U.S. patent application number 14/957221 was filed with the patent office on 2016-03-24 for fiber optic connection device with ruggedized tethers.
The applicant listed for this patent is CommScope Technologies LLC. Invention is credited to Jeffrey Gniadek, Yu Lu, Michael Noonan, Randy Reagan.
Application Number | 20160085032 14/957221 |
Document ID | / |
Family ID | 36764597 |
Filed Date | 2016-03-24 |
United States Patent
Application |
20160085032 |
Kind Code |
A1 |
Lu; Yu ; et al. |
March 24, 2016 |
FIBER OPTIC CONNECTION DEVICE WITH RUGGEDIZED TETHERS
Abstract
A loop back connector and methods for testing lines in a fiber
optic network are disclosed. The loop back connector includes a
ferrule having an interface side constructed for optical connection
to a multifiber optical cable. The loop back connector also
includes first and second optical loop back paths, each having
first and second terminal ends positioned at the interface side.
The terminal ends of each loop back path are adapted to be aligned
to fibers in the multifiber optical cable. The method includes
injecting a signal on a first optical path at a first location,
looping back the signal at a second location onto a second optical
path, and receiving the signal on the second optical path at the
first location.
Inventors: |
Lu; Yu; (Eden Prairie,
MN) ; Reagan; Randy; (Morristown, NJ) ;
Noonan; Michael; (Shrewsbury, MA) ; Gniadek;
Jeffrey; (Northbridge, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CommScope Technologies LLC |
Hickory |
NC |
US |
|
|
Family ID: |
36764597 |
Appl. No.: |
14/957221 |
Filed: |
December 2, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13771376 |
Feb 20, 2013 |
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14957221 |
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13247671 |
Sep 28, 2011 |
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13771376 |
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12505862 |
Jul 20, 2009 |
8041178 |
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13247671 |
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11406825 |
Apr 19, 2006 |
7565055 |
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12505862 |
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60672534 |
Apr 19, 2005 |
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60764133 |
Feb 1, 2006 |
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Current U.S.
Class: |
385/69 |
Current CPC
Class: |
G02B 6/3895 20130101;
G02B 6/3897 20130101; G02B 6/3827 20130101; G01M 11/33 20130101;
G02B 6/4475 20130101; G02B 6/3823 20130101; G02B 6/3885 20130101;
G02B 6/4473 20130101; G02B 6/385 20130101; G02B 6/3849 20130101;
G02B 6/447 20130101; G02B 6/4472 20130101; G02B 6/3878 20130101;
G02B 6/3887 20130101 |
International
Class: |
G02B 6/38 20060101
G02B006/38; G02B 6/44 20060101 G02B006/44 |
Claims
1. A fiber optic connection device comprising: a ruggedized
multi-fiber connector including a threaded collar; a plurality of
tethers; a breakout structure that provides an optical fiber
transition from the multi-fiber connector to the tethers, the
break-out structure having a breakout end face defining a breakout
surface area, the tethers extending outwardly from the breakout end
face; and first and second groups of ruggedized port-defining
structures mounted at ends of the tethers, the ruggedized
port-defining structures defining ports adapted for receiving
single fiber connectors, the first group of ruggedized
port-defining structures being spaced a first distance from the
breakout end face, the second group of ruggedized port-defining
structures being spaced a second distance from the breakout end
face, the first and second distances being different distances such
that the first and second groups of ruggedized port defining
structures are staggered relative to one another, the first and
second groups of ruggedized port-defining structures each defining
a collective end face area that is larger than the breakout surface
area.
2. The fiber optic connection device of claim 1, wherein the
breakout structure is a first breakout structure, and wherein
second breakout structures are positioned between the first
breakout structure and the first and second groups of ruggedized
port-defining structures.
3. The fiber optic connection device of claim 1, further comprising
a multi-fiber cable that extends between the multi-fiber connector
and the breakout structure.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of Ser. No. 13/771,376,
filed Feb. 20, 2013, which is a continuation of application Ser.
No. 13/247,671, filed Sep. 28, 2011, now abandoned, which is a
continuation of application Ser. No. 12/505,862, filed Jul. 20,
2009, now U.S. Pat. No. 8,041,178, which is a continuation of
application Ser. No. 11/406,825, filed Apr. 19, 2006, now U.S. Pat.
