NZ749887B2 - Flexible optical-fiber ribbon - Google Patents
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- NZ749887B2 NZ749887B2 NZ749887A NZ74988716A NZ749887B2 NZ 749887 B2 NZ749887 B2 NZ 749887B2 NZ 749887 A NZ749887 A NZ 749887A NZ 74988716 A NZ74988716 A NZ 74988716A NZ 749887 B2 NZ749887 B2 NZ 749887B2
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- 239000003365 glass fiber Substances 0.000 title claims abstract description 294
- 239000011159 matrix material Substances 0.000 claims abstract description 72
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- 239000000463 material Substances 0.000 claims 1
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Abstract
The flexible optical-fiber ribbon can be reversibly adapted to both planar and non-planar shapes (e.g., packed via folding or rolling) without damaging the optical-fiber ribbon or its constituent optical fibers. This is achieved by bonding the plurality of optical fibres with a cured ribbon matrix (14) having elongation to break of at least 200% and a low Young's modulus of 1-20 MPa at 20 C. 14) having elongation to break of at least 200% and a low Young's modulus of 1-20 MPa at 20 C.
Description
FLEXIBLE OPTICAL-FIBER RIBBON
FIELD OF THE INVENTION
The present invention relates to optical-fiber ribbons.
BACKGROUND
Optical fibers provide ages over conventional ication lines.
As compared with traditional wire-based networks, l-fiber communication ks
can transmit cantly more information at significantly higher speeds. Optical fibers,
therefore, are being singly employed in communication networks. US. Patent
No. 5,682,454, which is hereby incorporated by nce in its entirety, discloses an
exemplary optical-fiber cable,
Optical fibers can be bonded together to form a planar, optical-fiber ribbon, which
itself may be ble into subunits (e. g., a twelve-fiber ribbon that is splittable into six—fiber
ts). Multiple optical-fiber ribbons may be aggregated to form a ribbon stack, which
can have various sizes and shapes, such as a rectangular ribbon stack or a trapezoidal ribbon
stack in which the uppermost and/or lowermost optical-fiber ribbons have fewer optical fibers
than those toward the center of the stack. The ribbon-stack configuration helps to increase
the density of optical elements (e. g., ribbonized optical fibers) within a round buffer tube
and/or a round optical-fiber cable. Even so, the placement of planar, optical-fiber ribbons as
rectangular or trapezoidal ribbon stacks within round tubes is spatially inefficient.
Mass-fusion splicing of optical-fiber ribbons requires a planar ribbon geometry,
however, rendering non—planar, optical—fiber ribbons unsuitable for mass—fusion ribbon
splicing operations.
SUMfl
Accordingly, in one aspect, the present invention embraces a flexible optical-fiber
ribbon that can be adapted to both planar and non-planar shapes (e. g., packed via g or
g) without damaging the l-fiber ribbon or its constituent optical fibers.
The optical-fiber ribbon may be manufactured as a substantially planar
optical-fiber ribbon that can be reversibly folded or rolled into a compact configuration to
facilitate efficient packing within an optical-fiber cable. In a planar configuration, the
optical-fiber ribbon is suitable for mass-fusion spicing.
In an exemplary embodiment, the flexible optical-fiber ribbon includes a plurality
of l fibers bonded in a side-by-side arrangement via a predominantly one-sided
application of ribbon-matrix material. The substantially cured ribbon-matrix material has
elongation—to-break and modulus teristics that promote reversible folding and rolling of
the optical-fiber ribbon.
The foregoing illustrative summary, as well as other exemplary objectives and/or
advantages of the invention, and the manner in which the same are accomplished, are further
explained within the following detailed description and its accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 depicts a cross-sectional perspective of an exemplary two-side,
edge—bonded optical—fiber ribbon.
Figures 2 and 3 depict cross-sectional perspectives of exemplary one-side,
edge-bonded optical-fiber ribbons having predominantly one-side edge bonding.
Figure 4 depicts a sectional ctive of another exemplary two—side,
edge-bonded optical-fiber .
Figure 5 depicts Young’s modulus as a function of temperature for various
ribbon-matrix materials.
Figure 6 depicts an exemplary one-side, onded ribbon efficiently packed
within a micromodule.
Figures 7 and 8 depict cross-sectional perspectives of an exemplary one-side,
edge-bonded optical-fiber ribbon having predominantly one-side edge bonding in a planar
configuration and a folded configuration, tively.
Figure 9 depicts dimensional parameters for exemplary optical—fiber ribbons.
DETAILED DESCRIPTION
In one aspect, the present invention embraces a flexible optical-fiber ribbon that
can be folded or rolled into a t shape and then unfolded or unrolled to a planar
arrangement of parallel optical fibers without breaking the ribbon structure or damaging the
constituent optical fibers. In a substantially planar geometry, the flexible optical-fiber ribbon
tates mass-fusion spicing. In a substantially non-planar geometry, the flexible
optical-fiber ribbon facilitates increased spatial efficiency within a fiber optic cabling
structure, such as a odule or a buffer tube.
