U.S. patent application number 15/788365 was filed with the patent office on 2018-04-12 for intranodal roadm fiber management apparatuses, systems, and methods.
The applicant listed for this patent is Coriant Operations, Inc.. Invention is credited to Bradley R. Kangas, Julia Y. Larikova, Yajun Wang, Richard Y. Younce.
Application Number | 20180102866 15/788365 |
Document ID | / |
Family ID | 52480477 |
Filed Date | 2018-04-12 |
United States Patent
Application |
20180102866 |
Kind Code |
A1 |
Younce; Richard Y. ; et
al. |
April 12, 2018 |
INTRANODAL ROADM FIBER MANAGEMENT APPARATUSES, SYSTEMS, AND
METHODS
Abstract
An intranodal reconfigurable optical add/drop multiplexer
(ROADM) fiber management apparatus, and a system employing the
apparatus. The apparatus comprises a plurality of ingress optical
ports, a plurality of egress optical ports, and a plurality of
optical interconnections interposed between ones of the plurality
of ingress optical ports and ones of the plurality of egress
optical ports. Each of the plurality of ingress optical ports
corresponds to one of the plurality of egress optical ports. Each
one of the plurality of ingress optical ports is optically coupled
by way of the optical interconnections to at least one of the
plurality of egress optical ports. Each one of the plurality of
egress optical ports is optically coupled by way of the optical
interconnections to at least one of the plurality of ingress
optical ports.
Inventors: |
Younce; Richard Y.;
(Yorkville, IL) ; Wang; Yajun; (Naperville,
IL) ; Larikova; Julia Y.; (Naperville, IL) ;
Kangas; Bradley R.; (Saint Charles, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Coriant Operations, Inc. |
Naperville |
IL |
US |
|
|
Family ID: |
52480477 |
Appl. No.: |
15/788365 |
Filed: |
October 19, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14467578 |
Aug 25, 2014 |
9819436 |
|
|
15788365 |
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61869905 |
Aug 26, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04J 14/0217 20130101;
H04J 14/0212 20130101; H04J 14/0204 20130101 |
International
Class: |
H04J 14/02 20060101
H04J014/02 |
Claims
1-20. (canceled)
21. A N-degree system, comprising: a line degree subsystem, the
line degree subsystem including N line degree modules; a plurality
of transceivers; and an add/drop subsystem interposed between the
line degree subsystem and the plurality of transceivers, the
add/drop subsystem including a plurality of subsystem modules,
wherein each of the N line degree modules selects wavelengths
received from at least one of the subsystem modules and outputs the
selected wavelengths to an egress path, and receives at least one
wavelength from an ingress path and outputs the at least one
wavelength to at least one of the plurality of subsystem
modules.
22. The N-degree system of claim 21, wherein the transceivers are
local transponders.
23. The N-degree system of claim 21, wherein each of the N line
degree modules includes one of a broadcast-and-select line degree
module or a route-and-select line degree module.
24. The N-degree system of claim 23, wherein the
broadcast-and-select line degree module includes: a wavelength
selective switch arranged to select wavelengths received from at
least one of the subsystem modules; an output amplifier arranged to
amplify wavelengths selected by the wavelength selective switch and
to provide amplified wavelengths to the egress path; an input
amplifier arranged to amplify the at least one wavelength received
from the ingress path; a broadcast splitter arranged to receive the
at least one wavelength amplified by the input amplifier, and to
output the at least one wavelength amplified by the input amplifier
to at least one of the plurality of subsystem modules.
25. The N-degree system of claim 21, wherein the at least one
wavelength includes a plurality of wavelengths, and wherein each of
the N line degree modules outputs one of the plurality of
wavelengths to an output, and selects the one of the plurality of
wavelengths output by the output of another one of the N line
degree modules.
26. The N-degree system of claim 21, wherein each of the subsystem
modules includes a waveguide module.
27. The N-degree system of claim 21, wherein at least some of the
subsystem modules include: a plurality of inputs, each of the
plurality of inputs being coupled to an output of a corresponding
one of the plurality of transceivers, and at least one output
coupled to a corresponding input of a corresponding one of the N
line degree modules.
28. The N-degree system of claim 27, wherein at least some others
of the subsystem modules include: at least one input coupled to a
corresponding output of a corresponding one of the N line degree
modules; and a plurality of outputs, each of the plurality of
outputs being coupled to an input of a corresponding one of the
plurality of transceivers.
29. The N-degree system of claim 28, wherein the corresponding one
of the plurality of transceivers is a local transponder arranged to
drop a wavelength received at the input of the transceiver, and to
add a wavelength received from a local source.
30. The N-degree system of claim 21, wherein the N-degree system is
colored and directional.
31. The N-degree system of claim 21, wherein one of the plurality
of subsystem modules includes a directionless switch module and
another one of the plurality of subsystem modules includes a
colorless fan-out module.
32. The N-degree system of claim 31, wherein at least one of the
plurality of subsystem modules comprises a directionless switch
module coupled to at least one of the N line degree modules, and a
colorless fan-out module interposed between the directionless
switch module and the plurality of transceivers.
33. The N-degree system of claim 32, wherein the colorless fan-out
module comprises: a first coupling module having an output coupled
to an input of the directionless module, and a plurality of inputs,
each of the plurality of inputs being coupled to an output of a
corresponding one of the plurality of transceivers, and a second
coupling module having an input coupled an output of the
directionless module, and also having a plurality of outputs, each
of which is coupled to an input of a corresponding one of the
transceivers.
34. The N-degree system of claim 33, wherein the directionless
module comprises; a third coupling module having a plurality of
inputs, at least one of which is coupled to the output of the first
coupling module, and also having an output; a wavelength selective
switch arranged to select wavelengths received from the output of
the third coupling module and provide selected wavelengths to the
line degree subsystem; a first amplifier interposed between the
output of the third coupling module and the wavelength selective
switch; a fourth coupling module having a plurality of outputs, at
least one of which is coupled to the input of the second coupling
module, and also having an input; a routing device arranged to
receive wavelengths from the line degree subsystem and provide at
least some of the received wavelengths to an output of the routing
device; and a second amplifier interposed between the output of the
routing device and the input of the fourth coupling module.
35. The N-degree system of claim 21, wherein the line degree
subsystem is colorless, directionless, and contentionless.
36. The N-degree system of claim 35, wherein each of the N line
degree modules includes one of (1) an erbium doped fiber amplifier
and a multicast switch or (2) a low port count module.
37. The N-degree system of claim 21, wherein the at least one
wavelength from the ingress path includes a plurality of
wavelengths, and wherein each of the N line degree modules
comprises: a route wavelength selective switch arranged to select
one or more of the plurality of wavelengths received from the
ingress path, and to output the one or more of the plurality of
wavelengths to the at least one of the plurality of subsystem
modules; and a select wavelength selective switch arranged to
select the wavelengths received from the at least one of the
subsystem modules, and to output the selected wavelengths to the
egress path.
38. The N-degree system of claim 37, wherein the add/drop subsystem
includes a plurality of multicast switches.
39. The N-degree system of claim 38, wherein the add/drop subsystem
also includes an amplifier array interposed between the plurality
of multicast switches and the line degree subsystem.
40. The N-degree system of claim 21, further comprising one of a
fiber shuffle or fiber paths interposed between the line degree
subsystem and the add/drop subsystem.
41. The N-degree system of claim 21, wherein the egress path
comprises a plurality of egress ports, and the ingress path
comprises a plurality of ingress ports, and wherein the N-degree
system selectively couples a wavelength received at any of the
plurality of ingress ports to any of the plurality of egress
ports.
42. The N-degree system of claim 21, wherein the N line degree
modules each include at least one expansion route-and-select line
degree module.
43. The N-degree system of claim 40, wherein the fiber shuffle is
an expansion shuffle having at least one of a star topology, a mesh
topology, or a combination of a star and mesh topology.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application No. 61/869,905, filed on Aug. 26, 2013, the entire
contents of which are hereby incorporated by reference as if set
forth fully herein.
BACKGROUND
Field
[0002] Example aspects described herein relate generally to optical
communication networks, and, more particularly, to intranodal
reconfigurable optical add/drop multiplexer (ROADM) fiber
management apparatuses, and methods and systems employing the
apparatuses.
Description of Related Art
[0003] Wavelength-division multiplexing (WDM) optical networks are
presently dominated by 10 gigabit per second (Gb/s) transmission on
dispersion-managed fiber plants. Such networks are typically
comprised of multiple nodes interconnected by WDM paths. Optical
signals (also referred to interchangeably herein as "traffic",
"wavelengths", and/or "channels") that are communicated across WDM
networks typically originate at a first endpoint (a source system)
that is local to one of the nodes (e.g., by way of a transmitter
portion of local transponder) and terminate at a second endpoint (a
destination system) that is local to another one of the nodes
(e.g., by way of a receiver portion of local transponder). In some
cases traffic is communicated from a source system at a source node
to a destination system at a destination node without traversing
any intermediate nodes. In other cases traffic is communicated from
a source system at a source node to a destination system at a
destination node by way of one or more intermediate nodes.
[0004] To facilitate the flow of traffic from source endpoints to
destination endpoints throughout the network, each of the nodes
includes a reconfigurable optical add/drop multiplexer (ROADM). As
described in further detail below in the context of the various
figures herein, a ROADM (which for convenience is also referred to
interchangeably herein as a "node") typically includes one or more
bidirectional WDM ports coupled to other nodes of the network by
way of one or more bidirectional WDM paths that carry WDMs signals
each having multiple individual channels. Each of the bidirectional
WDM ports of the ROADM is referred to herein as a degree and
includes an ingress WDM port and a corresponding egress WDM port.
The ROADM also includes one or more local add ports and/or local
drop ports coupled to one or more local source systems and/or
destination systems, respectively, from which traffic may originate
and/or terminate.
[0005] The ROADM of a particular node facilitates the flow of
traffic through that node of the network by receiving traffic
either from a source system local to that node by way of a local
add port, or from another node by way of an ingress WDM port, and,
depending on the intended destination for the traffic, routing the
traffic either to a destination system local to that node by way of
a local drop port, or to another node by way of an egress WDM port.
Traffic that a ROADM receives by way of its ingress WDM port from
another node of the network and routes by way of its egress WDM
port to another node of the network is referred to as "express
traffic."
[0006] Traffic that a ROADM either receives from a source system
local to that node or routes to a destination system local to that
node is referred to as "local traffic." More particularly, traffic
that a ROADM receives from a source system local to that node by
way of a local add port, and routes by way of its egress WDM port
to another node of the network is referred to as "local add
traffic." Traffic that a ROADM receives by way of an ingress WDM
port from another node of the network, and routes by way of a local
drop port to a destination system local to the node is referred to
as "local drop traffic."
[0007] Carriers are beginning to build all-coherent networks to
fulfill rising 100 Gb/s service demands and expand network
capacity. Although 100 Gb/s is the initial target data rate, some
operators desire that new networks also support future 400 Gb/s
data rates. In order to support faster data rates and/or provide
additional functionality, modifications to ROADM/node architectures
may be needed.
[0008] Each ROADM includes multiple components (e.g., a line
subsystem, an add/drop subsystem, and local transponders), which
are coupled to one another by way of intranodal optical fiber
paths. Each of the ROADM components may be implemented according to
one of several different architectures, and therefore any
particular ROADM can be implemented according to one of numerous
possible configurations. New node architectures should be flexible
enough to support additional functionality and/or future
transmission formats and as they become available. For instance,
fixed filtering using a wavelength selective switch (WSSs) and a
fixed add/drop structure (e.g., a fixed filtered AWG) may not
fulfill the needs of 400 Gb/s service, which may require
variability in bandwidth. In such a case, flexible grid wavelength
selective switches (WSS) and add/drop elements with programmable
center frequencies and bandwidths (i.e. colorless add/drop
elements) may be desirable to provide colorless functionality. In
some cases, in addition to colorless functionality, further
architectural enhancements may be desired, such as colorless and
directionless (CD) functionality employing a route-and-select WSS
and a directionless add/drop element, and/or colorless,
directionless, and contentionless (CDC) functionality employing a
contentionless add/drop element as well.
[0009] Additionally, node modifications may also be needed to
configure the node to accommodate an increased number of degrees
and/or an increased number of add/drop modules, depending on the
particular application. Thus, node configurations may vary from
node to node and may change over time as needs evolve.
[0010] Management of the numerous intranodal optical fiber paths to
be established between ROADM components (e.g., between the line
subsystem and the add/drop subsystem) can be complex and
burdensome, and the complexity and burden are only compounded by
the needs for node architecture modification and flexibility
described above. Installation and maintenance of the intranodal
fiber paths can be operationally difficult and prone to error.