No. 7,565,055, which claims the benefit of provisional application
Ser. No. 60/672,534, filed Apr. 19, 2005 and claims the benefit of
provisional application Ser. No. 60/764,133, filed Feb. 1, 2006,
which applications are incorporated herein by reference in their
entirety.
TECHNICAL FIELD
[0002] The present invention relates to fiber optic cable networks.
More specifically, the present invention relates to termination of
fiber optic cables.
BACKGROUND
[0003] Passive optical networks are becoming prevalent in part
because service providers want to deliver high bandwidth
communication capabilities to customers. Passive optical networks
are a desirable choice for delivering high speed communication data
because they may not employ active electronic devices, such as
amplifiers and repeaters, between a central office and a subscriber
termination. The absence of active electronic devices may decrease
network complexity and cost and may increase network
reliability.
[0004] Passive optical networks may employ optical splitters to
take a signal from a single incoming fiber and make it available to
a number of output fibers. For example, a distribution cable may
include 24 optical fibers and may run from a central office to a
distribution location, such as an equipment enclosure. At the
equipment enclosure, each fiber in the distribution cable may be
split into a number of outgoing fibers which are made available to
subscribers. For example, passive optical networks may employ 1:2,
1:4, 1:8, 1:16 and 1:32 splitting ratios for making optical data
available to subscriber locations. Outgoing fibers from the
equipment enclosure, i.e. at the output of the optical splitters,
need to be attached to subscriber locations. Since the outgoing
fibers may be housed in a cable for protection, a subset of the
fibers needs to be accessed and made available to a like number of
subscribers.
[0005] Current techniques employ splices for breaking a subset of
fibers out of a distribution cable. These splices are normally
performed in the field using trained personnel after the
distribution cable is installed. This form of splicing is referred
to as manual splicing, or field splicing. Manual splicing may be
time consuming and may be expensive in terms of labor because
personnel must be specially trained and performing splicing
operations may be time intensive. In addition, material costs
associated with splicing cables may be expensive since splice
enclosures need to be environmentally secure within a wide range of
variables. Manual splicing may also require specialized tools.
[0006] Passive optical networks may be extended via connectors
located along the distribution cable, creating branched optical
paths. Branch cables may be connected to these connectors after the
distribution cable is installed, for example because no subscribers
were located near the distribution cable when it was originally
installed. A technician or other personnel installing a branch
cable from the connector location to a subscriber location
generally tests the link between a central office and the connector
to ensure optical continuity at the time the branch cable is
installed. Testing typically involves travel between the central
office location and the connector location to inject a signal at
one location and detect that signal at the second location. The
distance between the central office and the connector location may
be substantial, and require time-consuming travel by the
technician.
SUMMARY
[0007] According to the present disclosure, a loop back connector
and methods for testing lines in a fiber optic network are
disclosed. The loop back connector has a ferrule, and can include
loop back paths for connecting fibers in a multifiber optical
cable. The ferrule has an interface side adapted to be aligned to a
multifiber optical connector. The loop back paths in the ferrule
optically connect two fibers in the multifiber optical connector.
In certain embodiments, the loop back plug can include a planar
lightwave circuit.
[0008] A method for testing lines in a fiber optic network is also
disclosed. The method includes inputting a signal onto a first
optical path at a first location, looping back the signal at a
second location to a second optical path and receiving the signal
from the second optical path at the first location. A loop back
connector can be used at the second location to loop back the
signal to the first location.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIGS. 1A-C illustrate exemplary networks that may use
factory integrated terminations consistent with the principles of
the invention;
[0010] FIG. 2 illustrates an exemplary distribution cable that may
be spliced using factory integrated terminations consistent with
the principles of the invention;
[0011] FIG. 3 illustrates an exemplary method for manufacturing a
distribution cable for use with a factory integrated termination
consistent with the principles of the invention;
[0012] FIG. 4 illustrates an exemplary method for installing a
factory integrated termination onto a distribution cable consistent
with the principles of the invention;
[0013] FIGS. 5A-5D illustrate exemplary aspects associated with the
installation of a factory integrated termination onto a
distribution cable consistent with the principles of the
invention;
[0014] FIGS. 5E-5F illustrate views of an exemplary factory
integrated termination that includes an MT female connector
consistent with the principles of the invention;
[0015] FIG. 6 illustrates the exemplary factory integrated
termination of FIG. 5E configured to include a radio frequency
identification (RFID) tag consistent with the principles of the
invention;
[0016] FIG. 7 illustrates an exemplary computer architecture that
may be used for implementing active RFID devices consistent with
the principles of the invention;
[0017] FIGS. 8A and 8B illustrate exemplary implementations of a
factory integrated termination utilizing a ruggedized MT connector
consistent with the principles of the invention;
[0018] FIGS. 9A and 9B illustrate an exemplary loop back connector
for use in testing factory integrated terminations consistent with
the principles of the invention;
[0019] FIG. 9C illustrates a schematic view of the loop back
connector of FIGS. 9A and B along with a schematic representation
of a four ribbon fiber consistent with the principles of the
invention;
[0020] FIG. 9D shows a planar lightwave chip suited for use in a
loop-back connector;
[0021] FIG. 9E shows the chip of FIG. 9D incorporated into a
ferrule structure of a loop-back connector and also shows a mating
connector adapted to be coupled to the loop-back connector;
[0022] FIG. 9F is a top view taken along section line 9F-9F of FIG.
