[0001] The present disclosure relates to optical fiber ribbons, and more specifically relates to ultra-violet curable binders for a plurality of optical transmission elements. The present application is based on, and claims priority from an Indian Application Number 202011042951 filed on 2nd October 2020, the disclosure of which is incorporated herein.

BACKGROUND
[0002] Optical fiber cables play a vital role in today’s networking infrastructure and long-haul communication. The optical fiber cables are designed to have a maximum number of optical fibers to meet the demands, of end-users, related to data, video, audio, or the like transmissions. Further, the optical fiber cables are designed to make them easy to install and maintain, easy to access, and easy to tear and cut whenever required.
[0003] To have maximum number of optical fibers in the existing optical fiber cables, it is important to achieve high packing density of optical fibers inside the optical fiber cable. In addition, the optical fibers that may be in any one of the forms like loose fibers, flat ribbons, bendable ribbons, intermittently bonded ribbons, group/subgroup of loose tubes, buffer tubes, micromodules, tight buffered and the like need to be tightly packed inside the optical fiber cable to achieve high density packing in limited space.
[0004] One of the methods to achieve high density packing of optical fibers is bundling. Bundling is process of making bundles of a plurality of optical fibers in groups and subgroups using a thread binder.
[0005] The thread binder basically holds the plurality of optical fibers compactly. These thread binders wound the plurality of optical fibers including, but not limited to, a group of loose fibers, flat optical fiber ribbons, a group of bendable optical fiber ribbons, a group of intermittently bonded optical fiber ribbons, a group/subgroup of loose tubes, a group of buffer tubes, a group of micromodules and a group tight buffered optical fibers to achieve the bundle. The thread binder wounds around circumference of the plurality of the optical fibers in a helical configuration by applying a predefined tension.
[0006] Conventionally, the thread binder is loosely wound around the plurality of optical fibers to avoid optical attenuations, the bundle of plurality of optical fibers may disperse leading to opening up the bundle. Since the conventional thread binders (or binder yarns) are flexible, they may loosen their grip and open up the bundle during manufacturing i.e., they are not able to maintain their lay length or a binder pitch that leads to opening up of the bundle during the optical fiber cable preparation at installation stage. Lately, to improve the thread binder holding characteristics and workability of the optical fiber cable, UV curable coating is proposed for the thread binders. One of such UV curable thread binders is disclosed in a patent document JP5224403. Though, the patent document JP5224403 teaches a UV curable binder with which the workability of an optical fiber cable bundled using a plurality of binders is improved by bonding the binders at intersection points, however, it does not talks about retainment of a single binder over the bundle.
[0007] Thus, there remains a need of an improved binder that maintains its lay length or the binder pitch and avoids opening up of the bundle during the optical fiber cable preparation at installation stage, thereby improving and supporting high density packing of the plurality of optical fibers.

OBJECT OF THE DISCLOSURE
[0008] A primary object of the present disclosure is to provide a coated thread binder. The coated thread binder is a UV curable composition (e.g., powder) coated binder.
[0009] Another object of the present disclosure is to provide a method of binding a plurality of optical transmission elements including, but not limited to, a group of loose fibers, a stack of flat optical fiber ribbons, a group of bendable optical fiber ribbons, a group of intermittently bonded optical fiber ribbons, a group/subgroup of loose tubes, a group of buffer tubes, a group of micromodules and a group tight buffered optical fibers with the coated thread binder.