[0011] In some cases, fiber ribbon cables (each of which includes
multiple, e.g., 12, fibers) may be employed to reduce the number of
cables employed for establishing intranodal fiber paths. Such
ribbon cables typically are terminated by a single multiple-fiber
push-on/pull-off (MPO) connector at each end that contains all 12
terminating fibers. However, as shown in FIG. 4 (described in
further detail below), a ROADM is often configured such that its
intranodal fiber paths are meshed, in that fibers from a single
module of the ROADM are routed to a variety of other modules of the
ROADM. Therefore, although coupling MPO-to-MPO ribbon cables
directly between ROADM modules may decrease the complexity of
managing the intranodal fiber paths somewhat, such an approach may
not enable the ROADM to provide the mesh topology often required of
intranodal ROADM paths.
SUMMARY
[0012] Existing limitations associated with the foregoing, as well
as other limitations, can be overcome by intranodal reconfigurable
optical add/drop multiplexer (ROADM) fiber management apparatuses
(also referred to herein as a "fiber shuffles" and/or as "fiber
interconnection apparatuses") and systems and methods that employ
such apparatuses to simplify the management of intranodal ROADM
fiber paths.
[0013] In one example embodiment herein, the apparatus includes a
plurality of ingress optical ports, a plurality of egress optical
ports, and a plurality of optical interconnections interposed
between ones of the plurality of ingress optical ports and ones of
the plurality of egress optical ports. Each of the plurality of
ingress optical ports corresponds to one of the plurality of egress
optical ports. Each one of the plurality of ingress optical ports
is optically coupled by way of the optical interconnections to at
least one of the plurality of egress optical ports. Each one of the
plurality of egress optical ports is optically coupled by way of
the optical interconnections to at least one of the plurality of
ingress optical ports.
[0014] In one example, for each one of the plurality of ingress
optical ports, the one of the plurality of ingress optical ports is
optically coupled by way of the optical interconnections to each
one of the plurality of egress optical ports, excluding one of the
plurality of egress optical ports that corresponds to the one of
the plurality of ingress optical ports.
[0015] According to another example embodiment, the apparatus is
housed in a single rack mountable enclosure, the enclosure
including a plurality of ingress optical connectors by which
respective ones of the plurality of ingress optical ports are
accessible, and a plurality of egress optical connectors by which
respective ones of the plurality of egress optical ports are
accessible.
[0016] Also in one example embodiment herein, the plurality of
optical interconnections is comprised of a plurality of topology
modules including at least one of a mesh topology module and a star
topology module.
[0017] In a further example embodiment herein, a contiguous group
of ones of the plurality of ingress optical connectors is coupled,
by way of the mesh topology module, to ones of the plurality of
egress optical connectors that are adjacently arranged in the
enclosure. In addition, at least one of the plurality of ingress
optical connectors and a corresponding at least one of the
plurality of egress optical connectors are terminated at a common
termination, in one example.
[0018] In one example, a group of ones of the plurality of ingress
optical connectors is coupled, by way of the star topology module,
to a group of ones of the plurality of egress optical connectors,
and at least one pair of corresponding ones of the optical ingress
connectors and the optical egress connectors that is not included
in the star topology module is interposed in the enclosure between
the group of ones of the plurality of ingress optical connectors
and the group of ones of the plurality of egress optical
connectors.
[0019] According to another example embodiment, the enclosure
includes one or more vacant slots that can accommodate one or more
additional topology modules.
[0020] Also in one example embodiment herein, individual ones of
the plurality of ingress optical connectors correspond to
respective ones of the plurality of egress optical connectors.
[0021] In a further example embodiment herein, the plurality of
optical interconnections is comprised of a plurality of topology
modules including at least one of a mesh topology module and a star
topology module. Each of the plurality of topology modules is
coupled to at least one of (1) a contiguous group of adjacent ones
of the plurality of ingress optical connectors and (2) a contiguous
group of adjacent ones of the plurality of egress optical
connectors.
[0022] In one example, each of the plurality of ingress optical
ports includes a plurality of ingress optical fibers, and each of
the plurality of egress optical ports includes a plurality of
egress optical fibers.
[0023] According to another example embodiment, a total number of
the plurality of optical ingress ports included in the apparatus is
equal to a total number of the plurality of optical egress ports
included in the apparatus.
[0024] In another example embodiment herein, an intranodal ROADM
fiber management system is provided. The system includes a line
subsystem including a plurality of line degree modules, an add/drop
subsystem including a plurality of add/drop modules, a plurality of
local transponders, and a fiber management apparatus. One or more
of the plurality of line degree modules is communicatively coupled
to one or more of the local transponders by way of the fiber
management apparatus and one or more of the add/drop
subsystems.
[0025] In a further example embodiment herein, the fiber management
apparatus included in the system comprises a plurality of ingress
optical ports, a plurality of egress optical ports, and a plurality
of optical interconnections interposed between ones of the
plurality of ingress optical ports and ones of the plurality of
egress optical ports. Each of the plurality of ingress optical
ports corresponds to one of the plurality of egress optical ports.
Each one of the plurality of ingress optical ports is optically
coupled by way of the optical interconnections to at least one of
the plurality of egress optical ports. Each one of the plurality of
egress optical ports is optically coupled by way of the optical
interconnections to at least one of the plurality of ingress
optical ports.
[0026] In one example, the plurality of line degree modules include
at least one of (1) a broadcast and select line degree module that
includes a splitter and a select wavelength selective switch (WSS)
and (2) a route and select line degree module that includes a route
WSS and a select WSS.
[0027] According to another example embodiment, the plurality of
add/drop modules includes at least one of (1) a colorless,
directionless, and contentionless (CDC) add/drop module having an
erbium doped fiber amplifier and a multicast switch and (2) a low
port count (LPC) CDC add/drop module.
[0028] Also in one example embodiment herein, the system further
includes at least one expansion fiber management apparatus, and one
or more of the plurality of line degree modules is communicatively
coupled to one or more of the local transponders by way of the
fiber management apparatus, the expansion fiber management
apparatus, and one or more of the add/drop subsystems.
[0029] In a further example embodiment herein, the expansion fiber
management apparatus includes a plurality of expansion line degree
modules. The a plurality of expansion line degree modules include
at least one of (1) a broadcast and select expansion line degree
module that includes a splitter and a select wavelength selective
switch (WSS) and (2) a route and select expansion line degree
module that includes a route WSS and a select WSS.
[0030] In one example, the fiber management apparatus is housed in
a first rack mountable enclosure, and the expansion fiber
management apparatus is housed in a second rack mountable
enclosure.
[0031] According to another example embodiment, at least two of (1)
one or more of the plurality of line degree modules, (2) one or
more of the plurality of add/drop modules, (3) one or more of the
plurality of local transponders, and (4) the fiber management
apparatus are optical coupled to one another by way of one or more
optical ribbon cables.
[0032] Also in one example embodiment herein, the system is coupled
to an optical network by way of at least one wavelength division
multiplexed path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The teachings claimed and/or described herein are further
described in terms of exemplary embodiments. These exemplary
embodiments are described in detail with reference to the drawings.
These embodiments are non-limiting exemplary embodiments,
wherein:
[0034] FIG. 1 shows an architecture of an example ROADM, in
accordance with at least one example aspect herein.
[0035] FIG. 2 shows an example ROADM that employs a
broadcast-and-select architecture, in accordance with an example
embodiment described herein.
[0036] FIG. 3 shows an example ROADM that employs a
route-and-select architecture, in accordance with an example
embodiment described herein.
[0037] FIG. 4 shows an example architecture of a ROADM that employs
multiple route-and-select line degree modules and LPC CDC add/drop
modules, in accordance with an example embodiment herein.
[0038] FIG. 5 shows further details of an example 10-port fiber
shuffle, in accordance with an example embodiment herein.
[0039] FIG. 6 shows an example labeling scheme for the ports of a
10-port shuffle, in accordance with an example embodiment
herein.
[0040] FIG. 7 illustrates an example manner by which components of
an example ROADM system may be interconnected by way of a fiber
shuffle, in accordance with an example embodiment herein.
[0041] FIG. 8 shows an example topology of optical fibers that are
internal to a fiber shuffle, in accordance with an example
embodiment herein.
[0042] FIG. 9 shows another example topology of optical fibers that
are internal to a fiber shuffle, in accordance with an example
embodiment herein.
[0043] FIG. 10 shows an example ROADM node system that employs both
a fiber shuffle and an expansion shuffle, in accordance with an
example embodiment herein.
[0044] FIG. 11 illustrates further details of an example ROADM node
system and the components thereof, in accordance with an example
embodiment herein.
[0045] FIG. 12 shows an example ROADM system that includes a
17-port shuffle interposed between 12 line degree modules 5 CDC
add/drop modules, in accordance with an example embodiment
herein.
[0046] FIG. 13 shows an example 10-port shuffle wherein each of the
ingress ports and each of the egress ports includes 3 MPO
terminations, each having 6 fibers, in accordance with an example
embodiment herein.
[0047] FIG. 14 shows a four-way mesh topology removed from a
context of a shuffle, in accordance with an example embodiment
herein.
[0048] FIG. 15 shows an example 10-port shuffle that includes three
instances of a four-way mesh topology, in accordance with an
example embodiment herein.
[0049] FIG. 16 illustrates an example shuffle constructed based on
a bidirectional 6-way star topology, in accordance with an example
embodiment herein.
[0050] FIG. 17 shows an example 6-way star topology removed from a
context of a shuffle, in accordance with an example embodiment
herein.
[0051] FIG. 18 shows an example 10-port shuffle including three
instances of a 6-way star topology, in accordance with an example
embodiment herein.
[0052] FIG. 19 shows an example 10-port shuffle including three
instances of a 6-way star topology, in accordance with an example
embodiment herein.
[0053] FIG. 20 shows an example 10-port shuffle, in accordance with
an example embodiment herein.
[0054] FIG. 21 illustrates an example arrangement by which three
mesh topologies and three star topologies can mate with ports and
terminations of a fiber shuffle, in accordance with an example
embodiment herein.
[0055] FIG. 22 illustrates another example arrangement by which
three mesh topologies and three star topologies can mate with ports
and terminations of a fiber shuffle, in accordance with an example
embodiment herein.
[0056] FIG. 23 illustrates yet another example arrangement by which
three mesh topologies and three star topologies can mate with ports
and terminations of a fiber shuffle, in accordance with an example
embodiment herein.
[0057] FIG. 24 shows a further arrangement by which three mesh
topologies and three star topologies can mate with ports and
terminations of a shuffle, in accordance with an example embodiment
herein.
[0058] FIG. 25 illustrates how components of an example 4-degree
ROADM system, including an example fiber shuffle, can be
interconnected, in accordance with an example embodiment
herein.
[0059] FIG. 26 illustrates how components of an example 8-degree
ROADM system, including an example fiber shuffle, can be
interconnected, in accordance with an example embodiment
herein.
[0060] FIG. 27 shows an example fiber shuffle having multiple
individual mesh topologies and star topologies, in accordance with
an example embodiment herein.
[0061] FIG. 28 shows another example embodiment of a 21-port
expandable shuffle, in accordance with an example embodiment
herein.
[0062] FIG. 29 shows an example 21-port shuffle, in accordance with
an example embodiment herein.
[0063] FIG. 30 shows an example mapping of mesh topology modules
and star topology modules to a fiber shuffle, in accordance with an
example embodiment herein.
[0064] FIG. 31 shows an example 5-port mesh topology module that
can be used to construct a fiber shuffle, in accordance with an
example embodiment herein.
[0065] FIG. 32 shows an example 8-port star topology module that
can be used to construct a fiber shuffle, in accordance with an
example embodiment herein.
[0066] FIG. 33 shows an example 21-port 4-degree shuffle, in
accordance with an example embodiment herein.
[0067] FIG. 34 shows an example 21-port 4-degree shuffle with
blocks indicating how a mesh topology module and star topology
modules are mapped, in accordance with an example embodiment
herein.
[0068] FIG. 35 shows an example construction of an 8-degree 21-port
shuffle, that employs two 1-rack unit mountable shelves, in
accordance with an example embodiment herein.
DETAILED DESCRIPTION
[0069] Presented herein are novel and inventive intranodal
reconfigurable optical add/drop multiplexer (ROADM) fiber
management apparatuses (sometimes referred to herein as fiber
shuffles), and systems and methods employing the apparatuses. In
accordance with some aspects described herein, as described below
in further detail, the apparatuses, methods, and systems employ a
modularized fiber shuffle, in some cases together with fiber ribbon
cables, to greatly simplify the management of intranodal (i.e.,
intra-ROADM) paths for express and local add/drop channels in an
optical network. In some example embodiments, to aid in the
installation, test, and identification of intranodal
interconnections, optical test channels can be routed between
modules (e.g., line degree modules, CDC add/drop modules, expansion
modules, local transponders, etc.) in parallel with the add, drop,
and/or express channels using a separate WDM channel. The test
channels can be used between the modules to verify proper
intranodal fiber setup, failure analysis, and to discover the port
interconnections between the modules within the node.