9E;
[0023] FIG. 9G shows the connectors of FIG. 9E coupled
together;
[0024] FIGS. 10A and 10B illustrate exemplary implementations of
factory integrated terminations employing ruggedized connectors on
tethers consistent with the principles of the invention; and
[0025] FIGS. 11A-11F illustrate exemplary implementation of factory
integrated terminations employing fiber drop terminals consistent
with the principles of the invention.
DETAILED DESCRIPTION
[0026] The following detailed description of implementations
consistent with the principles of the invention refers to the
accompanying drawings. The same reference numbers in different
drawings may identify the same or similar elements. Also, the
following detailed description does not limit the invention.
Instead, the scope of the invention is defined by the appended
claims and their equivalents.
[0027] FIGS. 1A-C illustrate exemplary networks 100 that may use
factory integrated terminations consistent with the principles of
the invention. A fiber distribution cable 102 may include a
proximal end 104 and a distal end 106. The proximal end 104 may be
associated with a central office 108 and may act as the beginning
of the distribution cable 102. The distal end 106 may be located
some distance away from the proximal end 104 and may act as the end
of the distribution cable 102. One or more splices 110 may be
located between the proximal end 104 and distal end 106 of the
distribution cable 102. For example, as a fiber distribution cable
102 is spliced into smaller cables, the overall number of cables
associated with the distribution cable 102 may increase while the
number of fibers remains constant. In some applications, the number
of splices 110 may increase geometrically as splice locations move
away from the proximal end 104 of the distribution cable 102.
[0028] The portion of a passive optical network 100 that is closest
to the beginning of a distribution cable 102 (the central office
108) is generally referred to as the F1 region, where F1 is the
"feeder fiber" from the central office 108 to a location before a
splitter, such as a splice 110. The F1 portion of the network 100
may include a distribution cable 102 having on the order of 12 to
48 fibers; however, alternative implementations may include fewer
or more fibers without departing from the spirit of the invention.
For example, a feeder cable such as the distribution cable 102 may
run from a central office 108 to a fiber distribution hub (FDH) 112
that includes one or more optical splitter modules, seen as splices
110. An FDH 112 is an equipment enclosure that may include a
plurality of optical splitters for splitting an incoming fiber in
the distribution cable 102 into a number of output fibers. For
example, an incoming fiber in the distribution cable 102 may be
split into 32 outgoing fibers using an optical splitter module
within the FDH 112. Each output of the splitter module may be
connected to a subscriber termination on a patch panel within the
FDH 112. The subscriber termination may be coupled to an optical
fiber in another distribution cable 102 that may run to a location
114 proximate to the subscriber's premises.
[0029] Splitters used in an FDH 112 may accept a feeder cable
having a number of fibers and may split those incoming fibers into
anywhere from 216 to 432 individual distribution fibers that may be
associated with a like number of subscriber locations 114. These
216 to 432 fibers may make up an F2 distribution cable, or F2
portion of the network. F2 may refer to fibers running from an FDH
112 to subscriber locations 114.
[0030] Factory integrated terminations may be used in the F2 region
to provide environmentally sound and cost effective splicing
protection. Factory integrated terminations may use factory
integrated access (tap) points 116 at specified points in the
distribution cable 102 instead of manually installed splices 110.
These access points 116 may be connectorized to provide a simple
plug and play approach in the distribution portion of the network
100 when connecting subscribers to the network. For example,
implementations consistent with the principles of the invention may
use rugged OSP connectors that can accommodate single or multi-port
connectors.