SUMMARY
[0010] In an aspect, the present disclosure provides a coated thread binder for a plurality of optical transmission elements and a method for binding the plurality of optical transmission elements to achieve a bundle of the plurality of the optical transmission elements. The coated thread binder is capable of binding the plurality of optical transmission elements including, but not limited to, a group of loose optical fibers, a stack of flat optical fiber ribbons, a group of bendable optical fiber ribbons, a group of intermittently bonded optical fiber ribbons, a group/subgroup of loose tubes, a group of buffer tubes, a group of micromodules and a group tight buffered optical fibers. The method includes binding the plurality of optical transmission elements compactly by the thread binder in a desired manner by applying a predetermined tension around a circumference of the plurality of optical transmission elements. The thread binder is rolled around the plurality of optical transmission elements to achieve the bundle of the plurality of optical transmission elements. The bundle comprising the plurality of optical transmission elements and the thread binder coated with a composition (e.g., powdered composition or powder) pass through one or more ultra-violet (UV) chambers. The one or more UV chambers cure and harden the composition. The hardening of the powder provides the thread binder ability to retain its shape around the plurality of optical transmission elements as that position becomes a low stress position for the cured composition.
[0011] 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 FIGURES
[0012] The invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the figures. The invention herein will be better understood from the following description with reference to the drawings, in which:
[0013] FIG. 1 illustrates an optical fiber cable comprising a plurality of bundles of a plurality of loose optical fibers wound by a thread binder.
[0014] FIG. 2 illustrates a plurality of optical fiber ribbons (i.e., intermittently bonded optical fiber ribbons) bundled by the thread binder.
[0015] FIG. 3 illustrates the thread binder gets bonded to another thread binder at a point of intersection and to a plurality of optical fibers.
[0016] FIG. 4 illustrates the thread binder applied to a plurality of loose tubes.
[0017] FIG. 5 illustrates the thread binder applied to a stack of optical fiber ribbons.