[0070] Additionally, in accordance with various example aspects
described herein, fiber shuffles are provided that are flexible
enough to manage a range of numbers of ROADMs and types of ROADM
modules (e.g., line degree modules, CDC add/drop modules, local
transponders, expansion modules, etc.). The fiber shuffle includes
a plurality of ports, each of which can be used for various types
of modules of a ROADM.
[0071] FIG. 1 shows an architecture of an example N-degree ROADM
100. In this example, the ROADM 100 represents one node of a
multiple-node WDM optical network (not shown in FIG. 1). Before
describing how the ROADM 100 functions, a description of the
components of the ROADM 100 and how those components are
interconnected will be provided. It should be understood that each
of components of the ROADM 100 described herein may be implemented
according to one of several different architectures. Therefore the
ROADM 100 can be implemented according to one of numerous possible
configurations.
[0072] In the example of FIG. 1, fiber paths throughout the ROADM
100 and/or throughout the network are symmetrical, with one fiber
being used to transmit optical signals between two points in a
first direction, and a second fiber being used to transmit optical
signals between those two points in the opposite direction;
however, this example should not be construed as limiting. Each
degree of the N-degree ROADM 100 is coupled to the network (not
shown in FIG. 1) by way of a respective pair of interoffice WDM
paths 106 (e.g., interoffice fiber optic cables), including an
ingress WDM path and an egress WDM path.
[0073] As shown in FIG. 1, the ROADM 100 includes a line degree
subsystem 102, intranodal fiber paths 112, an add/drop subsystem
110, and local transponders 108. For convenience, the following
description of components of the ROADM 100 is provided in the
context of one of the degrees of the ROADM 100. A similar
description applies to the components of each other degree of the
ROADM 100 as well.
[0074] The line degree subsystem 102 includes multiple (e.g., N)
WDM line degree OADM modules 104, one per each degree of the ROADM
100. In the example of FIG. 1, the WDM line degree OADM modules 104
are broadcast-and-select type line degree modules that include an
input amplifier 120, a broadcast splitter 122, a select WSS module
128, and an output amplifier 130. The ingress portion of the WDM
path 106 is coupled to an ingress port 116 of the line degree
module 104, which is coupled to a multiple-fiber broadcast output
port 118 of the line degree module 104 by way of the input
amplifier 120 and the splitter 122. A multiple-fiber select input
port 124 of the line degree module 104 is coupled to the egress
portion of the WDM path 106 by way of the select WSS module 128,
the output amplifier 130, and an egress port 126 of the line degree
module 104. As described below, because of the broadcasting and
selecting functions performed by the splitter 122 and the WS S 128,
respectively, the architecture of the example line subsystem 102
shown in FIG. 1 is sometimes referred to as a broadcast-and-select
architecture.
[0075] In the example of FIG. 1, the add/drop subsystem 110
includes a plurality of arrayed waveguide (AWG) modules 114 and
132, with each degree having an ingress AWG module 114 and an
egress AWG module 132. One fiber of the multiple-fiber output port
118 of the line degree module 104 is coupled to an input port 134
of the ingress AWG module 114 by way of a respective one of the
intranodal fiber paths 112 (e.g., a local drop traffic path, as
described below). Each other fiber of the multiple-fiber output
port 118 of the line degree module 104 is coupled, by way of a
respective one of the intranodal fiber paths 112, to a respective
fiber of the multiple-fiber select input port 124 of a respective
one of the other line degree modules 104 that corresponds to one of
the other degrees of the ROADM 100 (e.g., an express traffic path,
as described below). In this way, the example ROADM 100 shown in
FIG. 1 may be described as "colored" and "directional", meaning
that any one of the local transponders 108 that is plugged into a
specific port of the ingress AWG module 114 or the egress AWG
module 132, which in turn is tied to a specific one of the degrees
of line subsystem 102, can only communicate at one specific
wavelength (or color) and with one specific distant node (or end
office).
[0076] Each of the local transponders 108 includes a receiver
portion that is coupled to a corresponding local destination system
(not shown in FIG. 1) for local drop traffic, and a transmitter
portion that is coupled to a corresponding local source system (not
shown in FIG. 1) for local add traffic. For local drop traffic,
each fiber of the multiple-fiber output port 136 of the ingress AWG
module 114 is coupled to a respective one of the local destination
systems by way of a receiving portion of a respective one of the
local transponders 108. For local add traffic, each one of the
local source systems is coupled to a respective fiber of the
multiple-fiber input port 138 of the egress AWG module 132 by way
of a respective one of the transmitting portions of a respective
one of the local transponders 108. An output port 140 of the egress
AWG module 140 is coupled to a respective fiber of the
multiple-fiber input port 124 of the select WSS module 128 of the
line degree module 104.
[0077] Broadcast-and-select line subsystem architectures, such as
that shown in FIG. 1 (102) have two drawbacks when it comes to
expressing 400 Gb/s signals. First, the nodal optical
signal-to-noise ratio (OSNR) decreases with higher degree counts.
This is due to the higher loss with large split ratios in the
broadcast splitter 122 (shown in FIG. 1 with only 4 ports but
typically has more than 4 ports). This may not be problematic for
applications employing low degree counts and robust modulation
formats such as quadrature phase-shift keying (QPSK). But with the
higher OSNR requirement of quadrature amplitude modulation (QAM)
applications and higher port counts desired to support flexible
add/drop structures, the broadcast-and-select architecture may
limit 400 Gb/s network reach.
[0078] A second drawback with the broadcast-and-select line
architecture is the port isolation in the select WSS (e.g., 128).
Each WSS 128 receives input channels broadcasted by splitters 122
from multiple ingress degrees and input channels provided by
multiple local transponders 108. The WSS 128 selects single
wavelengths for transmission, but signals from unselected
wavelengths (e.g., from other degrees) may not be perfectly
blocked. This may not be problematic for applications with low
degree counts and tolerant transmission formats, but it may limit
QAM in high port count scenarios. Thus, in some cases a different
architecture can be employed as the line degree subsystem 102, such
as a route-and-select architecture described below.
[0079] Having described the components of the ROADM 100 and how
those components are interconnected, a description of how the
components of the ROADM 100 function will now be provided. As
mentioned above, each individual optical channel signal (e.g.,
.lamda..sub.1, also referred to interchangeably herein as
"traffic", a "wavelength", and/or a "channel") that is communicated
across the multiple-node WDM network originates at a first endpoint
(a source system) that is local to one of the ROADMs and terminates
at a second endpoint (a destination system) that is local to
another one of the ROADMs. The signal (e.g., .lamda..sub.1) can be
communicated from a source system local to a source ROADM to a
destination system local to a destination ROADM without traversing
any intermediate ROADMs. The signal can also be communicated from a
source system local to a source ROADM to a destination system local
to a destination ROADM by way of one or more intermediate ROADMs.
In general, the ROADM 100 functions by facilitating the flow of
signals through that particular node, for example, by multiplexing
and/or routing signals so that they reach the intended destination
systems, which may be local to the ROADM 100 or may instead be
local to a distant ROADM of the network.
[0080] Traffic that the ROADM 100 receives from another ROADM of
the network, and routes (referred to as pass-through switching) to
yet another ROADM of the network, is referred to as "express
traffic." Traffic that the ROADM 100 receives from a source system
local to the ROADM 100, and routes to another ROADM of the network
is referred to as "local add traffic." Traffic that the ROADM 100
receives from another ROADM of the network, and routes to a
destination system local to the ROADM 100 is referred to as "local
drop traffic."
[0081] Thus, for a given individual wavelength or channel signal
(e.g., .lamda..sub.1), the ROADM 100 may be (1) local to a source
system from which the signal originates, (2) local to a destination
system to which the signal is to be communicated, or (3) an
intermediate ROADM, local neither to the source nor the destination
system of the signal, that forwards the signal along its path to
the destination system which is local to another ROADM of the
network. Under each of these three scenarios, the individual
wavelength or channel signal (e.g., .lamda..sub.1) traverses a
different path through the components of the ROADM 100, as
described in further detail below.
[0082] In a case where the individual wavelength signal (e.g.,
.lamda..sub.1) is a local drop signal to be communicated to a
destination system local to the ROADM 100, the following is an
example path through which the signal can traverse. The signal
(e.g., .lamda..sub.1) is one wavelength of a multiple-wavelength
(e.g., .lamda..sub.1 to .lamda..sub.n) WDM signal that is received
at the input port 116 of the input amplifier 120, from the output
port 126 of another ROADM (not shown in FIG. 1) by way of an
ingress path of the WDM paths 106. The WDM signal is then amplified
by the input amplifier 120, and then broadcasted to the input port
134 of the ingress AWG module 114 (as part of the local drop path)
and to respective fibers of the multiple-fiber input port 124 of
the select WS S modules 128 of the other degrees of the ROADM (as
part of express traffic paths), by way of respective fibers of the
multiple-fiber output port 118 of the splitter 122 and respective
ones of the intranodal paths 112. The ingress AWG module 114
demultiplexes the WDM signal (e.g., .lamda..sub.1 to .lamda..sub.n)
received at the input port 134 into its individual constituent
wavelengths (e.g., one of which is .lamda..sub.1), and provides
(i.e., drops) each wavelength to a destination system local to the
ROADM 100 by way of a receiving portion of a respective one of the
local transponders 108.
[0083] In a case where the individual wavelength signal (e.g.,
.lamda..sub.1) is a local add signal that is to be communicated
from a source system local to the ROADM 100 to a destination system
that is local to another distant ROADM (not shown in FIG. 1) of the
network, the following is an example path the signal can traverse.
The signal (e.g., .lamda..sub.1) is transmitted (i.e., added) by a
source system local to the ROADM 100 to a respective fiber of the
multiple-fiber input port 138 of the egress AWG module 132 by way
of a transmitting portion of a respective one of the local
transponders 108. The egress AWG module 132 multiplexes the signal
(e.g., .lamda..sub.1) into a WDM signal (e.g., .lamda..sub.1 to
.lamda..sub.n) that also includes wavelengths received from other
source systems local to the ROADM 100, and provides the WDM signal
to a respective fiber of the multiple-fiber input port 124 of the
select WSS module 128 by way of a respective one of the intranodal
fiber paths 112. In addition to the WDM signal (e.g., .lamda..sub.1
to .lamda..sub.n) received from the output port 140 of the egress
AWG module 140, the select WSS module 128 also receives multiple
other WDM signals, one per input fiber of the input port 124, from
egress AWG modules 132 and/or splitters 122 of other degrees of the
ROADM 100. The select WSS module 128 selects (passes) specific ones
of the individual wavelengths signals (e.g., .lamda..sub.1) that
are part of the WDM signals received at the fibers of input port
124, and blocks other ones of the individual wavelengths signals
(e.g., .lamda..sub.1) that are part of the WDM signals received at
the fibers of input port 124. A WDM signal (e.g., .lamda..sub.1 to
.lamda..sub.n) including only the individual wavelengths signals
(e.g., .lamda..sub.1) selected by the select WSS module 128 is
amplified by the output amplifier 130, and then provided to its
destination in the network by way of an egress path of the WDM
paths 106.
[0084] In a case where the ROADM 100 is not local to the source
system or the destination system of the signal, but instead is
intermediate to the source or the destination system of the signal
(which is an express signal), the following is an example path
through which the signal can traverse. The signal (e.g.,
.lamda..sub.1) is one wavelength of a multiple-wavelength (e.g.,
.lamda..sub.1 to .lamda..sub.n) WDM signal that is received at the
input port 116 of the input amplifier 120, from the output port 126
of another ROADM (not shown in FIG. 1) by way of an ingress path of
the WDM paths 106. The WDM signal is then amplified by the input
amplifier 120, and then broadcasted to the input port 134 of the
ingress AWG module 114 (as part of the local drop path, described
above) and to respective fibers of the multiple-fiber input port
124 of the select WS S modules 128 of the other degrees of the
ROADM (as part of express traffic paths now described), by way of
respective fibers of the multiple-fiber output port 118 of the
splitter 122 and respective ones of the intranodal paths 112. A
select WSS module 128 of a respective one of the other line degree
modules 104 of the ROADM 100 selects (passes) specific n ones of
the individual wavelength signals (e.g., including the express
signal .lamda..sub.1) that are part of the WDM signals received at
the fibers of input port 124, and blocks all other ones of the
individual wavelengths signals that are part of the WDM signals
received at the fibers of input port 124. A WDM signal (e.g.,
.lamda..sub.1 to .lamda..sub.n) including only the n individual
wavelength signals (e.g., .lamda..sub.1) selected by the select WSS
module 128 is amplified by the output amplifier 130, and then
provided to its destination in the network by way of an egress path
of the WDM paths 106.