[0031] FIG. 2 illustrates an exemplary distribution cable 200 that
may be spliced using factory terminations consistent with the
principles of the invention. The distribution cable of FIG. 2 may
include a protective outer sheath 202 that provides strength and
abrasion resistance to optical fibers running inside the
distribution cable. The outer sheath 202 may be manufactured from
UV resistant plastic and may include reinforcing fibers. The
distribution cable 200 may also include a strength member 204
passing through the center of the cable 200. The strength member
204 may be used to tension the distribution cable 200 without
damaging or stretching optical fibers running inside the cable
200.
[0032] The distribution cable 200 may also include fiber ribbons
206. For example, a distribution cable 200 may include one or more
fiber ribbons 206. A fiber ribbon 206 may include 4, 6, 8, 12, or
more optical fibers enclosed within a protective ribbon sheath 208.
The ribbon sheaths 208 may be color coded and/or labeled to
facilitate identification of a desired ribbon. Ribbon sheaths 208
may be structural plastic tubes for providing additional protection
to fibers making up a ribbon 206. A typical distribution cable 200
may include 48 to 432 individual fibers that may be contained in
anywhere from 8 to 108 ribbons.
[0033] When distribution cables 200 contain a large number of
ribbons 206, it may become difficult to retrieve a desired ribbon
from a cable to perform a manual splice and/or a factory integrated
termination. Implementations consistent with the principles of the
invention may employ an optical fiber having on the order of 12
ribbon tubes with each ribbon tube including on the order of four
optical fibers. Distribution fibers having 12 ribbon tubes
facilitate easy identification of a desired ribbon when performing
splices. As a result, the time required to perform a manual splice
and/or a factory integrated termination may be reduced.
[0034] FIG. 3 illustrates an exemplary method for manufacturing a
distribution cable for use with factory integrated terminations
consistent with the principles of the invention. The method of FIG.
3 commences with the receipt of one or more design parameters for a
distribution cable (act 302). For example, a design parameter may
indicate that a distribution cable should include 12 ribbons with
each ribbon having four optical fibers. A desired number of fiber
ribbons may be assembled into a distribution cable (act 304).
Breakout locations for factory integrated terminations may be
identified (act 306). For example, breakout locations may
correspond with geographic locations of utility poles or ground
mounted pedestals. A desired ribbon may be broken out of the
assembled distribution cable at a determined location (act 308).
The portion of ribbon broken out of the distribution cable may be
terminated using a factory integrated termination (act 310). The
terminated ribbon may be tested for signal integrity and
environmental integrity after the installation of the factory
integrated termination is complete (act 312). The distribution
cable may be shipped to an installation location and installed (act
314).
[0035] FIG. 4 illustrates an exemplary method for installing a
factory integrated termination onto a distribution cable consistent
with the principles of the invention. A distribution cable may be
received at an assembly facility (act 402). Splice locations may be
determined using information associated with one or more
installation locations (act 404). A cut may be made in the jacket
of the distribution cable at a first location associated with a
splice location (act 406). For example, in one implementation, a
piece of jacket approximately 0.25 inches in length may be removed
from the distribution cable at the first location to provide access
to one or more ribbons contained therein.
[0036] A ribbon may be selected and the ribbon jacket/sheath along
with the fibers making up the ribbon may be severed at the first
location (act 408). A second cut may be made in the outer jacket of
the distribution cable at a second location, which is a determined
distance away from the first location (act 410). The outer jacket
of the distribution cable may be removed at the second location to
provide access to ribbons contained therein. The ribbon that was
cut in act 408 is identified and the ribbon is pulled out of the
distribution fiber from the second location (act 412). For example,
in one implementation, the second cut is made approximately 78
inches (on the order of 2 meters) away from the first cut. When the
ribbon is pulled from the distribution cable, approximately 78
inches of the ribbon will be exposed outside of the distribution
cable.
[0037] An external cable sheath may be placed over the extracted
ribbon to provide additional structural rigidity and environmental
protection (act 414). For example, a piece of UV resistant
structural shrink tubing may be placed over the extracted ribbon. A
jacket/tubing over-mold may be installed over the external cable
jacket that was installed in act 414 (act 416). The jacket/tubing
over-mold may be coupled to the external jacket using adhesive or
other attachment technique known in the art. An over-mold may be
installed over the second location including the extracted ribbon,
external jacket and/or jacket/tubing over-mold (act 418). The
over-mold may operate to seal the outer jacket of the distribution
cable at the second location and may seal the exposed ribbon and
may maintain the ribbon at a desired position with respect to the
distribution cable. The over-mold may also provide structural
integrity to the second location and to the exposed ribbon.