As depicted in s 1—4, exemplary, flexible optical-fiber ribbons 10 each
include a plurality of optical fibers 11 arranged side—by-side such that the optical fibers 11 are
substantially parallel to one another. Each optical fiber 11, which includes a component glass
fiber 12 and one or more surrounding coating layers 13, may be closely spaced or uous
with an adjacent optical fiber 11 but typically should not cross over one another along the
length of the optical-fiber ribbon 10. The optical fibers 11 may be ched, encapsulated,
edge , joined, or otherwise aggregated by a substantially cured ribbon-matrix
material 14. The resulting optical-fiber ribbon has a substantially planar (i.e., flattened)
geometry that defines a relatively narrow height, a relatively wide width, and a substantially
continuous length (e. g., over 1,000 meters, such as 5,000 meters or more).
As used herein, an optical-fiber ribbon 10 as depicted in Figures 1—4 inherently
defines an upper side (i.e., the top), a lower side (i.e., the bottom), a left edge, and a right
edge. The respective upper and lower sides define the major surfaces of the optical-fiber
ribbon. Those having ordinary skill in the art will appreciate that flipping the optical-fiber
ribbon 180 degrees over its major transverse axis will e the top and bottom, and so the
terms can be used interchangeably herein depending on the frame of reference. Similarly,
those having ordinary skill in the art will appreciate that yaw rotating the optical-fiber ribbon
180 degrees will reverse the right edge and left edge, and so the terms can be used
interchangeably herein depending on the frame of nce. Accordingly, as used herein the
terms “first side” and “second, opposite side” refer to the tive upper and lower sides of
the optical-fiber ribbon, or vice versa depending on the frame of reference.
As used herein, the term “cured” refers to a ribbon-matrix material that has
achieved at least 90 t of its maximum attainable modulus (e.g., Young’s modulus). In
exemplary ments of the flexible optical-fiber ribbon, the cured ribbon-matrix material
is at least 95 percent cured (i.e., the ribbon—matrix al has ed at least 95 percent of
its maximum able Young’s modulus).
An exemplary, flexible optical-fiber ribbon may be manufactured using a die
to selectively apply a -matrix material to one or both major surfaces of a side-by-side
array of optical fibers. Thereafter, the ribbon-matrix material is cured upon the optical fibers,
typically via UV-curing lamp(s) to initiate curing, to form the optical-fiber ribbon. Curing of
the ribbon-matrix material may be enhanced using in-line thermal ovens, too.
In one ary embodiment depicted in Figure l, the optical—fiber ribbon 10
es optical fibers 11 dual-edge bonded with a cured ribbon-matrix material 14 (i.e., a
two—side, edge-bonded optical-fiber ribbon). Ribbon-matrix material 14 is applied (1’) to the
first side of the parallel optical fibers 11 (i.e., the upper side as depicted in Figure 1) to fully
fill the curved, triangular regions defined by adjacent optical fibers 11 and (ii) to the second,
opposite side of the parallel optical fibers 11 (i.e., the lower side as depicted in Figure l) to
fully fill the curved, triangular regions defined by adjacent optical fibers 11.
In another exemplary embodiment, the optical -fiber ribbon includes optical fibers
one-side, edge bonded with a cured —matrix material (i.e., at least 90-percent cured). In
this regard, “one-side edge g” refers to an optical-fiber-ribbon geometry in which the
ribbon-matrix material is surficially applied to one side of the arrangement of parallel optical
fibers (e. g., via a inantly one-sided application of ribbon-matrix material to the
parallel l fibers). Those having ordinary skill in the art will appreciate that some
leakage can occur when applying the ribbon-matrix material to one side of the side-by-side
arrangement of parallel l fibers.
Typically, the cured ribbon-matrix material edge bonds the plurality of optical
fibers in a side-by—side arrangement such that at least 70 percent (e. g., 75 percent or more) of
the cured ribbon-matrix material is present on one side of the optical-fiber ribbon (i.e., either
on the optical-fiber ribbon’s upper side or lower side). In some ments of the
optical-fiber ribbon, the cured ribbon-matrix material edge bonds the plurality of optical
fibers in a side-by-side arrangement such that at least 80 percent (e. g., 90 percent or more) of
the cured ribbon-matrix material is oned on one side of the optical-fiber ribbon
(i.e., either on the optical-fiber ribbon’s upper side or lower side).
As depicted in Figures 2 and 3, respectively, the ribbon-matrix material 14 may be
applied to only one side of the parallel optical fibers 11 to partly fill (Figure 2) or to fully fill
(Figure 3) the curved, triangular regions defined by nt optical fibers 11. In this way,
WO 22031
the cured ribbon-matrix material 14 one-side, edge bonds the parallel optical fibers 11 in a
side-by-side arrangement. Those having ordinary skill in the art will appreciate that, even
with the selective application of ribbon-matrix material 14 predominantly to only one side of
the l-fiber ribbon 10 (i.e., either the top or bottom of the optical-fiber ribbon 10), some
ribbon-matrix material 14 may migrate between adjacent optical fibers 11 or ooze around the
t optical fibers 11 such that some cured ribbon-matrix material 14 is present on both
sides of the l-fiber ribbon 10 (e. g., 85 percent on the upper side and 15 percent on the
lower side, or vice versa depending on the frame of nce).
In another exemplary embodiment depicted in Figure 4, the optical-fiber ribbon 10
includes optical fibers 11 dual-edge bonded with a cured -matrix al 14.
