U.S. patent application number 12/901720 was filed with the patent office on 2011-04-21 for fiber optic connectors and structures for large core optical fibers and methods for making the same.
Invention is credited to Seldon David Benjamin, Radawan Hall, Micah Colen Isenhour, Michael de Jong, Dennis Michael Knecht, James Phillip Luther, Randy LaRue McClure.
Application Number | 20110091166 12/901720 |
Document ID | / |
Family ID | 43879358 |
Filed Date | 2011-04-21 |
United States Patent
Application |
20110091166 |
Kind Code |
A1 |
Benjamin; Seldon David ; et
al. |
April 21, 2011 |
Fiber Optic Connectors and Structures for Large Core Optical Fibers
and Methods for Making the Same
Abstract
Fiber optic connectors and other structures that can be easily
and quickly prepared by the craft for termination and/or
connectorization in the field are disclosed. More specifically, the
fiber optic connectors and other structures disclosed are intended
for use with glass optical fibers having a large core. In one
embodiment, the fiber optic connector includes a a body having a
portion with a retaining structure for securing an optical fiber
and a front portion having a passageway sized to receive an optical
fiber and a buffer layer through a front end. Methods of making the
fiber optic connectors and other structures are also disclosed. The
methods disclosed allow "rough cutting" of the optical fibers with
a buffer layer thereon by the craft.
Inventors: |
Benjamin; Seldon David;
(Painted Post, NY) ; Jong; Michael de;
(Colleyville, TX) ; Hall; Radawan; (Granite Falls,
NC) ; Isenhour; Micah Colen; (Lincolnton, NC)
; Knecht; Dennis Michael; (Hickory, NC) ; Luther;
James Phillip; (Hickory, NC) ; McClure; Randy
LaRue; (Corning, NY) |
Family ID: |
43879358 |
Appl. No.: |
12/901720 |
Filed: |
October 11, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61299105 |
Jan 28, 2010 |
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61251924 |
Oct 15, 2009 |
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61299091 |
Jan 28, 2010 |
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61251911 |
Oct 15, 2009 |
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Current U.S.
Class: |
385/81 ;
264/1.25; 385/135; 385/78 |
Current CPC
Class: |
G02B 6/02033 20130101;
G02B 6/382 20130101; G02B 6/3887 20130101; G02B 6/25 20130101; G02B
6/3849 20130101; G02B 6/3825 20130101; G02B 6/3858 20130101 |
Class at
Publication: |
385/81 ; 385/135;
385/78; 264/1.25 |
International
Class: |
G02B 6/36 20060101
G02B006/36; G02B 6/00 20060101 G02B006/00; G02B 6/26 20060101
G02B006/26 |
Claims
1. A fiber optic connector, comprising: a body of the fiber optic
connector having a portion with a retaining structure for securing
an optical fiber and a front portion having a passageway sized to
receive an optical fiber and a buffer layer through a front end,
wherein the fiber optic connector allows the optical fiber and the
buffer layer to extend to a mating front face of the fiber optic
connector.
2. The fiber optic connector of claim 1, further including an
optical fiber with a buffer layer, wherein the buffer layer is
secured by the retaining structure.
3. The fiber optic connector of claim 2, wherein optical fiber is a
silica-based optical fiber
4. The fiber optic connector of claim 2, wherein optical fiber is
not polished to a fine finish.
5. The fiber optic connector of claim 2, further including a boot,
wherein the boot applies a forward biasing force to the optical
fiber.
6. The fiber optic connector of claim 2, wherein optical fiber has
a core that is 80 microns or greater.
7. The fiber optic connector of claim 2, wherein the optical fiber
has a protective coating with a Young's modulus greater than 700
MPa and a thickness of 15 microns or less.
8. The fiber optic connector of claim 1, wherein the retaining
structure is formed by one or more cantilevered arms and a clamping
structure for biasing the one or more cantilevered arms toward each
other.
9. The fiber optic connector of claim 8, wherein the clamping
structure includes a boot, a crimp, or a cam, or a cantilever arm
structure with a threaded compression nut.
10. The fiber optic connector of claim 1, wherein the retaining
structure is reversible.
11. The fiber optic connector of claim 1, wherein the passageway
has a diameter of about 250 microns or greater.
12. The fiber optic connector of claim 1, further including a dust
cap that acts as a stop for insertion of the optical fiber.
13. The fiber optic connector of claim 1, further including a dust
cap having an index matching gel therein.
14. The fiber optic connector of claim 1, the inner housing further
including a grommet at the front end.