[0038] The over-mold may include a poured plastic covering molded
over the exposed portions of the distribution cable. The over-mold
may overlap the intact distribution cable jacket at each end of the
second cut. The cured over-mold may produce a strong weather-tight
seal around the distribution cable and the exposed ribbon and/or
ribbon jacket.
[0039] An alternative implementation of an over-mold may employ a
two-piece pre-formed clamshell that closes over the junction of the
distribution cable and exposed ribbon forming a strong
weather-tight seal around the 48-fiber cable as well as the 4-fiber
ribbon jacket. Another alternative process may be a
heat-shrink/gasket material combination covering the junction of
the distribution cable as well as the exposed ribbon.
[0040] Another alternate design may include an MT female connector
within the over-mold. This design may eliminate the need for a
jacket over the exposed ribbon. The ribbon may be terminated to an
MT female connector. The MT female connector may be captured with
the over-mold. The over-mold may be configured and adapted to pass
over cable installation pulleys when the distribution cable is
deployed in the field.
[0041] The first location may be sealed using shrink tubing,
over-molding and/or other techniques known in the art (act 420).
The distribution cable and exposed ribbon may be tested for signal
integrity and/or environmental integrity (act 422). The
distribution cable may be shipped to an installation location and
installed (act 424). For example, the distribution cable may be
suspended between utility poles with the factory integrated
terminations located so as to correspond to utility pole locations.
The factory integrated terminations may be terminated with
connectors, receptacles, and/or other devices used for making
optical signals available to a subscriber.
[0042] Implementations of factory integrated terminations may allow
the distribution cable to maintain its original strength and
lifetime performance. The over-mold may be designed to withstand
the tough OSP environment, and may add minimal weight to the
cable.
[0043] FIGS. 5A-5D illustrate exemplary aspects associated with the
installation of a factory integrated termination onto a
distribution cable consistent with the principles of the invention.
FIG. 5A illustrates the operations described in conjunction with
acts 406-412 of FIG. 4. FIG. 5B illustrates the operations
described in conjunction with act 414 of FIG. 4. FIG. 5C
illustrates the operations described in conjunction with act 416 of
FIG. 4. FIG. 5D illustrates the operations described in conjunction
with act 418 of FIG. 4.
[0044] FIGS. 5E and 5F illustrate views of an exemplary factory
integrated termination 500 that includes an MT female connector 502
consistent with the principles of the invention. Implementations of
the factory integrated termination may be equipped with connectors
and/or receptacles to facilitate easy connection of distribution
devices such as fiber distribution hubs and connectorized-tethers.
This implementation may eliminate the need for a jacket over the
exposed ribbon since the ribbon is terminated directly to an MT
female connector 502 within the over-mold.
[0045] FIG. 6 illustrates the exemplary factory integrated
termination 500 of FIG. 5E configured to include an radio frequency
identification (RFID) tag 600 consistent with the principles of the
invention. Implementations of factory integrated terminations may
be equipped with RFID tags to facilitate the inclusion of
machine-readable information into splice locations. RFID tags are
devices that can store information and transmit information using
radio frequency waves. RFID tags may be passive devices that do not
include a power source or they may be active. Passive RFID tags are
queried using a radio frequency signal from a transceiver. When
irradiated with radio frequency energy, passive RFID tags become
low powered transmitters. The querying transceiver may read
transmissions from the RFID tag.
[0046] In contrast, active RFID tags may include a power source,
such as a battery. Active RFID tags may perform more complex
operations and may transmit over greater distances as compared to
passive RFID tags. An active RFID tag may be in a sleep mode until
it is queried by a transceiver. When queried, the active RFID tag
may turn on a transmitter and may transmit information to the
transceiver.
[0047] RFID tags may receive information for storage via radio
frequency or they may be programmed when they are manufactured
using techniques known in the art. When queried, RFID tags may send
the stored information to a querying device. For example, an RFID
tag 600 can be encoded with information about the geographic
location of the splice and with information about subscribers that
are connected to fibers attached to a breakout, or splice. When
queried, the RFID tag 600 may make the encoded information
available to the querying device.
