U.S. patent number RE47,418 [Application Number 15/651,267] was granted by the patent office on 2019-06-04 for optical connectors with inorganic adhesives and methods for making the same.
This patent grant is currently assigned to Corning Optical Communications LLC. The grantee listed for this patent is Corning Optical Communications LLC. Invention is credited to Michael Edward DeRosa, Shawn Michael O'Malley, Vitor Marino Schneider.
United States Patent |
RE47,418 |
DeRosa , et al. |
June 4, 2019 |
Optical connectors with inorganic adhesives and methods for making
the same
Abstract
One embodiment of the disclosure relates to an optical
connector. The optical connector may include a ferrule, a
waveguide, and an inorganic adhesive composition. The ferrule may
include a fiber-receiving passage defining an inner surface. The
inorganic adhesive composition may be disposed within the ferrule
and in contact with the inner surface of the ferrule and the
waveguide. The inorganic adhesive composition may include at least
about 50% by weight of metal oxide.
Inventors: |
DeRosa; Michael Edward (Painted
Post, NY), O'Malley; Shawn Michael (Horseheads, NY),
Schneider; Vitor Marino (Painted Post, NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
Corning Optical Communications LLC |
Hickory |
NC |
US |
|
|
Assignee: |
Corning Optical Communications
LLC (Hickory, NC)
|
Family
ID: |
52740270 |
Appl.
No.: |
15/651,267 |
Filed: |
July 17, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
14041506 |
Sep 30, 2013 |
9086548 |
Jul 21, 2015 |
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C09J
5/00 (20130101); C09J 1/00 (20130101); B32B
37/142 (20130101); G02B 6/3861 (20130101); B32B
37/142 (20130101); G02B 6/3854 (20130101); C09J
1/00 (20130101); G02B 6/3861 (20130101); G02B
6/3854 (20130101); G02B 6/3865 (20130101); C09J
2400/12 (20130101); G02B 6/3885 (20130101); G02B
6/3887 (20130101); C09J 5/00 (20130101); G02B
6/3865 (20130101); G02B 6/3863 (20130101); G02B
6/3885 (20130101); G02B 6/3863 (20130101); C09J
2400/12 (20130101); G02B 6/3887 (20130101) |
Current International
Class: |
G02B
6/36 (20060101); C09J 5/00 (20060101); B32B
37/14 (20060101); G02B 6/38 (20060101); C09J
1/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Dietz, R. L., "Optical fiber sealing withs older glass: Design
Guidelines, "Proceedings of SPIE, 2004, vol. 5578, pp. 642-651.
cited by examiner .
Accuratus, "Zirconium Oxide, ZrO2. Ceramic Properities,"
XP-002711172, Retrieved on Aug. 8, 2013 from
http://accuratus.com/zire.html. 1 page. cited by examiner .
Conzone, S.D., et al., "Low temperature joining of Zerodur and SiO2
for optical device manufacture," Proceedings of SPIE: Inorganic
Optical Materials III, vol. 4452, 2001, pp. 107. cited by applicant
.
Gvishi, R., et al., "UV-curable glassy material for the manufacture
of bulk and nano-structured elements," Journal of the European
Optical Society, Rapid Publications, vol. 7, Mar. 22, 2012, 5
pages. cited by applicant .
Luvalle, M., et al., "Acceptance Testing for the Pistoning Failure
Mode in Fiber Optic Connectors," Proceedings of SPIE: Optical Fiber
and Component Mechanical Reliability and Testing, vol. 4215, 2001,
pp. 168-182. cited by applicant .
Park, J., et al., "Critical Aspect of Curing Epoxy Adhesive: Fiber
Pistoning of LC Connector," IEEE Transactions on Device and
Materials Reliability, vol. 5, Issue 3, 2005, pp. 572-580. cited by
applicant .
Non-Final Office Action for U.S. Appl. No. 14/041,506, dated Feb.
10, 2015, 11 pages. cited by applicant .
Notice of Allowance for U.S. Appl. No. 14/041,506, dated May 7,
2015, 8 pages. cited by applicant.
|
Primary Examiner: Hughes; Deandra M
Attorney, Agent or Firm: Weeks; Adam R.
Claims
What is claimed is:
1. An optical connector comprising a ferrule, a waveguide, and an
inorganic adhesive composition, wherein: the ferrule comprises a
fiber-receiving passage defining an inner surface; the inorganic
adhesive composition is disposed within the ferrule and in contact
with the inner surface of the ferrule and the waveguide; the
inorganic adhesive composition comprises at least about 50% by
weight of metal oxide; and the inorganic adhesive composition
comprises yttria-stabilized zirconia.
2. The optical connector of claim 1, wherein the ferrule .[.is.].
.Iadd.comprises .Iaddend.a ceramic material.
3. The optical connector of claim 1, wherein the inorganic adhesive
composition .[.is.]. .Iadd.comprises .Iaddend.substantially the
same material as the ferrule.
4. The optical connector of claim 1, wherein the ferrule comprises
zirconia or yttria-stabilized zirconia.
5. The optical connector of claim 1, wherein the inorganic adhesive
composition further comprises one or more nanostructures of
graphene, carbon, silver, gold, platinum, or combinations
thereof.
6. The optical connector of claim 1, wherein the inorganic adhesive
composition comprises at least about 50% .Iadd.by weight of
.Iaddend.yttria-stabilized zirconia.
7. The optical connector of claim 1, wherein: the inorganic
adhesive composition is characterized by an adhesive CTE .alpha.1
that varies by less than about 10.times.10-6/K over a temperature
range from about -50.degree. C. to about 80.degree. C.; the ferrule
is characterized by a ferrule CTE .alpha.2 that varies by less than
about 15.times.10-6/K over a temperature range from about
-50.degree. C. to about 80.degree. C.; and the inorganic adhesive
composition is configured such that, over a temperature range from
about -50.degree. C. to about 80.degree. C.,
|.alpha.1-.alpha.2|.ltoreq.15.times.10-6/K.
8. The optical connector of claim 1, wherein the waveguide
comprises an optical fiber.