15. A method for making a fiber optic connector assembly,
comprising: providing a body having a portion with a retaining
structure and a passageway therethrough; providing an optical fiber
having a core and a protective layer; and inserting the optical
fiber into the passageway of the body so that the core and the
protective layer extend to a mating front face of the fiber optic
connector; and securing the optical fiber to the fiber optic
connector.
16. The method of claim 15, further including the step of securing
a boot to the inner housing.
17. The method of claim 15, the retaining structure including one
or more cantilevered arms.
18. The method of claim 15, wherein optical fiber is a silica-based
optical fiber and not polished.
19. The method of claim 15, wherein optical fiber has a core that
is 80 microns or greater.
20. The method of claim 15, the step of inserting further including
abutting the optical fiber to a dust cap that includes an index
matching gel.
21. The method of claim 15, the fiber optic connector further
including a latching mechanism.
22. The method according to claim 15, further comprising inserting
said cleaved or cut fiber in a connector without stripping said
buffer.
23. The method according to claim 22, wherein said method includes
at least one of the following: no polishing of fiber end surface,
no stripping of any coatings; no curing of adhesive(s).
24. The method according to claim 22, wherein said method includes
placing said cut or cleaved fiber into an optical connector;
placing anther fiber in said connector, wherein said cut or cleaved
fiber is optically coupled to said another fiber.
25. The method according to claim 22, including placing a quantity
of gel between said fibers.
26. The method according to claim 25, wherein said fibers are not
attached to one another by an adhesive.
27. A mechanical splice body, comprising: a tube having a having a
passageway between a first end and a second end, the passageway
sized for receiving a first optical fiber having a buffer layer
into the first end and a second optical fiber having a buffer layer
into the second end; and a first retaining structure; and a second
retaining structure.
28. A method for making a fiber optic connection, comprising:
providing a mechanical splice body having a first end, a second
end, and a bore therethrough; providing a first optical fiber
having a core and a protective layer; providing a second optical
fiber having a core and a protective layer; inserting the first
optical fiber into the bore from the first end so that the core and
the protective layer are disposed within the bore; and inserting
the second optical fiber into the bore from the second end so that
the core and the protective layer are disposed within the bore and
the second optical fiber abuts the first optical fiber, thereby
making an optical connection.
Description
BACKGROUND
[0001] This application claims the benefit of priority under 35 USC
119(e) of U.S. Provisional Application Ser. No. 61/299,105 filed on
Jan. 28, 2010 and U.S. Provisional Application Ser. No. 61/251,924
filed on Oct. 15, 2009 and U.S. Provisional Application Ser. No.
61/299,091 filed on Jan. 28, 2010 and U.S. Provisional Application
Ser. No. 61,251,911 filed on Oct. 15, 2009.
FIELD
[0002] The disclosure is directed to fiber optic connectors along
with other structures and methods for making the same. More
specifically, the disclosure is directed to fiber optic connectors
and other structures for large core optical fibers and methods for
making the same.
TECHNICAL BACKGROUND
[0003] Optical fiber is increasingly being used for a variety of
applications, including but not limited to broadband voice, video,
and data transmission. Optical fibers may be formed from different
types of materials such as plastic or glass depending on the
application. Typically, plastic optical fibers (POF) have been used
in short distance optical networks since they are relatively easy
to terminate by untrained personnel. However, POF has limitations
such as not being suitable for longer distance optical networks
because the losses using POF increase dramatically with the
transmission distance. On the other hand, glass optical fiber has
extremely wide bandwidth and low noise operation with relatively
low-losses over long distances. However, terminating or
connectorizing conventional glass optical fibers is more
complicated than terminating POF because it usually requires
special cleaving tools and/or stripping tools for preparing the
optical fibers. Moreover, conventional terminations or splicing of
glass optical fibers may require a skilled technician and/or
specialized equipment. For instance, fiber optic connectors for
conventional glass optical fibers typically have a fine polish on
the end face of the ferrule holding the glass optical fiber that is
best accomplished in a factory setting with dedicated equipment.
Field-terminated optical fiber connectors having a mechanical
splice are available to the craft but are not typically used for
short distance optical networks even though they are suitable for
these applications.
[0004] Thus, there is an unresolved a need for a fiber optic
connectors and other structures for use with glass optical fibers
that are simple, cost-effective, reliable, easy to assemble, and
which offers easy connection and disconnection for short distance
optical fiber networks.
SUMMARY
[0005] Embodiments of the disclosure are directed to fiber optic
connectors and other structures that can be easily and quickly
prepared by the craft for termination and/or connectorization in
the field. More specifically, the fiber optic connectors and other
structures disclosed are intended for use with glass optical fibers
having a large core. Methods of making the fiber optic connectors
and other structures are also disclosed. The methods disclosed
allow "rough cutting" of the optical fibers with a buffer layer
thereon.