[0085] Having described the components and functionality of the
example ROADM 100, reference will now be made to FIG. 2 to
illustrate an example ROADM 200 that employs an alternative
add/drop subsystem architecture, in accordance with an example
embodiment herein. As shown in FIG. 2, the ROADM 200 includes many
of the same components (e.g., the line subsystem 202, intranodal
fiber paths 204, add/drop subsystem 206, and local transponders
208) as those that were described above in connection with the
ROADM 100 of FIG. 1. Because the components that appear in both
ROADM 100 and ROADM 200 are configured and function in a similar
manner as described above in the context of FIG. 1, a complete
description of the configuration and functionality of each
component of FIG. 2 will not be repeated here.
[0086] However, one difference between the ROADM 100 and the ROADM
200 is that, whereas the ROADM 100 employs an AWG architecture
add/drop subsystem 110, the ROADM 200 employs a two-tiered
colorless and directionless (CD) add/drop subsystem 206. Since the
two-tiered colorless and directionless add/drop subsystem 206
functions in a known manner to route signals between the local
add/drop transponders 208 and the line degree subsystem 202, a
complete description of its functionality is not provided herein.
In general, the add/drop subsystem 206 aggregates add channels from
the local transponders 208 and presents the aggregated add channels
to the line subsystem 202 for transmission to a destination in the
network. The add/drop subsystem 206 also routes drop channels from
the line subsystem 202 to receivers in the local transponders
208.
[0087] The add/drop subsystem 206 includes a directionless switch
module 218 and a colorless fan-out module 220. Although the
add/drop subsystem 206 is shown in FIG. 2 as being coupled to a
broadcast-and-select line subsystem architecture (202), the
add/drop subsystem 206 can be configured with other types of line
subsystem architectures instead, such as a route-and-select
architecture. Because all channels pass through a single EDFA 222
in the directionless switch module 218 before being routed to the
line degree modules 210, the architecture shown in FIG. 2 may
provide blocking functionality.
[0088] The example architectures of add/drop subsystems described
herein (e.g., CD and CDC), are provided for illustrative purposes
only. Additional add/drop subsystem architectures, such as
architectures based on M.times.N WSS for directionless switching
and multiplexing, may be employed in lieu of the example
architectures described herein. Additionally, although CD
functionality has been described in the context of a
broadcast-and-select line subsystem architectures, and CDC
functionality has been described in the context of a
route-and-select line subsystem architectures, either type of line
subsystem architectures can be employed together with any of a
number of types of add/drop subsystem architectures. Although
various example embodiments herein are described in the context of
a route-and-select line degree subsystem and a LPC CDC MCS-based
add/drop subsystem, this is for illustrative purposes only and
should not be construed as limiting the scope of the present
invention. Additionally, other combinations of architectures and
port sizes are contemplated and are within the scope of the various
example embodiments described herein.
[0089] Having described the example ROADMs 100 and 200, reference
will now be made to FIG. 3 to illustrate an example ROADM 300 that
employs an alternative line degree subsystem architecture and an
alternative add/drop subsystem architecture, in accordance with an
example embodiment herein. As shown in FIG. 3, the ROADM 300
includes many of the same components (e.g., the line subsystem 302,
intranodal fiber paths 312, add/drop subsystem 306, and local
transponders 310) as those that were described above in connection
with the ROADM 100 of FIG. 1 and/or the ROADM 200 of FIG. 2.
Because the components that appear in both ROADM 100 and ROADM 300
are configured and function in a similar manner as described above
in the context of FIG. 1, a complete description of the
configuration and functionality of each component of FIG. 3 will
not be repeated here.
[0090] One difference between the ROADM 100 and the ROADM 300 is
that, whereas the line degree modules 104 of the ROADM 100 include
a broadcast splitter 122 that broadcasts the WDM signal received
from the network to the local add/drop subsystem 110 and to a line
degree module 104 of each other degree of the ROADM 100, the
example ROADM 300 instead employs a route WSS 302 that provides the
WDM signal received from the network only to either the local
add/drop module 306 or to a line degree module 104 of a select one
of the other degrees of the ROADM 300. This type of line degree
subsystem architecture is referred to as a route-and-select
architecture, because of the routing and selecting functions
performed by a route WSS 302 and a select WSS 304, respectively.
Employing a route-and-select architecture can mitigate the loss and
isolation challenges described above by using the route WSS 302 to
steer each ingress wavelength only to the desired destination
(e.g., an egress degree or a local transponder). Eliminating unused
wavelengths at a select WS S 304 removes the leakage of extraneous
channels because interfering wavelengths are simply not present at
the select WSS 304. In terms of loss, the route-and-select ROADM
300 has a fixed loss (typically 12-16 dB) from a pair of WSSs
(i.e., the route WSS 302 and the select WSS 304) regardless of the
number of degrees. In this way, a high degree count
route-and-select WSS can be employed to serve many flexible
add/drop structures with no deleterious reduction in node OSNR.
[0091] Which particular add/drop subsystem architecture is employed
in a ROADM may depend, at least in part, on desired functionality.
For instance, variable bandwidth channels may necessitate colorless
add/drop functionality. Along with colorless add/drop
functionality, colorless and directionless (CD) add/drop
functionalities may be desired to improve the usability of high
cost transponders. Additionally, colorless, directionless, and
contentionless (CDC) add/drop structures have non-blocking
benefits. Each type of functionality may be a factor in determining
which add/drop subsystem architecture to employ.
[0092] Another difference between the ROADM 100 and the ROADM 300
is that, whereas the ROADM 100 employs an AWG architecture add/drop
subsystem 110, the add/drop subsystem employed in the ROADM 200 is
a non-blocking colorless, directionless, and contentionless (CDC)
module 306. Since the CDC add/drop module 306 functions in a known
manner to route signals between the local add/drop transponders 310
and the line degree subsystem 308, a complete description of its
functionality is not provided herein.
[0093] For convenience, only a pair of route-and-select line degree
modules 308 is shown in FIG. 3, along with the CDC add/drop module
306 and a pair of transponders 310; a complete illustration of the
modules (306, 308, and 310) and the fiber interconnections
therebetween (e.g., made by way of intranodal fiber paths 312) is
not provided in FIG. 3. In addition, each of the line degree
modules 308 and the CDC add/drop module 306 are shown as having
only four input ports (e.g., input ports 318 of each one of the
line degree modules 308, and input ports 320 of the CDC add/drop
module 306) and four output ports (e.g., output ports 322 of each
one of the line degree module 308, and output port 324 of the CDC
add/drop module 306) (each port being coupled to a corresponding
one of the intranodal fiber paths 312) between the line degree
modules 308 and the CDC add/drop module 306. In some cases,
however, there may be additional (e.g., twenty) ports on the line
degree modules 308 and additional (e.g., eight) ports on the CDC
add/drop module 306. The CDC add/drop module 306 includes multiple
16.times.8 multicast switches (MCSs) 314, each of which connects 16
local transponders 310 with up to 8 route-and-select WDM line
degree modules 308. In the add direction, outputs of the 16 local
transponders 310 are switched and combined by the MCS 314. A CDC
add/drop module 306 of this size may have high optical loss and so
an erbium-doped fiber amplifier (EDFA) array 316 may be added to
the CDC add/drop module 306 to overcome the loss and meet minimum
optical power requirements of the line subsystem 308.
[0094] A CDC add/drop module such as the module 306, which includes
the 16.times.8 MCS 314 and the EDFA array 316, may be expensive and
may suffer from degraded performance due to its high loss. A low
port count (LPC) CDC add/drop module based on an 8.times.6 MCS can
support 8 line degree modules and 6 local transponders but has low
loss which may eliminate the need for an EDFA array, which, in
turn, may reduce the cost of the CDC add/drop module and boost its
optical performance. One drawback, however, associated with an
architecture employing a LPC CDC add/drop module is the lower
number of adds/drops that can be supported on the LPC CDC module
(e.g., 6 instead of 16).
[0095] As can be appreciated in view of the above descriptions of
the ROADMS 100, 200, and 300 of FIGS. 1, 2, and 3, respectively,
there are numerous architecture options for implementing a ROADM
(e.g., broadcast-and-select, route-and-select, two-tiered CD
add/drop modules, CDC add/drop modules, LPC CDC add/drop modules,
etc.). Which architectures are used for a particular ROADM can
depend on the particular needs of that node, which may change
requiring reconfiguration of the ROADM interconnections (e.g., the
intranodal fiber paths 112, 204, or 312 described above in the
contexts of FIG. 1, 2, or 3, respectively). As mentioned above,
managing the reconfiguration of such ROADM interconnections can be
complex and prone to error.
[0096] To illustrate an example of such interconnections, reference
will now be made to FIG. 4, which shows an example architecture of
a ROADM 400 that employs multiple route-and-select line degree
modules 402 and LPC CDC add/drop modules 404 based on 8.times.6
MCSs (MCSs not explicitly shown in FIG. 4). As shown in FIG. 4, the
ROADM 400 includes many of the same components (e.g., the line
degree subsystem 402, intranodal fiber paths 410, add/drop
subsystem 404, and local transponders 406) as those that were
described above in connection with the ROADMs 100, 200, and/or 300
of FIGS. 1, 2, and/or 3, respectively. Because the components that
appear in both ROADM 400 and ones of the ROADMs 100, 200, and/or
300 are configured and function in a similar manner as described
above in the context of FIGS. 1, 2 and/or 3, a complete description
of the configuration and functionality of each component of FIG. 4
will not be repeated here.
[0097] In one example embodiment, the input and output ports of the
line degree modules 402, the add/drop modules 404, and the local
transponders 406 of the ROADM 400 of FIG. 4 generally correspond to
(and are interconnected in much the same way as) the input and
output ports of the line degree modules 104, the add/drop modules
110, and the local transponders 108 of the ROADM 100 of FIG. 1,
although different numbers of inputs and outputs are shown in FIGS.
1 and 4. Accordingly, a description of how the input and output
ports of the line degree modules 402, the add/drop modules 404, and
the local transponders 406 of the ROADM 400 are interconnected,
which is apparent from FIG. 4, is not provided here.
[0098] Additionally, since each LPC CDC add/drop module 404
supports fewer local transponders 406 (6 local transponders, in
this example), and since it may be desirable that at least one port
of each line degree module 402 be coupled (e.g., via an optical
fiber) to a port of each CDC add/drop module 404, there may be a
need to expand ports on the line degree modules 402 so that the
total number of local transponders 406 (e.g., 36 local transponders
(6 per CDC add/drop module 404), in this example) can be supported
overall. Thus, shown in FIG. 4 are expansion route-and-select line
degree modules 408 that subtend the route-and-select line degree
modules 402. In the example of FIG. 4, there is one expansion
module 408 for each degree. This approach effectively expands the
number of ports of each line degree module 402, thereby enabling
the line degree modules 402 to accommodate a greater number of CDC
add/drop modules 404 and local transponders 406. Further
description of an expansion scheme is provided below in the context
of FIG. 10 and FIG. 11. Although FIG. 4 shows only one port of each
line degree module 402 as being coupled to a port of a
corresponding one of the CDC add/drop modules 404 by way of a
corresponding one of the expansion line degree modules 408, in some
cases, a greater number of ports of the line degree modules 402 can
be coupled to a greater number of ports of the CDC add/drop modules
404 by way of additional expansion line degree modules (not shown
in FIG. 4). For example, two ports from each line degree module 402
can be coupled via optical fibers to two expansion modules (408)
per degree.
[0099] Each fiber path (e.g., each of the intranodal fiber
connections 410) is shown in FIG. 4 as being bidirectional.
Accordingly, each fiber path shown in FIG. 4 may be realized with,
for example, a fiber pair. Additionally, the 9-port line degree
modules 402, in practice, may scale to 20 or more ports resulting
in many hundreds of fiber jumpers between modules. Thus, as
illustrated in FIG. 4, it is clear that management of individual
fiber cables (i.e., intranodal fiber connections 410) between each
of the ports of the modules 402, 404, 408 can be complex,
especially in cases where ROADM configuration changes are
frequently desired due to continuously evolving needs. Installation
and maintenance of these fibers can also be operationally difficult
and prone to error.
[0100] Using fiber ribbon cables (each of which includes multiple,
e.g., 12, fibers) to establish intranodal fiber paths can reduce
the number of cables. Such ribbon cables typically are terminated
by a single multiple-fiber push-on/pull-off (MPO) connector at each
end that contains all 12 terminating fibers. In some cases, each
MPO connector (or any other connector and/or termination described
herein) includes at least one ingress fiber and at least one egress
fiber, thus providing bidirectional (or symmetrical) connectivity
between endpoints. However, as shown in FIG. 4, the intranodal
fiber paths are meshed in that fibers from a single module are
routed to a variety of other modules. Therefore, although coupling
MPO-to-MPO ribbon cables directly between ROADM modules would
decrease the complexity of managing the intranodal fiber paths,
such an approach would not enable the mesh topology often required
of intranodal ROADM paths.
