one or more layers, wherein each layer is wound by a pair of binders.
5. The optical fiber cable (200) as claimed in claim 1, wherein the plurality of tubes (204) is stranded around a central strength member (206).
6. The optical fiber cable (200) as claimed in claim 1, wherein the plurality of tubes (204) is stranded in SZ fashion.
7. The optical fiber cable (200) as claimed in claim 1, wherein the first binder (208) and the second binder (210) are wound around the plurality of tubes (204)

helically, wherein the first binder (208) is wound in a clockwise direction and the second binder (210) is wound in an anti-clockwise direction.
8. The optical fiber cable (200) as claimed in claim 1, wherein the first binder (208) and the second binder (210) are wound around the plurality of tubes (204) helically, wherein the first binder (208) and the second binder (210) are wound in a same direction.
9. The optical fiber cable (200) as claimed in claim 1, wherein a difference between a first stranding angle and a second stranding angle of the first binder (208) and the second binder (210) respectively is greater than or equal to 5 degrees.
10. The optical fiber cable (200) as claimed in claim 1, wherein the first binder (208) and the second binder (210) are single-end type binders.
11. The optical fiber cable (200) as claimed in claim 1, wherein the first binder (208) and the second binder (210) are dual-end type binders.