[0006] 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 that description or
recognized by practicing the same as described herein, including
the detailed description that follows, the claims, as well as the
appended drawings.
[0007] It is to be understood that both the foregoing general
description and the following detailed description present
embodiments that are intended to provide an overview or framework
for understanding the nature and character of the claims. The
accompanying drawings are included to provide a further
understanding of the disclosure, and are incorporated into and
constitute a part of this specification. The drawings illustrate
various embodiments and together with the description serve to
explain the principles and operation.
BRIEF DESCRIPTION OF THE FIGURES
[0008] FIG. 1 is an end view of a large core optical fiber having a
buffer layer after being "rough cut" for use in the fiber optic
connectors disclosed herein;
[0009] FIG. 2 is a contour representation of a "rough cut" optical
fiber;
[0010] FIGS. 3A and 3B depicts a comparison between an optical
fiber "rough cut" with a buffer layer disposed at the cut portion
and an optical fiber "rough cut" without a buffer layer disposed at
the cut portion;
[0011] FIGS. 4-6 depict various views of a fiber optic connector
having the optical fiber of FIG. 1 where the ferrule of the
connector has a bore sized to receive the optical fiber and the
buffer layer at a front end face of the ferrule;
[0012] FIG. 7 depicts a fiber optic connector having a dust cap
attached to the same that acts as a stop for optical fiber
insertion;
[0013] FIGS. 8-10 depict another fiber optic connector that does
not require a ferrule for holding and centering the optical fiber
having the buffer layer;
[0014] FIG. 11 schematically depicts the fiber optic connector of
FIGS. 8-10;
[0015] FIG. 12 schematically depicts the fiber optic connector of
FIG. 11 being mated to another similar fiber optic connector using
a simple adaptor.
[0016] FIG. 13 depicts a partially exploded view of another fiber
optic connector;
[0017] FIGS. 14-17 depict explanatory steps for assembling the
components of the fiber optic connector of FIG. 13;
[0018] FIGS. 18-22A depict explanatory steps for attaching the
"rough cut" optical fiber having the buffer layer to the fiber
optic connector of FIG. 13;
[0019] FIG. 22B depicts another embodiment of the fiber optic
connector;
[0020] FIGS. 22C and 22D depicts the fiber optic connector of FIG.
22B;
[0021] FIG. 23 depicts various views of yet another fiber optic
connector;
[0022] FIG. 24 depicts an explanatory mechanical splice body;
and
[0023] FIG. 25 graphically depicts the loss for glass optical
fibers having large cores compared with conventional plastic
optical fibers.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Reference will now be made in detail to the preferred
embodiments of the disclosure, examples of which are illustrated in
the accompanying drawings. Whenever possible, like reference
numbers will be used to refer to like components or parts.
[0025] The embodiments and methods described herein are suitable
for making optical connections for short distance optical networks.
The concepts of the disclosure advantageously allow the simple,
quick, and economical connection and disconnection of glass optical
fibers. Reference will now be made in detail to the preferred
embodiments, examples of which are illustrated in the accompanying
drawings. Whenever possible, like reference numbers will be used to
refer to like components or parts.
[0026] FIG. 1 is an end view of an optical fiber 10 having a buffer
layer 18 forming an optical fiber/buffer layer assembly 20 after
being "rough cut" for use in the fiber optic connectors or other
structures disclosed herein. Optical fiber 10 has a large glass
core with a thin cladding layer such as a plastic cladding layer,
which is then protected with a protective coating as described in
more detail herein. Stated another way, optical fiber 10 is a
glass-based optical fiber such as a silica-based optical fiber. As
used herein, "a large glass core" means the optical fiber has a
core with a diameter of 80 microns or greater. Using optical fibers
with large glass core aids in the alignment of the abutting optical
fiber cores. In this embodiment, optical fiber 10 has a core with a
diameter of about 200 microns and cladding that is about 15
microns. The protective coating of optical fiber 10 generally
covers the cladding and is also relatively thin such as about 10
microns. A polyvinylchloride (PVC) buffer layer 18 upcoats optical
fiber 10 to 1.5 millimeters, but other suitable materials and/or
dimension are possible for the buffer layer. Moreover, optical
fiber 10 preferably has a concentricity error with buffer layer 18
that is 20 microns or less. The construction of optical fiber 10
with buffer layer 18 is advantageous for short distance optical
fiber networks or other applications due to the simplicity in
preparing the same for connectorization. By way of example, special
cleaving tools and/or stripping tools are not required for
preparing optical fiber 10. Instead, optical fiber 10 and buffer
layer 18 can be "rough cut" in a single step using a common razor
blade. By way of example, the protective coating inhibits the core
of optical fiber 10 from being pushed off center during the cutting
process with a simple tool such as a utility blade. Simply stated,
the construction of the coating helps maintain the concentricity of
optical fiber 10 with respect to buffer layer 18, thereby allowing
a low-loss optical connection. Thus, preferably, the buffer layer
remains on fiber during and after cutting, and does not need to be
stripped.