[0101] Described herein are various example embodiments that
provide an apparatus for managing intranodal fiber paths that
optically couple ROADM components (e.g., line degree modules,
expansion modules, and/or CDC modules). In one example embodiment,
the apparatus includes an additional piece of equipment (sometimes
referred to herein as a "fiber shuffle") that replaces the
intranodal fiber paths 112, 204, 312, and/or 410 described above in
the contexts of FIGS. 1, 2, 3, and/or 4, respectively, and that is
operable to shuffle optical fibers that provide meshed optical
paths between the input and output ports of ROADM components. The
fiber shuffle allows for direct MPO connections to the ROADM
components and includes internal fiber routing of individual fibers
from its connectors to other connectors within the shuffle. The MPO
cables from each ROADM component are then cabled directly to the
shuffle. The shuffle thus facilitates the establishment of
individual fiber paths between various ROADM components, while
greatly simplifying the management of intranodal fiber paths.
[0102] One feature of a ROADM node is that it can be configured to
handle a variable number of degrees and a variable number of
add/drop modules so that it can be sized for a particular
application, which may be different for each node of a network and
may change over time. For instance, at one particular node 4 line
degrees modules and 6 CDC add/drop modules may be needed, whereas
another node may require 6 line degree modules and 4 CDC add/drop
modules. Also, a node may initially be configured with 2 line
degree modules and 2 CDC add/drop modules, and in the future may be
expanded to include an increased number of line degree modules
and/or CDC add/drop modules. Thus, the various example embodiments
herein provide a fiber shuffle that is sufficiently flexible to
support a range of module numbers and types, and that includes
ports that can be used for various module types. In this way, the
fiber shuffle can facilitate different interconnect patterns
between line degree modules, expansion line degree modules, and/or
CDC add/drop modules (see, e.g., the various interconnect patterns
between the components of FIG. 4).
[0103] Having described an example fiber shuffle in general terms,
reference will now be made to FIG. 5 to describe an example 10-port
fiber shuffle 500 in greater detail, in accordance with an example
embodiment herein. The fiber shuffle 500 includes 10 bidirectional
(or symmetrical) ports 502, 504 (numbered 1 to 10 in FIG. 5), each
port comprising a multiple-fiber ingress port 502 a multiple-fiber
egress port 504, which are shown in FIG. 5 as being vertically
aligned. For instance, port 1 is comprised of a 9-fiber ingress
port 1 (one of the 10 ingress ports 502) and a 9-fiber egress port
1 (one of the 10 egress ports 504).
[0104] In the example shuffle 500, each port (e.g., ingress ports 1
through 10, egress ports 1 through 10) includes a plurality (e.g.,
9) of fibers. By way of a hardwired topology internal to the
shuffle 500, the ports of the shuffle 500 are mutually meshed in
that each port (e.g., port 1) is coupled to each other port (e.g.,
ports 2 through 10) by way of respective ones of the 9 fibers of
the respective ports. For example, the 9 fibers of ingress port 1
are coupled to respective fibers of egress ports 2 through 10. For
example, the 9 fibers of egress port 1 are coupled to respective
fibers of ingress ports 2 through 10. In this way, by way of the
internal topology of the shuffle 500, a signal that is received at
any one of the ingress ports 502 can be outputted by way of any one
of the nine other egress ports 504.
[0105] As described above, in one example embodiment, the shuffle
500 can replace the intranodal fiber paths 112, 204, 312, and/or
410 described above in the contexts of FIGS. 1, 2, 3, and/or 4,
respectively, and can shuffle optical fibers that provide meshed
optical paths between the input and output ports of ROADM
components. The fiber shuffle 500 also allows for direct MPO
connections to ROADM components (not shown in FIG. 5) and includes
internal fiber routing of individual fibers from its connectors to
other connectors within the shuffle. The MPO cables from each ROADM
component can then be cabled directly to the shuffle 500. The
shuffle 500 thus facilitates the establishment of individual fiber
paths between various ROADM components, while greatly simplifying
the management of intranodal fiber paths.
[0106] For instance, as will be described in further detail below,
in one example embodiment the bidirectional shuffle ports 502, 504
can be cabled (external to the shuffle 500) to a single module in
the system, be it a line degree module or CDC add/drop module
(neither of which is shown in FIG. 5). In the case of a
route-and-select line degree module, the ingress port 1 (502) at a
top portion of the shuffle 500 can be connected to a route WSS port
of the line degree module, and the egress port 1 (504) at a bottom
portion of the shuffle 500 can be connected to a select WSS port of
the line degree module.
[0107] Additionally, as described in further detail below in
connection with FIGS. 13 through 19, the topology of the shuffle
500 may be modularized (e.g., broken down into discrete modular
components) to increase the ease and flexibility of manufacturing
the shuffle 500 and reconfiguring a ROADM that employs the shuffle
500.
[0108] Having described an example shuffle 500, reference will now
be made to FIG. 6 to describe an example front panel of a 10-port
shuffle 600. The shuffle 600 is similar to the shuffle 500
described above in the context of FIG. 5, except that, whereas the
shuffle 500 has 9 fibers per ingress port and 9 fibers per egress
port, the shuffle 600 has 12 fibers per ingress port and 12 fibers
per egress port.
[0109] FIG. 6 shows an example 10-port shuffle 600 where each port
is comprised of a pair of 12-fiber MPO connectors 602 (e.g., one
MPO connector 602 for each ingress port and one MPO connector 602
for each egress port, positioned below its corresponding ingress
port) and each port is labeled. According to the port labeling
shown in the example shuffle 600 of FIG. 6, the shuffle 600 can
support up to 8 line degree modules and/or up to 8 CDC add/drop
modules (such as the line degree modules 104, 210, 308, 402 and/or
the modules of the add/drop subsystems 110, 206, 306, 404 described
above in the contexts of FIGS. 1 through 4). For simplicity of
management, line degree modules can be connected to the ports of
the shuffle 600 in a direction from left-to-right, for instance,
beginning with port 1 and continuing on to the port 2, and so
forth, up to a port corresponding to the total number of line
degree modules (8 or less in this example). CDC add/drop modules
can be connected to the ports of the shuffle 600 in a direction
from right-to-left, for instance, beginning with port 10 and
continuing on to port 9, and so forth, down to a port corresponding
to the total number of CDC add/drop modules (8 or less in this
example). It can be seen in the example shuffle 600 that port 3
through port 8 can be used for either line degree modules or CDC
add/drop modules. In this way, the shuffle 600 can support from 1
to 8 line degree modules and from 1 to 8 CDC add/drop modules.
[0110] Having described an example front patent of the shuffle 600,
reference will now be made to FIG. 7 to describe how an example
shuffle 702 can be interconnected to other ROADM components using
fiber ribbon cables. As shown in FIG. 7, the ROADM 700 includes
many of the same components (e.g., the line degree modules 704,
add/drop modules 708, and local transponders 706) as those that
were described above in connection with the ROADMs 100, 200, and/or
300 of FIGS. 1, 2, and/or 3, respectively. Because the components
that appear in the ROADM 700 and in one or more of ROADMs 100, 200,
and/or 300 are configured and function in a similar manner as
described above in the context of FIGS. 1, 2, and/or 3, a complete
description of the configuration and functionality of each
component of FIG. 7 will not be repeated here.
[0111] FIG. 7 illustrates how components of an example ROADM system
700 may be interconnected by way of an example fiber shuffle 702
(e.g., in lieu of intranodal fiber paths 112, 204, 312, and/or 410
of FIGS. 1 through 4, respectively), in accordance with an example
embodiment herein. In the example ROADM system 700, by way of
multiple cables 710, 712, and 714 and a topology (not shown)
internal to the shuffle 702, the 4 line degree modules 704 can be
coupled to one another and to each of 6 local transponders 706 by
way of corresponding ones of 6 CDC add/drop modules 708. In
particular, cables 710 couple the line degree modules 704 to the
shuffle 702; cables 712 couple the shuffle 702 to the add/drop
modules 708; and cables 714 couple the add/drop modules 708 to the
local transponders 706, as shown in FIG. 7. In one example
embodiment, the cables 710 and 712, together with the shuffle 702,
replace the intranodal fiber paths 112, 204, 312, and/or 410
described above in the contexts of FIGS. 1 through 4,
respectively.
[0112] Having described how components of a ROADM may be
interconnected to the shuffle 702, reference will now be made to
FIG. 8 to describe how fibers of ROADM components may be coupled to
fibers of other ROADM components via an internal shuffle
topology.
[0113] FIG. 8 shows an example topology (interconnection pattern)
804 of optical fibers that are internal to the example shuffle 702
described above in connection with FIG. 7. By way of the example
topology 804 shown in FIG. 8, which is the same as topologies
described in further detail above in the context of the shuffle 500
(FIG. 5), each of the 4 line degree modules 704 is coupled to each
other one of the 4 line degree modules 704 (for routing express
traffic) and also to each of the 6 CDC add/drop modules 708 (for
routing local add traffic and local drop traffic).
[0114] Note that the route WSS 802 (e.g., which may be the route
WSS 302 described above in the context of FIG. 3) of degree 1 is
coupled to all egress ports of the shuffle 702 except for egress
port 1 (i.e., egress ports 2 through 9) by way of ingress port 1
and optical fibers 804 that are internal to the shuffle 702. Degree
1 select WSS 806 (e.g., which may be the select WSS 304 described
above in the context of FIG. 3) is coupled to all ingress ports of
the shuffle 702 except for ingress port 1 (i.e., ingress ports 2
through 9) by way of egress port 1 and optical fibers 804 that are
internal to the shuffle 702. Because in most cases there is no need
for a particular degree (e.g., degree 1) to select channels that
are received on that degree to be transmitted on the same degree,
in the example topology shown in FIG. 8 ingress degree 1 and egress
degree 1 are not coupled to one another by internal optical fibers
804. The flow of signals throughout the line degree modules 704 and
the add/drop modules 708 by way of the shuffle 702 is similar to
the flow of signals throughout the example ROADMs 100, 200, 300,
and 400, and so is not repeated here.
[0115] The CDC add/drop modules 1 through 6 shown in FIG. 8 are
similarly coupled to ports of the shuffle 702. Each CDC add/drop
module (e.g., the CDC add/drop module 1) is coupled to a
corresponding one of the bidirectional ports of the shuffle 702
(e.g., port 10, which is comprised of ingress port 10 and egress
port 10). Transmit channels (i.e., adds) from local transponders
(not explicitly shown in FIG. 8) are switched and combined within
corresponding CDC add/drop modules (e.g., the CDC add/drop module
1), and are coupled to a corresponding one of the ingress ports of
the shuffle 702 (e.g., one of ingress ports 1 through 9). The
egress ports of the shuffle 702 (e.g., egress port 10) is connected
back to that same CDC add/drop module (e.g., CDC add/drop module 1)
for splitting, switching, and final handoff of an optical signal to
the local transponder for reception. Note that only the first 8
fibers for each of the example 8.times.6 MCS-based CDC add/drop
modules shown in FIG. 8 are connected to the port of the shuffle
702. By way of the example topology 804 of the shuffle 702 shown in
FIG. 8, each of the CDC add/drop modules 1 through 6 is coupled to
each of the line degree modules 1 through 4. Careful tracing of the
optical paths 804 shown in the shuffle 702 confirms that as many as
8 line degree modules or as many as 8 CDC add/drop modules can be
completely interconnected by way of the shuffle 702, following the
growth pattern described above in the context of FIG. 6.
[0116] Although FIG. 8 has been described as having 4 degree
modules 704, 6 add/drop modules 708 (and 6 local transponders
(receiver/transmitter pairs)), this is by example only. As shown in
the labeling of FIG. 7, multiple different configurations are
possible for connecting ROADM components to the shuffle 702. To
illustrate this, reference will now be made to FIG. 9, which shows
the example shuffle 702 interconnected to 8 line degree modules 904
and 2 add/drop modules 906 (and local transponders).
[0117] FIG. 9 shows an example topology 902 of optical fibers that
are internal to the example shuffle 702 described above in
connection with FIGS. 7 and 8. Whereas in the example of FIG. 7 the
shuffle 702 is coupled to 4 line degree modules 704 and 6 CDC
add/drop modules, in the example of FIG. 9 the shuffle 702 is
coupled to 8 line degree modules 904 and 2 CDC add/drop modules
906. By way of the example topology 902 shown in FIG. 9, which is
the same as topologies described in further detail above in the
context of the shuffles 500 (FIG. 5) and 702 (FIG. 8), each of the
8 line degree modules 904 is coupled to each other one of the 8
line degree modules 904 (for routing express traffic) and also to
each of the 2 CDC add/drop modules 906 (for routing local add
traffic and local drop traffic).
[0118] Having described example manners by which a fiber shuffle
may couple ROADM components (e.g., line degree modules, add/drop
modules, local transponders, etc.), reference will now be made to
FIG. 10 to describe an example embodiment that employs an expansion
shuffle to increase the number of ROADM components that a main
shuffle can accommodate. FIG. 10 shows an example ROADM system 1000
that employs both a fiber shuffle 1002 (which may further represent
the example shuffles 600 and/or 702 described above in the context
of FIG. 6 through FIG. 9) and an expansion shuffle 1004 (also
referred to herein as an "expansion fiber management apparatus").