Ribbon-matrix material 14 is applied (1') to the first side of the parallel optical fibers 11
(i.e., the upper side as depicted in Figure 4) to fully fill the curved, triangular regions defined
by adjacent optical fibers 11 and (ii) to the second, opposite side of the parallel optical
fibers 11 (i.e., the lower side as depicted in Figure 4) to partially fill the curved, triangular
regions defined by adjacent optical fibers 11. Optionally, ribbon-matrix material can be
applied to the first and second sides of the parallel optical fibers to partly fill the curved,
triangular regions on both the optical-fiber ribbon’s upper side and lower side.
The substantially cured ribbon-matrix material has tion—to-break and
modulus characteristics that promote reversible g and/or rolling of the optical—fiber
ribbon. As used herein, the properties for the ribbon-matrix material are reported at standard
temperature and pressure (STP), namely room temperature (i.e., 20°C) and atmospheric
pressure (i.e., 760 torr).
In exemplary embodiments, the cured ribbon-matrix material has elongation-to-
break (i.e., fracture strain) of at least 200 percent at 20°C, such as at least 300 percent at 20°C
(e.g., 350 percent or more). Typically, the cured ribbon-matrix material has elongation-to-
break of at least 400 percent at 20°C, such as at least 500 percent at 20°C (e.g., 600 percent or
more). In some embodiments of the optical-fiber ribbon, the cured ribbon—matrix material
has elongation-to-break of at least 700 t at 20°C, such as between about 800 percent
and 1,500 percent (e. g., between about 1,000 percent and 1,200 percent), If elongation-to—
break is too low, the -matrix material will crack and te when the l-fiber
ribbon is folded or rolled (e.g., if the ribbon—matrix material is not cured before folding or
rolling). Elongation-to-break (i.e., fracture strain) for ribbon-matrix materials can be
determined via either ISO 527-3 : 1995 (Determination of Tensile Properties) or
ASTM D882 - 12 (Standard Test Method for Tensile Properties of Thin Plastic Sheeting),
each of which is hereby incorporated by nce in its entirety.
The cured ribbon-matrix material typically has low Young’s modulus over a broad
temperature range. In ary embodiments, the cured ribbon-matrix material has
Young’s modulus of between about 0.5 and 20 MPa at 20°C (e.g., 1—20 MPa), such as
between 1 and 15 MPa at 20°C inclusively. Typically, the cured ribbon-matrix material has
Young’s modulus of between 1.5 and 10 MPa at 20°C inclusively, such as between 2 and
MPa at 20°C inclusively. In some embodiments of the optical-fiber ribbon, the cured
ribbon-matrix material has Young’s modulus of less than 3 MPa at 20°C. Modulus
(e.g., Young’s s) for ribbon—matrix materials can be ined via either
ISO 527-3:l995 (Determination of Tensile Properties) or ASTM D882 - 12 (Standard Test
Method for Tensile Properties of Thin Plastic Sheeting).
Moreover, the cured -matrix material typically maintains low Young’s
s even at low temperatures. In exemplary embodiments, the cured ribbon-matrix
material has Young’s modulus of 100 MPa or less at —40°C, such as 75 MPa or less at —40°C
(e.g., 60 MPa or less at —40°C). Typically, the cured -matrix al has s
modulus of 50 MPa or less at —40°C, such as 25 MPa or less at —40°C. In some ments
of the optical-fiber ribbon, the cured ribbon-matrix material has s modulus of less
than 15 MPa at —40°C (e.g, between 1 and 10 at —40°C). In notable, exemplary
embodiments of the optical-fiber ribbon, the cured -matrix material maintains Young’s
modulus of between 1 and 20 MPa over the temperature range of —40°C and 20°C.
Low-temperature Young’s modulus can be determined via dynamic mechanical is
(DMA), also referred to as dynamic mechanical thermal analysis (DMTA), such as by using a
TA 2980 Dynamic Mechanical Analyzer.
By way of contrast, folding or rolling a conventional optical-fiber ribbon having a
high-modulus ribbon-matrix material tends to impart high, localized stresses to the
constituent optical fibers, especially at low temperatures (between 0°C and —50°C). Such
extreme ribbon deformation can cause not only increased l-fiber attenuation but also
ace delamination, such as between the optical fiber’s glass and surrounding primary
coating or between the optical fiber’s outer coating (e.g., a secondary coating or tertiary ink
layer) and the surrounding ribbon-matrix material. On the other hand, if the modulus of the
ribbon-matrix material is too low, the folding and rolling of the optical-fiber ribbon tends to
be irreversible (e.g., the optical-fiber ribbon resists returning from a compact configuration to
a planar configuration as is necessary to facilitate mass-fusion splicing operations).
In other exemplary embodiments of the optical—fiber ribbon, the cured
ribbon-matrix material has Shore A hardness between 40 and 75, such as Shore A hardness
n 50 and 70. Hardness (e.g., Shore A hardness) for -matrix materials can be
determined via ISO 868:2003 (Determination of indentation hardness by means of a
durometer (Shore hardness), which is hereby incorporated by reference in its entirety.
