U.S. patent application number 16/142513 was filed with the patent office on 2019-11-14 for compact devices for wavelength-division multiplexing applications.
The applicant listed for this patent is ALLIANCE FIBER OPTIC PRODUCTS, INC.. Invention is credited to Chen Xia, Andy Fenglei Zhou.
Application Number | 20190346626 16/142513 |
Document ID | / |
Family ID | 68464602 |
Filed Date | 2019-11-14 |
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United States Patent
Application |
20190346626 |
Kind Code |
A1 |
Xia; Chen ; et al. |
November 14, 2019 |
COMPACT DEVICES FOR WAVELENGTH-DIVISION MULTIPLEXING
APPLICATIONS
Abstract
Disclosed is a compact device for wavelength-division
multiplexing applications. In particular, disclosed is a device
that includes a housing and a core at least partially positioned
within the housing. The core includes a first single fiber stub, a
second single fiber stub, and at least one functional layer
positioned between a first fiber of the first single fiber stub and
a second fiber of the second single fiber stub. The at least one
functional layer is configured to: (i) permit routing of a
transmission signal of a multiplexed signal along an optical path
from the first fiber stub to the second fiber stub, and (ii)
prevent routing of a non-transmission signal of the multiplexed
signal along the optical path from the first fiber stub to the
second fiber stub. A distance between a first ferrule of the first
fiber stub and a second ferrule of the second fiber stub is less
than about 0.05 mm.
Inventors: |
Xia; Chen; (Fremont, CA)
; Zhou; Andy Fenglei; (Fremont, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ALLIANCE FIBER OPTIC PRODUCTS, INC. |
Sunnyvale |
CA |
US |
|
|
Family ID: |
68464602 |
Appl. No.: |
16/142513 |
Filed: |
September 26, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62670267 |
May 11, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/29382 20130101;
G02B 6/2937 20130101; G02B 6/29389 20130101; G02B 6/262 20130101;
G02B 6/29368 20130101; G02B 6/3877 20130101; G02B 6/29359
20130101 |
International
Class: |
G02B 6/293 20060101
G02B006/293 |
Claims
1. A device for multiplexing, comprising: a housing; and a core at
least partially positioned within the housing, the core comprising:
a first single fiber stub comprising a first ferrule and a first
fiber at least partially positioned within the first ferrule, the
first fiber configured for optical communication of a multiplexed
signal comprising a transmission signal and a non-transmission
signal; a second single fiber stub comprising a second ferrule and
a second fiber at least partially positioned within the second
ferrule, the second fiber configured for optical communication of
the transmission signal; and at least one functional layer
positioned between the first fiber and the second fiber; wherein
the at least one functional layer is configured to: (i) permit
routing of the transmission signal of the multiplexed signal along
an optical path from the first fiber to the second fiber, and (ii)
prevent routing of the non-transmission signal of the multiplexed
signal along the optical path from the first fiber to the second
fiber; and wherein a distance between the first ferrule and the
second ferrule is less than about 1 micron.
2. The device of claim 1, wherein the core further comprises a
sleeve, at least a portion of the first ferrule positioned within
the sleeve and at least a portion of the second ferrule positioned
within the sleeve.
3. The device of claim 1, wherein the first single fiber stub
comprises a first port and the second single fiber stub comprises a
second port, and wherein the core comprises no more than two
ports.
4. (canceled)
5. The device of claim 1, wherein the first ferrule abuts a first
side of the at least one functional layer, and the second ferrule
abuts a second side of the at least one functional layer.
6. The device of claim 1, wherein the at least one functional layer
is attached to the first ferrule.
7. The device of claim 1, wherein the at least one functional layer
is deposited onto the first ferrule.
8. The device of claim 1, wherein the at least one functional layer
comprises at least one WDM filter having a passband to filter the
multiplexed signal by wavelength.
9. The device of claim 1, wherein the at least one functional layer
comprises at least one tap filter to filter the multiplexed signal
by optical intensity.
10. The device of claim 1, wherein the optical path between the
first fiber and the second fiber is devoid of a collimating
element.
11. The device of claim 1, wherein the optical path between the
first fiber and the second fiber is devoid of at least one of a
collimating lens or a gradient index fiber segment.
12. The device of claim 1, wherein the at least one functional
layer is configured to reflect the non-transmission signal of the
multiplexed signal in a reverse direction in the first fiber.
13. The device of claim 12, wherein a first end face of the first
ferrule is perpendicular to a longitudinal axis of the first
ferrule.
14. The device of claim 1, wherein the at least one functional
layer is configured to reflect the non-transmission signal of the
multiplexed signal away from the first fiber.
15. The device of claim 14, wherein a first end face of the first
ferrule is non-perpendicular to a longitudinal axis of the first
ferrule.
16. The device of claim 1, wherein the first fiber is radially
offset from the second fiber to attenuate propagation of the
transmission signal between the first fiber and the second
fiber.
17. The device of claim 1, wherein the first fiber is axially
aligned with the second fiber.
18. A device for multiplexing, comprising: a first ferrule having a
first optical fiber configured for optical communication of a
multiplexed signal comprising a transmission signal and a
non-transmission signal; a second ferrule having a second optical
fiber configured for optical communication of the transmission
signal; and at least one functional layer positioned between the
first optical fiber and the second optical fiber, the at least one
functional layer configured to: (i) permit routing of the
transmission signal of the multiplexed signal along an optical path
from the first optical fiber to the second optical fiber, and (ii)
prevent routing of the non-transmission signal of the multiplexed
signal along the optical path from the first optical fiber to the
second optical fiber; wherein a distance between the first ferrule
and the second ferrule is less than about 1 micron.