[0048] FIG. 7 illustrates an exemplary device architecture that may
be used for implementing active RFID tags consistent with the
principles of the invention. Architecture 700 may also be
implemented in computers, querying devices, RFID programming
devices, and devices used for testing factory integrated
termination assemblies without departing from the spirit of the
invention. The implementation illustrated in conjunction with FIG.
7 is exemplary and other configurations may alternatively be
used.
[0049] Architecture 700 may include a processor 720, a bus 722, a
memory 730, a read only memory (ROM) 740, a storage device 750, an
input device 760, an output device 770, and a communication
interface 780. Bus 722 permits communication among the components
of architecture 700 and may include optical or electrical
conductors capable of conveying data and instructions.
[0050] Processor 720 may include any type of conventional
processor, microprocessor, or processing logic that may interpret
and execute instructions, and may be implemented in a standalone or
distributed configuration such as in a parallel processor
configuration. Memory 730 may include a random access memory (RAM)
or another type of dynamic storage device that stores information
and instructions for execution by processor 720. Memory 730 may
also be used to store temporary variables or other intermediate
information during execution of instructions by processor 720.
[0051] ROM 740 may include a conventional ROM device and/or another
static storage device that stores static information and
instructions for processor 720. Storage device 750 may include a
magnetic disk or optical disk and its corresponding drive and/or
some other type of magnetic or optical recording medium and its
corresponding drive for storing information and instructions.
[0052] Input device 760 may include one or more conventional
interfaces, components, and/or mechanisms that permit an operator
to input information to architecture 700, such as a keyboard, a
mouse, a pen, voice recognition and/or biometric mechanisms, etc.
Output device 770 may include one or more conventional mechanisms
that output information to an operator and may include a display, a
printer, one or more speakers, etc. Communication interface 780 may
include any transceiver-like mechanism that enables architecture
700 to communicate with other devices and/or systems. For example,
communication interface 780 may include a wireless transceiver for
communicatively coupling an RFID tag to, for example, a handheld
transceiver.
[0053] Architecture 700 may perform processing in response to
processor 720 executing sequences of instructions contained in
memory 730. Such instructions may be read into memory 730 from
another computer-readable medium, such as storage device 750, or
from a separate device via communication interface 780. It should
be understood that a computer-readable medium may include one or
more memory devices, carrier waves, or data structures. Execution
of the sequences of instructions contained in memory 730 may cause
processor 720 to perform certain acts that will be described
hereafter in conjunction with method diagrams and signal flow
diagrams. In alternative embodiments, hardwired circuitry may be
used in place of or in combination with software instructions to
implement functions performed by architecture 700. Thus,
implementations consistent with the invention are not limited to
any specific combination of hardware circuitry and software.
[0054] FIGS. 8A and 8B illustrate exemplary implementations of a
factory integrated terminations 800 utilizing a ruggedized MT
connector consistent with the principles of the invention.
Implementations of factory integrated terminations 800 may include
tethers 802 that are terminated with connectors. For example, an MT
female connector 804 may be installed on a distal end of one or
more fibers associated with a ribbon that has been extracted from,
or broken out of, a distribution cable 102. Examples of connectors
and/or receptacles that may be adapted for use on the distal end of
an extracted ribbon are further described in U.S. Pat. Nos.
6,648,520 and 6,579,014, assigned to Corning Cable Systems LLC.
[0055] An implementation, such as the one shown in FIG. 8A may
include a ribbon tether 804 having four fibers that may be
terminated with a single SC/APC connector. Implementations
terminated with a connector may be plugged with a mating plug
and/or receptacle until one or more subscribers are connected to
the tether 802. The mating plug and/or receptacle may act as a
dummy plug to protect fibers within the connector from dirt and
moisture. The use of connectorized tethers 802 may allow capital
expenditures associated with distribution devices, such as fiber
drop terminals, to be postponed until subscribers are actually
connected to the distribution cable 102.
[0056] FIGS. 9A and 9B illustrate an exemplary loop back connector
900 for use in testing factory integrated terminations consistent
with the principles of the invention. Implementations terminated
with a connector 902 may be plugged with a loop back connector 900
that can be used to facilitate testing of the tether. The loop back
plug, or connector, may be configured to couple a first fiber in
the tether 904 to a second fiber in the tether 904. At the central
office, a test signal can be injected onto the first fiber and
detected on the second fiber at the central office. Use of a loop
back connector 900 may eliminate shuttling back and forth between a
tether 904 and a central office when testing is performed.