Suitable compositions for the ribbon-matrix material include low-modulus
elastomers and silicones, such as able silicones and RTV silicones (i.e., room
temperature—vulcanization silicone). The UV-cured silicones have some advantages over
RTV silicones, including faster curing and reduced shrinkage. In addition, unlike UV-cured
silicones, RTV silicones require exposure to humidity and high temperatures for ed
time periods and can generate unwanted byproducts (e.g., acetic acid) during curing. Suitable
UV-curable silicones include E® SI 5240““ UV-cured silicone and Addisil
UV-cured silicones (e.g., UV 50 EX, UV 60 EX, and UV 7O EX). As will be appreciated by
those having ordinary skill in the art, UV curing can be enhanced by modifying UV-lamp
configurations, introducing more photoinitiator, introducing a different photoinitiator, making
slight chemical modifications (e.g., hybrid silicone/acrylate systems), and/or employing
supplemental thermal curing. For silicone acrylates, an exemplary photoinitiator is
2-hydroxymethyl-l- phenylpropane-l-one (HMPP) (e.g., Ciba ves’
DAROCUR® 1173). Other photoinitiators with similar photodecomposition mechanisms are
TEGo® PC 750 or TEGO® A16.
Figure 5 depicts Young’s modulus as a function of temperature for various
ribbon—matrix materials, including a suitable able silicone (i.e., LOCTITE® SI 524OTM
UV-cured silicone) and conventional able tes (i.e., DSM 4 and
DSM 9D9-518, respectively). Modulus was measured via c al analysis (DMA).
>l< >l< >l<
The flexible optical-fiber ribbon may be manufactured as a planar optical-fiber
ribbon. In its substantially planar geometry, the optical-fiber ribbon is le for
mass-fusion spicing. Unlike conventional optical-fiber ribbons, which will become damaged
if forcibly folded or , the t flexible optical-fiber ribbon is capable of being
reversibly folded or reversibly rolled into a compact configuration without sustaining
damage. In its substantially non-planar, compact geometry, the optical-fiber ribbon may be
more efficiently packed (e.g., folded or ) within optical-fiber cablings, such as a
le micromodule or a buffer tube. In ary cabling embodiments, one, two, three,
or four flexible optical-fiber ribbons (e.g., twelve-optical-fiber ribbons) may be positioned
within a micromodule, such as Prysmian’s FLEXTUBE® micromodule.
Figure 6 depicts a flexible, de, edge-bonded twelve-optical-fiber ribbon 10
efficiently packed within a tearable FLEXTUBE® micromodule 20 having an approximately
1.2-millimeter inner diameter. Those having ry skill in the art will appreciate that the
flexible l-fiber ribbon reverts to its planar geometry when unpacked from the
micromodule, thereby facilitating mass-fusion spicing.
In its planar geometry, the optical-fiber ribbon defines a maximum ribbon
cross-sectional width (Wmax) (e.g., a major transverse axis). The l-fiber ribbon is
sufficiently flexible and durable to withstand — without ng the structure of the
optical-fiber ribbon, including its constituent optical fibers — repeated transverse folding or
rolling from its maximum ribbon cross-sectional width (Wmax) to a significantly reduced
ribbon cross—sectional width (Wf) (i.e., Wmax >> Wf). In this regard, damage to the
optical-fiber ribbon would include cracks or splits to the cured ribbon-matrix al, as well
as delamination at the interface of the optical fibers and the cured ribbon-matrix material.
As noted, the ribbon-matrix material may be applied to only one side of the
parallel optical fibers to partially fill the curved, triangular regions defined by adjacent optical
fibers to achieve an exemplary one—side, edge-bonded optical-fiber ribbon. Figure 7 s
such an exemplary de, edge-bonded optical-fiber ribbon in a planar ribbon
configuration. Figure 8 depicts the same exemplary one-side, edge—bonded optical—fiber
ribbon in a compact ribbon configuration after transverse folding about the length of the
optical-fiber ribbon.
In one exemplary embodiment, the optical-fiber ribbon is reversibly, transversely
foldable (or reversibly, transversely rollable) from a planar ribbon configuration defining a
maximum ribbon cross-sectional width (Wmax) to a anar ribbon configuration defining
a reduced ribbon cross-sectional width (Wf) that is 75 percent or less (e.g., 60 percent or less)
of the maximum ribbon cross—sectional width (Wmax) without damaging the ure of the
optical-fiber ribbon. er, the optical-fiber ribbon can withstand such reversible
packing for at least three cycles (e.g., five cycles or more), typically for at least ten cycles
(e.g., 20 cycles or more).
In r exemplary embodiment, the optical-fiber ribbon is reversibly,
transversely foldable (or reversibly, transversely rollable) from a planar ribbon configuration
defining a maximum ribbon cross-sectional width (Wmax) to a non—planar ribbon
configuration defining a reduced ribbon sectional width (Wf) that is 50 percent or less
(e.g., 40 percent or less) of the maximum ribbon cross-sectional width (Wmax) without
damaging the ure of the optical-fiber ribbon. Moreover, the optical-fiber ribbon can
withstand such reversible packing for at least three cycles (e.g., five cycles or more), typically
for at least ten cycles (e.g., 20 cycles or more).
In yet another exemplary embodiment, the optical-fiber ribbon is ibly,
transversely foldable (or reversibly, transversely rollable) from a planar ribbon configuration
defining a maximum ribbon cross-sectional width (Wmax) to a non—planar ribbon
configuration defining a reduced ribbon cross-sectional width (Wf) that is 35 percent or less
(e.g., 25 percent or less) of the maximum ribbon cross-sectional width (Wmax) without
damaging the structure of the optical—fiber ribbon. Moreover, the optical -fiber ribbon can
withstand such reversible packing for at least three cycles (e.g., five cycles or more), typically
for at least ten cycles (e.g., 20 cycles or more).
