Description:TECHNICAL FIELD
The present disclosure relates to the field of optical fiber cables and, in particular, relates to an optical fiber cable with uniformly distributed Water Blocking Elements (WBEs).

BACKGROUND
Optical fiber cables having one or more optical fibers are widely used to transmit information or data in form of an optical signal from one place to another. Generally, to pass a Water Penetration Test (WPT) in an optical fiber cable, one or more Water Swellable Yarns (WSYs) and one or more Water Blocking Tapes (WBTs) are used inside a cable core. However, as a fiber identification (ID) increase (inner diameter of the cable increases), passing the WPT becomes increasingly difficult. The number of the one or more WSYs and one or more WBTs to be used inside an optical fiber cable can be calculated on the basis of absorption of the one or more WSYs and one or more WBT. There are various optical fiber cables that are known in the art. For example, CN115421262A discloses that the WSY are distributed uniformly around the optical fiber ribbons. Another reference CN107797206B discloses that the WSY are distributed uniformly among the optical fiber bundle micro-units in the core. Yet another reference CN111897073A discloses that the WSY are distributed uniformly inside the optical fiber core. Yet another reference CN206020761U discloses that the WSY are distributed uniformly around the optical fiber core. Moreover, some prior art references disclose arrangement of Water Blocking Elements (WBEs) that will not work efficiently to stop water penetration. For example, when (i) the WBEs are distributed in the optical fiber cable such that a measure of offset of center of mass vector (σ) is approximately 0 and scatter factor (S) is greater than 0.8 (as shown in FIG. 1A), the scatter is too much, (ii) the WBEs are distributed in the optical fiber cable such that a measure of offset of center of mass vector (σ) is approximately 0 and scatter factor (S) is less than 0.3 (as shown in FIG. 1B), the scatter is too less, (iii) the WBEs are distributed in the optical fiber cable such that a measure of offset of center of mass vector (σ) is greater than 0.2 and scatter factor (S) is between 0.3 and 0.8, (as shown in FIG. 1C), the center of mass of WBE will be offset from the centre of the optical fiber cable, (iv) the WBEs are distributed in the optical fiber cable such that a measure of offset of center of mass vector (σ) is greater than 0.2 and scatter factor (S) is less than 0.3, (as shown in FIG. 1D), the center of mass of WBE will be offset from the centre of the optical fiber cable and the scatter will be too less. Moreover, none of the prior art reference considers detailing with respect to the optimized parameters to pass WPT.
Thus, there is a need for an optical fiber cable that is capable of solving aforementioned problems of the conventional optical fiber cables.
SUMMARY
In an aspect of the present disclosure, an optical fiber cable is disclosed. The optical fiber cable has a plurality of optical fibers, a plurality of Water Blocking Elements (WBEs), and a sheath such that the sheath surrounds the plurality of optical fibers and the plurality of WBEs. Specifically, the plurality of WBEs are distributed inside the sheath with a scatter coefficient (S) that is greater than 0.3 and less than 0.8.
BRIEF DESCRIPTION OF DRAWINGS
Having thus described the disclosure in general terms, reference will now be made to the accompanying figures, where:
FIGs 1A-1D illustrate a cross-sectional view of optical fiber cables of prior arts.
FIG. 1E illustrates a cross-sectional view of an optical fiber cable.
FIG. 1F illustrates another cross-sectional view of the optical fiber cable.
FIG. 2 illustrates a cross-sectional view of another optical fiber cable.
It should be noted that the accompanying figures are intended to present illustrations of exemplary aspects of the present disclosure. These 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.
DEFINITIONS
The term “optical fiber cable” as used herein refers to a cable that encloses a plurality of optical fibers.
The term “cable core” as used herein refers to a space inside a sheath of an optical fiber cable that has all signal carrying optical fibers.
The term “scatter coefficient (S)” as used herein refers to a normalised distribution of a spreadof a plurality of Water Blocking Elements (WBEs) about a center of mass of WBEs.
The term “Cartesian co-ordinate system” as used herein refers to a coordinate system that specifies each point uniquely by a pair of real numbers called coordinates, which are signed distances to a point from two fixed perpendicular oriented lines, called coordinate lines, coordinate axes or just axes (plural of axis) of the system.
The term “Centre of mass” as used herein refers to a unique point at any given time where a weighted relative position of a distributed mass sums to zero.
The term “sheath” as used herein is referred to as an outermost layer or an outermost layer of the optical fiber cable that holds and protects the contents of the optical fiber cable.
The term “strength member” as used herein is referred to as a cable element made up of filaments or yarns that provides strength to the optical fiber cable.
The term “Intermittently Bonded Ribbon (IBR)” as used herein refers to an optical fiber ribbon having a plurality of optical fibers positioned parallel such that the plurality of optical fibers is intermittently bonded to each other by a plurality of bonded portions that are placed along the length of the plurality of optical fibers. The plurality of bonded portions is separated by a plurality of unbonded portions. An intermittently bonded ribbon fiber cable consists of fibers bonded using matrix material.