9. An optical connector comprising a ferrule, a waveguide, and an
inorganic adhesive composition, wherein: the ferrule comprises a
fiber-receiving passage defining an inner surface; the inorganic
adhesive composition is disposed within the ferrule and in contact
with the inner surface of the ferrule and the waveguide; the
inorganic adhesive composition comprises at least about 50% by
weight of metal oxide .Iadd.comprising zirconia or
yttria-stabilized zirconia.Iaddend.; and the inorganic adhesive
composition has a CTE in a range of between about 80% and 125% of
the CTE of the ferrule over a temperature range from about
-50.degree. C. to about 80.degree. C.
10. A method for securing a waveguide to a ferrule of an optical
connector, the method comprising: depositing an inorganic adhesive
composition precursor onto the waveguide or into a fiber-receiving
passage defining an inner surface of the ferrule; inserting the
waveguide into the fiber-receiving passage, such that the inorganic
adhesive composition precursor is disposed within the ferrule and
in contact with the inner surface of the ferrule; and solidifying
the inorganic adhesive composition precursor to form an inorganic
adhesive composition, wherein .[.and.]. the inorganic adhesive
composition comprises at least about 50% by weight of metal oxide
.Iadd.comprising zirconia or ytrria-stabilized zirconia.Iaddend.,
and wherein the solidification comprises exposing the inorganic
adhesive composition precursor to a temperature in a range of from
about 200.degree. C. to about 1200.degree. C.
11. The method of claim 10, wherein the inorganic adhesive
composition comprises .Iadd.at least about 50% by weight of
.Iaddend.zirconia or yttria-stabilized zirconia.
12. The method of claim 10, wherein the inorganic adhesive
composition precursor comprises a metallic salt, another metal ion
containing compound, or combinations thereof in a solvent.
13. The method of claim 12, wherein the metallic salt and/or the
other metal ion containing compound comprises ions of zinc, tin,
aluminum, indium, iron, tungsten, titanium, zirconium, silicon,
silicon nitride, boron, boron nitride, copper, silver, yttrium,
rare earth ions, or combinations thereof.
14. The method of claim 12, wherein the metallic salt and/or the
other metal ion containing compound comprises ions of zirconium,
yttrium, or both.
15. The method of claim 12, wherein the solvent is a polar aprotic
solvent.
16. The method of claim 12, wherein the inorganic adhesive
composition precursor .[.is.]. .Iadd.comprises .Iaddend.a sol-gel
solution.
17. The method of claim 10, wherein the waveguide comprises an
optical fiber.
18. A method for securing a waveguide to a ferrule of an optical
connector, the method comprising: depositing an inorganic adhesive
composition precursor onto the waveguide or into a fiber-receiving
passage defining an inner surface of the ferrule; inserting the
waveguide into the fiber-receiving passage, such that the inorganic
adhesive composition precursor is disposed within the ferrule and
in contact with the inner surface of the ferrule; solidifying the
inorganic adhesive composition precursor to form an inorganic
adhesive composition, wherein .[.and.]. the inorganic adhesive
composition comprises at least about 50% by weight of metal oxide;
and crystallizing the inorganic adhesive composition after the
solidification.
19. The method of claim 18, wherein the inorganic adhesive
composition is crystallized by exposure to a temperature in a range
of from about 200.degree. C. to about 1200.degree. C.
.Iadd.20. An optical connector comprising at least one waveguide
and an inorganic adhesive composition, wherein: the inorganic
adhesive composition bonds the at least one waveguide to a part of
the optical connector; the inorganic adhesive composition comprises
at least about 50% by weight of metal oxide; and the inorganic
adhesive composition comprises yttria-stabilized
zirconia..Iaddend.
.Iadd.21. The optical connector of claim 20, further comprising a
ferrule that defines at least one longitudinal bore for receiving
the at least one waveguide, wherein the part of the optical
connector to which the at least one waveguide is bonded by the
inorganic adhesive composition comprises the ferrule..Iaddend.
.Iadd.22. The optical connector of claim 21, wherein the at least
one longitudinal bore defines at least one inner surface, and at
least a portion of the inorganic adhesive composition is disposed
within the ferrule and in contact with the at least one inner
surface..Iaddend.
.Iadd.23. The optical connector of claim 21, wherein the ferrule
comprises a ceramic material, and the inorganic adhesive
composition comprises substantially the same material as the
ferrule..Iaddend.
.Iadd.24. The optical connector of claim 21, wherein: the inorganic
adhesive composition is characterized by an adhesive coefficient of
thermal expansion (CTE) .alpha.1 that varies by less than about
10.times.10.sup.-6/K over a temperature range from about
-50.degree. C. to about 80.degree. C.; the ferrule is characterized
by a ferrule CTE .alpha.2 that varies by less than about
15.times.10.sup.-6/K over a temperature range from about
-50.degree. C. to about 80.degree. C.; and the inorganic adhesive
composition is configured such that, over a temperature range from
about -50.degree. C. to about 80.degree. C.,
|.alpha.1-.alpha.2|.ltoreq.15.times.10.sup.-6/K..Iaddend.
.Iadd.25. The optical connector of claim 20, further comprising a
connector housing and a ferrule at least partially disposed within
the connector housing, wherein the part of the optical connector to
which the at least one waveguide is bonded by the inorganic
adhesive composition is disposed within the connector
housing..Iaddend.
.Iadd.26. The optical connector of claim 25, wherein the ferrule is
biased forwardly relative to the connector housing..Iaddend.
.Iadd.27. The optical connector of claim 25, wherein at least a
portion of the inorganic adhesive composition is arranged in
contact with the ferrule..Iaddend.
.Iadd.28. The optical connector of claim 20, wherein the inorganic
adhesive composition further comprises one or more nanostructures
of graphene, carbon, silver, gold, platinum, or combinations
thereof..Iaddend.
.Iadd.29. The optical connector of claim 20, wherein the inorganic
adhesive composition comprises at least about 50% by weight of
yttria-stabilized zirconia..Iaddend.
.Iadd.30. The optical connector of claim 20, wherein the at least
one waveguide comprises at least one stub optical
fiber..Iaddend.
