U.S. patent application number 11/829185 was filed with the patent office on 2009-01-29 for optical connector assembly.
This patent application is currently assigned to PHASOPTX. Invention is credited to Laurent Buffard, Eric Weynant.
Application Number | 20090028508 11/829185 |
Document ID | / |
Family ID | 40295439 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090028508 |
Kind Code |
A1 |
Weynant; Eric ; et
al. |
January 29, 2009 |
OPTICAL CONNECTOR ASSEMBLY
Abstract
The present solution relates to a system and method of an
optical connector assembly for interconnecting two optical fibers.
The optical connector assembly has a splice with a fiber conduit
for holding bare ends of the two optical fibers together.
Additionally, the optical connector has two corresponding ferrules.
The two corresponding ferrules are for securing optical fibers and
for aligning the bare end of an optical fiber into the splice
without catching an edge. The method includes compressing along the
longitudinal axis a first ferrule against the splice to force a
guiding member of the first ferrule into a first aperture of the
splice, thus opening a conduit of the splice at the first aperture.
Once the optic fiber is inserted, the method includes releasing the
compression along the longitudinal axis of the first ferrule
against the splice to allow the splice to apply radial retention
forces on fibers. A sheath to form a connector body of the optical
connector assembly interconnects the ferrules.
Inventors: |
Weynant; Eric; (Outremont,
CA) ; Buffard; Laurent; (Lyon, FR) |
Correspondence
Address: |
EDELL, SHAPIRO & FINNAN, LLC
1901 RESEARCH BOULEVARD, SUITE 400
ROCKVILLE
MD
20850
US
|
Assignee: |
PHASOPTX
Montreal
QC
|
Family ID: |
40295439 |
Appl. No.: |
11/829185 |
Filed: |
July 27, 2007 |
Current U.S.
Class: |
385/98 |
Current CPC
Class: |
G02B 6/3801 20130101;
G02B 6/3806 20130101 |
Class at
Publication: |
385/98 |
International
Class: |
G02B 6/255 20060101
G02B006/255 |
Claims
1. An optical connector assembly for interconnecting two optical
fibers and having a splice for holding bare ends of said fibers
together while optically coupled, and two corresponding ferrules
for securing said fibers to lead into said splice, said ferrules
being interconnected by a sheath to form a connector body, wherein:
said splice comprises a first fiber conduit with a first extremity
for receiving a first one of said fiber ends and a second extremity
for receiving a second one of said fiber ends, where said first
fiber conduit holds and confines said fiber ends to be in end to
end alignment in said first fiber conduit, where said first
extremity comprises at least one aperture; and a first one of said
ferrules comprising at least one fiber guiding member adapted to
fit within said at least one aperture of said first extremity of
said first fiber conduit for aligning said first and second fiber
conduits and for guiding said first fiber end into said first fiber
conduit without catching an edge, wherein said at least one fiber
guiding member comprises a projection, and said at least one
aperture comprises an enlargement of said first fiber conduit.
2. (canceled)
3. The optical connector assembly as claimed in claim 1, wherein
said projection and said aperture cooperate to exert a separation
force on said first extremity, said splice comprising a slot to
allow for expansion of said first fiber conduit at said first
extremity through axial displacement between said projection and
said aperture.
4. The optical connector assembly as claimed in claim 1, wherein
said projection is an annular projection.
5. The optical connector assembly as claimed in claim 3, further
comprises at least one spacer between said splice and said opposing
ferrule for preventing said axial displacement.
6. The optical connector assembly as claimed in claim 5, wherein
said spacer is supported by said splice.
7. The optical connector assembly as claimed in claim 5, wherein
said spacer is supported by said sheath.
8. The optical connector assembly as claimed in claim 6, wherein
said spacer is a collar with extending fingers with spacing ends
that is slipped along the splice and clipped between said ferrule
and said splice.
9. The optical connector assembly as claimed in claim 7, wherein
said spacer is a pin that is slipped through from an outer side
along a radial of said sheath and lodged between said ferrule and
splice.
10. The optical connector assembly as claimed in claim 1, wherein
said ferrule is secured to said sheath with at least one
attachment.
11. The optical connector assembly as claimed in claim 10, wherein
said at least one attachment is an axial positioning nut that is
displaced along the ferrule against an outer side of said
sheath.
12. The optical connector assembly as claimed in claim 1, wherein
said splice is made of shape memory alloy.