19. (canceled)
20. The device of claim 18, wherein the optical path is devoid of a
collimating element.
21. A method of forming a compact device for multiplexing and
demultiplexing, comprising: positioning a first fiber stub
proximate a first side of a functional layer, wherein the first
fiber stub comprises a first ferrule and a first fiber at least
partially positioned within the first ferrule, the first fiber
configured for optical communication of a multiplexed signal
comprising a transmission signal and a non-transmission signal; and
positioning a second fiber stub proximate a second side of the
functional layer, the second fiber stub comprising a second ferrule
and a second fiber at least partially positioned within the second
ferrule, the second fiber configured for optical communication of
the transmission signal, wherein a distance between the first
ferrule and the second ferrule is less than about 1 micron and the
functional layer is configured to: (i) permit routing of the
transmission signal of the multiplexed signal from the first fiber
within the first ferrule to the second fiber within the second
ferrule, and (ii) prevent routing of the non-transmission signal of
the multiplexed signal from the first fiber to the second
fiber.
22. The method of claim 21, further comprising peeling the
functional layer off of a filter; and wherein the positioning of
the first fiber stub proximate the first side of the functional
layer comprises applying the peeled off functional layer to a first
end face of the first fiber stub.
23. The method of claim 22, further comprising: at least partially
inserting the second fiber stub into a connector sleeve such that
the connector sleeve frictionally engages the second ferrule of the
second fiber stub; applying an adhesive between the second ferrule
and an inner surface of the connector sleeve; at least partially
inserting the first fiber stub into the connector sleeve such that
the connector sleeve frictionally engages the first ferrule of the
first fiber stub; and applying an adhesive, through a slit in the
connector sleeve, to the first ferrule and the second ferrule to
connect the first ferrule and the second ferrule to the connector
sleeve.
24. The device of claim 1, wherein the at least one functional
layer comprises a single film.
25. The device of claim 1, wherein the at least one functional
layer is bi-directional such that: the second fiber is further
configured for optical communication of a second multiplexed signal
comprising a second transmission signal and a second
non-transmission signal; the first fiber is further configured for
optical communication of the second transmission signal; and the at
least one functional layer is further configured to: (i) permit
routing of the second transmission signal of the second multiplexed
signal along a second optical path from the second fiber to the
first fiber, and (ii) prevent routing of the second
non-transmission signal of the second multiplexed signal along the
optical path from the second fiber to the first fiber.
26. The device of claim 15, wherein the first end face of the first
ferrule is non-perpendicular by an angle of eight degrees to the
longitudinal axis of the first ferrule.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of priority of U.S.
Provisional Application Ser. No. 62/670,267, filed May 11, 2018,
the content of which is relied upon and incorporated herein by
reference in its entirety.
BACKGROUND
[0002] The disclosure relates to wavelength-division multiplexing
and demultiplexing, and more particularly to compact two-port
devices.
[0003] Wavelength-division multiplexing (WDM) is a technology that
multiplexes (e.g., adds) a number of distinct wavelengths of light
onto a single optical fiber and demultiplexes (e.g., divides) a
number of distinct wavelengths of light from a single optical
fiber, thereby increasing information capacity and enabling
bi-directional flow of signals. Multiple optical signals are
multiplexed with different wavelengths of light combined by a
multiplexer at a transmitter, directed to a single fiber for
transmission of the signal, and split by a demultiplexer to
designated channels at a receiver. By combining multiple
wavelengths of light into a single channel, WDM assemblies and
associated devices can be used as components in an optical network,
such as a passive optical network (PON).
[0004] In certain applications, a three-port device may be used as
an optical add-and-drop multiplexer (OADM), However, in other
applications, the three-port device is too large and/or too
complicated to manufacture. Further, in some applications, long
fibers at port ends of the three-port device require extra care to
avoid damage. For some applications, a two-port device may be used
instead.
[0005] FIG. 1 is a cross-sectional top view of a two-port device
100. The two-port device 100 includes a first subassembly 102(1)
and a second subassembly 102(2) in optical communication with the
first subassembly 102(1). The first subassembly 102(1) includes a
first port 104(1), a first ferrule 105(1) (e.g., ceramic), a first
fiber optic collimator 106(1) having a first capillary 108(1)
(e.g., glass) and a first fiber 110(1), and the first subassembly
102(1) further including a first collimating element 112(1) (e.g.,
C-lens or collimating lens, G-lens or gradient-index (GRIN) lens).
The first fiber 110(1) is positioned within the first capillary
108(1). Similarly, the second subassembly 102(2) includes a second
port 104(2), a second ferrule 105(2) (e.g., ceramic), a second
fiber optic collimator 106(2) having a second capillary 108(2)
(e.g., glass) and a second fiber 110(2), and the second subassembly
102(2) further including a second collimating element 112(2) (e.g.,
C-lens or collimating lens, G-lens or gradient-index (GRN) lens).
The second fiber 110(2) is positioned within the second capillary
108(2). A filter 114 having a thickness T1 is positioned between
the first collimator 106(1) (and the first collimating element
112(1)) and the second collimator 106(2) (and the second
collimating element 112(2)). The first collimating element 112(1)
and the second collimating element 112(2) are required in order to
transmit a multiplexed signal from the first subassembly 102(1) to
the second subassembly 102(2) due to the thickness T1 of the filter
114, a first air gap G1(1) between the first collimating element
112(1) and the filter 114, and a second air gap G1(2) between the
filter 114 and the second collimating element 112(2). In other
words, as a multiplexed signal is transmitted between the first
port 104(1) and the second port 104(2), the multiplexed signal must
travel through the first collimating element 112(1) and the second
collimating element 112(2).