.Iadd.31. The optical connector of claim 20, wherein the at least
one waveguide comprises a plurality of optical fibers..Iaddend.
.Iadd.32. An optical connector comprising a ferrule, at least one
waveguide, and an inorganic adhesive composition, wherein: the
ferrule comprises at least one fiber-receiving passage defining at
least one inner surface; the inorganic adhesive composition is
disposed within the optical connector and in contact with the at
least one waveguide; the inorganic adhesive composition comprises
at least about 50% by weight of metal oxide comprising zirconia or
yttria-stabilized zirconia; and the inorganic adhesive composition
has a coefficient of thermal expansion (CTE) in a range of between
about 80% and 125% of a CTE of the ferrule over a temperature range
from about -50.degree. C. to about 80.degree. C..Iaddend.
.Iadd.33. The optical connector of claim 32, further comprising a
connector housing, wherein at least a portion of the ferrule is
arranged within the connector housing, and the ferrule is biased
forwardly relative to the connector housing..Iaddend.
.Iadd.34. The optical connector of claim 33, wherein at least a
portion of the inorganic adhesive composition is disposed within
the ferrule and in contact with the at least one inner
surface..Iaddend.
.Iadd.35. The optical connector of claim 32, wherein the at least
one waveguide comprises at least one stub optical
fiber..Iaddend.
.Iadd.36. A method for securing at least one waveguide to an
optical connector, wherein the optical connector includes an
inorganic adhesive composition precursor deposited into the optical
connector, the method comprising: inserting the at least one
waveguide into the optical connector, such that the inorganic
adhesive composition precursor is in contact with the at least one
waveguide and with a part of the optical connector; and solidifying
the inorganic adhesive composition precursor to form an inorganic
adhesive composition that bonds the at least one waveguide to the
part of the optical connector, wherein the inorganic adhesive
composition comprises at least about 50% by weight of metal oxide
comprising zirconia or yttria-stabilized zirconia, and wherein the
solidification comprises exposing the inorganic adhesive
composition precursor to a temperature in a range of from about
200.degree. C. to about 1200.degree. C..Iaddend.
.Iadd.37. The method of claim 36, wherein the optical connector
comprises a ferrule and a connector housing, at least a portion of
the ferrule is arranged within the connector housing, and the
ferrule is biased forwardly relative to the connector
housing..Iaddend.
.Iadd.38. The method of claim 37, wherein at least a portion of the
inorganic adhesive composition precursor is disposed within the
ferrule..Iaddend.
.Iadd.39. The method of claim 37, further comprising depositing the
inorganic adhesive composition precursor onto the at least one
waveguide or into a fiber-receiving passage defining an inner
surface of the ferrule..Iaddend.
.Iadd.40. The method of claim 36, wherein the exposing of the
inorganic adhesive composition precursor to a temperature in the
range of from about 200.degree. C. to about 1200.degree. C.
comprises heating the inorganic adhesive composition precursor with
a laser..Iaddend.
.Iadd.41. The method of claim 36, wherein the inorganic adhesive
composition precursor comprises at least about 50% by weight of
zirconia or yttria-stabilized zirconia..Iaddend.
.Iadd.42. The method of claim 36, wherein the inorganic adhesive
composition precursor comprises a metallic salt, another metal ion
containing compound, or combinations thereof in a
solvent..Iaddend.
.Iadd.43. The method of claim 42, wherein the metallic salt and/or
the other metal ion containing compound comprises ions of zinc,
tin, aluminum, indium, iron, tungsten, titanium, zirconium,
silicon, silicon nitride, boron, boron nitride, copper, silver,
yttrium, rare earth ions, or combinations thereof..Iaddend.
.Iadd.44. The method of claim 42, wherein the metallic salt and/or
the other metal ion containing compound comprises ions of
zirconium, yttrium, or both..Iaddend.
.Iadd.45. The method of claim 42, wherein the solvent is a polar
aprotic solvent..Iaddend.
.Iadd.46. The method of claim 42, wherein the inorganic adhesive
composition precursor comprises a sol-gel solution..Iaddend.
.Iadd.47. The method of claim 36, wherein the at least one
waveguide comprises at least one stub optical fiber..Iaddend.
.Iadd.48. A method for securing at least one waveguide to an
optical connector, wherein the optical connector includes an
inorganic adhesive composition precursor deposited into the optical
connector, the method comprising: inserting the at least one
waveguide into the optical connector, such that the inorganic
adhesive composition precursor is in contact with the at least one
waveguide and with a part of the optical connector; solidifying the
inorganic adhesive composition precursor to form an inorganic
adhesive composition that bonds the at least one waveguide to the
part of the optical connector, wherein the inorganic adhesive
composition comprises at least about 50% by weight of metal oxide;
and crystallizing the inorganic adhesive composition after the
solidification..Iaddend.
.Iadd.49. The method of claim 48, wherein the inorganic adhesive
composition is crystallized by exposure to a temperature in a range
of from about 200.degree. C. to about 1200.degree. C..Iaddend.
.Iadd.50. The method of claim 48, wherein the optical connector
comprises a ferrule and a connector housing, at least a portion of
the ferrule is arranged within the connector housing, and the
ferrule is biased forwardly relative to the connector
housing..Iaddend.
.Iadd.51. The method of claim 50, wherein at least a portion of the
inorganic adhesive composition precursor is disposed within the
ferrule..Iaddend.
.Iadd.52. The method of claim 50, further comprising depositing the
inorganic adhesive composition precursor onto the at least one
waveguide or into a fiber-receiving passage defining an inner
surface of the ferrule..Iaddend.
.Iadd.53. The method of claim 48, wherein the inorganic adhesive
composition precursor comprises a sol-gel solution..Iaddend.
Description
BACKGROUND
The disclosure relates generally to materials and methods for
adhering parts within optical connectors and more particularly to
adhesive compositions for use in adhering optical fibers to
ferrules within optical connectors, and the methods making the
same.
No admission is made that any reference cited herein constitutes
prior art. Applicants expressly reserve the right to challenge the
accuracy and pertinency of any cited documents.
SUMMARY
One embodiment of the disclosure relates to an optical connector.