13. A method for assembling an optical connector comprising:
aligning a first aperture of a splice over corresponding projection
of a first ferrule; compressing along a longitudinal axis said
first ferrule against said splice to force projection of said first
ferrule into said first aperture of said splice, thus opening a
conduit of said splice at said first aperture; inserting an optic
fiber through a conduit of said first ferrule, through said first
aperture of said splice and into said conduit of said splice;
releasing compression along a longitudinal axis of said first
ferrule against said splice to allow said splice to apply radial
retention forces on said fiber; aligning a projection of a second
ferrule with corresponding second aperture of said splice;
compressing along a longitudinal axis said second ferrule against
said splice to force said projection of said second ferrule into
said second aperture of said splice, thus opening said conduit of
said splice at said second aperture; inserting an optic fiber
through a conduit of said second ferrule, through said second
aperture of said splice and into said conduit of said splice; and
releasing compression along a longitudinal axis of said second
ferrule against said splice to allow said splice to apply radial
retention forces on said fiber, wherein said releasing provides a
first gap between said splice and said first ferrule, a spacer is
placed between said first ferrule and said splice to maintain said
first gap when compressing said second ferrule against said
splice.
14. (canceled)
15. The method of claim 13 wherein said aligning is done once said
splice is placed in a sheath to which said first ferrule is
attached.
16. (canceled)
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of optical fiber
connectors and in particular, to reusable optical fiber
connectors.
BACKGROUND OF THE INVENTION
[0002] The current state of the art technology in the field of
optical fiber connectors does not make it easy for technicians
working in the field to install or repair optical connections.
There are generally two types of connectors, namely fusion
connectors and mechanical connectors.
[0003] In the case of fusion connectors, the two fiber ends to be
coupled are mounted in an instrument that allows for the precision
alignment of the two fibers adjacent to one another with their
respective cores in alignment. At this point, sufficient heat is
provided to melt and fuse the cores together. During the fusion
process, a number of problems can arise that will result in poor
optical connection between the fibers, such as misalignment between
the fiber cores as a result of the heating process or even a
failure of joining of the two cores during the heating process. The
failure rate of making a fiber connection using fusion in the field
is often greater than 50%.
[0004] In the case of mechanical connectors, it is common in many
types of connectors to place the fiber ends in a single "V" groove
on a substrate in end-to-end abutment and then to build a packaging
around the fibers with the use of optical gels and/or adhesives to
complete the connection. When the fibers are not of the same
diameter, the alignment of fibers in a groove in a substrate is not
good. With conventional mechanical splicing technology, the chances
of assembling a successful connection in the field can be about 1
in 3.
[0005] A mechanical splice for optical fibers that provides an
easier way to connect fibers with greater rates of success than the
rate of success associated with the previous state of the art has
been developed by the Applicants of the present invention. In U.S.
patent application publication 2005/0220418 published on Oct. 6,
2005, based on PCT/CA03/00232 published as WO 2003/071328, there is
disclosed a mechanical splice made of shape memory alloy
construction having an axial passageway or conduit that is
expandable to receive an optical fiber end. The splice can then
exert a moderate radial pressure to retain the optical fiber
securely centered in the axial passageway and ensure an end-to-end
coupling between two optical fiber ends.
[0006] Such technology however requires special tooling for opening
and closing the axial passageway in order to controllably secure
and release the optical fiber ends to provide the desired optical
coupling. Examples of instruments adapted to allow the controlled
expansion and contraction of the axial passageway in the mechanical
splice is known from Applicant's own previous PCT publications, WO
2004/015473 published Feb. 19, 2004 and WO 2005/040876 published
May 6, 2005.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a system
and a method for an optical connector assembly using a mechanical
splice of the type having an axial conduit adapted to exert a
radial retention and alignment force on fiber optic ends in which a
special tool or device for controllably causing the axial conduit
to expand and contract is not required.
[0008] It is a further object of the present invention to provide a
system and a method for an optical connector assembly in which
precision alignment between the optical fiber and the axial
passageway of the mechanical splice is not required.
[0009] In accordance with some embodiments of the present
invention, there is provided an optical connector assembly for
interconnecting two optical fibers and having a splice for holding
bare ends of said fibers together while optically coupled, and two
corresponding ferrules for securing the fibers to lead into the
splice, the ferrules being interconnected by a sheath to form a
connector body. In these embodiments, the splice has a first fiber
conduit or axial passageway with a first extremity for receiving a
first one of the fiber ends and a second extremity for receiving a
second one of the fiber ends. The first fiber conduit holds and
confines the fiber ends to be in an end-to-end alignment in the
first fiber conduit, and the first extremity has at least one
aperture. At least one of the ferrules has one or more fiber
guiding members adapted to fit within the aperture of the first
extremity of the first fiber conduit for aligning the first and
second fiber conduits and for guiding the first fiber end into the
first fiber conduit without catching an edge.