Eliminating shuttling can produce significant time and cost savings
when testing deployed distribution cables 102. An exemplary method
of testing a fiber drop terminal from a single location using loop
back connectors is shown in U.S. patent applications Ser. Nos.
11/198,848 and 11/198,153, assigned to Fiber Optic Network
Solutions Corp, the disclosures of which are hereby incorporated by
reference.
[0057] FIG. 9C illustrates a schematic view of the loop back
connector 900 of FIGS. 9A and 9B along with a schematic
representation of a four fiber ribbon consistent with the
principles of the invention.
[0058] Another aspect of the present disclosure relates to
configurations for reducing the size of loop back testing devices
and for facilitating the ease of manufacturing loop back testing
devices. In one embodiment, a planar lightwave circuit (PLC) is
incorporated into the loop back device to provide a loop back
function. For example, a planar lightwave circuit can be
incorporated into a multi-fiber connector (MFC) assembly for
guiding a light signal emitted from one fiber of the MFC back into
another fiber of the same MFC. In this way, the PLC functions to
loop signals between fibers of an MFC. By providing this loop back
function, test signals can be generated and tested from the same
location (e.g., a central office).
[0059] It will be appreciated that planar lightwave circuits are
well known in the art. For example, planar lightwave circuits and
methods for manufacturing planar lightwave circuits are disclosed
in U.S. Pat. Nos. 6,961,503; 6,937,797; 6,304,706; 6,787,867; and
6,507,680, the disclosures of which are hereby incorporated by
reference in their entireties.
[0060] It will be appreciated that PLC technology has numerous
advantages. For example, since PLC production is similar to the
semiconductor wafer process, the manufacturing costs can be
relatively low. Furthermore, PLC technology can have very low
insertion losses and consistent insertion loss values between each
waveguide path. To make a PLC loop back chip mateable with a
standard MFC, the dimensions of the waveguides of the PLC can be
designed according to MFC intermateability specifications (e.g.,
TIA/EIA-604 for a MPO connector). Additionally, alignment features
can be fabricated into the PLC chip. In certain embodiments, a
predetermined insertion loss can be engineered into the waveguide
design with wavelength sensitivity for measurement identification
purposes.
[0061] FIG. 9D shows a schematic PLC chip 950 including a generally
rectangular substrate 952 and a plurality of waveguides/light
guides 954. As shown in FIG. 9D, six of the waveguides 954 are
shown. Each waveguide 954 has a looped configuration with terminal
ends 956 positioned at an interface side 958 of the substrate 952.
When the PLC chip 950 is integrated into the ferrule of a loop-back
connector, the ends 956 are exposed and adapted to be aligned with
corresponding fibers of a multi-termination (MT) connector desired
to be optically coupled to the loop-back connector. The PLC chip
950 can include alignment structures (e.g., v-grooves, pin
receptacles, pins, or other structures) for ensuring that the ends
956 of the waveguides 954 align with the corresponding fibers of
the MT connector to which the PLC chip 950 is optically
coupled.
[0062] It will be appreciated that the PLC chip 950 can be
manufactured by a number of different techniques. In one
embodiment, the PLC chip is manufactured by initially providing a
bottom substrate including glass having a first index of
refraction. An intermediate layer of glass is then deposited over
the bottom layer. The intermediate layer preferably has a second
index of refraction suitable for a waveguide. The first and second
indexes are different from one another. The intermediate layer is
then etched to define the waveguides 954. Thereafter, a top layer
of glass having an index of refraction comparable to the bottom
layer can be applied over the intermediate layer.
[0063] It will be appreciated that the thicknesses of the bottom
layer and the top layer can be different. For example, the top
layer can be thinner than the bottom layer.
[0064] The interface side 958 of the PLC chip 950 can be polished
to improve performance. Furthermore, the interface side 958 can be
angled to match a corresponding angle of a MT connector to which
the PLC chip 950 is desired to be optically coupled. In one
embodiment, the interface side 958 can be polished at about an 80
degree angle.
[0065] Referring to FIGS. 9E and 9F, the PLC chip 950 is shown
integrated into a ferrule structure 960 of a multi-termination
loop-back connector 962. For example, the PLC chip 950 is shown
mounted within a receptacle 964 defined within the ferrule
structure 960 of the connector 962. A cap 966 or other retaining
structure can be used to retain the PLC chip 950 in the receptacle
964. It will be appreciated that the PLC chip 950 can be free to
float slightly within the receptacle 964. In certain embodiments,
the PLC chip 950 can be spring biased upwardly.