The optical connector may comprise a ferrule, a waveguide (such as
an optical fiber, lens, or other structure configured to guide
light), and an inorganic adhesive composition. The ferrule may
comprise a fiber-receiving passage defining an inner surface. The
inorganic adhesive composition may be disposed within the ferrule
and in contact with the inner surface of the ferrule and the
waveguide. The inorganic adhesive composition may comprise at least
about 50% by weight of metal oxide.
An additional embodiment of the disclosure relates to a method for
securing a waveguide to a ferrule of an optical connector. The
method may comprise depositing an inorganic adhesive composition
precursor onto the waveguide or into a fiber-receiving passage
defining an inner surface of the ferrule. The method may also
comprise inserting the waveguide into the fiber-receiving passage,
such that the inorganic adhesive composition precursor is disposed
within the ferrule and in contact with the inner surface of the
ferrule. The method may also comprise solidifying the inorganic
adhesive composition precursor to form an inorganic adhesive
composition. The inorganic adhesive composition may comprise at
least about 50% by weight of metal oxide.
Additional features and advantages will be set forth in the
detailed description which follows, and in part will be readily
apparent to those skilled in the art from the description or
recognized by practicing the embodiments as described in the
written description and claims hereof, as well as the appended
drawings.
It is to be understood that both the foregoing general description
and the following detailed description illustrate the concepts of
the present disclosure with reference to specific examples, and are
intended to provide an overview or framework to understand the
nature and character of the claims.
The accompanying drawings are included to provide a further
understanding, and are incorporated in and constitute a part of
this specification. The drawings illustrate one or more
embodiments, and together with the description serve to explain
principles and operation of the various embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a lengthwise cross-sectional view of a fiber optic
mechanical splice connector to be mounted on an end portion of a
field optical fiber;
FIG. 2 illustrates a fiber-receiving passage of a connector
ferrule;
FIG. 3 is a perspective view of a ferrule according to another
embodiment; and
FIG. 4 is a lengthwise cross-sectional view of a connector
according to another embodiment.
DETAILED DESCRIPTION
Reference will now be made in greater detail to various
embodiments, some embodiments of which are illustrated in the
accompanying drawings. Whenever possible, the same reference
numerals will be used throughout the drawings to refer to the same
or similar parts. Generally, disclosed herein are various
embodiments of inorganic adhesive compositions for use in adhering
optical fibers or other waveguides to ferrules within optical
connectors, and the methods for use thereof. The various
embodiments of inorganic adhesive compositions described herein may
provide desirable properties, such as, but not limited to, high
adhesion strength and/or improved performance following
environmental aging. Various embodiments of the inorganic adhesive
compositions disclosed herein may also have other desirable
properties for the process of securing an optical fiber within a
ferrule, such as, but not limited to, shortened process cycle time,
no required mixing, and/or no potlife issues.
Referring to FIG. 1, a field-installable, mechanical splice fiber
optic connector 10 suitable for use with the present technology is
shown. The fiber optic connector 10 may include features similar to
those of a member of the UNICAM.RTM. family of mechanical splice
connectors available from Corning Cable Systems, LLC of Hickory,
N.C., USA. While one embodiment of a fiber optic connector is
depicted in FIG. 1, it should be understood that the inorganic
adhesive compositions and methods for adhering a glass fiber to a
ferrule as described herein are applicable to any fiber optic
connector of any design. Such fiber optic connectors include, but
are not limited to, single-fiber (see, e.g., ferrule 12 of
connectors 10, 10' as shown in FIGS. 1 and 4) or multi-fiber (see,
e.g., ferrule 12' as shown in FIG. 3) connectors, such as fusion
splice or mechanical splice connectors. Examples of typical single
fiber mechanical splice connectors are provided in U.S. Pat. Nos.
4,755,018; 4,923,274; 5,040,867; and 5,394,496. Examples of typical
multi-fiber mechanical splice connectors are provided in U.S. Pat.
Nos. 6,173,097; 6,379,054; 6,439,780; and 6,816,661.
As is illustrated with .[.further.]. reference to FIG. 2, the
mechanical splice connector 10 includes a connector ferrule 12
defining a lengthwise, longitudinal bore, referred to herein as a
fiber-receiving passage 30. The fiber-receiving passage 30, which
is illustrated in exaggerated scale in FIG. 2, defines an inner
surface of the ferrule 12, which may be contacted with an inorganic
adhesive composition 40 to secure an optical fiber, such as a stub
optical fiber 14. The inorganic adhesive composition 40 may be
disposed within the ferrule 12 and in contact with the inner
surface of the ferrule 12 and the stub optical fiber 14. Various
embodiments of the inorganic adhesive composition 40, including
variations of inorganic adhesive compositions are described in
detail herein. In various embodiments, the inorganic adhesive
composition 40 may generally comprise a ceramic material, as is
described in detail herein.
The ferrule 12 may comprise a ceramic material, such as, but not
limited to, zirconia, yttria-stabilized zirconia (YSZ), alumina,
titanium-doped alumina, glass-filled PPS, or combinations thereof.
However, other materials of construction of the ferrule are
contemplated herein, such as metals, ceramics, polymers, or
combinations thereof.
The stub optical fiber 14 may be a flexible, transparent optical
fiber made of glass or plastic. It may function as a waveguide to
transmit light between the two ends of the optical fiber. Optical
fibers typically include a transparent core surrounded by a
transparent cladding material with a lower index of refraction.
Light may be kept in the core by total internal reflection. Glass
optical fibers may comprise silica, but some other materials, such
as fluorozirconate, fluoroaluminate, and chalcogenide glasses, as
well as crystalline materials, such as sapphire, may be used.
Although shown as the stub fiber 14 in FIG. 1, in other embodiments
waveguides that are not stub fibers may be included and used in
combination with the ferrule 12, 12' and processes disclosed
herein. This includes not only optical fibers that are not stub
optical fibers, but also other waveguides such as lenses (e.g.,
gradient index lenses).