Before a description of FIG. 10 is provided, a general description
of expansion modules will be provided.
[0119] As mentioned above in the context of FIG. 4, in various
example embodiments herein, expansion modules (e.g., expansion
route-and-select line degree modules) are employed to expand the
number of ports of each (non-expansion) line degree module of a
ROADM, thereby enabling the (non-expansion) line degree modules to
accommodate a greater number of CDC add/drop modules and/or local
transponders. In one example, each expansion module is a line
degree module (e.g., in addition to the non-expansion line degree
modules of the ROADM) that functions in a manner similar to that of
a non-expansion line degree module (e.g., element 308 described
above in the context of FIG. 3). For example, each expansion module
can contain a route-and-select WSS (such as elements 302 and 304
described above in the context of FIG. 3) and an EDFA (the input
and output amplifiers shown in each module 308) to overcome the
losses of the internal WSS. In some example embodiments, more than
one expansion module can be allocated to each line degree module,
thereby increasing the number of effective add/drop ports of the
ROADM. Although various example embodiments are described herein in
which expansion modules are coupled between line degree modules and
CDC add/drop modules, this should not be construed as limiting.
Other expansion architectures are contemplated, such as a
multi-tiered expansion architecture, wherein a line degree module
is coupled to CDC add/drop modules by way of two or more expansion
modules that are connected to one another in a daisy chain.
[0120] Referring now to FIG. 10, the system 1000 includes many
components similar to those describe above in the context of FIG.
7, and so the configuration and functionality of those components
is not repeated here. However, the ROADM 1000 also includes an
expansion shuffle 1004, expansion modules 1006, and cable 1012,
which together, as described in further detail below, enable each
of the 8 degree modules 1010 to be coupled to each of a plurality
of local add/drop transponders (not shown in FIG. 10) by way of 9
add/drop modules 1008. In particular (as described in further
detail below in the context of FIG. 11), each line degree module
1010 is coupled to each other line degree module 1010 by way of the
internal topology of the main shuffle 1002. Each line degree module
1010 is also coupled to each add/drop module 1008 by way of a path
including the internal topology of the main shuffle 1002, port 9 of
the main shuffle 1002, cable 1012, port 1022 of the expansion
shuffle 1004, jumpers 1016, cables 1014, expansion modules 1020,
cables 1024, the internal topology of the expansion shuffle 1004,
and cables 1026.
[0121] In some example embodiments, the main shuffle 1002 can be
any one of the shuffles 600 or 702 described above in the context
of FIG. 6 through FIG. 9. The expansion shuffle 1004 is an
additional shuffle, distinct from the main shuffle 1002, that has
been added to the system 1000 so as to couple line degree modules
1010 to subtended CDC modules 1008 by way of expansion modules
1006. Note that ports 9 and 10 of the main shuffle 1002 are shown
with two labels indicating that those ports can be used in either
of two ways. In this particular example, ports 9 and 10 of the main
shuffle 1002 can be used either to couple the line degree modules
1010 to CDC add/drop modules (e.g., 1008) without an expansion
shuffle interposed therebetween, or to couple the line degree
modules 1010 to CDC add/drop modules 1008 by way of the expansion
shuffle 1008, as now illustrated. The labeling of the main shuffle
1002 shown in FIG. 10 is provided as an example only, and is not
limiting; other labeling schemes are contemplated. For instance,
the expansion option on the main shuffle is not limited to ports 9
and 10. In other example embodiments, any of the ports 1 through 10
of the main shuffle 1002 can be used for expansion modules.
[0122] The main shuffle 1002 and expansion shuffle 1004 are coupled
to one another in this example by way of a 12-fiber MPO cable 1012
interposed between port 9 of the main shuffle 1004 and a main port
1022 of the expansion shuffle 1004. The expansion modules 1006 are
coupled to corresponding fiber jumper ports 1017 of the expansion
shuffle 1004 by way of MPO cables 1015 in a manner similar to that
by which the line degree modules 1010 are connected to the ports
(Degree 1 through Degree 8) of the main shuffle 1002. One
exception, however, is that while in the case of the line degree
modules 1010 the line input and output fiber paths 1018 on the line
1010 degree modules are connected to an interoffice fiber plant
(not shown in FIG. 10), the line input and output ports 1020 of the
expansion modules 1006 are connected to a corresponding pair (one
for each direction) of the expansion shuffle fiber jumper ports
1016.
[0123] As can be appreciated in view of the above description of
FIG. 10, employing an expansion shuffle 1004 in conjunction with a
main shuffle 1002 in the manner described can provide flexibility
by enabling an increased number of ROADM components to be
interconnected in a convenient manner. For instance, by using only
one port (e.g., port 9) of the main shuffle 1002, together with the
expansion shuffle 1004, line degree modules 1010 can be coupled to
multiple ROADM components (e.g., the 9 add/drop modules 1026 shown
in FIG. 10).
[0124] Having described an example system 1000 employing an
expansion shuffle 1004, reference will now be made to FIG. 11 to
describe further details of system 1000 and the components thereof.
The system 1000 includes 8 line degree modules 1010, 8 expansion
modules 1006, 9 CDC add/drop modules 1008, and multiple local
transponders 1102. The line degree modules 1010 are coupled to the
main shuffle 1002 as described above in the context of FIG. 10. One
of the ports (port 9 in this example) of the main shuffle 1002 is
coupled via the multi-fiber ribbon cable 1012 to the main port 1022
of the expansion shuffle 1004. By way of the cable 1012 and the
main port 1022, each of the 8 line degree modules 1010 is provided
with an optical path to the line input and line output ports 1020
of the 8 expansion modules 1006. Each of the fibers of the cable
1012 is coupled to the expansion shuffle 1004 by way of the main
port 1022, and from there is routed to the line input and output
ports 1020 of the expansion modules 1006 by way of a fiber
connector 1016 (e.g., mounted to a faceplate of the expansion
shuffle 1004) and one of cables 1014. In another example
embodiment, the MPO cable 1012 from the main shuffle 1002 is
terminated with 12 dual-fiber connectors (not shown in FIG. 11),
which are directly plugged into corresponding ones of the line
input ports 1020 and/or line output ports 1020 of the expansion
modules 1006. The expansion modules 1006 are coupled to the local
transponders 1102 by way of the internal fiber topology 1106 of the
expansion shuffle 1004 and respective ones of the CDC add/drop
modules 1008. In various example embodiments herein, the internal
topology 1106 of the expansion shuffle 1004 can be implemented by
employing any one or a combination of one or more mesh topologies
and/or one or more star topologies, which are described below in
the context of FIGS. 13 through 19.
[0125] Although various example embodiments described herein
include 9-port route-and-select degree modules (e.g., 308, 402,
408, 704, 904, 1006, 1010), this is by example only and should not
be construed as limiting. Other example embodiments are
contemplated that can be directly scaled to manage fiber paths in
line degree modules having a higher port count. For example,
16-port (e.g., 16-fiber) line degree modules can be accommodated in
a 17-port main shuffle with 16-fiber MPO cables per port, and the
internal fiber topologies 1104 (in the main shuffle 1002) and 1106
(in the expansion shuffle 1004) shown in FIG. 11 can be scaled to
accommodate such a higher port count implementation. If an 8-degree
ROADM including such elements (e.g., 16-port line degree modules, a
17-port main shuffle) is arranged in a manner similar to that of
the ROADMs described above (e.g., 500, 700, 1000), and 8.times.6
MCS-based CDC add/drop modules are employed, each of the CDC
add/drop modules can be coupled to the 8 line degree modules of the
ROADM by using only 8 of the 16 fibers in the 16-fiber MPO cable.
In a case where greater than 8 degrees are required (e.g., 12
degrees), a larger MCS-based CDC add/drop module (e.g., a
12.times.6 MCS-based CDC add/drop module) can be employed to couple
each of the CDC add/drop modules to each of the 12 line degree
modules in the ROADM.
[0126] In the various example embodiments described thus far
herein, ROADM components are meshed in that each line degree module
of the ROADM is coupled by way of fibers to every other line degree
module of the ROADM and to every other local transponder of the
ROADM. In some example embodiments, however, there may be no need
to couple every one of the CDC add/drop modules (or every one of
the local transponders) to every one of the 12 line degree modules
of the ROADM. In such a case, certain local transponder channels
may be limited to being routed to a subset of the line degree
modules in the ROADM, but this limitation may be acceptable from a
network routing perspective. In such an example embodiment, LPC CDC
add/drop module (e.g., an 8.times.6 CDC add/drop module) may be
employed even in ROADM systems having a number of degrees that is
larger than the maximum number that the LPC CDC add/drop module can
accommodate fully (e.g., greater than 8 degree in this
example).
[0127] FIG. 12 shows an example ROADM system 1200 that includes a
17-port shuffle 1202 interposed between 12 line degree modules 1204
and 58.times.6 CDC add/drop modules 1206. By way of the topology
1208 internal to the shuffle 1202, every one of the 12 line degree
modules 1204 is coupled to every one of the ports 13 through 17 of
the shuffle. Thus, each of the CDC add/drop modules 1206 can
(depending on which particular fibers of the ports 13 through 17
are used) be coupled to any of the 12 line degree modules 1204.
However, because the 8.times.6 CDC add/drop modules 1206 have only
8 fibers available to be coupled to the shuffle 1202, in the
example of FIG. 12, each of the CDC add/drop modules 1206 can
(depending on which particular fibers of the ports 13 through 17
are used) only be coupled to a maximum of 8 of the 12 line degree
modules 1204. In the example shown in FIG. 12, one of the CDC
add/drop modules 1206 (CDC 1) is coupled to eight particular ones
of the line degree modules 1204 (degrees 1 through 8), another of
the CDC add/drop modules 1206 (CDC 2) is coupled to eight
particular ones of the line degree modules (degrees 2 through 9),
and so forth. In this manner, a single shuffle may be installed at
a ROADM node, and the node may be configured by (1) employing LPC
CDC add/drop modules, in which case fiber cables may be tailored to
suit the needs of that particular node by coupling specific fibers
of the LPC CDC add/drop modules to specific fibers of the shuffle,
as needed, or (2) employing higher port-count CDC add/drop modules
to provide complete interconnections between every CDC add/drop
module and line degree module.
[0128] As mentioned above, various example topologies internal to
fiber shuffles are possible, and which specific topology is used
can depend on multiple factors, such as the specific needs of a
particular node, which may evolve over time and warrant
reconfiguration of shuffle topologies and/or other ROADM
components. To simplify the configuration and reconfiguration of
shuffle internal topologies, such topologies can be assembled, in
accordance with various example embodiments herein, based on one or
more subtopologies (e.g., mesh topologies and/or star topologies),
as described in further detail below in connection with FIGS. 13
through 35.
[0129] In accordance with some of the example embodiments herein,
industry-standard MPO multi-fiber terminations, which are available
in specific numbers of fibers, are employed in a shuffle to couple
line degree modules to CDC add/drop modules. Each MPO multi-fiber
termination, in one example, includes at least one ingress fiber
and at least one egress fiber, thus providing bidirectional (or
symmetrical) connectivity between endpoints. Using the shuffle 500
shown in FIG. 5 as an example, it can be seen that the topology of
the shuffle 500 is composed of multiple instances of two underlying
interconnection patterns (also referred to herein as topologies),
namely an N-way mesh topology and an M-way star topology, which
will be described in further detail below. In some example
embodiments herein, the internal topology of a shuffle is
constructed from multiple instances of such mesh topologies and/or
star topologies, each of which can be fabricated as an individual
module and/or cable (e.g., a ribbon cable). In this manner, the
internal topology of a shuffle can be simplified and/or grouped
into subcomponents (e.g., one for each mesh topology and one for
each star topology), which also can simplify the manufacturing of a
shuffle and/or the scaling of a size of a shuffle to accommodate an
increased number of internal fiber connections.