[0010] In other embodiments, the optical connector assembly is
provided for interconnecting two optical fibers and has a splice
for holding bare ends of the fibers together while optically
coupled, and two corresponding ferrules for securing the fibers to
lead into the splice. The two ferrules are interconnected by a
sheath to form a connector body. In these embodiments, at least one
of the ferrules is adapted to engage the mechanical splice with
inter-engaging members that allow for mechanical expansion and
contraction of a first fiber conduit of the splice by adjusting the
position of the ferrule with respect to the splice by a suitable
mechanism such as an adjustment nut acting between the sheath.
[0011] In another embodiment, once a first fiber optic is placed in
the first fiber conduit of the splice, the first ferrule releases
exerted compression against the splice forming a first gap between
the first ferrule and the splice. To maintain the first gap a
spacer is placed between the first ferrule and the splice.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] These and other objects of the present invention will be
better understood by way of the following detailed description of a
preferred embodiment with reference to the appended drawings in
which:
[0013] FIG. 1 shows a perspective view of a mechanical splice
according to some embodiments of the invention having expansion
slots at opposite ends that are at right angles to one another;
[0014] FIG. 2 illustrates a sectional side view of an
inter-connection of the splice and the two ferrules in which one
ferrule is a cylindrical plug while the other ferrule is of the
type adapted to terminate an optical fiber cable;
[0015] FIG. 3 is a side sectional view of an optical connector
assembly having the components of FIG. 2 and including a sheath and
axial positioning nut fixing the two ferrules in contact with
splice to force all three parts in axial alignment;
[0016] FIG. 4a is a perspective view of a connector without its
sheath in which the ferrules mate with the splice using tabs and
slots;
[0017] FIG. 4b is a perspective view of the splice of the
embodiment of FIG. 4a;
[0018] FIG. 5a is a perspective view of a connector without its
sheath in which the ferrules mate with the splice using cross
shaped tabs and corresponding slots;
[0019] FIG. 5b is a perspective view of the splice of the
embodiment of FIG. 5a;
[0020] FIG. 5c is a perspective view of the ferrule of the
embodiment of FIG. 5a;
[0021] FIG. 6a is a perspective view of a connector without its
sheath in which the ferrules mate with the splice using protruding
center portions and corresponding channels;
[0022] FIG. 6b is a perspective view of the splice of the
embodiment of FIG. 6a;
[0023] FIG. 6c is a perspective view of the ferrule of the
embodiment of FIG. 6a;
[0024] FIG. 7a is a perspective view of a connector without its
sheath in which the ferrules mate with the splice using v-shaped
channels and corresponding v-shaped tabs;
[0025] FIG. 7b is a perspective view of the splice of the
embodiment of FIG. 7a and a perspective view of the ferrule of the
embodiment of FIG. 7a;
[0026] FIG. 8 is a perspective view of a spacer to secure the
splice in place and a side sectional view of an optical connector
assembly having the spacer slipped over the splice;
[0027] FIG. 9 is a side sectional view of an optical connector
assembly having the spacer moved into position to secure the splice
in place;
[0028] FIG. 10a is a perspective view of an optical connector with
a pin placed through the body of the sheath, in between the splice
and the ferrule;
[0029] FIG. 10b is a side sectional view of a portion of an optical
connector having a pin between the splice and the ferrule;
[0030] FIG. 11 is a side sectional view of an optical connector
assembly having a clamp with flange abutment to secure the ferrule;
and
[0031] FIG. 12 is a side sectional view of an adaptor connecting
two optical connectors.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0032] With reference to FIG. 1, a mechanical splice (20) has a
fiber conduit (22) that is an axial passageway. The splice (20) is
made of a shape memory material and has a generally cylindrical
construction. The splice (20) may however have other suitable
polygonal shapes that may have curved, linear or a combination of
curved and linear surfaces. Additionally, the shape of the splice
(20) may change along a length of the splice (20). Shape memory
materials provide high levels of elasticity, while at the same
time, provide the desired levels of rigidity suitable for optic
fiber coupling.
[0033] It will be appreciated by a person skilled in the art of
such materials that a shape memory material suitable for making
such a splice can be polymer based, an alloy of copper and aluminum
along with a wide variety of other shape memory materials. The
essential property for a suitable material to make a mechanical
splice that retains fiber ends in a fiber conduit in optical
alignment is the ability for the material to expand and contract.