The light may be guided down the core of the optical fiber 14 by an
optical cladding with a lower refractive index that traps light in
the core through total internal reflection. The cladding may be
coated by a buffer and/or another coating(s) that protects it from
moisture and/or physical damage. These coatings may be UV-cured
urethane acrylate composite materials applied to the outside of the
optical fiber 14 during the drawing process. The coatings may
protect the strands of glass fiber. The optical fiber 14 may
comprise an inner primary coating, and an outer secondary coating.
Optical fiber coatings may be applied in concentric layers.
Still referring to FIG. 1, the forward end (also referred to herein
as the end face) 11 of the ferrule 12 is typically precision
polished such that the stub optical fiber 14 is flush with (as
shown) or slightly protruding from the end face of the ferrule 12.
However, the stub optical fiber 14 may also protrude outwardly from
the end face 11 of the ferrule 12 a predetermined distance, if
desired. Furthermore, the end face 11 may be oriented generally
perpendicular to the optical fiber receiving passage to provide an
Ultra Physical Contact (UPC) type connector, or may be formed at a
predetermined angle to provide an Angled Physical Contact (APC)
type connector, in a known manner. In addition, although a single
fiber ferrule 12 is shown for purposes of convenience, the ferrule
12 may define a plurality of lengthwise-optical fiber receiving
passages therethrough for receiving a corresponding plurality of
stub optical fibers to provide a multi-fiber mechanical splice
connector or other multi-fiber connector (see generally multi-fiber
ferrule 12' as shown in FIG. 3 for a multi-fiber connector).
Generally, the rear end 13 of the ferrule 12 is inserted into and
secured within the forward end of a ferrule holder 16 so that the
stub optical fiber 14 extends rearwardly a predetermined distance
from the ferrule between a pair of opposed splice components 17,
18, disposed within the ferrule holder. In turn, the ferrule holder
16, including the ferrule 12 and splice components 17, 18 is
disposed within a connector housing 19. A cam member 20 is movably
mounted between the ferrule holder 16 and the connector housing 19
for engaging a keel portion of the lower splice component 18, as
will be described. If desired, the ferrule 12, the ferrule holder
16 and the cam member 20 may be biased relative to the connector
housing 19, for example by a coil spring 21, to ensure physical
contact between the end face 11 of the ferrule 12 and the end face
of an opposing ferrule in a mating fiber optic connector or optical
device. Finally, a spring retainer 22 may be disposed between the
connector housing 19 and a medial portion of the cam member 20 and
fixed to the connector housing so as to retain one end of the
spring 21 relative to the connector housing. As a result, the
ferrule 12, the ferrule holder 16 and the cam member 20 are biased
forwardly, yet permitted to piston rearwardly relative to the
connector housing 19.
As illustrated by the horizontal directional arrow in FIG. 1, a
field optical fiber 15 may be inserted into the rear end of the
ferrule holder 16 opposite the ferrule 12 and the stub optical
fiber 14. Although not required, the mechanical splice connector 10
may be provided with a means, for example a lead-in tube 24 (FIG.
4), for guiding the field optical fiber 15 into the ferrule holder
16 and between the splice components 17, 18 in general alignment
with the stub optical fiber 14. In some embodiments, at least one
of the splice components 17, 18 has a groove formed therein for
receiving the stub optical fiber 14 and the field optical fiber 15.
As shown .[.herein.]. .Iadd.in FIG. 1.Iaddend., the lower splice
component 18 is provided with a lengthwise V-shaped groove for
receiving and guiding the stub optical fiber 14 and the field
optical fiber 15 into fine alignment. Typically, the field optical
fiber 15 is coated or tight-buffered with a buffer 25 that is
stripped back to expose a predetermined length of the end of the
field optical fiber. The mechanical splice connector 10 may be
further provided with a crimp tube or other strain relief mechanism
(not shown) for retaining and strain relieving the buffer 25 of the
field optical fiber 15. With the buffer 25 removed, the field
optical fiber 15 can be inserted and advanced into the rear of the
mechanical splice connector 10 between the splice components 17, 18
until the end portion of the field optical fiber 15 makes physical
contact with the end portion of the stub optical fiber 14. The cam
member 20 is actuated by moving or rotating the cam member 20
relative to the ferrule holder 16 about the longitudinal axis of
the connector 10, to engage the keel on the .Iadd.lower
.Iaddend.splice component 18 and thereby force the lower splice
component 18 in the direction of the upper splice component 17.
Movement of the lower splice component 18 causes the end portion of
the stub optical fiber 14 and the end portion of the field optical
fiber 15 to seat within the V-shaped groove formed in the lower
splice component 18, thereby aligning and simultaneously securing
the field optical fiber 15 relative to the stub optical fiber 14
between the splice components. Accordingly, the field optical fiber
15 is optically coupled to the stub optical fiber 14. Further, as
used herein, the portion of the connector where the optical
coupling results is referred to as a "termination area." In other
embodiments, the field optical fiber 15 or another optical fiber
may be inserted into the ferrule directly, and attached thereto as
disclosed herein, in place of the stub fiber 14.
Generally, it should be understood that the inorganic adhesive
compositions described herein may have application in adhering an
optical fiber with any part of an optical connector, and are not
limited to the adhesion of a stub optical fiber to the inner wall
of .[.the.]. .Iadd.a .Iaddend.ferrule. For example, the inorganic
adhesive compositions described herein may be used to bond any part
of an optical connector to any optical fiber connected thereto,
including the stub optical fiber and field optical fiber.
Various embodiments of inorganic adhesive compositions will now be
disclosed herein. As used herein, an "adhesive" is a substance
capable of holding materials together by surface attachment.
Additionally, as used herein, an "inorganic adhesive composition"
or "inorganic adhesive composition precursor" is an adhesive or
precursor to an adhesive, respectively, which contains inorganic
materials, usually a majority by weight of inorganic materials,
such as metal oxides, other inorganic additives, or both. Inorganic
adhesive compositions, as described herein, may contain some amount
of organic material, such as organic adhesion promoters. However,
in one embodiment, the inorganic adhesive composition may generally
comprise a ceramic material. In some embodiments, the inorganic
adhesive composition may comprise one or more metal oxides such as,
but not limited to, oxides of zinc, tin, aluminum, indium, iron,
tungsten, titanium, zirconium, silicon, silicon nitride, boron,
boron nitride, copper, silver, yttrium, rare earth ions, or
combinations thereof. The inorganic adhesive may comprise one or
more metal oxides doped with one or more other metal oxides, such
as yttria-stabilized zirconia, sometimes referred to herein as
"YSZ." In some embodiments, the inorganic adhesive composition may
be substantially the same material as the ferrule. For example, the
ferrule may comprise a ceramic material, such as zirconia or YSZ,
and the inorganic adhesive may comprise zirconia or YSZ.