[0006] FIG. 2 is a cross-sectional top view of a two-port device
200. The two-port device 200 includes a first subassembly 202(1)
and a second subassembly 202(2) in optical communication with the
first subassembly 202(2). The first subassembly 202 includes a
first port 204(1), a first fiber optic collimator 206(1) having a
first ferrule 208(1) and a first fiber 210(1) with a first
collimating element 212(1) (e.g., graded-index fiber segment), and
a filter 214. The first fiber 210(1) is positioned within the first
ferrule 208(1). Similarly, the second subassembly 202(2) includes a
second port 204(2), a second fiber optic collimator 206(2) having a
second ferrule 208(2) and a second fiber 210(2) with a second
collimating element 212(2) (e.g., graded-index fiber segment). The
second fiber 210(2) is positioned within the second ferrule 208(2).
A filter 214 having a thickness T2 is positioned between the first
ferrule 208(1) (and first collimating element 212(1)) and the
second ferrule 208(2) (and the second collimating element 212(2)).
The first collimating element 212(1) and the second collimating
element 212(2) are required in order to transmit a multiplexed
signal from the first subassembly 202(1) to the second subassembly
202(2) due to the thickness T2 of the filter 214 and an air gap G2
between the filter 214 and the second ferrule 208(2). In other
words, as a multiplexed signal is transmitted between the first
port 204(1) and the second port 204(2), the multiplexed signal must
travel through the first collimating element 212(1) and the second
collimating element 212(2).
[0007] Referring to FIGS. 1 and 2, as noted above, these two-port
WDM devices 100, 200 require collimating elements in the light path
to function properly (among other reasons (e.g., for economic
reasons, engineering reasons, mass-production reasons, etc.)) which
adds to the size, manufacturing complexity, and/or cost, etc.
[0008] Accordingly, there is a need for two-port devices that are
reliable, cost effective, and/or user friendly, and/or have a
compact form-factor, easy replication, and/or versatility.
[0009] No admission is made that any reference cited herein
constitutes prior art. Applicant expressly reserves the right to
challenge the accuracy and pertinency of any cited documents.
SUMMARY
[0010] Disclosed herein are compact devices for wavelength-division
multiplexing. In particular, disclosed is a two-port device with a
core including a first single fiber stub, a second single fiber
stub, and at least one functional layer. Each single fiber stub
includes a ferrule and a fiber at least partially positioned within
the ferrule. A first fiber of the first single fiber stub is
configured for optical communication of a multiplexed signal
including a transmission signal and a non-transmission signal (also
called a demultiplexed signal). A second fiber of the second single
fiber stub is configured for optical communication of the
transmission signal. The functional layer is positioned between the
first fiber and the second fiber and is configured to: (i) permit
routing of the transmission signal of the multiplexed signal along
an optical path from the first fiber to the second fiber, and (ii)
prevent routing of the non-transmission signal of the multiplexed
signal along the optical path from the first fiber to the second
fiber. A distance between the first ferrule and the second ferrule
is less than 0.05 mm. Accordingly, the two-port device has a
compact form factor and easy manufacturability for
wavelength-division multiplexing applications.
[0011] An additional embodiment of the disclosure relates to a
two-port device including at least one functional layer positioned
between a first fiber and a second fiber. The at least one
functional layer is configured to: (i) permit routing of a
transmission signal of a multiplexed signal along an optical path
from the first fiber to the second fiber, and (ii) prevent routing
of a non-transmission signal of the multiplexed signal along the
optical path from the first fiber to the second fiber. A distance
between the first fiber and the second fiber is less than 0.05
mm.
[0012] An additional embodiment of the disclosure relates to a
method of forming a two-port device. The method includes
positioning a first ferrule of a first single fiber stub adjacent
to a first side of a functional layer and positioning a second
ferrule of a second single fiber stub adjacent to a second side of
the functional layer such that a distance between the first ferrule
and the second ferrule is less than 0.05 mm and such that the at
least one functional layer is configured to: (i) permit routing of
a transmission signal of a multiplexed signal from a first fiber
within the first ferrule of the first single fiber stub to a second
fiber within the second ferrule of the second single fiber stub,
and (ii) prevent routing of a non-transmission signal of the
multiplexed signal from the first fiber to the second fiber.
[0013] 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 embodiments as described herein,
including the detailed description which follows, the claims, as
well as the appended drawings.
[0014] It is to be understood that both the foregoing general
description and the following detailed description are merely
exemplary, and are intended to provide an overview or framework to
understanding 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.
[0015] BRIEF DESCRIPTION OF TI-IE DRAWINGS
[0016] FIG. 1 is a cross-sectional top view of a two-port
wavelength division multiplexing (WDM) device with collimating
lenses;
[0017] FIG. 2 i s a cross-sectional top view of a two-port WDM
device with collie ating fiber segments;
[0018] FIG. 3A is a perspective view of a core of an embodiment of
a two-port device devoid of collimating elements and with a
thin-film filter less than 0.05 mm thick;
[0019] FIG. 3B is a cross-sectional top view of the core of FIG.
3A;
[0020] FIG. 4A is a cross-sectional top view of another embodiment
of the core of FIGS. 3A and 3B with radially offset alignment of
the first and second optical fibers;
[0021] FIG. 4B is a cross-sectional top view of another embodiment
of the core of FIG. 4A without a functional layer;
[0022] FIG. 5 i s a cross-sectional top view of another embodiment
of the core of FIGS. 3A and 3B with an angled interface between the
first and second optical fibers;
[0023] FIG. 6A is a perspective view of a two-port device including
the core of FIGS. 3A and 3B;
[0024] FIG. 6B is an exploded perspective view of the two-port
device of FIG. 6A; and
[0025] FIG. 7 is a flowchart of steps for manufacturing a two-port
device of FIGS. 3A-6B.