DETAILED DESCRIPTION
[0018] 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.
[0019] 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.
[0020] 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.
[0021] Unlike conventional thread binder, a thread binder of the present disclosure is coated with an ultra-violet (UV) curable composition (or powder) that avoids opening of a plurality of optical transmission elements. The coated thread binder is capable of binding different types of optical transmission elements including, but not limited to, a group of loose optical fibers, a stack of flat optical fiber ribbons, a group of bendable optical fiber ribbons, a group of intermittently bonded optical fiber ribbons, a group/subgroup of loose tubes, a group of buffer tubes, a group of micromodules and a group tight buffered optical fibers.
[0022] FIG. 1 illustrates an optical fiber cable (100) comprising a plurality of bundles (106). The plurality of bundles comprises a plurality of optical fibers (102). In an example, the plurality of optical fibers is a group of intermittently bonded optical fiber ribbons wound by a thread binder (104).
[0023] FIG. 2 illustrates a plurality of optical fiber ribbons bundled by the thread binder and forming a bundle from the plurality of bundles (106). The bundle comprises the plurality of optical fibers (102). In an example, the plurality of optical fibers is a group of intermittently bonded optical fiber ribbons (106). Each optical fiber ribbon from the group of intermittently bonded optical fiber ribbons comprising the plurality of optical fibers (102) bonded to each other intermittently with a special material to impart a rolling capability along the width of the ribbon. The plurality of optical fibers may be, but not limited to, a glass optical fiber, a plastic optical fiber. The plurality of optical fibers may be of different diameters i.e., 250 micrometres, 200 micrometres or the like. Generally, an optical fiber refers to a medium associated with signal transmission 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. The plurality of optical fibers may be single-mode optical fibers or multi-mode optical fibers. The single-mode optical fibers allows only one mode of light while the multi-mode fibers support multiple transverse guided modes for a given optical frequency and polarization. The plurality of optical fibers may be of ITU.T G.657A2 category. Alternatively, the plurality of optical fibers may be of ITU.T G.657A1 or G.657B3 or G.652D or other category. The International Telecommunication Union’s Telecommunication Standardization Sector (ITU-T) is one of the three sectors of the ITU. The ITU is the United Nations specialized agency in the field of telecommunications. ITU-T is responsible for studying technical, operating and tariff questions and issuing recommendations on them with a view to standardizing telecommunications on a worldwide basis.
[0024] The plurality of optical fibers (102) is a part of the group of intermittently bonded optical fiber ribbons (in rolled configuration) and may be wound with a single thread binder (as shown in FIG. 2) or with a double thread binder (as shown in FIG. 3) in helical manner and forms the bundle (106). The thread binder (104) is defined by a pitch distance “A” (108). The pitch distance “A” (108) is defined as a travelling of the thread binder (104) around a circumference of the bundle (106) with a predefined tension from a point “1” to “2”, making a 360-degree round in helical direction around a central axis of the bundle (106). The winding operation is performed along a longitudinal axis of the bundle (106). The winding operation may be performed in one direction. Alternatively, the winding operation may be performed in any suitable direction.
[0025] The thread binder (104) is an ultraviolet (UV) curable binder. Once the thread binder (104) is placed around the bundle (106), the bundle (106) and the thread binder (104) pass through one or more ultra-violet (UV) chambers. The one or more ultra-violet (UV) chambers may include a UV LED (light emitting diode) or a UV lamp. The thread binder (104) is coated with a UV curable material or composition such as powdered composition or with powder embedded in an adhesive or with liquid resin or with any other suitable composition from all side. Alternatively, the thread binder (104) is coated first with an adhesive material and passes through a UV curable powder container. The UV curable material may be applied on the thread binder (104) as desired. In an implementation, the UV curable material may be embedded in the thread binder (104). When the bundle (106) and the thread binder (104) pass through the one or more UV chambers, the UV curable composition or material gets cured and hardened. The hardening of the UV curable material gives the thread binder (104) ability to retain its shape as that position becomes a low stress state for the cured UV curable material. This UV curable thread binder avoids opening of the bundle (106).
[0026] The thread binder (104) is made of a plurality of threads. The plurality of threads is flexible threads. All threads of the thread binder (104) need not be coated with the UV curable powder thereby controlling the sticking of thread binder with the plurality of optical fibers as too much sticking may impact optical properties of the plurality of optical fibers. In an implementation, the thread binder (104) can be placed only in one direction. In another implementation, there could be multiple thread binders that can be placed in clockwise and anti-clockwise directions. For example, the thread binder (110) is placed in clockwise direction and the thread binder (104) is placed in anti-clockwise direction (as shown in FIG. 3).
[0027] In an example, the thread binder may be made from a water swellable yarn. The water swellable yarn may help in combining the properties such as prevention of water penetration and binding. In another example, the thread binder may be made from any suitable material such as, but not limited to, polypropylene, polyvinyl alcohol, nylon, poly-aramid, polyethylene, liquid crystal polymers.
[0028] Advantageously, the thread binder gets hardened and bonded with the bundle (106) in a way that it retains its shape while not causing stress on the bundle (106), allowing denser packaging.
[0029] Further, the thread binder may also be used to bind the other forms of the plurality of optical transmission elements including, but not limited, to a stack of flat optical fiber ribbons, a group of bendable optical fiber ribbons, a group/subgroup of loose tubes, a group of buffer tubes, a group of micromodules and a group tight buffered optical fiber. The plurality of optical transmission elements in any other form may be wound in the same manner as described for the group of intermittently bonded optical fiber ribbon comprising the plurality of optical fibers to form the bundle. The thread binder is the ultraviolet (UV) curable binder having a plurality of flexible threads coated with the ultraviolet curable material. The ultraviolet curable material is capable of getting hardened by exposure to ultraviolet light to produce rigid threads. In rigid shape, the thread binder (104) binds with at least some optical transmission elements of the plurality of optical transmission elementsand with other thread binders.
[0030] In general, the curing process is performed after binding the plurality of optical fibers or the bundle with the thread binder. The curing process is a chemical process employed in polymer chemistry and process engineering that produces the toughening or hardening of a polymer material by cross-linking of polymer chains. During the curing, the UV curable material gets hardened and the binder gets bonded to the plurality of optical transmission elements or optical fibers (102) and to another thread binder (110) at a point of intersection (as shown in FIG. 3). The thread binder gets bonded with the plurality of optical transmission elements in lower side and can make contact with another binder, if bound, from upper side. Further, in the cured state, the thread binder gets hardened. The hardening of thread binder reduces tension in threads and hence, make them stay in a low-stressed state.
[0031] FIG. 4 illustrates the thread binder applied to a plurality of loose tubes. The optical fiber cable (100) comprises the bundle of the plurality of optical transmission elements (fibers) arranged in the plurality of loose tubes (112). The plurality of loose-tubes comprises of the plurality of optical fiber placed with water-resistant gel to protect optical fibers.
[0032] FIG. 5 illustrates the thread binder applied to a stack of optical fiber ribbons. The stack of optical fiber ribbons comprises the optical fiber ribbons placed on top of each other to form an array of optical fiber ribbons.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.