[0130] FIG. 13 shows an example 10-port shuffle 1300. Although not
shown in FIG. 13, the shuffle 1300 can be coupled to other ROADM
components (e.g., line degree modules, add/drop modules, local
transponders, etc.) in manners similar to those described above in
the contexts of FIG. 7 and/or FIG. 10. Each of the 10 ingress ports
1302 and each of the 10 egress ports 1304 of the shuffle 1300
includes 3 MPO terminations 1306, each MPO termination 1306 having
a total of 6 fibers (3 ingress fibers for the ingress port 1302 and
3 egress fibers for the egress port 1304). Paths between ports 1
through 4 for termination 1 are set in bold to illustrate the
four-way mesh topology 1308. The four-way mesh topology 1308 can be
described as follows: (1) fiber 1 of ingress port 1, fiber 2 of
ingress port 1, and fiber 3 of ingress port 1 are coupled to
respective ones of fiber 1 of egress port 2, fiber 1 of egress port
3, and fiber 1 of egress port 4; (2) fiber 1 of ingress port 2,
fiber 2 of ingress port 2, and fiber 3 of ingress port 2 are
coupled to respective ones of fiber 1 of egress port 1, fiber 2 of
egress port 3, and fiber 2 of egress port 4; (3) fiber 1 of ingress
port 3, fiber 2 of ingress port 3, and fiber 3 of ingress port 3
are coupled to respective ones of fiber 2 of egress port 1, fiber 2
of egress port 2, and fiber 3 of egress port 4; and (4) fiber 1 of
ingress port 4, fiber 2 of ingress port 4, and fiber 3 of ingress
port 4 are coupled to respective ones of fiber 3 of egress port 1,
fiber 3 of egress port 2, and fiber 3 of egress port 3. As can be
seen in FIG. 13, in the four-way mesh topology 1308 there are no
fibers that couple any single ingress port to that same egress port
(e.g., no fibers of ingress port 1 are coupled to any fibers of
egress port 1).
[0131] As can be seen from FIG. 13, the mesh topology 1308 is
four-way in that it couples four ports (ports 1 through 4) to one
another, and the mesh 1308 utilizes all three fibers of the first
termination (termination 1) 1306. The mesh 1308 is provided by
example only, and the number of ports that it couples and/or the
number of fibers and/or terminations that is utilizes are not
limited to those of this example. In some example embodiments, a
mesh topology is provided that, based on the number of fibers
(e.g., N fibers) included in each termination of a shuffle, can
mutually couple N+1 ports to one another. In this example, the
number of ports that a mesh topology can mutually couple to one
another is based on the number of fibers included in each
termination of the shuffle.
[0132] Although the mesh topology 1308 shown in FIG. 13 is a
four-way mesh topology 1308, wherein each is provided by way of
example only. Mesh topologies having different configurations
(e.g., N-way mesh topologies, and/or) are contemplated.
[0133] To further illustrate the four-way mesh topology 1308
provided for port 1 through port 4 of the shuffle 1300, FIG. 14
shows the four-way mesh topology 1308 with other portions of the
shuffle 1300 removed for clarity. As can be seen from FIG. 14, by
way of the mesh topology 1308, each of ports 1 through 4 is coupled
to each other one of ports 1 through 4. In particular, by way of
the mesh topology 1308, ingress port 1 is coupled to egress ports 2
through 4, and egress port 1 is coupled to ingress ports 2 through
4; ingress port 2 is coupled to egress ports 1, 3, and 4, and
egress port 2 is coupled to ingress ports 1, 3, and 4; ingress port
3 is coupled to egress ports 1, 2, and 4, and egress port 3 is
coupled to ingress ports 1, 2, and 4; ingress port 4 is coupled to
egress ports 1 through 3, and egress port 4 is coupled to ingress
ports 1 through 3.
[0134] Having described an example mesh subtopology, reference will
now be made to FIG. 15, which shows that the example 10-port
shuffle 1300 of FIG. 13 includes three instances of the four-way
mesh topology 1308. For convenience, the three instances of the
four-way mesh topology shown in FIG. 15 are labeled mesh 1502, mesh
1504, and mesh 1506. As described above in the context of mesh
1308, mesh 1502 (which may further represent mesh 1308) provides
coupling for various ones of fiber 1, fiber 2, and fiber 3 of port
1, port 2, port 3, and port 4. In the same manner, mesh 1504
provides coupling for various ones of fiber 4, fiber 5, and fiber 6
of port 4, port 5, and port 6. Likewise, mesh 1506 provides
coupling for various ones of fiber 7, fiber 8, and fiber 9 of port
7, port 8, port 9, and port 10.
[0135] Having described an example mesh topology that can be
employed in a fiber shuffle, reference will now be made to FIG. 16,
which illustrates a shuffle 1600 that is constructed based on an
example bidirectional 6-way star topology 1602. The 6-way star
topology 1602 can be described as follows: (1) fiber 4 of ingress
port 1, fiber 5 of ingress port 1, and fiber 6 of ingress port 1
are coupled to respective ones of fiber 1 of egress port 5, fiber 1
of egress port 6, and fiber 1 of egress port 7; (2) fiber 4 of
ingress port 2, fiber 5 of ingress port 2, and fiber 6 of ingress
port 2 are coupled to respective ones of fiber 2 of egress port 5,
fiber 2 of egress port 6, and fiber 2 of egress port 7; (3) fiber 4
of ingress port 3, fiber 5 of ingress port 3, and fiber 6 of
ingress port 3 are coupled to respective ones of fiber 3 of egress
port 5, fiber 3 of egress port 6, and fiber 3 of egress port 7; (4)
fiber 1 of ingress port 5, fiber 2 of ingress port 5, and fiber 3
of ingress port 5 are coupled to respective ones of fiber 4 of
egress port 1, fiber 4 of egress port 2, and fiber 4 of egress port
3; (5) fiber 1 of ingress port 6, fiber 2 of ingress port 6, and
fiber 3 of ingress port 6 are coupled to respective ones of fiber 5
of egress port 1, fiber 5 of egress port 2, and fiber 5 of egress
port 3; and (6) fiber 1 of ingress port 7, fiber 2 of ingress port
7, and fiber 3 of ingress port 7 are coupled to respective ones of
fiber 6 of egress port 1, fiber 6 of egress port 2, and fiber 6 of
egress port 3.
[0136] To further illustrate a 6-way star topology (e.g., topology
1602 described above) that may be included in a fiber shuffle, FIG.
17 shows a 6-way star topology 1700 removed from a context of a
shuffle for clarity. In this example, fiber 1 through fiber 3 of
termination 1 through termination 3 are coupled to fiber 1 through
fiber 3 of termination 4 through termination 6.
[0137] As can be seen from FIG. 17, a star topology (e.g., 1700)
couples a set of N inputs (e.g., 6 inputs, in the example of FIG.
17) to a separate set of M outputs (6 outputs, in the example of
FIG. 17), where N and M have the same number of ingress and egress
fibers (6 ingress fibers and 6 egress fibers, in the example of
FIG. 17).
[0138] Together FIG. 18 and FIG. 19 show that the example 10-port
shuffle 1600 of FIG. 16 includes three instances of the 6-way star
topology 1602. For convenience, the three instances of the 6-way
star topology shown in FIG. 18 and FIG. 19 are labeled star 1802,
star 1804, and star 1806. As described above in the context of star
1602, star 1802 (which may further represent star 1602) provides
coupling for various ones of fiber 4, fiber 5, and fiber 6 of port
1, port 2, and port 3, and fiber 1, fiber 2, and fiber 3 of port 5,
port 6, and port 7. In a similar manner, star 1804 (only half of
which is set in bold in FIG. 17) provides coupling for various ones
of fiber 7, fiber 8, and fiber 9 of port 4, port 5, and port 6, and
fiber 4, fiber 5, and fiber 6 of port 8, port 9, and port 10.
Likewise, star 1806 (which is not set in bold in FIG. 17) provides
coupling for various ones of fiber 7, fiber 8, and fiber 9 of port
4, port 5, and port 6, and fiber 4, fiber 5, and fiber 6 of port 8,
port 9, and port 10.
[0139] As can be appreciated in view of the above description of
FIG. 13 through 19, in one example embodiment the entire 10-port
shuffle 1300 can be defined in terms of 3 mesh topologies (i.e.,
mesh topology 1502, mesh topology 1504, and mesh topology 1506) and
3 star topologies (i.e., star topology 1802, star topology 1804,
and star topology 1806). Additionally, each of the mesh topologies
and/or the star topologies is fully independent. Thus, according to
various example embodiments herein, the internal topology of a
fiber shuffle can be constructed by incorporating these two types
of topologies (the mesh topology and the star topology) only, in a
modular fashion, thereby simplifying the manufacturing and
management of such fiber shuffles.
[0140] Having described various example embodiments for shuffle
topology modularization (e.g., by way of mesh subtopologies and/or
star subtopologies), reference will now be made to FIGS. 20 through
35 to describe various example embodiments for front panel
configurations that provide simplified management of intranodal
fiber paths between ROADM components.
[0141] By virtue of the independence between each of the mesh
topologies and/or star topologies that can be combined in a fiber
shuffle, the topologies employed in a fiber shuffle can be physical
arranged in the shuffle so as to fit available rack space more
readily. For example, FIG. 20 shows an example 10-port shuffle 2000
constructed such that each of the 10 ports 2002 includes 3
terminations 2004, with each of the terminations 2004 including 3
fiber pairs (3 pairs each of one ingress fiber and one egress
fiber). For example, fiber pair 1 of termination 1 of port 1
includes one ingress fiber and one egress fiber. In some example
embodiments herein, and as described in further detail below, the
ports (and fibers thereof) 2002 shown in the example shuffle 2000
of FIG. 20 can correspond to the ports described above in the
contexts of the example shuffles 500 (FIG. 5), 702 (FIGS. 8 and 9),
1002 (FIG. 10), 1300 (FIGS. 13 and 15), and/or 1600 (FIGS. 16, 18,
and 19). Mesh subtopologies and/or star subtopologies can be mapped
to ports of the front panel 2000 to provide simplified management
of intranodal fiber paths between ROADM components, as described in
further detail below.
[0142] Having described an example front panel arrangement of a
shuffle 2000, reference will now be made to FIG. 21 to describe how
sub-topologies can be mapped to the ports (and fibers thereof) of
the front panel of the shuffle 2000, such that the entire topology
1300 shown in FIG. 15 may be realized using 3 mesh topologies
(1502, 1504, 1506) and 3 star topologies (1802, 1804, 1806)
described in connection with FIGS. 15, 18, and 19.
[0143] FIG. 21 illustrates an example arrangement by which the
three mesh topologies and the three star topologies can mate with
the ports and terminations of the shuffle 2000. In particular,
blocks corresponding to each of the three mesh topologies 1502,
1504 and 1506 and the three star topologies 1802, 1804, and 1806
are overlaid upon the ports 2002 and terminations 2004 illustrated
in FIG. 20 to indicate the mating arrangement between the
topologies and the ports and terminations of the shuffle 2000.
[0144] In particular, in the example front panel arrangement of the
shuffle 2000, the fibers of the mesh subtopology 1502 are mapped to
fibers 1 through 3 (i.e., termination 1) of ports 1 through 4; the
fibers of the mesh subtopology 1504 are mapped to fibers 4 through
6 (i.e., termination 2) of ports 4 through 7; the fibers of the
mesh subtopology 1506 are mapped to fibers 7 through 9 (i.e.,
termination 3) of ports 7 through 10; the fibers of the star
subtopology 1802 are mapped to fibers 7 through 9 (i.e.,
termination 3) of ports 1 through 3 and to fibers 1 through 3
(i.e., termination 1) of ports 8 through 10; the fibers of the star
subtopology 1804 are mapped to fibers 4 through 6 (i.e.,
termination 2) of ports 1 through 3 and to fibers 1 through 3
(i.e., termination 1) of ports 5 through 7; and the fibers of the
star subtopology 1806 are mapped to fibers 7 through 9 (i.e.,
termination 3) of ports 4 through 6 and to fibers 4 through 6
(i.e., termination 2) of ports 8 through 10.
[0145] FIG. 22 illustrates another alternative example embodiment
for mapping 3 mesh subtopologies (1502, 1504, 1506) and 3 star
topologies (1802, 1804, 1806) to the front panel of the shuffle
2000 to fully realize the entire shuffle topology 1300 shown in
FIG. 13. In this example embodiment, each of the topologies (1502,
1504, 1506, 1802, 1804, and 1806) is constructed as a single
hardware circuit card, ribbon cable, and/or the like, which enables
each of the topologies to mate with a contiguous group of adjacent
ones of the terminations 2004.
[0146] In particular, in the example front panel arrangement of the
shuffle 2000, shown in FIG. 22, the fibers of the mesh subtopology
1502 are mapped to fibers 1 through 3 (i.e., termination 1) of
ports 1 through 4; the fibers of the mesh subtopology 1504 are
mapped to fibers 4 through 6 (i.e., termination 2) of ports 1
through 4; the fibers of the mesh subtopology 1506 are mapped to
fibers 7 through 9 (i.e., termination 3) of ports 1 through 4; the
fibers of the star subtopology 1802 are mapped to fibers 1 through
3 (i.e., termination 1) of ports 5 through 10; the fibers of the
star subtopology 1804 are mapped to fibers 4 through 6 (i.e.,
termination 2) of ports 5 through 10; and the fibers of the star
subtopology 1806 are mapped to fibers 7 through 9 (i.e.,
termination 3) of ports 5 through 10. Physically locating each of
the topologies in a grouped block of terminations in a manner
similar to that shown in FIG. 22 enables construction of the
shuffle to be less complex and more modular, and also simplifies
field replacement.