DETAILED DESCRIPTION
[0026] Reference will now be made in detail to the present
preferred embodiments, examples 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 like parts.
[0027] Terms such as "left," "right," "top," "bottom," "front,"
"back," "horizontal," "parallel," "perpendicular," "vertical,"
"lateral," "coplanar," and similar terms are used for convenience
of describing the attached figures and are not intended to limit
this description. For example, terms such as "left side" and "right
side" are used with specific reference to the drawings as
illustrated and the embodiments may be in other orientations in
use. Further, as used herein, terms such as "horizontal,"
"parallel," "perpendicular," "vertical," "lateral," etc., include
slight variations that may be present in working examples.
[0028] As used herein, the terms "optical communication," "in
optical communication," and the like mean, with respect to a group
of elements, that the elements are arranged such that optical
signals are passively or actively transmittable therebetween via a
medium, such as, but not limited to, an optical fiber, one or more
ports or connectors, free space, index-matching material (e.g.,
structure or gel), reflective surface, or other light directing or
transmitting means.
[0029] As used herein, the term "port" means an interface for
actively or passively passing (e.g., receiving, transmitting, or
both receiving and transmitting) optical signals. A port may
include, by way of non-limiting examples, one or more fiber optic
connectors, optical splices, optical fibers, free-space, ferrules,
or a combination of the foregoing.
[0030] As used herein, the terms "stub" and "pigtail" mean a one or
more optical fibers in a ferrule. The fiber or fibers may extend
from the ferrule and may each be terminated with a fiber optical
connector but are not required to be terminated a fiber optic
connector. As used herein, the term "single fiber stub" means a
single optical fiber in a ferrule.
[0031] Further, as used herein, it is intended that term "optical
fibers" and similar terms include all types of single mode and
multi-mode light waveguides, including optical fibers that may be
glass core, plastic core, uncoated, coated, colored, buffered,
ribbonized and/or have other organizing or protective structure in
a cable such as one or more tubes, strength members, jackets or the
like. Likewise, other types of suitable optical fibers include
bend-insensitive optical fibers, or any other expedient of a medium
for transmitting light signals. An example of a bend-insensitive,
or bend resistant, optical fiber is ClearCurve.RTM. Multimode fiber
commercially available from Corning Incorporated. Suitable fibers
of this type are disclosed, for example, in U.S. Patent Application
Publication Nos. 2008/0166094 and 2009/0169163.
[0032] Disclosed herein are compact two-port devices for use in
wavelength-division multiplexing devices. In particular, disclosed
is a two-port device with a core including a first single fiber
stub, a second single fiber stub, and at least one functional
layer. Each single fiber stub includes a ferrule and a fiber at
least partially positioned within the ferrule. A first fiber of the
first single fiber stub is configured for optical communication of
a multiplexed signal including a transmission signal and a
non-transmission signal (also called a demultiplexed signal). A
second fiber of the second single fiber stub is configured for
optical communication of the transmission signal. The functional
layer is positioned between the first fiber and the second fiber
and is configured to: (i) permit routing of the transmission signal
of the multiplexed signal along an optical path from the first
fiber to the second fiber, and (ii) prevent routing of the
non-transmission signal of the multiplexed signal along the optical
path from the first fiber to the second fiber. A distance between
the first ferrule and the second ferrule is less than 0.05 mm.
Accordingly, the two-port device has a compact form factor and easy
manufacturability for wavelength-division multiplexing
applications.
[0033] FIG. 3A is a perspective view of a core 300 of a two-port
device (see, e.g., the two-port device 600 of FIG. 6) with a
thin-film filter and devoid of collimating elements such as
collimating lenses, collimating fiber segments, or other
collimating elements. As used herein, the term "devoid of
collimating elements" means that the device does not include an
additional device in the core for narrowing the optical signals
between the first and second fibers of the first and second first
and second fiber stubs. The core 300 (may also be referred to as a
fiber optic core, WDM core, core assembly, etc.) includes a first
subassembly 302(1) (e.g., first WDM subassembly), a second
subassembly 302(2) (e.g., second WDM subassembly), a connector
sleeve 304, a mounting ring 306 (e.g., metal ring), and a
functional layer 307 (e.g., WDM filter) (FIG. 3B) positioned in the
connector sleeve 304 between the first subassembly 302(1) and the
second subassembly 302(2).
[0034] As shown in FIG. 3B, the functional layer 307 may be a
thin-film-filter having a thickness T3 of less than 50 microns. As
used herein, the term "functional layer" means an element capable
of permitting passage through the element of certain optical
signals and preventing passage through the element of other optical
signals. Examples of a functional layer include thin-film WDM
filters, WDM layers, tap filters, and tap layers. In certain
embodiments, the functional layer 307 has a thickness T3 of less
than 30 microns. In other embodiments, the functional layer 307 has
a thickness T3 of less than 15 microns. In yet other embodiments,
the functional layer 307 has a thickness T3 of less than 10
microns. In still other embodiments, the functional layer 307 has a
thickness T3 of less than 1 micron. In certain embodiments, the
functional layer 307 has a thickness T3 between about 1 micron and
about 50 microns, between about 1 micron and about 30 microns,
between about 1 microns and about 15 microns, or between about 1
micron and about 10 microns.