The stub optical fiber may be secured to a ferrule of an optical
connector by a method generally comprising depositing an inorganic
adhesive composition precursor onto the stub optical fiber or into
a fiber-receiving passage defining an inner surface of the ferrule,
inserting the stub optical fiber into the fiber-receiving passage,
such that the inorganic adhesive composition precursor is disposed
within the ferrule and in contact with the inner surface of the
ferrule, and solidifying the inorganic adhesive composition
precursor to form an inorganic adhesive composition. In some
embodiments, the solidification process may sufficiently sinter the
inorganic adhesive composition precursor.
The inorganic adhesive composition precursor may comprise a
metallic salt or other metal ion containing compound in a solvent.
The metallic salt and/or other metal ion containing compound may
comprise ions of zinc, tin, aluminum, indium, iron, tungsten,
titanium, zirconium, silicon, silicon nitride, boron, boron
nitride, copper, silver, yttrium, rare earth ions, or combinations
thereof. In one embodiment, the metallic salt and/or other metal
ion containing compound may comprise ions of zirconium, yttrium, or
both.
In some embodiments, the solvent may be a polar aprotic solvent.
The polar aprotic solvents described herein have ion solvating
properties that facilitate the process of making a stable inorganic
adhesive composition precursor. The inorganic adhesive composition
precursor may be a sol-gel solution. The sol-gel described herein
may be different from traditional sol-gel chemistry in several
important ways. For example, the proposed material reaction to form
the sol-gel solution may not use alcohol solvents or conventional
water/acid catalysis. Instead, the reaction may utilize metal salt
concentrations in polar aprotic solvents (e.g. DMF, NMP) at
relative high concentration (0.5-2.0 M).
Polar aprotic solvents such as, for example, dimethylformamide
(DMF) and n-methyl pyrrolidone (NMP), can be used to produce stable
precursor solutions with metal salts and/or other metal ion
containing compounds. Polar aprotic solvents may be described as
solvents that share ion dissolving power with protic solvents but
lack an acidic hydrogen. These solvents generally have intermediate
dielectric constants and polarity. Aprotic solvents do not commonly
display hydrogen bonding or have an acidic hydrogen. They are
commonly able to stabilize ions. Table 1 shows a description and
selected properties of some suitable polar aprotic solvents.
TABLE-US-00001 TABLE 1 Dichloromethane CH.sub.2Cl.sub.2 1.3266
(DCM) g/ml Tetrahydrofuran
/--CH.sub.2--CH.sub.2--O--CH.sub.2--CH.sub.2--\ 0.886 (THF) g/ml
Ethyl acetate CH.sub.3--C(.dbd.O)--O--CH.sub.2--CH.sub.3 0.894 g/ml
Acetate CH.sub.3--C(.dbd.O)--CH.sub.3 0.786 g/ml Dimethylformamide
H--C(.dbd.O)N(CH.sub.3).sub.2 0.944 (DMF) g/ml Acetonitrile (MeCN)
CH.sub.3--C.ident.N 0.786 g/ml Dimethylsulfozide
CH.sub.3--S(.dbd.O)--CH.sub.3 1.092 (DMSO) g/ml
Various metal oxides can be included in the inorganic adhesive
composition based on the components of the inorganic adhesive
composition precursor. For example, an inorganic adhesive
composition comprising YSZ can be prepared by utilizing .[.and.].
.Iadd.an .Iaddend.inorganic adhesive composition precursor. Such an
inorganic adhesive composition precursor may be prepared by mixing
a first zirconia containing metal salt solution and a second yttria
containing salt solution. The first solution may include zirconium
oxychloride octohydrate (Zr(OCl.sub.2).8H.sub.2O, >99% from
Sigma-Aldrich) dissolved in N,N-dimethylformamide (DMF). The second
solution may include Yttrium Chloride (YCl.sub.3 from Sigma
Aldrich) dissolved in N,N-dimethylformamide (DMF). The first and
second solutions may be prepared with molar concentrations having
stoichiometry to achieve a ratio between the atom % values of
Zirconia and Yttrium. For example, samples may contain 1%, 2%, 4%
and 8% atom content of Yttrium in Zirconia. An ultrasonic bath may
be used to facilitate mixing. The inorganic adhesive composition
precursor may be clear and of significant viscosity.
An advantage of the inorganic adhesive compositions disclosed
herein is the stability of the inorganic adhesive composition
precursor. The inorganic adhesive composition precursor can be
stored in ambient conditions for at least a month without
significant degradation of the sol-gel chemical structure of the
metal ions or the solvent.
The inorganic adhesive composition precursor is converted into the
inorganic adhesive composition through a solidification step. The
solidification may comprise exposing the inorganic adhesive
composition precursor to a temperature in a range of from about
200.degree. C. to about 1200.degree. C. In other embodiments, the
solidification may comprise exposing the inorganic adhesive
composition precursor to a temperature in a range of from about
250.degree. C. to about 1100.degree. C., from about 300.degree. C.
to about 800.degree. C., or from about 300.degree. C. to about
600.degree. C. During the solidification, the solvent may be
liberated from the inorganic adhesive composition precursor and at
least some of the components of inorganic adhesive composition
precursor may be sintered.