The term “linear density” as used herein refers to a measure of a mass of a water blocking element per unit length.
The term “water absorption rate” as used herein refers to an amount of water absorbed by 1 gram (gm) of a Water Blocking Element (WBE) in one minute of time.
The term “scatter coefficient” as used herein refers to a spread of a plurality of Water Blocking Element (WBEs) with respect to a centre of mass of all the WBEs inside an optical fiber cable.
DETAILED DESCRIPTION
The detailed description of the appended drawings is intended as a description of the currently preferred aspects of the present disclosure, and is not intended to represent the only form in which the present disclosure may be practiced. It is to be understood that the same or equivalent functions may be accomplished by different aspects that are intended to be encompassed within the spirit and scope of the present disclosure.
Moreover, although the following description contains many specifics for the purposes of illustration, anyone skilled in the art will appreciate that many variations and/or alterations to said details are within the scope of the present technology. Similarly, although many of the features of the present technology are described in terms of each other, or in conjunction with each other, one skilled in the art will appreciate that many of these features can be provided independently of other features. Accordingly, this description of the present technology is set forth without any loss of generality to, and without imposing limitations upon, the present technology.
FIG. 1E illustrates a cross-sectional view of an optical fiber cable 100. The optical fiber cable 100 may have a plurality of water blocking elements that may be scattered uniformly to prevent water ingression into the optical fiber cable 100. In other words, the optical fiber cable 100 may have reduced water ingression due to the presence of a plurality of uniformly scattered water blocking elements. The optical fiber cable 100 may have a cable core 102, a plurality of optical fibers 104a-104n (hereinafter interchangeably referred to and designated as “the optical fibers 104”), a plurality of Water Blocking Elements (WBEs) 106 of which first through ninth WBEs 106a-106i are shown, and a sheath 108.
The cable core 102 of the optical fiber cable 100 may be adapted to house the optical fibers 104 along a length of the cable core 102. The optical fibers 104 may be adapted to enable a transmission of information by way of one or more optical signals and/or communication signals. In some aspects of the present disclosure, the optical fibers 104 may be, but not limited to, a single mode optical fiber, a multimode optical fiber, a single core optical fiber, a multicore optical fiber, and the like. Aspects of the present disclosure is intended to include and/or otherwise cover any type of the optical fiber of the optical fibers 104 known to a person of ordinary skill in the art, without deviating from the scope of the present disclosure. In some aspects of the present disclosure, the optical fibers 104 may be in the form of loose fiber. In some aspects of the present disclosure, the optical fibers 104 may be in the form of ribbons. In some aspects of the present disclosure, when the optical fibers 104 are in the form of ribbons, the ribbons may be Intermittently Bonded Ribbons (IBRs). In some aspects of the present disclosure, the optical fibers 104 may be in the form of, but not limited to, a loose fiber, a ribbon, and the like. Aspects of the present disclosure are intended to include and/or otherwise cover the optical fibers 104 in any form that may be known to a person of ordinary skill in the art, without deviating from the scope of the present disclosure.
The plurality of WBEs 106 (i.e., the first through ninth WBEs 106a-106i) may be uniformly distributed inside the sheath 108. Specifically, the plurality of WBEs 106 (i.e., the first through ninth WBEs 106a-106i) may be uniformly distributed inside the cable core 102. To quantify the uniformity in distribution of the plurality of WBEs 106:
Let N be number of the plurality of WBEs 106,
di be a linear density of the ith WBE of the plurality of WBEs 106, and
xi be a distance vector of the ith WBE of the plurality of WBEs 106. A Cartesian co-ordinate system (X, Y) may be attached to a cross-sectional plane of the optical fiber cable 100 and an optical fiber cable 200 (as shown in FIG. 1F and FIG. 2) with (0,0) at a center of the optical fiber cable 100 and the optical fiber cable 200. R be a radius of the optical fiber cable 100 and the optical fiber cable 200 and t be a thickness of one or more layers 112 below the sheath 108.
=1=1Ndixii=1Ndi is a center of mass vector of the plurality of WBEs 106,
ρ=i=1N‖xi-‖2N is a root mean square distance of all the plurality of WBEs 106 from the center of mass of the plurality of WBEs 106,
S=R-t is a measure of scatter coefficient (S) of the plurality of WBEs 106 in cross-section of the optical fiber cable 100 with respect to the center of mass of plurality of WBEs 106,
σ=‖→‖R-t is a measure of offset of center of mass vector of the plurality of WBEs w.r.t. geometric center of the optical fiber cable 100.
As per the above equation, to pass a Water Penetration Test (WPT), the plurality of WBEs 106 may be distributed inside the sheath 108 and thus inside the cable core 102 with a scatter coefficient (S) of greater than 0.3 and less than 0.8. When the scatter coefficient (S) is below 0.3, the plurality of WBEs 106 may be too close to each other and distribution may not be sufficient to block water and when the scatter coefficient (S) is above 0.8, the plurality of WBEs 106 may be too far from each other and distribution may not be sufficient to block water. Therefore, the scatter coefficient (S) may be kept in the range of 0.3 to 0.8 to efficiently block water ingression inside the optical fiber cable 100. Specifically, the scatter coefficient (S) may be determined as follows:
S=R-t
where is the root mean square distance of all the plurality of WBEs from a center of mass of the plurality of WBEs,
R is a radius of the optical fiber cable, and
t is a thickness of the one or more layers 112.
In some aspects of the present disclosure, a measure of offset of center of mass vector (σ) of the plurality of WBEs 106 is less than 0.2. Specifically, the measure of offset of the center of mass vector (σ) of the plurality of WBEs 106 of less than 0.2 may facilitate to quantify the uniformity.
In some aspects of the present disclosure, each WBE of the plurality of WBEs 106 may have a linear density in a range of 900 denier to 9000 denier. In some aspects of the present disclosure, the plurality of WBEs 106 may have greater than 4 WBEs. Although FIG. 1E illustrates that the plurality of WBEs 106 has nine WBEs (i.e., the first through ninth WBEs 106a-106i), it will be apparent to a person skilled in the art that the scope of the present disclosure is not limited to it. In various other aspects, the plurality of WBEs 106 may have any number of WBEs greater than 4, without deviating from the scope of the present disclosure. In such a scenario, each WBE is adapted to serve one or more functionalities in a manner similar to the functionalities of the first through ninth WBEs 106a-106i as described above.
In some aspects of the present disclosure, each WBE of the plurality of WBEs 106 may have a water absorption rate of greater than 30 millilitres/gram/minute (ml/gm/min). Specifically, a WBE with a water absorption rate of less than 30 ml/gm/min may cause penetration of water inside the optical fiber cable 100 that may further degrade one or more elements of the optical fiber cable 100. Therefore, the plurality of WBEs 106 is selected such that the water absorption rate of each WBE of the plurality of WBEs 106 is greater than 30 ml/gm/min.
In some aspects of the present disclosure, each WBE of the plurality of WBEs 106 may be, but not limited to, Water swellable yarns (WSY), strength yarns coated with Superabsorbent Powder (SAP), and the like. Aspects of the present disclosure is intended to include and/or otherwise cover any type of the plurality of WBEs 106 known to a person of ordinary skill in the art, without deviating from the scope of the present disclosure.
The sheath 108 may surround the cable core 102. Specifically, the sheath 108 may surround the plurality of optical fibers 104 and the plurality of WBEs 106 that are disposed inside the cable core 102. In some aspects of the present disclosure, the sheath 108 may be adapted to reduce abrasion and to provide the optical fiber cable 100 with extra protection against one or more external mechanical effects. In some aspects of the present disclosure, the sheath 108 may be made up of a material such as, but not limited to, polyethylene (PE), Low-Smoke Zero-Halogen (LSZH), Polyvinyl chloride (PVC), Thermoplastic polyurethane (TPU), and the like. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the material for the sheath 108 known to a person of ordinary skill in the art, without deviating from the scope of the present disclosure.
In some aspects of the present disclosure, the optical fiber cable 100 may have one or more tubular structures 110 of which first through tenth tubular structures 110a-110j are shown. Each tubular structure of the one or more tubular structures 110 may enclose one or more optical fibers of the plurality of fibers 104. In some aspects of the present disclosure, the one or more tubular structures 110 (i.e., the first through tenth tubular structures 110a-110j) may be, but not limited to, a loose tube, a micromodule, and the like. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the one or more tubular structures 110, without deviating from the scope of the present disclosure. In some aspects of the present disclosure, the optical fiber cable 100 may have one or more bundles of optical fibers (not shown). In some aspects of the present disclosure, the bundles of optical fibers may be, but not limited to, bundles of loose fibers bundle of ribbons, bundles of IBRs, and the like.
In some aspects of the present disclosure, the optical fiber cable 100 may further have the one or more layers 112. The one or more layers 112 may be disposed in between the cable core 102 and the sheath 108. Specifically, the one or more layers 112 may facilitate to protect the optical transmission elements from contacting the sheath 108 and further provide strength to the optical fiber cable 100 and/or lower the water penetration in the cable core 102 of the optical fiber cable 100. Although FIG. 1E illustrates that the one or more layers 112 has one layer (i.e., the layer 112), it will be apparent to a person skilled in the art that the scope of the present disclosure is not limited to it. In various other aspects, the one or more layers 112 may have any number of layers, without deviating from the scope of the present disclosure. In such a scenario, each layer is adapted to serve one or more functionalities in a manner similar to the functionalities of the layer 112 as described herein. In some aspects of the present disclosure, the one or more layers 112 may be, but not limited to, a water blocking tape (WBT), a dielectric armor, a metal armor, a tube, an inner sheath, and the like. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the one or more layers 112 known to a person of ordinary skill in the art, without deviating from the scope of the present disclosure.