[0035] In certain embodiments, the functional layer 307 is a WDM
layer or WDM filter (e.g., for wavelength management) having a
passband to filter a multiplexed signal by wavelength. In certain
embodiments, the functional layer 307 is a tap layer or tap filter
(e.g., for optical intensity management) to filter the multiplexed
signal by optical intensity or power. In certain embodiments, the
functional layer 307 may include multiple functional layers. In
certain embodiments, the functional layer 307 could be in the form
of either a very thin filter or specific film peeled off from a
filter in certain technology, or a deposited layer (e.g., by direct
deposition) onto the first ferrule 312(1) and/or the second ferrule
312(2). For example, in certain embodiments, the functional layer
307 is peeled off (e.g., from a filter) and applied to the first
ferrule 312(1) and/or the second ferrule 312(2). In certain
embodiments, the functional layer 307 is deposited onto the first
ferrule 312(1) and/or the second ferrule 312(2). in certain
embodiments, the functional layer 307 may be soaked in between the
first ferrule 312(1) and the second ferrule 312(2) in
index-matching gel, or other UV epoxy, or an air layer.
[0036] Referring now to FIG. 3B, the first subassembly 302(1)
includes a first port 308(1), a first single fiber stub 310(1)
having a first ferrule 312(1), and a first fiber 314(1) (may also
be referred to herein as a first optical fiber) at least partially
positioned within the first ferrule 312(1). In particular, the
first ferrule 312(1) includes a first medial end 3154(1), a first
distal end 31.513(1) opposite the first medial end 315A(1), and a
first channel 316(1) extending therebetween. A first end face
318A(1) at the first medial end 315A(1) of the first ferrule 312(1)
is generally perpendicular to a first axis A(1) of the first
ferrule 312(1) (and the first fiber 314(1)).
[0037] Similarly, the second subassembly 302(2) includes a second
port 308(2), a second single fiber stub 310(2) having a second
ferrule 312(2), and a second fiber 314(2) (may also be referred to
herein as a second optical fiber) at least partially positioned
within the second ferrule 312(2), :In particular, the second
ferrule 312(2) includes a second medial end 315A(2), a second
distal end 315B(2) opposite the second medial end 315A(2), and a
second channel 316(2) extending therebetween. A second end face
318A(2) at the second medial end 315A(2) of the second ferrule
312(2) is generally perpendicular to a second axis A(2) of the
second ferrule 312(2) (and the second fiber 314(2)),
[0038] The first and second ferrules 312(1), 312(2) may be made of
ceramic, metal, glass, plastic, etc., depending on the requirements
for robustness and/or flexibility. A securing element (e.g.,
adhesive, a mechanical fastener, etc.) can be disposed around the
first and second fibers 314(1), 314(2) at the distal ends of the
first and second ferrules 312(1), 312(2) to secure the first and
second fibers 314(1), 314(2) to the first and second ferrules
312(1), 312(2). The first fiber 314(1) is in optical communication
with the first port 308(1), and the second fiber 314(2) is in
optical communication with the second port 308(2).
[0039] The connector sleeve 304 includes a first end 320A, a second
end 320B opposite the first end 320A, and a sleeve channel 322
extending therebetween along a central axis B. Further, the
connector sleeve 304 includes a slit 324 (FIG. 3A) extending
between the first end 320A and the second end 320B along (but
offset from) the central axis B. In certain embodiments, the
connector sleeve 304 is made of metal, ceramic, and/or plastic,
etc.
[0040] At least a portion of the first ferrule 312(1) and the first
fiber 314(1) is positioned within the sleeve channel 322 at the
first end 320A of the connector sleeve 304, and at least a portion
of the second ferrule 312(2) and the second fiber 314(2) is
positioned within the sleeve channel 322 at the second end 320B of
the connector sleeve 304. The connector sleeve 304 is configured to
frictionally engage the first ferrule 312(1) and the second ferrule
312(2). In particular, the slit 324 (FIG. 3A) allows the connector
sleeve 304 to expand to frictionally receive the first ferrule
312(1) and the second ferrule 312(2). In the embodiments
illustrated in FIGS. 3A and 3B, the first fiber 314(1) is axially
aligned with the second fiber 314(2) and the first subassembly
302(1) is in optical communication with the second subassembly
302(2).
[0041] The mounting ring 306 is positioned around the first ferrule
312(1) and is configured for mounting the core 300 within a housing
of the two-port device (see, e.g., the two-port device 600 of FIG.
6). It is noted that the mounting ring 306 could alternatively or
additionally be positioned around the second ferrule 312(2).
[0042] The functional layer 307 is positioned between the first
medial end 315A(1) of the first ferrule 312(1) (and the first fiber
314(1)) and the second medial end 315A(2) of the second ferrule
312(2) (and the second fiber 314(2)). The functional layer 307
includes a first side 326A and a second side 326B opposite the
first side 326A. In certain embodiments, the first medial end
315A(1) of the first ferrule 312(1) (and the first fiber 314(1))
abuts (e.g., contacts) the first side 326A of the functional layer
307, and/or the second medial end 315A(2) of the second ferrule
312(2) (and the second fiber 314(2)) abuts (e.g., contacts) the
second side 326B of the functional layer 307. In certain
embodiments, the functional layer 307 is attached to one or both of
the first and second ferrules 312(1), 312(2) by laser welding,
glass welding, or adhesive (e.g., epoxy, glue), or a combination of
any of the foregoing.