[0027] FIG. 2 shows a contour representation of "rough cut" optical
fiber 10 using a Keyence microscope with surface profile capacity.
Optical fiber 10 was cleaved using a common utility blade as
opposed to a precision cleaver as would be used when terminating an
optical fiber used in typical telecommunication optical network.
The surface of optical fiber 10 is multifaceted as shown; however,
it is not shattered. The construction of optical fiber 10 with
buffer layer 18 allows "rough cutting." By way of example, FIG. 3
depicts a comparison between optical fiber 10 "rough cut" with
buffer 18 thereon (picture A) and the optical fiber "rough cut"
after the buffer layer was removed (picture B). Both optical fibers
were "rough cut" with respective brand new utility blades. Buffer
layer 18 has been removed from optical fiber 10 in picture A so the
condition of optical fiber 10 thereunder can be viewed for
comparison purposes with picture B. Specifically, picture A shows
that optical fiber 10 is in relatively pristine condition compared
with the optical fiber in picture B after "rough cutting". In other
words, the optical fiber in picture B has more damage than the
optical fiber 10 cut with the buffer layer 18 as shown in picture
A. Fiber optic connectors and other structures disclosed herein use
the rough cut optical fibers with the buffer layer 18 intact at the
front end face of the optical fiber.
[0028] Simply stated, special tools and procedures are not required
for connectorizing and/or splicing the rough cut optical fibers.
Furthermore, the structures disclosed herein are also advantageous
since they allow the use of high-quality glass optical fiber
without requiring polishing to a fine finish as typically done for
glass optical fibers having small optical fiber cores; however, the
"rough cut" end face the optical fiber/buffer layer may be smoothed
if desired. Consequently, an untrained person can quickly and
easily make connections of suitable quality for optical networks
while advantageously using glass optical fibers, instead, of using
plastic optical fibers.
[0029] FIGS. 4-6 depict various views of a fiber optic connector
100. FIG. 4 shows a partially assembled view of fiber optic
connector 100 and FIG. 5 shows an assembled fiber optic connector
100. Fiber optic connector 100 includes a ferrule 30 having a bore
(not numbered) sized to receive the optical fiber 10 and buffer
layer 18 at a front end face 32 of the ferrule 30 as best shown in
FIG. 6. In other words, ferrule 30 has a bore that extends from a
rear of the ferrule to a front (i.e., the front end face) of the
ferrule 30 where the bore is sized to receive the rough cut optical
fiber 10 with the buffer layer 18 at the front end face 32 of the
ferrule 30. The bore of ferrule 30 has a diameter of 250 microns or
greater at the front end face 32, but ferrules can have any
suitable sized bore that is matched to the outer diameter of the
buffer layer surrounding the optical fiber. Illustratively, the
bore of ferrule 30 has a diameter slightly larger than 1.5
millimeters for receiving optical fiber 10 and buffer layer 18
having the outer diameter of 1.5 millimeters at the front end face
32 for abutting with another optical fiber. By way of example,
other suitable bore sizes at the front end face 32 are 900 microns,
700 microns, 500 microns, but other sizes matched to the outer
diameter of the buffer layer are possible.
[0030] Fiber optic connector 100 may include other suitable
components. Illustratively, FIG. 6 depicts an end view of fiber
optic connector 100 showing an outer housing 90 for aligning and/or
latching the same and an inner housing 80 that cooperates with the
outer housing 90. Further, fiber optic connectors may include one
or more retaining structures for securing the optical fiber to the
fiber optic connector. Preferably the retaining structure does not
require the use of adhesives. In this embodiment, the optical
fiber/buffer layer is secured with a crimp structure on the buffer
layer 18, but other retaining structures are possible. Examples of
other suitable retaining structures include a camming feature or
other suitable structure for securing the optical fiber to the
fiber optic connector. In still further embodiments, the retaining
structure may be reversible, that is, the retention may be undone
in case the optical fiber requires repositioning. For instance, the
cam feature may be reversed to unclamp the optical fiber for
repositioning the same within the fiber optic connector.