Further, the optical fiber cable 100 has one or more strength members 114 of which first through eighth strength members 114a-114h are shown. The one or more strength members 114 may be disposed within the sheath 108. In some aspects of the present disclosure, the one or more strength members 114 may be made up of a material such as, but not limited to, aramid yarns, glass roving yarns, and the like. Aspects of the present disclosure are intended to include and/or otherwise cover any type of the material of the one or more strength members 114, known to a person of ordinary skill in the art, without deviating from the scope of the present disclosure.
FIG. 1F illustrates another cross-sectional view of the optical fiber cable 100. As illustrated, the optical fiber cable 100 has the cable core 102, the plurality of WBEs 106 of which the first through ninth WBEs 106a-106i are shown, the sheath 108, and the one or more layers 112. As illustrated, a Cartesian co-ordinate system (X, Y) is attached to a cross-sectional plane of the optical fiber cable 100 with (0,0) at the center of the optical fiber cable 100. In some aspects of the present disclosure, the distribution of the first through ninth WBEs 106a-106i may be determined as follows:
S=R-t
where is the root mean square distance of all the plurality of WBEs from a center of mass of the plurality of WBEs,
R is an inner radius of the optical fiber cable, and
t is a thickness of the one or more layers 112.
As illustrated, the plurality of WBEs 106 is uniformly distributed within the cable core 102 such that the center of mass vector (σ) of the plurality of WBEs 106 is approximately 0 and the scatter coefficient (S) is approximately 0.5. In other words, the center of mass of the plurality of WBEs 106 substantially coincides with center of cable i.e., the center of mass vector (σ) of the plurality of WBEs 106 is approximately 0, thus, optimizing the scattering of the plurality of WBEs 106 such that the optical fiber cable 100 passes the water penetration test (WPT).
FIG. 2 illustrates a cross-sectional view of the optical fiber cable 200. The optical fiber cable 200 may be substantially similar to the optical fiber cable 100 with like elements referenced with like reference numerals. However, the distribution of the plurality of WBEs 106 in the optical fiber cable 200 is different. As illustrated, the optical fiber cable 200 has the cable core 102, the plurality of WBEs 106 of which the first through ninth WBEs 106a-106i are shown, the sheath 108, and the one or more layers 112. As illustrated, the Cartesian co-ordinate system (X, Y) is attached to a cross-sectional plane of the optical fiber cable 200 with (0,0) at the center of the optical fiber cable 200. In some aspects of the present disclosure, the distribution of the first through ninth WBEs 106a-106i may be determined as follows:
S=R-t
where is the root mean square distance of all the plurality of WBEs from a center of mass of the plurality of WBEs,
R is an inner radius of the optical fiber cable, and
t is a thickness of the one or more layers 112.
As illustrated, the plurality of WBEs 106 is uniformly distributed within the cable core 102 such that the center of mass vector (σ) of the plurality of WBEs 106 is less than 0.2 and the scatter coefficient (S) is approximately 0.6. In other words, the center of mass of the plurality of WBEs 106 may be slightly offset from the center of the optical fiber cable 200, but within permissible range, thus, optimizing the scattering of the plurality of WBEs 106 such that the optical fiber cable 200 passes the water penetration test (WPT).
Thus, the optical fiber cables 100 and 200 have uniform distribution of the plurality of WBEs 106 such that water ingression is considerably reduced. Specifically, the plurality of WBEs 106 may be uniformly distributed within the cable core 102 of the optical fiber cable 100, 200 such that the center of mass vector (σ) of the plurality of WBEs 106 is less than 0.2 and the scatter coefficient (S) is greater than 0.3 and less than 0.8, thus, optimizing the scattering of the plurality of WBEs 106 such that the optical fiber cables 100 and 200 passes the water penetration test (WPT).
The foregoing descriptions of specific aspects of the present technology have been presented for the purpose of illustration and description. They are not intended to be exhaustive or to limit the present technology to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The aspects were chosen and described in order to best explain the principles of the present technology and its practical application, to thereby enable others skilled in the art to best utilize the present technology and various aspects with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present technology.
While several possible aspects of the invention have been described above and illustrated in some cases, it should be interpreted and understood as to have been presented only by way of illustration and example, but not by limitation. Thus, the breadth and scope of a preferred aspect should not be limited by any of the above-described exemplary aspects. , Claims:I/We Claim(s):
1. An optical fiber cable (100, 200) comprising:
a plurality of optical fibers (104) and a plurality of water blocking elements (WBEs) (106); and
a sheath (108) that surrounds the plurality of optical fibers (104) and the plurality of WBEs (106);
wherein the plurality of WBEs (106) are distributed inside the sheath (108) with a scatter coefficient (S) that is greater than 0.3 and less than 0.8.