[0043] As a result, the distance between the first medial end
315A(1) of the first ferrule 312(1) (and the first fiber 314(1))
and the second medial end 315A(2) of the second ferrule 312(2) (and
the second fiber 314(2)) is minimized to about the thickness T3 of
the functional layer 307. In certain embodiments, the distance
between the first medial end 315A(1) of the first ferrule 312(1)
(and the first fiber 314(1)) and the second medial end 315A(2) of
the second ferrule 312(2) (and the second fiber 314(2)) is about
the same as the thickness T3 of the functional layer 307. In some
embodiments, the distance T3 between the first medial end 315A(1)
of the first ferrule 312(1) (and the first fiber 314(1)) and the
second medial end 315A(2) of the second ferrule 312(2) (and the
second fiber 314(2)) is less than about 50 microns. In certain
embodiments, the distance T3 is less than about 30 microns. In
other embodiments, the distance T3 is less than 15 microns. In
other embodiments, the distance T3 is less than 10 microns. In yet
other embodiments, the distance T3 is less than 1 micron. In
certain embodiments, the functional layer 307 has a thickness T3
between about 1 micron and about 50 microns. In other embodiments,
the functional layer 307 has a thickness T3 between about 1 and
about 30 microns. In yet other embodiments, the functional layer
307 has a thickness T3 between about 1 and about 15 microns. In
certain embodiments, the functional layer 307 has a thickness T3
between about 1 and about 10 microns. Due to the small distance T3
between the first medial end 315A(1) of the first ferrule 312(1)
(and the first fiber 314(1)) and the second medial end 315A(2) of
the second ferrule 312(2) (and the second fiber 314(2)), a
collimating element is not required for the propagation of an
optical signal between the first fiber 314(1) and the second fiber
314(2). Thus, the optical light path between the first and second
fibers 314(1), 314(2) within the core 300 and through the
functional layer 307 is devoid of a collimating element, such as a
collimating lens or a gradient index fiber segment. In other words,
the optical light path between the first and second fibers 314(1),
314(2) is devoid of a collimating element.
[0044] In operation, as an example, a multiplexed optical signal,
including a first signal (also called a first sub-signal of the
multiplexed signal) and a second signal (also called a second
sub-signal of the multiplexed signal), is transmitted to the first
port 308(1). The first signal may be a transmission signal
.lamda..sub.T (e.g., data signal) and the second signal may be a
reflection signal .lamda..sub.R (e.g., monitoring signal, blocking
signal, etc.). The functional layer 307 is configured to allow
propagation of the first signal (the transmission signal
.lamda..sub.T) from the first fiber 314(1) through the functional
layer 307 and then through the second fiber 314(2) to the second
port 308(2). The functional layer 307 is configured to block or
reflect the second signal (the reflection signal .lamda..sub.R)
back down the first fiber 314(1). The second signal may then be
directed to an optical element such as an optical time-domain
reflectometer (OTDR). In other words, the functional layer 307 is
configured to reflect at least one of the signals (e.g., the second
signal) of the multiplexed signal from the first fiber 314(1) in a
reverse direction back within the first fiber 314(1). Thus, in some
embodiments the functional layer 307 is configured to route part of
a multiplexed signal between the first port 308(1) and second port
308(2).
[0045] Thus, in some embodiments the functional layer 307 is
positioned between the first fiber 314(1) and the second fiber
314(2) and is configured to: (i) permit routing of the transmission
signal (e.g., the first signal or transmission signal
.lamda..sub.T) of the multiplexed signal along an optical path from
the first fiber 314(1) to the second fiber 314(2), and (ii) prevent
routing of the non-transmission signal (also called a demultiplexed
signal, a second signal or reflection signal .lamda..sub.R) of the
multiplexed signal along the optical path from the first fiber
314(1) to the second fiber 314(2). As discussed above, a distance
D.sub.1 between the first ferrule 312(1) and the second ferrule
312(2) may be less than about 0.05 mm, less than about 0.03 mm,
less than about 0.01 mm, or less than about 0.001 mm.
[0046] In certain embodiments, the core 300 includes no more than
two ports 308(1), 308(2). In other words, in certain embodiments,
the core 300 includes only a first port 308(1) and a second port
308(2). It is noted that the core 300 is bi-directional, and the
signal multiplexing and/or demultiplexing works the same when
propagated from the first port 308(1) to the second port 308(2) or
from the second port 308(2) to the first port 308(1).
[0047] In certain embodiments (see e.g., FIG. 5 below), the
functional layer 307 is configured to reflect at least one of the
signals (sub-signals) of the multiplexed signal out of an optical
light path between the first fiber 314(1) and the second fiber
314(2),
[0048] In the embodiment illustrated in FIG. 3B, the functional
layer 307, the first end face 318A(1) of the first ferrule 312(1),
and the second end face 318A(2) of the second ferrule 312(2) are
substantially perpendicular to the first axis A(1) of the first
ferrule 312(1) (and first fiber 314(1)) and the second axis A(2) of
the second ferrule 312(2) (and second fiber 314(2)). As a result,
when the reflection signal.lamda..sub.R is reflected by the
functional layer 307, the reflection signal .lamda..sub.R is
transmitted back through the first fiber 314(1). In certain
embodiments, one or more two-port devices (e.g., OTDR) are used to
monitor network performance by monitoring these reflection signals
.lamda..sub.R. The configuration of core 300 can be used for signal
monitoring, signal blocking, and/or signal attenuation, etc. For
example, the two-port device could be used to monitor fiber
quality, monitor fiber performance (e.g., if a fiber has been cut
or otherwise damaged in the field), etc. The first fiber 314(1)
within the first ferrule 312(1) is axially aligned with the second
fiber 314(2) within the second ferrule 312(2) to propagate the
transmission signal .lamda..sub.T between the first fiber 314(1)
and the second fiber 314(2).
[0049] FIG. 4A is a cross-sectional top view of another embodiment
of a core 400 with radially offset alignment of the first and
second optical fibers 314(1), 314(2). The core 400 is similar to
the core 300 of FIGS. 3A and 3B except where otherwise noted. In
particular, the core 400 includes a first subassembly 302(1), a
second subassembly 302(2) in optical communication with the first
subassembly 302(1), a connector sleeve 404, a mounting ring 306,
and a functional layer 307 positioned in the connector sleeve 404
between the first subassembly 302(1) and the second subassembly
302(2).