The heating may be by oven, hot plate, or any other suitable
heating mechanism. In some embodiments.[.. Other.]..Iadd., other
.Iaddend.heating mechanisms such as microwave and inductive heating
may be used. Time and temperature of such heating processes may
vary depending upon the heating mechanism utilized in the
solidification step. In one embodiment, the inorganic adhesive
composition precursor may be heated with a laser. For example, a
laser having a 40 W power rating at 810 nm focused on a spot size
of approximately 2 mm may be used. However, the use of various
laser powers, wavelengths, and surface areas is contemplated
herein. The heating step may take less than about 3 minutes, less
than about 2 minutes, less than about 1 minute, less than about 45
seconds, less than about 30 seconds, less than about 20 seconds,
less than about 15 seconds, less than about 10 seconds, or even
less than about 5 seconds. However, the time may be dependent upon
the power of the laser and the contacting surface of the laser. The
adhesive composition may then be allowed to cool by any process,
such as by accelerated cooling or through cooling in an ambient
atmosphere at or near room temperature.
Following the solidification step, the inorganic adhesive
composition may be crystallized. The crystallization may be caused
by an exposure to a temperature in a range of from about
200.degree. C. to about 1200.degree. C. In other embodiments, the
crystallization may comprise exposing the inorganic adhesive
composition .[.precursor.]. to a temperature in a range of from
about 250.degree. C. to about 1100.degree. C., from about 300
.degree. C. to about 800 .degree. C., or from about 300.degree. C.
to about 600.degree. C. The crystallization step may utilize
heating in an Argon atmosphere inside a glove box. In some
embodiments, the inorganic adhesive composition may be partially or
fully crystallized following the solidification step. However, in
some embodiments, the inorganic adhesive composition requires
further heating to produce a crystallized inorganic adhesive
composition.
In some embodiments, it is possible to control not only the amount
of certain metal oxides present in the inorganic adhesive
composition, such as the amount of Yttrium and Zirconia, but also
to control the crystallinity of the inorganic adhesive composition
through the composition of the inorganic adhesive composition
precursor. For example, for Zirconia sol concentrations in the
inorganic adhesive composition precursor having less than 1.3 M
zirconia salt, the resultant adhesive may be quasi-amorphous.
However, for Zirconia sol concentrations in the .[.organic.].
.Iadd.inorganic .Iaddend.adhesive composition precursor having
greater than 1.3 M zirconia salt, the resultant adhesives may be
crystalline.
The inorganic adhesive composition may comprise one or more metal
oxides as its majority component. For example, the .Iadd.inorganic
.Iaddend.adhesive composition may comprise at least about 50% by
weight of metal oxide. In other embodiments, the .Iadd.inorganic
.Iaddend.adhesive .Iadd.composition .Iaddend.may comprise at least
about 60%, 70%, 80%, 90%, .Iadd.or .Iaddend.95% by weight of metal
oxide. In one embodiment, the inorganic adhesive composition
comprises 100% by weight of metal oxide. In another embodiment, the
inorganic adhesive composition may comprise greater than 90% by
weight of zirconia, or may even be 100% by weight of zirconia. In a
further embodiment, the inorganic adhesive composition may comprise
greater than 90% by weight of YSZ, or may even be 100% by weight of
YSZ. Zirconia or YSZ inorganic adhesive compositions may be
especially desirable when the material of the ferrule is zirconia
or YSZ, respectively. As used herein, an inorganic adhesive
composition comprising metal oxide may comprise one or more
chemical species of metal oxide. The inorganic adhesive composition
may comprise one or more metal oxides as its majority component.
For example, the .Iadd.inorganic .Iaddend.adhesive composition may
comprise 50% by weight of a single chemical species of metal oxide.
In other embodiments, the .Iadd.inorganic .Iaddend.adhesive
.Iadd.composition .Iaddend.may comprise at least about 60%, 70%,
80%, 90%, .Iadd.or .Iaddend.95% by weight of a single chemical
species of metal oxide. In one embodiment, the inorganic adhesive
composition comprises 100% by weight of a single chemical species
of metal oxide.
The inorganic adhesive compositions described herein may comprise
one or more additional additives. The additives may enhance the
adhesion and/or strength of the inorganic adhesive composition.
Such additives may include, but are not limited to, nanostructures
of graphene, carbon, silver, gold, platinum, or combinations
thereof. For example, the nanostructures may be metallic
nanoparticles (such as nanoparticles of gold, platinum, silver,
aluminum, .[.cooper.]. .Iadd.copper.Iaddend., etc.), semiconductor
nanoparticles (such as carbon nanotubes/nanodots, graphene,
graphene oxide, CdS, CdTe). The additives can be doped into the
inorganic adhesive composition precursor and are contained in the
inorganic adhesive composition following curing. The additives may
comprise between about 0% and about 50% by weight of the inorganic
adhesive composition. For example, in some embodiments, the
additives may .[.comprise.]. .Iadd.be .Iaddend.less than or equal
to about 40% by weight of the inorganic adhesive composition, less
than or equal to about 30% by weight of the inorganic adhesive
composition, less than or equal to about 20% by weight of the
inorganic adhesive composition, less than or equal to about 10% by
weight of the inorganic adhesive composition, or less than or equal
to about 50% by weight of the inorganic adhesive composition.
In one embodiment, the inorganic adhesive composition may comprise
an adhesion promoter. In one embodiment, the adhesion promoter may
be incorporated into the inorganic adhesive composition precursor.
In another embodiment, the fiber or ferrule, or both, may be coated
with the adhesion promoter prior to the deposition of the inorganic
adhesive composition precursor onto the optical fiber or into a
fiber-receiving passage defining an inner surface of the ferrule.
The adhesion promoter may enhance the interfacial bonding of the
inorganic adhesive composition with the ferrule, fiber, or both.
The adhesion promoter may include, without limitation, titanates
(such as Tyzor 131 commercially available from DuPont), zirconates,
(such as Tyzor 217 commercially available from DuPont), silanes
(such as SIB 1824 and SIB 1821 commercially available from Gelest).
The inorganic adhesive composition may comprise an amount of
adhesion promoter of less than or equal to about 10% of the weight
of the adhesion promoter, less than or equal to about 8% of the
weight of the adhesion promoter, less than or equal to about 6% of
the weight of the adhesion promoter, less than or equal to about 4%
of the weight of the adhesion promoter, less than or equal to about
3% of the weight of the adhesion promoter, less than or equal to
about 2% of the weight of the adhesion promoter, or even less than
or equal to about 1% of the weight of the adhesion promoter.