[0031] Of course, fiber optic connectors can have other components
and/or features. FIG. 7 depicts a fiber optic connector having a
dust cap 95 attached to the same. Dust cap 95 may act as a stop for
optical fiber insertion. In other words, during assembly dust cap
95 remains attached to ferrule 30 and the optical fiber/buffer
layer is inserted until it abuts the dust cap 95 indicating that it
inserted to the correct position. In further embodiments, dust cap
95 may be preloaded with an index-matching gel within the same so
that when the optical fiber 10 abuts the same index-matching gel is
applied to an end face of the optical fiber. Other suitable
components include boots, springs, etc. Likewise, the concepts
disclosed may be used with fiber optic connectors having any
suitable configuration such as SC, FC, ST, LC or the like and the
concepts may be used with multifiber connectors also.
[0032] FIGS. 8-10 depict a fiber optic connector 200 suitable for
connectorizing a large core optical fiber with a rough cut as
discussed above, except fiber optic connector 200 does not require
a ferrule for holding and centering the optical fiber/buffer layer.
Instead, a body of fiber optic connector 200 has a portion with a
retaining structure for securing an optical fiber and a front
portion having a passageway sized to receive the optical fiber and
buffer layer through a front end of the body. Thus, fiber optic
connector 200 allows the optical fiber/buffer layer to extend to a
mating front face of fiber optic connector 200. Specifically, FIG.
8 depicts an assembled fiber optic connector 200 before the optical
fiber/buffer layer assembly 20 is attached and FIG. 9 depicts the
optical fiber/buffer layer attached to fiber optic connector 200.
FIG. 10 shows a completely assembled fiber optic connector 200 with
a boot installed. Additionally, fiber optic connector 200 can
include other suitable components and/or such as a dust cap,
index-matching gel, one or more housings, springs, etc.
[0033] For instance, fiber optic connector 200 includes a dust cap
295 attached to the same. Dust cap 295 may act as a stop for
optical fiber/buffer layer assembly 20 insertion as discussed.
Further, dust cap 295 may be preloaded with an index-matching gel
so that when the optical fiber 10 abuts the same index-matching gel
is applied to an end face of the same. As shown, dust cap 295 is
secured to fiber optic connector 200 using a cantilever latch 298.
Consequently, when inserting the optical fiber/buffer layer
assembly 20 to the proper location abutting the dust cap 295, the
dust cap 295 is inhibited from being unintentionally displaced.
[0034] FIG. 11 schematically depicts fiber optic connector 200
having a body 250 with a retaining structure 260 for securing the
optical fiber/buffer layer assembly 20. More specifically, body 250
has a front portion (not numbered) having a passageway sized for
receiving the optical fiber/buffer layer assembly 20 through a
front end of body 250 as shown. Like fiber optic connector 100, the
passageway of fiber optic connector 200 has a diameter of about 250
microns or greater. Retaining structure 260 of body 250 includes
one or more cantilevered arms as shown. The retaining structure 260
is biased together onto the optical fiber/buffer layer assembly 20
using a suitable clamping structure such as a crimp, cam, threaded
collar, boot, or the like. As shown in FIG. 11, boot 290 acts as
the clamping structure for biasing the one or more cantilevered
arms toward each other. Further, boot 290 may apply a forward
biasing force to the optical fiber/buffer layer assembly 20 to
maintain its position in the fiber optic connector. In other
embodiments, a crimp band or the like could be placed either over
or under the boot to increase the clamping force. In embodiments
using a cam or threaded collar as the clamping structure, the
retaining structure may be reversible to release the retaining
structure from the optical fiber/buffer layer assembly 20 by
reversing the cam or unscrewing the threaded collar.
[0035] FIG. 12 schematically depicts the fiber optic connector 200
of FIG. 11 being mated to another similar fiber optic connector 200
using an adaptor. One exemplary adaptor 220 is shown schematically
as a simple tube that is sized for receiving optical fiber/buffer
layer assembly 20 within respective ends, but the adaptor can have
structure such as a housing and the like as known for mating and
securing fiber optic connector with a suitable footprint such as a
LC connectors. The adaptor 220 may contain index matching gel that
becomes applied to end of fiber upon insertion of fiber into
adaptor. (I.e., the gel has substantially the same index of
refraction as the fiber's waveguiding portion) For example, greater
than 1.0, preferably between 1.3 and 1.6 and more preferably
between 1.4 and 1.5. An example of a common index-matching material
is a low-viscosity index polymer with a molecular weight typically
less than 30,000 Daltons to which is added a small amount of
gelling agent, such as fumed silica or metal soap to make the gel
phixotropic. Such materials are popular because they are
inexpensive and do not require significant technical expertise to
manufacture. Preferably the fibers are not attached to one another
by an adhesive.