[0050] As noted above, the connector sleeve 404 includes a first
end 320A, a second end 320B opposite the first end 320A, and a
sleeve channel 322 extending therebetween. The connector sleeve 404
further includes a first portion 406(1) proximate the first end
320A and a second portion 406(2) proximate the second end 320B. The
first portion 406(1) and the second portion 406(2) are radially
offset by a distant D from one another. In other words, the first
portion 406(1) and the second portion 406(2) are not axially
aligned with one another.
[0051] The first subassembly 302(1) is positioned within the first
portion 406(1) of the connector sleeve 404, and the second
subassembly 302(2) is positioned within the second portion 406(2)
of the connector sleeve 404. Accordingly, the first axis A(1) of
the first subassembly 302(1) is radially offset from the second
axis A(2) of the second subassembly 302(2). Further, the first
fiber 314(1) within the first ferrule 312(1) is radially offset
from the second fiber 314(2) in the second ferrule 312(2) by a
distance 1) to attenuate propagation of the transmission signal
.lamda..sub.T between the first fiber 314(1) and the second fiber
314(2). Offsetting the axial alignment of the first fiber 314(1)
and the second fiber 314(2) can attenuate the signal (e.g., tune
power) transmitted between the first fiber 314(1) and the second
fiber 314(2). The greater the offset distance D, the greater the
attenuation of the propagated signal. In certain embodiments, the
coupling efficiency between the first ferrule 312(1) and the second
ferrule 312(2) is customized by this offset and the signal
attenuation is well controlled.
[0052] In other embodiments, the first ferrule 312(1) and the
second ferrule 312(2) are axially aligned, but the second fiber
314(2) is radially offset within the second ferrule 312(2) such
that the first ferrule 312(1) and the second ferrule 312(2) are
offset.
[0053] FIG. 4B is a cross-sectional top view of a core 400' that is
similar to the core 400 of FIG. 4A but does not include the
functional layer 307. The core 400' is similar to the core 400 of
FIG. 4A except where otherwise noted. In particular, the functional
layer 307 is omitted. As in FIG. 4A, the first fiber 314(1) within
the first ferrule 312(1) is radially offset from the second fiber
314(2) in the second ferrule 312(2) by a distance D to attenuate
propagation of the transmission signal .lamda..sub.T between the
first fiber 314(1) and the second fiber 314(2). Without the
functional layer 307, the first ferrule 312(1) can directly contact
the second ferrule 312(2) such that a distance between the first
ferrule 312(1) and the second ferrule 312(2) is nominal (e.g.,
about 0 mm or close thereto).
[0054] FIG. 5 is a cross-sectional top view of another embodiment
of a core 500 that is similar to the core 300 of FIGS. 3A and 3B
but has an angled interface between the first and second optical
fibers 314(1), 314(2). The core 500 is similar to the core 300 of
FIGS. 3A and 3B except where otherwise noted. In particular, the
core 500 includes a first subassembly 502(1), a second subassembly
502(2) in optical communication with the first subassembly 502(1),
a connector sleeve 304, a mounting ring 306, and a functional layer
307 positioned in the connector sleeve 304 between the first
subassembly 502(1) and the second subassembly 502(2).
[0055] A first end face 318A(1) at the first medial end 315A(1) of
the first ferrule 312(1) (and the first fiber 314(1)) is generally
non-perpendicularly angled by angle .theta. (e.g.,) 8.degree. to a
first axis A(1) of the first ferrule 312(1) (and the first fiber
314(1)). A second end face 318A(2) at the second medial end 315A(2)
of the second ferrule 312(2) (and the second fiber 314(2)) is
generally non-perpendicularly angled (by angle .theta.) to a second
axis A(2) of the second ferrule 312(2) (and the second fiber
314(2)).
[0056] In operation, as an example, a multiplexed optical signal
may include a first signal (a transmission signal .lamda..sub.T)
and a second signal (a reflection signal .lamda..sub.R). The
functional layer 307 is configured to allow propagation of the
transmission signal .lamda..sub.T from a first port 308(1) to the
first fiber 314(1) and through the functional layer 307 to the
second fiber 314(2) to the second port 308(2). The functional layer
307 is also configured to block or reflect the reflection signal
.lamda..sub.R, for example, by reflecting it to a fiber optic
attenuator (FOA). In other words, the functional layer 307 routes
sub-signals of a multiplexed signal between the first port 308(1)
and second port 308(2).
[0057] The functional layer 307, the first medial end 315A(1) of
the first ferrule 312(1), and the second medial end 315A(2) of the
second ferrule 312(2) are non-perpendicular to the first axis A(1)
of the first ferrule 312(1) and the second axis A(2) of the second
ferrule 312(2). As a result, when the reflection signal
.lamda..sub.R is reflected by the functional layer 307, the
reflection signal .lamda..sub.R is not transmitted back through the
first fiber 314(1). Instead, the reflection signal .lamda..sub.R is
reflected away from the first fiber 314(1) (in other words,
external to the first fiber 314(1)) to block the reflection signal
.lamda..sub.R from transmitting. In certain embodiments, one or
more two-port devices (e.g., FOA) are used to attenuate signals by
blocking these reflection signals .lamda..sub.R. The configuration
of the core 500 can be used for signal blocking and/or signal
attenuation, or other uses.