We Claim:
1. An ultraviolet (UV) curable binder (104) for binding a plurality of optical transmission elements (102) for use in an optical fiber cable (100), comprising:
a plurality of flexible threads coated with an ultraviolet curable material, wherein the ultraviolet curable material is capable of getting hardened by exposure to ultraviolet light to produce rigid threads.

2. The UV curable binder of claim 1 is coated with the UV curable material on all sides.

3. The UV curable binder of claim 1, wherein the UV curable material is embedded in the UV curable binder.

4. The UV curable binder of claim 1 comprises the plurality of flexible threads, wherein at least some of the plurality of flexible threads is coated with the UV curable material.

5. The UV curable binder of claim 1, wherein in rigid shape, the UV curable binder binds with at least some optical transmission elements of the plurality of optical transmission elements and/or with another UV curable binder.

6. The UV curable binder of claim 1, wherein the plurality of optical transmission elements may be a group of loose optical fibers, a stack of flat optical fiber ribbons, a group of bendable optical fiber ribbons, a group of intermittently bonded optical fiber ribbons, a group/subgroup of loose tubes, a group of buffer tubes, a group of micromodules and/or a group of tight buffered optical fibers.

7. The UV curable binder of claim 1 is capable of retaining its shape in a low-stressed state once cured.

8. The UV curable binder of claim 1, wherein the UV curable material may be powder, powder embedded in an adhesive, liquid resin or any other suitable material.

9. The UV curable binder of claim 1, wherein curing is achieved by passing the UV curable binder through one or more UV chambers.

10. The UV curable binder of claim 1 is made from polypropylene, polyvinyl alcohol, nylon poly-aramid, polyethylene, liquid crystal polymers or any suitable material.

11. An optical fiber cable (100), comprising:
a plurality of optical transmission elements, wherein the plurality of optical transmission elements is bound using an ultraviolet curable binder.

12. The optical fiber cable (100) of claim 11, wherein the ultraviolet curable binder is coated with a UV curable material on all sides.

13. The optical fiber cable (100) of claim 11, wherein the UV curable material is embedded in the UV curable binder.

14. The optical fiber cable (100) of claim 11, wherein the ultraviolet curable binder comprises a plurality of flexible threads, wherein at least some of the plurality of flexible threads is coated with the UV curable material.

15. The optical fiber cable (100) of claim 11, wherein in rigid shape, the UV curable binder binds with at least some optical transmission elements of a plurality of optical transmission elements and/or with another UV curable binder.

16. The optical fiber cable (100) of claim 11, wherein the optical transmission elements may be a group of loose optical fibers, a stack of flat optical fiber ribbons, a group of bendable optical fiber ribbons, a group of intermittently bonded optical fiber ribbons, a group/subgroup of loose tubes, a group of buffer tubes, a group of micromodules and/or a group of tight buffered optical fibers.

17. The optical fiber cable (100) of claim 11, wherein the ultraviolet curable binder is capable of retaining its shape in a low-stressed state once cured.

18. The optical fiber cable (100) of claim 11, wherein the UV curable material may be powder, powder embedded in an adhesive, liquid resin or any other suitable material.

19. The optical fiber cable (100) of claim 11, wherein curing is achieved by passing the UV curable binder through one or more UV chambers.

20. The optical fiber cable (100) of claim 11, wherein the ultraviolet curable binder is made from polypropylene, polyvinyl alcohol, nylon poly-aramid, polyethylene, liquid crystal polymers or any suitable material.