With some shape memory materials, it will be appreciated that up to
8-10% deformation can be achieved. When deformations exceed
approximately 5%, as is the case for many shape memory alloys, it
is possible to use such materials to be controllably expanded and
contracted to allow for positioning and securing of fibers in axial
alignment in the fiber conduit. Applicants have found that the
holding force of such a mechanical splice on a fiber is better than
any adhesive and can allow for a fiber to be held and released
without damage. Thus, the mechanical splice, as illustrated in FIG.
1, allows for the optical connector assembly to be reusable.
[0034] The conical enlargements (26) of the splice (20) as shown in
FIG. 1 serve a dual purpose. On the one hand, they allow the splice
(20) to receive fiber-guiding members (27) that are cylindrical
collar extensions of the ferrules (30a) or (30b) for the purposes
of centering the splice (20) vis-a-vis the ferrules and thus
guiding the fibers being inserted into the splice (20) from the
respective ferrules (30).
[0035] The other purpose of the interaction between the conical
enlargement (26) and the guiding members (27) is that relative
axial displacement between the splice (20) and one of the ferrules
(30a) or (30b) will cause an outward radial expansion force to be
exerted on the splice (20). The splice (20) is provided with
suitable expansion slots (24) or (25), and the displacement action
causes the splice (20) to expand under the mechanical force
allowing for the fiber to be inserted into the conduit (22).
[0036] It will be appreciated that the interacting members between
the ferrule (30a, 30b) and the splice (20) can take different
shapes. As shown in FIGS. 4a and 4b, tabs (44) can fit into
corresponding channels (42). In this embodiment, the channels (42)
provided at the ends of the splice (20) are aligned with the
expansion slots (24, 25). The channels (42), however, have a
greater opening but are not as deep as the expansion slots (24,
25). The corresponding tabs (44) of the ferrules (30a, 30b) act as
fiber guiding members, while the channels (42) of the splice (20)
receive the corresponding tabs (44).
[0037] In another embodiment of the system, as presented in FIGS.
5a and 5b, additional slots (52) are provided at the ends of the
splice (20) for receiving corresponding tabs of the ferrules (30a,
30b). On each end of the splice (20), the slot (52) having a
limited depth and extending across the end surface by passing
through its center is provided. The provided slot (52) is at a
right angle with the expansion slot (24) or the expansion slot
(25). It will be appreciated by a person skilled in the art that
the slot (52) may well be at any other suitable angle from the
expansion slot (24) and expansion slot (25). In FIG. 5c, the
ferrules (30a, 30b) are presented with corresponding tabs (54) to
the slots (52) on the splice (20). The corresponding tabs (54) are
shaped in a cross and do no fully extend across the surface of the
end. However, a person skilled in the art will acknowledge that
such tabs (54) may fully extend across the end surface of the
ferrule (30a, 30b) also. The corresponding tabs (54) of the
ferrules (30a, 30b) act as fiber guiding members, while the slots
(52) receive the corresponding tabs (54).
[0038] Moreover, in another embodiment of the system, as presented
in FIGS. 6a and 6b, a protruding center portion (62) along the
expansion slot (24, 25) axis is provided at each end of the splice
(20). In FIG. 6c, the ferrules (30a, 30b) are presented with
corresponding channels (64) to the protruding center portions (62)
of the splice (20).
[0039] Illustrated in FIG. 7a is another embodiment of the system.
In this embodiment, a v-shaped channel (72) along the expansion
slot (24, 25) axis is provided at each end of the splice (20). In
FIG. 7b, the ferrules (30a, 30b) are presented with corresponding
v-shaped tabs (74) to the corresponding v-shaped channels (72) of
the splice (20).
[0040] In the embodiment illustrated in FIGS. 1, 2 and 3, the axial
compression force between the ferrules (30) and the splice (20) is
symmetrical with the intent to either expand or contract the fiber
conduit (22) symmetrically. However, it will be appreciated that in
some cases it may be desirable to expand the splice at one end only
with the effect of leaving an optical fiber at an opposite end
secured in the fiber conduit while the fiber may be freely inserted
up to a point of abutment and optical alignment from the end at
which the expansion force is generated.
[0041] It will also be appreciated that in the case of some shape
memory materials, the application of certain temperatures may cause
the material to expand or contract as desired in order to allow the
fiber ends to be positioned into optical alignment and then held in
the fiber conduit with sufficient radial force to retain the fibers
in optical alignment.
[0042] FIG. 3 illustrates one common type of connector, namely a
cable to optical plug. It will be appreciated that the connector
can be for connecting in a variety of configurations, such as cable
to cable, an optical device to a cable, an optical plug to a
socket, etc.