[0058] FIGS. 6A and 6B are views of a two-port device 600 including
the core 300 of FIGS. 3A-3B. However, it is noted that the two-port
device 600 could instead include the core 400 or core 500 of FIGS.
4 and 5, respectively. The two-port device 600 (e.g., pluggable
two-port device) includes a housing 602, an outer shell 604, the
core 300 (may also be referred to herein as a ferrule body), the
sleeve 606, and a spring lever attachment 608. In particular, at
least a portion of the first subassembly 302(1) of the core 300 is
positioned in the outer shell 604, the housing 602 or both the
outer shall 604 and the housing 602. The mounting ring 306 mounts
the core 300 within the outer shell 604, the housing 602 or both
the outer shell 604 and the housing 602. The outer shell 604, the
first subassembly 302(1) or the outer shell and the first
subassembly 302(1) are positioned within the housing 602. At least
a portion of the second subassembly 302(2) of the core 300 is
positioned in the sleeve 606. At least a portion of the sleeve 606,
the second subassembly 302(2) or the sleeve and the second
subassembly 302(2) is positioned within the spring lever attachment
608. The spring lever attachment 608 is mechanically attached to
the housing 602 to contain the outer shell 604, the core 300, and
the sleeve 606 within the housing 602.
[0059] The two-port device 600 could be used as a device core
engine in multiple scenarios (e.g., wavelength demultiplexing,
signal blocking, isolation, and/or power attenuation, etc.).
[0060] In certain embodiments, the two-port device 600 is a
pluggable device with connector interfaces (e.g., SC connector
(e.g., subscriber connector, square connector, standard connector,
etc.), LC connector (little connector, lucent connector, local
connector), FC connector (ferrule connector, fiber channel), ST
connector (straight tip connector) or MU connector (miniature
unit), etc. on either port. in certain embodiments, the end surface
could be PC (physical contact), UPC (ultra physical contact), or
APC (angled physical contact) customized. For example, in certain
embodiments, the end surface has an APC surface of 8.degree..
[0061] The two-port device 600 disclosed herein is easily
manufactured, easy to use, and has a compact form factor. As an
example, the two-port device may be used for new deployment,
diagnosis, and/or upgrade of PON (passive optical network) within
FTTH (fiber to the home) solutions.
[0062] The two-port device 600 provides low insertion loss,
simplicity in assembly, and low cost manufacturing due a simplified
structure. in certain embodiments, the build of the device is
simplified and the optical path is simplified so that the two-port
device 600 is more cost effective and provides a better optical
performance. In certain embodiments, the two-port device 600
provides low insertion los, such as due to the straight optical
path within the ceramic ferrule (and/or simple optical
structure).
[0063] FIG. 7 is a flowchart illustrating a method 700 for
manufacturing a two-port device of FIGS. 3A-6B. Reference is made
to core 300 of FIGS. 3A and 3B specifically, although the steps 700
also apply to cores 400 and 500 of FIGS. 4 and 5. In step 702, a
first side of at least one functional layer 307 is applied
proximate to a first end face 318(1) of a first ferrule 312(1) of a
first single fiber stub 310(1). In step 704, a second ferrule
312(2) of a second single fiber stub 310(2) is at least partially
inserted into a second end 320B of a connector sleeve 304. In step
706, the second ferrule 312(2) is attached to the connector sleeve
304 by applying an adhesive (e.g., glue, thin film glue, etc.)
between the second ferrule 312(2) and an inner surface of the
connector sleeve 304. In step 708, the first end face 318(1) of the
first ferrule 312(1) is at least partially inserted into a first
end 320A of the connector sleeve 304. In step 710, a second side
326B of the at least one functional layer 307 is positioned
proximate the second ferrule 312(2) of the second single fiber stub
310(2) such that a distance D.sub.1 between the first ferrule
312(1) and the second ferrule 312(2) is less than about 0.05 mm (in
other embodiments, the distance may be less than about 0.03 mm,
less than about 0.01 mm, or less than about 0.001 mm, or directly
contacting) and such that the functional layer 307 is configured
to: (i) permit routing of a transmission signal of a multiplexed
signal from a first fiber 314(1) within the first ferrule 312(1) of
the first single fiber stub 310(1) to a second fiber 314(2) within
the second ferrule 312(2) of the second single fiber stub 310(2),
and (ii) prevent routing of a non-transmission signal (also called
a demultiplexed signal or a second signal) of the multiplexed
signal from the first fiber 314(1) to the second fiber 314(2). In
step 712, an adhesive (e.g., glue, thin film glue, etc.) is applied
through a slit 324 in the connector sleeve 304 to the first ferrule
312(1) and/or second ferrule 312(2) to attach the first ferrule
312(1) and/or second ferrule 312(2) to the connector sleeve 304
and/or to each other.
[0064] It is noted that the connector sleeve 304, the first single
fiber stub 310(4 the second single fiber stub 310(2), and the
functional layer 307 could be assembled in other various ways and
orders. For example, the second ferrule 312(2) could be inserted
into the connector sleeve 304 after the first ferrule 312(1) and
the functional layer 307 are inserted into the connector sleeve
304.
[0065] 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 invention. Many modifications and other
embodiments of the embodiments set forth herein will come to mind
to one skilled in the art to which the embodiments pertain having
the benefit of the teachings presented in the foregoing
descriptions and the associated drawings. Therefore, it is to be
understood that the description and claims are not to be limited to
the specific embodiments disclosed and that modifications and other
embodiments are intended to be included within the scope of the
appended claims. It is intended that the embodiments cover the
modifications and variations of the embodiments provided they come
within the scope of the appended claims and their equivalents.
Although specific terms are employed herein, they are used in a
generic and descriptive sense only and not for purposes of
limitation.
* * * * *