[0036] FIG. 13 depicts a partially exploded view of an explanatory
SC fiber optic connector 300 using the disclosed concepts. As
shown, fiber optic connector 300 includes a ferrule 330, a ferrule
holder 332, a crimp body 360, a spring 370, a spring push 375, an
inner housing 380, and an outer housing 390. Ferrule 330 has a bore
sized to receive optical fiber/buffer layer assembly 20 at its
front end face. Likewise the ferrule holder 332 has a bore sized to
receive crimp body 360 therethrough. In this embodiment, crimp body
360 has a bore sized to receive optical fiber/buffer layer assembly
20 such as about 1.5 millimeters, but the bore may have other
suitable sizes for receiving the same. The assembly of these
components of fiber optic connector 300 is illustrated in FIGS.
14-17. More specifically, FIG. 14 shows ferrule 330 attached to
ferrule holder 332 with crimp body 360 retained within the ferrule
holder 332 and the spring 345 slid over the sub-assembly. Next, the
sub-assembly of FIG. 14 is inserted into inner housing 380 as shown
in FIG. 15 and then spring push 375 is slid over crimp body 360 to
engage the rear portion of inner housing 380 until it is fully
seated as shown in FIG. 16. Thereafter, outer housing 390 is
attached over a portion of the inner housing 380 as shown in FIG.
17 and a dust cap with or without an index-matching gel may be
secured to ferrule 330 if desired. The fiber optic connector
assembly is ready for attaching the optical fiber/buffer layer
assembly thereto.
[0037] FIGS. 18-22A depict explanatory steps for attaching a "rough
cut" optical fiber/buffer layer assembly 20 to the sub-assembly of
FIG. 17. FIG. 18 is a schematic representation of optical
fiber/buffer layer assembly 20 being "rough cut" with a utility
blade. "Rough cutting" of the optical fiber/buffer layer assembly
20 may be accomplished by merely pushing a blade 7 down and through
the assembly in a suitable fashion and does not require any special
tools. Thereafter, the "rough cut" optical fiber/buffer layer
assembly 20 is inserted into the assembled fiber optic connector
300. As shown, in FIG. 19, the optical fiber/buffer layer assembly
20 is inserted until it abuts a dust cap 395. In this embodiment,
dust cap 395 has a reservoir that includes an index-matching gel
(not visible) therein, thereby applying the index-matching gel to
the end face of the optical fiber/buffer layer assembly 20.
Thereafter, the optical fiber/buffer layer assembly 20 is secured
to the fiber optic connector.
[0038] FIGS. 20 and 21 depict optical fiber/buffer layer assembly
20 being secured to fiber optic connector 300 using a crimp tool
399. FIG. 20 shows fiber optic connector 300 with optical
fiber/buffer layer assembly 20 inserted therein is placed into the
jaw of crimp tool 399. Thereafter, crimp tool 399 is actuated to
deform crimp body 360 about the buffer layer 18, thereby securing
optical fiber/buffer layer assembly 20 to fiber optic connector
300. Then the fiber optic connector 300 is removed from crimp tool
399 and a boot 392 that was previously threaded onto optical
fiber/buffer layer assembly 20 may be slid onto the rear portion of
fiber optic connector 300, thereby forming the assembly shown in
FIG. 22A. Although this embodiment uses a crimp tool 399 for
securing optical fiber/buffer layer assembly 20 to fiber optic
connector 300 other embodiments with different retention structures
may not require a crimp tool for securing the same. For instance,
the retention structure could use a threaded compression nut for
biasing one or more cantilever arm together to clamp the optical
fiber/buffer layer assembly 20. Other embodiments may use a cam
structure that secures the optical fiber/buffer layer assembly 20
by rotating the cam.