Those having ordinary skill in the art will ize compacting larger—count
l-fiber ribbons (e.g., twelve-optical-fiber s, 24-optical-fiber ribbons, or
36-optical-fiber ribbons), such as depicted in Figure 8, is typically more efficient than
compacting smaller-count optical-fiber ribbons (e.g., four-optical-fiber ribbons or
six-optical-fiber ribbons).
Alternatively, similar flexibility and lity can be calculated using as the
starting measurement a transverse major axis that is defined by the opposite, outermost
optical fibers within the optical-fiber ribbon (e. g., the distance n the first and twelfth
optical fibers in a lZ-fiber ribbon).
The t flexible optical-fiber ribbon may be manufactured to comply with the
c requirements set forth in Telcordia Technologies GRCORE (Issue 4, July 2013),
namely Section 5 (“Requirements for l Fiber Ribbons”), which itself references
Publication No. ANSI/ICEA S640-2011 for ard for Optical Fiber Outside Plant
ication Cable,” (Fifth Edition — 2011), such as section 7.14 (“Ribbon
Dimensions”), CORE (Issue 4, July 2013) and Publication No. ANSI/ICEA S—87—
640-2011 (Fifth Edition, 2011), each of which is hereby incorporated by reference in its
entirety, provide the following maximum dimensions for optical—fiber ribbons:
Table l gMaximum Ribbon Dimensions)
optical-fiber optical-fiber
ribbon width (W) ribbon height (h) alignment alignment
0pt1calf1bers(n)
(pm) (pm) extreme fibers (b) planarity (p)
Accordingly, in an exemplary embodiment, the optical-fiber ribbon conforms to the
ribbon-dimension requirements ed in Table 1 (above) as disclosed in both
GRCORE (Issue 4, July 2013) and Publication No. ANSI/ICEA S640-2011
(Fifth n, 2011). Figure 9 depicts the dimensional ters presented in Table l.
Alternatively, optical-fiber planarity within an optical-fiber ribbon may be
expressed as a function of optical-fiber width (i.e., optical—fiber er). For example,
optical-fiber planarity can be defined as the normal distance between the extreme upper and
lower optical fibers within the optical-fiber ribbon relative to a transverse ne defined by
the opposite, outermost optical fibers within the optical-fiber ribbon (e.g., a baseline
ting either the respective centers of the two outermost optical fibers or the
corresponding glass cladding edges of the two outermost optical fibers). See Figure 9. After
establishing an appropriate transverse baseline and identifying the uppermost and lowermost
optical fibers in the optical-fiber ribbon, optical-fiber planarity can be determined as the sum
of the perpendicular distance from the defined transverse baseline (1') to the respective centers
of the glass cores of the uppermost and lowermost l fibers or (ii) to the corresponding
glass cladding edges of the uppermost and lowermost optical fibers. Those having ordinary
skill in the art will iate that, in determining optical-fiber planarity using glass cladding
edges, the same corresponding position (e.g., six o’clock) must be selected for the opposite,
outermost optical fibers within the optical-fiber ribbon (i.e., in establishing the ne) and
for the respective glass cladding edges of the uppermost and lowermost l fibers (i.e., in
determining normal distance to the baseline).
In exemplary embodiments of the optical-fiber ribbon, the normal distance
between the e upper and lower optical fibers is less than 40 percent of the mean width
of the optical fibers (i.e., optical-fiber diameter) within the optical—fiber ribbon. In other
exemplary embodiments of the optical-fiber ribbon, the normal ce between the e
upper and lower optical fibers is less than 30 percent (e.g., less than 20 percent, such as
percent or less) of the mean width of the optical fibers within the optical-fiber ribbon.
This normalized l-fiber planarity should be measured from a transverse baseline
defined by the te, outermost l fibers within the optical-fiber ribbon, namely from
the respective centers of the optical fibers’ glass cores or from the tive, corresponding
glass cladding edges of the optical fibers (e. g., the respective six-o’clock ons). This
concept is discussed at Section 5 (“Requirements for Optical Fiber Ribbons”) in Telcordia
Technologies GR—20-CORE (Issue 4, July 2013).
Similarly, optical-fiber spacing within an optical-fiber ribbon may be expressed as
a function of optical—fiber width (i.e., l—fiber diameter), such as by mean separation
between adjacent optical fibers (e.g., from the optical fibers’ tive outermost coating
layers) within the l-fiber ribbon. In exemplary embodiments of the optical-fiber ,
the mean separation between adjacent optical fibers within the optical-fiber ribbon is less
than 15 percent (e.g., less than 10 percent) of the mean width of the optical fibers
(i.e., optical—fiber diameter) within the optical-fiber ribbon. In exemplary embodiments of
the optical-fiber ribbon, the mean separation between adjacent optical fibers within the
optical-fiber ribbon is less than 5 percent of the mean width of the optical fibers within the
l-fiber ribbon, such as where nt optical fibers are substantially contigmous to one
another within the optical-fiber ribbon.
By way of contrast, some conventional optical-fiber ribbons achieve flexibility via
intermittent bonding with a high-modulus ribbon-matrix material (e. g., 300 MPa), such as
disclosed in US. Patent No. 9,086,555, which is hereby incorporated by reference in its
entirety. The l fibers within such intermittently bonded l-fiber ribbons, such as a
“spider web ribbon,” can freely move when not clamped or otherwise secured. Whether the
optical fibers are clamped or not, intermittently bonded optical-fiber ribbons employ complex
bonding patterns and typically fail to satisfy the spacing and planarity requirements disclosed
in both GR-ZO-CORE (Issue 4, July 2013) and Publication No. ANSI/ICEA S-87—640-2011
(Fifth Edition, 2011). This renders conventional, intermittently bonded optical-fiber ribbons
(e.g., “spider web ribbon”) poor candidates for mass-fusion splicing.