2. The optical fiber cable (100, 200) of claim 1, where a measure of offset of center of mass vector (σ) of each WBE of the plurality of WBEs (106) with respect to the geometrical center of the cable (100, 200) is less than 0.2.

3. The optical fiber cable (100, 200) of claim 1, wherein each WBE of the plurality of WBEs (106) has a linear density in a range of 900 denier to 9000 denier.

4. The optical fiber cable (100, 200) of claim 1, wherein the plurality of WBEs (106) comprising greater than 4 WBEs.

5. The optical fiber cable (100, 200) of claim 1, wherein each WBE of the plurality of WBEs (106) has a water absorption rate of greater than 30 millilitres/gram/minute (ml/gm/min).

6. The optical fiber cable (100, 200) of claim 1, wherein the plurality of optical fibers (104) are in the form of one of, loose fiber, ribbons, intermittently bonded ribbons (IBRs), or a combination thereof.

7. The optical fiber cable (100, 200) of claim 1, further comprising one or more tubular structures (109) such that each tubular structure of the one or more tubular structures (109) encloses one or more fibers of the plurality of optical fibers (104).

8. The optical fiber cable (100, 200) of claim 7, wherein the one or more tubular structures (109) comprising one of, a loose tube, a micromodule, or a combination thereof.

9. The optical fiber cable (100, 200) of claim 1, further comprising a cable core (102) and one or more layers (112) such that the one or more layers (112) are disposed in between the cable core (102) and the sheath (108).

10. The optical fiber cable (100, 200) of claim 9, wherein the one or more layers (112) comprising one of, a water blocking tape (WBT), a dielectric armor, a metal armor, a tube, an inner sheath, or a combination of thereof.