It may be desirable, in some embodiments, to match the coefficient
of thermal expansion (CTE) of the inorganic adhesive composition
with the CTE of the ferrule and/or fiber. The inorganic adhesive
compositions disclosed herein may have an advantage over other
adhesives, such as polymer based adhesives, because the CTE of the
inorganic .[.adhesives.]. .Iadd.adhesive composition
.Iaddend.disclosed herein may be more similar to the ferrule and/or
the fiber. For example, an inorganic adhesive composition may have
a CTE more similar to a ceramic ferrule and/or the glass of the
fiber than an organic adhesive, such as a polymer.
In one embodiment, the inorganic adhesive composition may have a
CTE in a range of between about 80% and 125% of the CTE of the
ferrule over a temperature range from about -50.degree. C. to about
80.degree. C. In other embodiments, the inorganic adhesive
composition may have a CTE in a range of between about 50% and
200%, 70% and 150%, or 90% and 110% of the CTE of the ferrule over
a temperature range from about -50.degree. C. to about 80.degree.
C. A non-inorganic adhesive composition, such as one comprising a
polymer as a major constituent, may not have a CTE within these
ranges.
In another embodiment, the inorganic adhesive composition is
characterized by an adhesive CTE .alpha.1 that may vary by less
than about 10.times.10.sup.-6/K over a temperature range from about
-50.degree. C. to about 80.degree. C. and the ferrule is
characterized by .Iadd.a .Iaddend.ferrule CTE .alpha.2 that may
vary by less than about 10.times.10.sup.-6/K over a temperature
range from about -50.degree. C. to about 80.degree. C. In such an
embodiment, the inorganic adhesive composition may be configured
such that, over a temperature range from about -50.degree. C. to
about 80.degree. C.,
|.alpha.1-.alpha.2|.ltoreq.15.times.10.sup.-6/K. In other
embodiments, |.alpha.1-.alpha.2|.ltoreq.40.times.10.sup.-6/K,
30.times.10.sup.-6/K, 20.times.10.sup.-6/K, 12.times.10.sup.-6/K,
10.times.10.sup.-6/K, 8.times.10.sup.-6/K, or even
5.times.10.sup.-6/K. For example, glass may have a CTE of about
8.5.times.10.sup.-6/K, YSZ may have a CTE of between about
6.times.10.sup.-6/K and 12.times.10.sup.-6/K at 25.degree. C. and
zirconia may have a CTE of about 10.3.times.10.sup.-6/K at
25.degree. C. However, for example, epoxy resins may have a CTE of
about 55.times.10.sup.-6/K at 25.degree. C. As such, an epoxy, or
other substance with a CTE much higher or lower than .Iadd.the
.Iaddend.fiber or ferrule may lack superior adhesion properties as
compared with the inorganic adhesive compositions described herein.
However, it should be understood that CTE matching, as described
herein, is not a requirement of the connectors and adhesives.
Various embodiments will be further clarified by the following
examples.
Example 1
The precursor solution of zirconium oxychloride octahydrate (Mol.
Wt. 322.25 grams/mole) was prepared by dissolving the salt into DMF
at a concentration of 1.3 molar. Care was taken to ensure that the
salt .[.is.]. .Iadd.was .Iaddend.completely dissolved via rapid
continuous agitation and ultrasonic bath treatment. Specifically,
15.46 grams of zirconium oxychloride were dissolved into 23 ml of
dimethylformamide to yield a final solution of about 30 ml. The
precursor solution was clear, colorless and stable for several
months. The solution could be adjusted to include salts of yttria
and/or scandium chloride. A volume of about 10 microliters of the
precursor solution was applied to the YSZ ferrule while threaded
onto the receiving fiber. The ferrule was moved forward over the
liquid to distribute the liquid throughout the fiber and ferrule
interface. An 810 nm solid state IR laser was used as a heating
source which when focused onto the ferrule solidified the liquid
into solid inorganic interfacial bonding material between the
spacing of the ferrule and fiber.
Unless otherwise expressly stated, it is in no way intended that
any method set forth herein be construed as requiring that its
steps be performed in a specific order. Accordingly, where a method
claim does not actually recite an order to be followed by its steps
or it is not otherwise specifically stated in the claims or
descriptions that the steps are to be limited to a specific order,
it is no way intended that any particular order be inferred.
It will be apparent to those skilled in the art that various
modifications and variations can be made without departing from the
spirit or scope of the present disclosure. Since modifications
combinations, sub-combinations and variations of the disclosed
embodiments incorporating the spirit and substance of the
disclosure may occur to persons skilled in the art, the present
disclosure should be construed to include everything within the
scope of the appended claims and their equivalents.
It is noted that one or more of the following claims utilize the
term "wherein" as a transitional phrase. For the purposes of
defining the present technology, it is noted that this term is
introduced in the claims as an open-ended transitional phrase that
is used to introduce a recitation of a series of characteristics of
the structure and should be interpreted in like manner as the more
commonly used open-ended preamble term "comprising."
It should be understood that any two quantitative values assigned
to a property may constitute a range of that property, and all
combinations of ranges formed from all stated quantitative values
of a given property are contemplated herein.
It is noted that terms like "commonly" and "typically," when
utilized herein, are not utilized to limit the scope of the claims
or to imply that certain features are critical, essential, or even
important to the structure or function of the claims. Rather, these
terms are merely intended to identify particular aspects of an
embodiment of the present disclosure or to emphasize alternative or
additional features that may or may not be utilized in a particular
embodiment of the present disclosure.
Having described the subject matter of the present disclosure in
detail and by reference to specific embodiments thereof, it is
noted that the various details disclosed herein should not be taken
to imply that these details relate to elements that are essential
components of the various embodiments described herein, even in
cases where a particular element is illustrated in each of the
drawings that accompany the present description. Rather, the claims
appended hereto should be taken as the sole representation of the
breadth of the present disclosure and the corresponding scope of
the various embodiments described herein. Further, it will be
apparent that features and attributes associated with embodiments
may be combined in different manners to result in other embodiments
falling within the scope of the appended claims.
* * * * *
References