[0066] When mounted in the ferrule structure 960, the polished
interface side 958 of the PLC chip 950 is exposed. The PLC chip 950
is shown including alignment openings 970 for use in aligning the
ends 956 of the waveguides 954 with corresponding fibers 972 of an
MT connector 974 to which the multi-termination loop back connector
962 is desired to be coupled. When the multi-termination connector
974 is connected to the multi-termination loop back connector 962
(as shown at FIG. 9G), pins 976 of the multi-termination connector
974 slide within the openings 970 of the PLC chip 950 to ensure
alignment between the ends 956 of the waveguides 954 and the ends
of the fibers 972. In certain embodiments, it will be appreciated
that the ferrule structure 960 can be incorporated into a loop-back
connector having a latching arrangement of the type shown at FIG.
9A.
[0067] In other embodiments, other types of alignment structures
can be used. For example, male alignment structures (e.g., posts)
can be provided at the PLC chip to facilitate connecting the loop
back connector with a corresponding female MT connector. In still
other embodiments, the PLC chip can be provided with v-grooves at
the ends of the chip for receiving corresponding pins provided on
the connector 524.
[0068] FIGS. 10A and 10B illustrate exemplary implementations of
factory integrated terminations 1000 employing ruggedized
connectors on tethers consistent with the principles of the
invention. The implementations illustrated in FIGS. 10A and 10B may
be have an MT connector 1002 on a first end 1004 and one or more
single port connectors 1006 on a second end 1008. In an example,
the multi-fiber connector 1002 includes a threaded collar 1003. In
an example, the single port connectors 1006 may include
single-fiber rugged adapters. The first end 1004 may plug into a
mating connector associated with a factory integrated termination.
The second end 1008 may include connectors for mating with
connectors attached to fiber optic cables associated with one or
more subscribers. The implementations of FIGS. 10A and 10B may
include a breakout 1010 that operates as a transition from a single
cable to multiple cables associated with connectors on the second
end.
[0069] FIGS. 11A-11F illustrate exemplary implementations of
factory integrated terminations employing fiber drop terminals 1100
consistent with the principles of the invention. Fiber drop
terminals 1100 are further described in U.S. patent application
Ser. Nos. 11/198,848 and 11/198,153, assigned to Fiber Optic
Network Solutions Corp, the disclosures of which have previously
been incorporated by reference. Fiber drop terminals 1100 may
operate to provide connection points for fiber optic cables
associated with subscribers. Fiber drop terminals 1100 may be
attached to structures such as utility poles, buildings, equipment
cabinets, etc.
[0070] Systems and methods consistent with the invention make
possible the fabrication, installation and testing of distribution
cables for passive optical networks. For example, a distribution
cable may be spliced using factory integrated termination
assemblies to provide compact and environmentally sound breakouts
to facilitate easy connection of subscribers to a communications
network.
[0071] The foregoing description of exemplary embodiments of the
invention provides illustration and description, but is not
intended to be exhaustive or to limit the invention to the precise
form disclosed. Modifications and variations are possible in light
of the above teachings or may be acquired from practice of the
invention. For example, while a series of acts have been described
with respect to FIGS. 3 and 4, the order of the acts may be varied
in other implementations consistent with the invention. Moreover,
non-dependent acts may be implemented in parallel.
[0072] For example, implementations consistent with the principles
of the invention can be implemented using connectors, receptacles,
over-molding techniques, and methods other than those illustrated
in the figures and described in the specification without departing
from the spirit of the invention. In addition, the sequence of
events associated with the methods described in conjunction with
FIGS. 3 and 4 can be performed in orders other than those
illustrated. Furthermore, additional events can be added, or
removed, depending on specific deployments, applications, and the
needs of users and/or service providers. Further, disclosed
implementations may not be limited to any specific combination of
hardware circuitry and/or software.
[0073] No element, act, or instruction used in the description of
the invention should be construed as critical or essential to the
invention unless explicitly described as such. Also, as used
herein, the article "a" is intended to include one or more items.
Where only one item is intended, the term "one" or similar language
is used. Further, the phrase "based on," as used herein is intended
to mean "based, at least in part, on" unless explicitly stated
otherwise.
[0074] The above specification, examples and data provide a
complete description of the manufacture and use of the composition
of the invention. Since many embodiments of the invention can be
made without departing from the spirit and scope of the invention,
the invention resides in the claims hereinafter appended.
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