[0039] One embodiment of the fiber optics connector retention
structure that utilises a threaded compression nut for biasing one
or more cantilever arm together to clamp the optical fiber/buffer
layer assembly 20 is shown, for example in FIGS. 22B-D. More
specifically, FIG. 22C illustrates the assembled connector FIG. 22B
depicts a partially exploded view of an explanatory SC fiber optic
connector 400. As shown, fiber optic connector 400 includes a
ferrule 430, a combined ferrule holder and cantilever arm structure
460', a threaded compression nut 478, a spring 470, a spring push
475, an inner housing 480, and an outer housing 490. Ferrule 430
has a bore sized to receive optical fiber/buffer layer assembly 20
at its front end face. In this embodiment, cantilever arm structure
460' has at least one bore 460'A sized to receive optical
fiber/buffer layer assembly 20 such as about 1.5 millimeters, but
the bore may have other suitable sizes for receiving the same. The
assembly of these components of fiber optic connector 400 is
illustrated in FIG. 22D. Ferrule 430 is attached to cantilever arm
structure 460' and the spring 445 slid over the sub-assembly. Next,
the sub-assembly is inserted into inner housing 480 and then spring
push 475 is slid over crimp body 460 to engage the rear portion of
inner housing 480 until it is fully seated. Thereafter, outer
housing 490 is attached over a portion of the inner housing 480 and
a dust cap with or without an index-matching gel may be secured to
ferrule 430 if desired. a threaded compression nut 478 may also be
installed on, cantilever arm structure 460'. The fiber optic
connector assembly is ready for attaching the optical fiber/buffer
layer assembly 20 thereto. FIGS. 22C-D depict exemplary steps for
attaching a "rough cut" optical fiber/buffer layer assembly 20 to
fiber optic connector 400. FIG. 18 is a schematic representation of
optical fiber/buffer layer assembly 20 being "rough cut" with a
utility blade. "Rough cutting" of the optical fiber/buffer layer
assembly 20 may be accomplished by merely pushing a blade 7 down
and through the assembly in a suitable fashion and does not require
any special tools. Thereafter, the "rough cut" optical fiber/buffer
layer assembly 20 is inserted into the assembled fiber optic
connector 400. As shown, in FIG. 19, the optical fiber/buffer layer
assembly 20 is inserted until it abuts a dust cap 395. In this
embodiment, dust cap 395 has a reservoir that includes an
index-matching gel (not visible) therein, thereby applying the
index-matching gel to the end face of the optical fiber/buffer
layer assembly 20. Thereafter, the optical fiber/buffer layer
assembly 20 is secured to the fiber optic connector by tightening
the threaded compression nut which compresses the cantilever arm
structure onto the fiber optic cable 20 to secure fiber optic cable
20.
[0040] The methods for making a fiber optic connector assembly may
include the steps of providing a ferrule having a bore therethrough
and a front end face and providing an optical fiber having a core
and a protective layer. "Rough cutting" the optical fiber/buffer
layer assembly, if necessary, and then inserting the optical fiber
into the bore of the ferrule so that the core and the protective
layer extend to the front end face of the ferrule. The method of
making the fiber optic assembly may further include the step of
abutting the optical fiber to a dust cap that includes an
index-matching gel. Likewise, the method may include the step of
securing the optical fiber to the connector, securing a boot to the
connector, and/or the other steps described herein such as
assembling the fiber optic connector. As described herein,
preferably, the fiber includes a buffer layer and is cleaved or cut
while retaining the buffer layer, and the cleaved or cut fiber is
inserted in a connector without stripping the buffer layer.
Preferably, the method includes at least one of the following: no
polishing of fiber end surface, no stripping of any coatings; no
use and/or no curing of adhesive(s). Preferably the cut or cleaved
fiber is placed into an optical connector and anther fiber in also
placed in the connector, such that the cut or cleaved fiber is
optically coupled to the other fiber. Preferably, a quantity (less
than 0.5 ml, preferably less than 0.1 ml) of oil or index matching
gel described above is placed between the two fibers. Thus, the
fibers are not attached to one another by an adhesive. Therefore,
the method of making the fiber optic assembly preferably includes:
no polishing of fiber end surface, no stripping of any coatings;
and no curing of adhesive(s).
[0041] Alternative, methods for making a fiber optic connector
assembly may includes the steps of providing a body having a
portion with a retaining structure and a passageway therethrough
such as schematically depicted in FIG. 11; providing an optical
fiber having a core and a protective layer; "rough cutting" the
optical fiber/buffer layer assembly, if necessary; and inserting
the optical fiber into the passageway of the body so that the core
and the protective layer extend to a mating front face of the fiber
optic connector. The method of making the fiber optic assembly may
further include the steps of abutting the optical fiber to a dust
cap that includes an index matching gel, securing the optical fiber
to the connector, securing a boot to the connector, and/or the
other steps described herein such as assembling the fiber optic
connector.
[0042] FIG. 23 depicts various views of still another fiber optic
connector 500. Fiber optic connector 500 includes a housing 580
that including a grommet insert 502 at the front end for centering
the optical fiber/buffer layer assembly 20 therein. Fiber optic
connector 500 is advantageous since it can accommodate different
sized optical fiber/buffer layer assemblies simply by using a
different sized grommet insert 502 within housing 580. By way of
example, a first grommet insert 502 can have a bore sized for a 1.5
millimeter OD and a second grommet insert 502 may have a bore sized
for a 900 micron OD, thereby allowing the use of different sized
optical fiber/buffer layer assemblies 20 with fiber optic connector
500. Additionally, fiber optic connector 500 includes a boot 592
that applies a forward biasing force to the optical fiber/buffer
layer assembly 20. Stated another way, boot 592 allows insertion of
the optical fiber/buffer layer assemblies with 20 into the boot 592
toward the ferrule, but inhibits withdrawal of the same from the
boot 592. Boot 592 may include any suitable structure such as
flexible internal fingers that provide the forward biasing
force/movement in a forward direction and inhibit rearward
displacement. Additionally, other fiber optic connectors disclosed
herein can use a similar boot that applies a forward biasing force.