[0043] As shown in FIG. 3, a sheath (32) interconnects the ferrule
(30b) and the ferrule (30a). The sheath has adaptations for
connecting to the ferrule (30b), namely a flange abutment (35),
while at its end near ferrule (30a), an outwardly extending flange
(36) is provided that forms a limit abutment for the cylindrical
optical connector plug provided by ferrule (30a). It will be
appreciated that the plug (30a) may include a further larger
circumference shroud or other type of mating member that forms part
of an optical plug-in socket arrangement. The axial retention nut
(34) may be mounted onto the sleeve of ferrule (30b) by threads
(not shown) that allow rotation of the nut (34) to exert or secure
the ferrule (30b) in the position illustrated in FIG. 3.
[0044] To assemble the optical connector assembly as illustrated in
FIG. 3, a user places ferrule (30b) into sheath (32) until flanges
(31) and flange abutment (35) meet. Then splice (20) is positioned
on the ferrule (30b) with the conical enlargement (26) fitting over
the fiber guiding member (27). The ferrule (30a) is inserted into
the sheath (32) to engage the splice (20). By pressing the ferrule
(30a) against the sheath (32), the splice (20) is caused to open.
In this position, a fiber piece can be inserted into the conduit of
the ferrule (30a) into the middle of the splice (20). The pressing
action is then released. This piece of fiber is then held in the
conduit of the ferrule (30a) and its exposed end is polished to be
flush with the outside surface of the ferrule (30a).
[0045] By loosening the retention nut (34), the ferrule (30b) can
be used to exert an axial force on the splice (20), and cause the
conduit (22) to open. A fiber cable with a short length of its
fiber exposed is inserted into the ferrule (30b) until the fiber
end from the cable abuts in the splice (20) the end of the piece of
fiber now solid with the ferrule (30a). The axial force is released
and the optical coupling can be tested. If the optical coupling
between the cable and the ferrule (30a) is sound, then the
retention nut (34) can be tightened.
[0046] It will be appreciated that the assembly shown in FIG. 3 may
be pre-assembled with the optical fiber secured and polished in
ferrule (30a) leaving only the fiber cable to be inserted in
ferrule (30b). In the field, the fiber cable is prepared and
inserted into the assembly as described above. Should the fiber
cable ever need to be repaired or replaced, the nut (34) can be
released and then axial pressure can be exerted on the splice (20)
using the ferrule (30b), and the fiber cable can be released from
the ferrule (30b) and replaced with a new cable.
[0047] In another embodiment, a space (82) is provided to secure
the splice (20) in place, once the optical connector is assembled,
as illustrated in FIGS. 8 and 9. The spacer (82) is made of a
collar (84) with extending fingers (86) that have spacing ends
(88). Although the spacer (82) requires at least one extending
finger (86), a person skilled in the art will understand that
additional extending fingers (86) can be provided. The spacer (82)
has a shorter length and has a slightly larger collar (84) opening
then the splice (20) as to be slipped over the splice (20) when
placed in the sheath (30) as shown in FIG. 8.
[0048] During the assembly of the optical connector, when the
ferrule (30a) is inserted into the sheath (32) to engage the splice
(20). By pressing the ferrule (30a) against the sheath (30), the
splice (20) is caused to open. The extending fingers (86) of the
spacer (82) open up as well. Once the fiber piece is inserted into
the conduit of the ferrule (30a) up to the middle of the splice
(20), the compression action against the splice (20) is released.
The spacer (82) is moved along the splice (20) towards the ferrule
(30a) as so the spacing ends (88) clip between the end of the
splice (20) and the end of the ferrule (30a) as presented in FIG.
9. The spacer (82) is moved into position with rods from the
outside passing through the sheath (32). The rods are removed once
the spacer (82) is placed in position.
[0049] The spacer (82), once in place, prevents the ferrule (30a)
from causing the conduit of the splice (20) to open. Similarly, to
prevent the ferrule (30b) from causing the conduit of the slice
(20) to open, presented in FIGS. 10a and 10b is a pin 102. The pin
102 is placed through the body of the sheath (32) between the
splice (20) and the ferrule (30b).
[0050] In another embodiment of the system, as presented in FIG.
11, to secure the ferrule (30b) in place, a clamp (112) with a
fiber conduit (113) is provided as an interface between the ferrule
(30b) and the splice (20). The clamp (112) has flanges (114) that
hold the clamp (112) in place within the flange abutment (35) of
the sheath (32). Moreover, the clamp (112) has a fiber guiding
member (116) that fits into the conical enlargement (26) of the
splice (20).
[0051] Presented in FIG. 12, is an illustration of how two optical
connectors (10) are connected together in an adapter (122). The
fiber conduit of both ferules (30b) are aligned to allow fiber
optic signals to pass.
* * * * *