It is desirable to increase the density of optical-fiber ribbons in buffer tubes or
cables, subject to other constraints (e. g., cable or mid-span attenuation). In this regard, the
l fibers themselves may be designed for increased packing density. For example, the
optical fiber may possess modified properties, such as ed refractive—index profile, core
or cladding dimensions, or primary-coating thickness and/or modulus, to improve
microbending and macrobending characteristics.
In one embodiment, the optical fibers employed in the t optical-fiber
ribbons may be conventional standard single-mode fibers (S SMF). Suitable single-mode
optical fibers (e.g., enhanced single—mode fibers (ESMF)) that are compliant with the
ITU-T G.652.D recommendations are commercially available, for instance, from an
Group (Claremont, North na, USA). The ITU-T G652 (November 2009)
endations and each of its attributes (i.e., A, B, C, and D) are hereby orated by
reference in their entirety.
In r embodiment, bend-insensitive —mode optical fibers may be
employed in the optical-fiber ribbons according to the present invention. Bend-insensitive
optical fibers are less tible to attenuation (e.g., caused by microbending or
macrobending). Exemplary single-mode glass fibers for use in the present optical-fiber
ribbons are commercially available from Prysmian Group (Claremont, North Carolina, USA)
under the trade name BendBright®, which is compliant with the ITU-T G.652.D
recommendations. That said, it is within the scope of the present invention to employ a
bend—insensitive glass fiber that meets the ITU-T G.657.A recommendations (e.g., the ITU-T
G.657.Al (November 2009) and the ITU-T G.657.A2 (November 2009) egories)
and/or the ITU-T G.657‘B recommendations (eg., the ITU-T G.657.B2 (November 2009)
and the ITU-T G.657.B3 (November 2009) subcategories). In this regard, the ITU-T
G.657.A1 (November 2009) subcategory fully encompasses the former ITU—T G657.A
(December 2006) category, and the ITU-T G.657.B2 (November 2009) subcategory fully
encompasses the former ITU-T G.657.B (December 2006) category. The ITU—T G.657.A/B
recommendations are hereby orated by reference in their entirety.
In this regard, exemplary bend-insensitive -mode glass fibers for use in the
present invention are commercially available from an Group mont,
North Carolina, USA) under the trade names BendBrightXS® and BendBright-EliteTM.
BendBrightXS® optical fibers and BendBright-EliteTM optical fibers are not only compliant
2016/044182
with both the ITU-T G.652.D and ITU-T G.657.A/B recommendations, but also demonstrate
significant improvement with respect to both ending and microbending. As compared
with such bend-insensitive single-mode optical fibers, conventional single-mode optical
fibers typically do not comply with either the ITU-T G.657.A recommendations or the ITU-T
B recommendations, but do typically comply with the ITU-T G.652 recommendations
(e. g, the ITU-T G.652.D recommendations).
As set forth in commonly assigned US. Patent No. 8,265,442, US. Patent
No. 8,145,027, US. Patent No. 8,385,705, and International Patent Application Publication
No. A1, pairing a bend-insensitive glass fiber (e.g., Prysmian Group’s
single-mode glass fibers available under the trade name BendBrightXS®) and a primary
coating having very low modulus achieves optical fibers having exceptionally low losses
(e. g., reductions in end ivity of at least 10X as compared with a single—mode
optical fiber employing a conventional coating system). The optical-fiber ribbons according
to the present invention may employ the optical-fiber coatings disclosed in US. Patent
No. 8,265,442, US. Patent No. 8,145,027, US. Patent No. 8,3 85,705, and International
Patent Application Publication No. A1, which are hereby incorporated by
reference in their entirety, with either single-mode optical fibers or multimode l fibers.
In another embodiment, the l fibers employed in the present optical-fiber
ribbons are conventional multimode l fibers having a 50-micron core (e.g, 0M2
multimode optical fibers) and complying with the ITU-T G.651.1 recommendations. The
ITU—T G.651.1 (July 2007) recommendations are hereby orated by reference in their
entirety. Exemplary multimode optical fibers that may be employed include MaxCapTM
multimode optical fibers (OM2+, 0M3, or 0M4), which are commercially available from
Prysmian Group (Claremont, North Carolina, USA).
Alternatively, the present l-fiber s may e bend-insensitive
multimode optical fibers, such as MaXCapTM-BB—OMX multimode optical fibers, which are
commercially available from Prysmian Group (Claremont, North Carolina, USA). In this
regard, bend-insensitive multimode optical fibers typically have macrobending losses of
(i) no more than 0.1 dB at a wavelength of 850 nanometers for a g of two turns around
a spool with a bending radius of 15 millimeters and (it) no more than 0.3 dB at a wavelength
of 1300 nanometers for a winding of two turns around a spool with a bending radius of
millimeters.