As shown, optical fiber/buffer layer assembly 20 extends beyond the
front end face of optical fiber connector 500 for mating with a
like optical fiber.
[0043] FIG. 24 depicts an explanatory mechanical splice body 600
that includes a tube (not numbered) having a having a passageway
(not numbered) between a first end 602 and a second end 604. The
passageway is sized for receiving a first optical fiber/buffer
layer assembly 20 into the first end 602 and a second optical
fiber/buffer layer assembly 20 into the second end 604. The
mechanical splice body 600 also includes a first retaining
structure 601 for securing the first optical fiber/buffer layer
assembly 20 and a second retaining structure 603 for securing the
second optical fiber/buffer layer assembly 20. The retaining
structures of mechanical splice body 600 may have any suitable
structure such as crimp feature or a camming feature for securing
the optical fiber/buffer layer assembly. Additionally, the
retaining structure may be reversible, thereby allowing
repositioning of the optical fiber/buffer layer assembly.
[0044] FIG. 25 graphically depicts the losses vs. distance for the
glass optical fiber 10 with a large core compared with a
conventional plastic optical fiber (POF). As shown, the y-intercept
represents the initial coupling loss for the different optical
waveguides and the slope of the curves represent the increased loss
based on transmission distances (i.e., as distance increases the
optical loss increases). As shown, plastic optical fiber (POF) is
represented by curve 700 and optical fiber 10 is represented by
curve 704. As shown, curve 704 has a coupling loss in a similar
range as the coupling loss of the POF represented by curve 700
(i.e., similar y-intercepts); however, the total loss is
dramatically larger for the POF compared with optical fiber 10.
Consequently, optical fiber 10 yields a much improved optical
performance compared with POF for all but the shortest distance
links.
[0045] One embodiment of optical fiber 10 includes: (i) a
multi-mode silica based glass core having a diameter between 80-300
.mu.m and an index of refraction n1; (ii) a cladding surrounding
the core having a thickness .ltoreq.20 .mu.m and index of
refraction n2<n1 with a delta index of refraction between the
core and cladding being defined as n1-n2. The cladding includes (a)
fluorine doped silica with a relative index of refraction
delta<0; or (b) a polymer with relative index of refraction
delta<0; (iii) a protective coating having a Young's modulus
greater than 700 MPa, a thickness .ltoreq.15 .mu.m, and an index of
refraction index of refraction n3>n2. Further, optical fiber 10
includes a buffer layer 18 as discussed herein.
[0046] A more specific variation of optical fiber 10 may include a
glass core with a graded index with a 175 .mu.m to 225 .mu.m
diameter where the cladding is a fluorinated polymer and has a
thickness between 10 .mu.m to 15 .mu.m, and the protective coating
having the a thickness of .ltoreq.10 .mu.m. Additionally, the
buffer layer 18 may have a shore D hardness of at least 60.
[0047] One advantage of the disclosed optical fibers is that the
protective coating minimizes the fiber movement inside the buffer
layer during "rough cutting" and also during subsequent use in the
fiber optic connector, due to strong adhesion of the protective
coating to both the cladding and the buffer layer. Yet another
advantage the optical fibers disclosed is that the protective
coating prevents the optical fiber core from moving off-center
during "rough cutting", thus minimizing coupling losses when this
fiber is coupled to another optical fiber. Yet another advantage of
the optical fibers disclosed is that the protective coating also
provides protection during handling and storage if the buffer layer
is not applied at the same time as the protective coating.
[0048] Although the disclosure has been illustrated and described
herein with reference to preferred embodiments and specific
examples thereof, it will be readily apparent to those of ordinary
skill in the art that other embodiments and examples can perform
similar functions and/or achieve like results. All such equivalent
embodiments and examples are within the spirit and scope of the
disclosure and are intended to be covered by the appended claims.
It will also be apparent to those skilled in the art that various
modifications and variations can be made to the present invention
without departing from the spirit and scope of the same. Thus, it
is intended that the present invention cover the modifications and
variations of this invention provided they come within the scope of
the appended claims and their equivalents.
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