In contrast, conventional multimode optical fibers, in accordance with the ITU-T
G.651.1 recommendations, have macrobending losses of (i) no more than 1 dB at a
wavelength of 850 nanometers for a g of two turns around a spool with a bending
radius of 15 millimeters and (ii) no more than 1 dB at a ngth of 1300 nanometers for a
winding of two turns around a spool with a bending radius of 15 millimeters. Moreover, as
measured using a winding of two turns around a spool with a bending radius of
millimeters, conventional multimode optical fibers typically have macrobending losses of
(i) greater than 0.1 dB, more typically greater than 0.2 dB (e.g., 0.3 dB or more), at a
wavelength of 850 nanometers and (ii) greater than 0.3 dB, more typically greater than 0.4 dB
(e.g., 0.5 dB or more), at a wavelength of 1300 nanometers.
Multimode optical fibers can be advantageous, because their relatively large core
diameter facilitates easy torization. Accordingly, it is within the scope of the present
invention to employ multimode optical fibers having enlarged core diameters
(e.g., 62.5 microns or greater), such as n about 70 microns and 100 s
(e.g., about 80 microns). An exemplary multimode l fiber having an enlarged core
diameter is disclosed in commonly assigned US. Patent No. 771 for a Bend-Resistant
Multimode Optical Fiber, (Molin et al.), which is hereby incorporated by reference in its
entirety. In particular, US. Patent No. 771 discloses a trench-assisted multimode
l fiber having ed bend resistance.
The optical fibers typically have an outer diameter of between about 235 microns
and 265 microns, although optical fibers having a smaller diameter may be employed in the
present optical-fiber ribbons.
By way of example, the component glass fiber may have an outer diameter of
about 125 microns. With respect to the optical fiber’s surrounding coating layers, the
y coating may have an outer diameter of between about 175 microns and 195 microns
(i.e., a primary coating thickness of between about 25 microns and 35 microns), and the
secondary coating may have an outer diameter of between about 235 microns and 265
microns (i.e., a secondary coating thickness of between about 20 microns and 45 microns).
Optionally, the optical fiber may include an outermost ink layer, which is typically between
two and ten microns.
In one alternative embodiment, an optical fiber may possess a reduced diameter
(e.g., an outermost er between about 150 microns and 230 microns). In this ative
optical fiber ration, the thickness of the primary coating and/or secondary coating is
reduced, while the diameter of the component glass fiber is maintained at about 125 microns.
(Those having ordinary skill in the art will appreciate that, unless otherwise specified,
er measurements refer to outer diameters.)
By way of illustration, in such exemplary embodiments, the primary coating layer
may have an outer diameter of between about 135 microns and about 175 microns (e. g., about
160 microns), typically less than 165 s (e.g., between about 135 microns and
150 microns), and usually more than 140 microns (e.g., between about 145 microns and
155 microns, such as about 150 s).
Moreover, in such exemplary embodiments, the secondary coating layer may have
an outer diameter of between about 150 microns and about 230 microns (e.g., more than
about 165 microns, such as 190—210 microns or so), typically between about 180 microns and
200 microns. In other words, the total diameter of the optical fiber is reduced to less than
about 230 microns (e.g., between about 195 microns and 205 microns, and especially about
200 microns). By way of further ration, an optical fiber may employ a ary
coating of about 197 microns at a tolerance of +/- 5 microns (i.e., a secondary-coating outer
diameter of between 192 microns to 202 microns). Typically, the secondary coating will
retain a thickness of at least about 10 microns (e.g., an optical fiber having a reduced
thickness secondary coating of between 15 s and 25 microns).
In another alternative embodiment, the outer er of the ent glass
fiber may be reduced to less than 125 microns (e.g., between about 60 microns and
120 microns), perhaps between about 70 microns and 115 microns (e. g., about 80—1 10
microns). This may be achieved, for instance, by ng the thickness of one or more
cladding . As compared with the prior alternative embodiment, (1') the total diameter of
the optical fiber may be reduced (i.e., the thickness of the primary and secondary coatings are
maintained in accordance with the prior alternative ment) or (ii) the respective
esses of the y and/or secondary coatings may be increased relative to the prior
alternative embodiment (e.g., such that the total diameter of the optical fiber might be
maintained).
By way of illustration, with respect to the former, a component glass fiber having
a er of between about 90 and 100 microns might be combined with a y coating
layer having an outer diameter of between about 110 microns and 150 microns (e.g., about
125 microns) and a secondary coating layer having an outer diameter of between about
130 microns and 190 microns (e. g., about 155 microns). With respect to the latter, a
component glass fiber having a diameter of between about 90 and 100 microns might be
combined with a primary g layer having an outer diameter of between about
120 microns and 140 s (e.g., about 130 microns) and a secondary coating layer having
an outer er of between about 160 microns and 230 microns (e. g., about
195-200 microns).
Reducing the diameter of the component glass fiber might make the resulting
optical fiber more susceptible to microbending attenuation. That said, the advantages of
further reducing optical-fiber diameter might be worthwhile for some optical-fiber
applications.
As noted, the present optical fibers may e one or more coating layers (e.g., a
primary coating and a secondary coating). At least one of the coating layers — typically the
secondary coating — may be colored and/or possess other markings to help identify
individual fibers. Alternatively, a tertiary ink layer may surround the primary and secondary
coatings.
In the cation and/or figures, typical embodiments of the invention have
been disclosed. The present invention is not limited to such exemplary embodiments. The
use of the term “and/or” includes any and all combinations of one or more of the associated
listed items. The figures are schematic representations and so are not necessarily drawn to
scale. Unless otherwise noted, specific terms have been used in a generic and descriptive
sense and not for es of limitation.
Claims (14)
1. An optical-fiber ribbon, comprising: a ity of optical fibers; and a cured ribbon-matIiX material edge bonding the plurality of optical fibers in a side-by-side ement such that at least 70 percent of the cured ribbon-matrix material is oned on one side of the optical—fiber ribbon, the cured ribbon—matrix material having (1') elongation-to-break of at least 200 percent at 20°C, (ii) Young's modulus of 1—20 MPa at 20°C, and (iii) Young's s of 100 MPa or less at —40°C‘
2. The optical-fiber ribbon according to Claim 1, wherein the cured ribbon-matrix material has elongation-to-break of at least 300 percent at 20°C.
3. The optical-fiber ribbon according to either Claim 1 or Claim 2, wherein the cured ribbon-matrix material has s modulus of 75 MPa or less at —40°C.
4. An optical-fiber ribbon, sing: a plurality of optical fibers; and a cured ribbon—matrix material bonding the plurality of optical fibers in a side-by-side arrangement, the cured ribbon-matrix material having (1') elongation-to-break of at least 350 percent at 20°C, (ii) Young's modulus of 1—15 MPa at 20°C, and (iii) Young’s modulus of 60 MPa or less at —40°C; wherein the optical-fiber ribbon is reversibly, transversely foldable from a planar ribbon configuration defining a m ribbon cross-sectional width (Wmax) to a non-planar ribbon configuration defining a reduced ribbon sectional width (Wf) that is 75 percent or less of the maximum ribbon cross-sectional width (Wmax) without damaging the structure of the optical-fiber ribbon.
5. The optical-fiber ribbon according to any one of the prior claims, wherein the cured ribbon-matrix material edge bonds the plurality of optical fibers in a side-by-side arrangement such that at least 75 percent of the cured -matrix material is positioned on one side of the optical-fiber ribbon.
6. The optical-fiber ribbon ing to any one of the prior claims, wherein the cured ribbon-matrix material edge bonds the plurality of optical fibers in a y-side ement such that at least 80 percent of the cured ribbon-matrix material is oned on one side of the optical-fiber ribbon.
7. The optical-fiber ribbon ing to any one of the prior claims, wherein the cured -matrix material edge bonds the plurality of optical fibers in a side-by-side arrangement such that at least 90 percent of the cured ribbon-matrix material is positioned on one side of the optical-fiber ribbon.
8. The optical-fiber ribbon according to any one of the prior claims, wherein the cured ribbon-matrix al bonds the plurality of optical fibers in a side-by-side arrangement via the application of ribbon-matrix material predominantly to only one side of the optical-fiber ribbon to at least partly fill the curved, triangular regions defined by adjacent optical fibers.
9. The optical-fiber ribbon according to any one of the prior claims, wherein the optical-fiber ribbon is reversibly, transversely foldable from a planar ribbon configuration defining a maximum ribbon cross-sectional width (Wmax) to a non—planar ribbon configuration defining a reduced ribbon cross-sectional width (Wf) that is 60 percent or less of the maximum ribbon cross-sectional width (Wmax) without damaging the structure of the optical-fiber ribbon.
10. The optical-fiber ribbon according to any one of the prior , wherein the optical-fiber ribbon is reversibly, transversely foldable from a planar ribbon configuration defining a maximum ribbon cross-sectional width (Wmax) to a non—planar ribbon configuration defining a reduced ribbon cross-sectional width (Wf) that is 50 percent or less of the maximum ribbon cross-sectional width (Wmax) without damaging the structure of the optical-fiber ribbon.
11. The optical-fiber ribbon according to any one of the prior claims, wherein the optical-fiber ribbon is reversibly, transversely le from a planar ribbon configuration defining a maximum ribbon cross-sectional width (Wmax) to a non—planar ribbon configuration g a reduced ribbon cross-sectional width (Wf) that is 35 percent or less of the m ribbon cross-sectional width (Wmax) without damaging the structure of the optical-fiber ribbon.
12. The l-fiber ribbon according to any one of Claims 9—1 1, wherein, for at least five folding cycles, the optical-fiber ribbon is reversibly, ersely foldable from the planar ribbon ration defining the maximum ribbon sectional width (Wmax) to a non-planar ribbon configuration defining the reduced ribbon cross—sectional width (Wf) without damaging the structure of the optical-fiber .
13. The optical-fiber ribbon according to any one of Claims 9—11, wherein, for at least ten folding cycles, the optical-fiber ribbon is reversibly, transversely foldable from the planar ribbon configuration defining the maximum ribbon cross-sectional width (Wmax) to a non-planar ribbon configuration g the reduced ribbon cross-sectional width (Wf) without damaging the structure of the optical-fiber ribbon.
14. The optical-fiber ribbon according to any one of Claims 9—11, wherein, for at least twenty g cycles, the optical-fiber ribbon is ibly, transversely foldable from the planar ribbon configuration defining the maximum ribbon cross-sectional width (Wmax) to a non-planar ribbon configuration defining the reduced ribbon cross-sectional width (Wf) without damaging the structure of the optical-fiber ribbon.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US2016/044182 WO2018022031A1 (en) | 2016-07-27 | 2016-07-27 | Flexible optical-fiber ribbon |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ749887A NZ749887A (en) | 2021-03-26 |
NZ749887B2 true NZ749887B2 (en) | 2021-06-29 |
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