[0147] FIG. 23 illustrates yet another example arrangement by which
the three mesh topologies and the three star topologies can mate
with the ports and terminations of the shuffle 2000. This
arrangement provides co-location of the mesh and star topologies
such that the 10-port shuffle 2000 can be built using separately
installed rack components populated with the appropriate number of
mesh and star topology modules to complete the optical topology of
the shuffle 2000.
[0148] FIG. 24 shows a further arrangement by which the 3 mesh
subtopologies (1502, 1504, 1506) and 3 star topologies (1802, 1804,
1806) can mate with the ports and terminations of a shuffle 2400
that includes a greater number of ports and/or terminations than
the shuffle 2000 described above. In this way, the shuffle 2400 has
room for expansion (e.g., by way of adding further mesh and/or star
topologies to vacant space in the shuffle 2400) as needed.
[0149] Having described example front panel arrangements of fiber
shuffles, reference will now be made to FIG. 25 to describe how
such a shuffle (e.g., shuffle 2000 having the front panel
arrangement of FIG. 22) can be interconnected to other components
of a ROADM (e.g., line degree modules, add/drop modules, local
transponders, etc.). The ROADM components 2508, 2510, 2512, shown
in FIG. 25 are interconnected by way of the shuffle 2502 in a
manner similar to those described above in connection with other
shuffles described in the various example embodiments provided
herein. Accordingly, a full description of the interconnections,
which are apparent from FIG. 25, is not provided here.
[0150] FIG. 25 illustrates how components of an example 4-degree
ROADM system 2500, including an example fiber shuffle 2502, can be
interconnected, in accordance with an example embodiment herein.
This example utilizes one mesh topology 2504 and one star topology
2506. Each of the four line degree modules 2508 (e.g., OADMs) is
coupled both to mesh topology 2504 and star topology 2506. CDC
add/drop modules 2510 are interposed and coupled between the star
topology 2506 and local transponders 2512. For example (as
described above in the context of FIG. 19), the line degree modules
2508 can be coupled to port 1 through port 4 and the CDC add/drop
modules 2510 can be coupled to port 5 through port 8.
[0151] The 10-port shuffle 2502 can be dynamically grown as the
number of ROADM degrees or CDC add/drop modules are increased. FIG.
26 illustrates how components of an example 8-degree ROADM system
2600, including an example fiber shuffle 2602, can be
interconnected, in accordance with an example embodiment herein.
This example utilizes two mesh topologies 2604 and 2606 and three
star topologies 2608, 2610, and 2612. Each of the line degree
modules 2620 for degree 1 through degree 4 is coupled both to mesh
topology 2604 and star topology 2612. Each of the line degree
modules 2620 for degree 5 through degree 8 is coupled both to mesh
topology 2606 and star topology 2612. In one example embodiment,
the line degree modules 2620 for degrees 1 through 4 are coupled to
the line degree modules 2620 for degrees 5 through 8 by way of the
star topology 2612. CDC add/drop modules 2614 are interposed and
coupled between the star topologies 2608 and 2610 and local
transponders 2618. In one example, the CDC add/drop modules 2614
are coupled to each of the line degree modules 2620 for degree 1
through degree 4 by way of the star topology 2608, and the CDC
add/drop modules 2614 are coupled to each of the line degree
modules 2620 for degree 5 through degree 8 by way of the star
topology 2610.
[0152] Having described example arrangements and mappings of a
front panel of a shuffle of a ROADM, reference will now be made to
FIG. 27 to describe how various subtopologies may be mapped (e.g.,
hardwired) to ports (fibers thereof) of a shuffle front panel to
provide flexibility as routing needs may evolve.
[0153] FIG. 27 shows an example N-port fiber shuffle 2700 having
multiple individual mesh topologies and star topologies mapped to
the ports thereof, and having 5 multi-fiber MPO terminations 2702,
each termination 2702 having (N-1)/5 fiber pairs. The size of each
mesh topology and/or star topology in the shuffle 2700 can be
configured based on the number of fibers included in each
multi-fiber MPO termination 2702 of the shuffle 2700. For example,
if the shuffle 2700 includes MPO terminations having 8 fibers
(which can support 4 bidirectional circuits), each mesh would have
a total of 5 MPO terminations and be arranged in a manner similar
to that of the 3 bidirectional termination example embodiments
described above. In this case, the star topology would have a total
of 8 MPO terminations and be arranged in a manner similar to that
described above in connection with the star topology 1900 of FIG.
19.
[0154] In one example embodiment, a fiber shuffle (e.g., such as
the shuffle 2700) can be constructed in the following manner. Given
R rows of connectors (e.g., MPO connectors), where each connector
supports N fiber ingress/egress pairs (i.e., 2.times.N fibers total
per connector), the number of columns is computed according to
Equation 1 shown below.
R.times.(N+1) (Equation 1)
[0155] The mesh size is (N+1) connectors, and the star size is
(2.times.N) connectors. R mesh topologies and (R-1)! star
topologies can be utilized to fully populate an R-row fiber
shuffle. The number of degrees supported by the mesh is N degrees
when CDC add/drop modules that support N degrees are coupled to the
shuffle.
[0156] Illustrated in FIG. 27 is a layout of a possible 21-port
shuffle 2700 having a front panel with multiple mesh topologies and
star topologies mapped to its ports thereby providing three
possible configurations, depending upon which ports are utilized.
In a first configuration (labeled configuration 1 in FIG. 27), the
shuffle 2700 can support N (e.g., 4) degrees (or combinations of
line degree modules and CDC add/drop modules), with as many as 17
CDC add/drop modules, and only employs a single mesh topology
(labeled in FIG. 27 as mesh 1) and four star topologies (labeled in
FIG. 27 as star 1-1, star 1-2, star 1-3, and star 1-4). In this
example, it is possible to add star topologies to the shuffle as
the number of CDC add/drop modules increases.
[0157] In a second configuration (labeled configuration 2 in FIG.
27), the shuffle 2700 can support 2*N (e.g., 8, where N=4) degrees
(or combinations of line degree modules and CDC add/drop modules),
and, in addition to the topologies employed in configuration 1
(i.e., mesh 1, star 1-1, star 1-2, star 1-3, and star 1-4), employs
a second mesh topology (labeled mesh 2 in FIG. 27), and additional
star topologies (labeled in FIG. 27 as star 2-1, star 2-2, and star
2-3). One of the additional star topologies interconnecting degrees
1 through degree 4 with degree 5 through degree 8, and the
remaining additional star topologies can each support an additional
CDC add/drop module. In this example embodiment, the number of star
topologies required can depend on the number of CDC add/drop
modules desired.
[0158] In a third configuration (labeled configuration 3 in FIG.
27), the 21-port shuffle 2700 employs a total of 5 mesh topologies
(labeled in FIG. 27 as mesh 1, mesh 2, mesh 3, mesh 4, and mesh 5)
and 10 star topologies (labeled in FIG. 27 as star 1-1, star 1-2,
star 1-3, star 1-4, star 2-1, star 2-2, star 2-3, star 3-1, star
3-2, and star 4-1), thereby accommodating up to 5*N (e.g., 20,
where N=4) possible degrees (or combinations of line degree modules
and CDC add/drop modules).
[0159] FIG. 28 shows yet another example embodiment of a 21-port
expandable shuffle 2800. In this example embodiment, each of three
configurations (configuration 1, configuration 2, and configuration
3) employs one or more rack-mountable units 2802, 2804, 2806, each
rack-mountable unit of which having a total of 5 slots capable of
hosting either a mesh topology module or star topology module.
Configuration 1 employs one rack-mountable unit 2802 that includes
one mesh topology module and four star topology modules.
Configuration 2 employs the same rack-mountable unit 2802 as
employed in configuration 1, and also includes a second
rack-mountable unit 2804 that includes one mesh topology module and
three star topology modules. Configuration 3 employs the same
rack-mountable units 2802 and 2804 as those employed in
configuration 2, and also includes a third rack-mountable unit
2806, which includes three mesh topology modules and three star
topology modules. Thus, in total, configuration 3 includes five
mesh topology modules and ten star topology modules. Because the
mesh topology modules and star topology modules are mutually
independent, each of the modules can be populated in the shuffle
2800 in a position that does not depend on a position of any other
modules.
[0160] FIG. 29 shows a 21-port shuffle 2900 employed to implement
configuration 2 described above in the context of FIG. 28, in
accordance with an example embodiment herein. In this example, the
shuffle 2900 is tailored to support the maximum possible number of
line degree modules and CDC add/drop modules in an 8-degree optical
network, without requiring the shuffle 2900 to have a number of MPO
connectors sufficient to provide complete connectivity between line
degree modules and CDC add/drop modules for a full 21-degree
optical network. FIG. 30 shows another view of an example mapping
of mesh topology modules and star topology modules to the shuffle
2900 (FIG. 29), optimized for 8 degrees, in accordance with
configuration 2 described above in connection with FIG. 27.
[0161] Reference will now be made to FIGS. 31 through 35 to
describe how front panels of a shuffle may be modularized, for
example, to increase the flexibility and ease of reconfiguration a
shuffle and/or a ROADM employing a shuffle. In some example
embodiments herein, components shown in FIGS. 31 through 35 can
correspond to similar components described above and/or shown in
other ones of the figures. FIG. 31 and FIG. 32 show an example
5-port mesh topology module 3100 and an example 8-port star
topology module 3200, respectively, each of which may be used to
construct a shuffle such as the shuffle 2900 shown in FIG. 29.
[0162] FIG. 33 shows an example 21-port 4-degree shuffle 3300
constructed using a single mesh topology module 3100 and four star
topology modules 3200 in a standard EIA rack unit mountable shelf.
In this example the star topology modules 3200 only need to be
added as CDC add/drop modules are added to the system. As shown in
FIGS. 21 and 22, the line degree modules of the system would be
coupled to the star topology modules 3200. FIG. 34 shows the
example 21-port 4-degree shuffle 3300 described above in connection
with FIG. 33, with blocks indicating how the mesh topology module
and star topology modules are mapped in the EIA shelf.
[0163] FIG. 35 shows how an 8-degree 21-port shuffle can be
constructed, in an example embodiment herein, by using two 1-rack
unit mountable shelves 3502 and 3504. In this example, the second
shelf 3505 includes a mesh topology module and can include up to
three star topology modules. This approach can be used to grow the
one-shelf 4-degree configuration described above in connection with
FIG. 33 and FIG. 34 into an 8-degree configuration by adding the
second shelf 3504 and the appropriate mesh topology modules and
star topology modules.
[0164] As can be appreciated in view of the above, the example
aspects herein provide an intranodal reconfigurable optical
add/drop multiplexer (ROADM) fiber management apparatus, and a
system employing the apparatus. In accordance with some aspects
described herein, the system employs a fiber shuffle and fiber
ribbon cables that greatly simplify the management of intranodal
(i.e., intra-ROADM) paths for express and local add/drop channels
in an optical network. In some example embodiments, to aid in the
installation, test, and identification of intranodal
interconnections, optical test channels can be routed between
modules (e.g., line degree modules, CDC add/drop modules, expansion
modules, local transponders, etc.) in parallel with the add, drop,
and/or express channels using a separate WDM channel. The test
channels can be used between the modules to verify proper
intranodal fiber setup, failure analysis, and to discover the port
interconnections between the modules within the node.
[0165] Additionally, in accordance with various example aspects
described herein, a fiber shuffle is provided that is flexible
enough to manage a range of numbers and types of modules of a ROADM
(e.g., line degree modules, CDC add/drop modules, local
transponders, expansion modules, etc.). The fiber shuffle includes
a plurality of ports, each of which can be used for various types
of modules of a ROADM.
[0166] In addition, in some example embodiments herein, a fiber
shuffle is provided wherein one or more mesh topologies and/or one
or more star topologies are located in a shelf (or rack-mountable
chassis) that also includes one or more line degree modules and/or
one or more add/drop modules (e.g., CDC add/drop modules). In this
way, cabling external to the shelf may not be required between the
one or more mesh topologies, the one or more star topologies, the
one or more line degree modules, and/or the one or more add/drop
modules.
[0167] It should be noted that the network configurations
represented in the figures described herein are merely provided for
illustrative purposes, and should not be construed as limiting the
scope of the invention. Also, in other embodiments, the networks
may have other configurations than those shown in the figures.
[0168] Additionally, while specific implementations of the
invention may have been described, the invention need not be so
limited. For example, various embodiments of the invention may
comprise different number of ports other than those described in
this disclosure.
[0169] In the foregoing description, example aspects of the
invention are described with reference to specific example
embodiments thereof. The specification and drawings are accordingly
to be regarded in an illustrative rather than in a restrictive
sense. It will, however, be evident that various modifications and
changes may be made thereto, in a computer program product or
software, hardware, or any combination thereof, without departing
from the broader spirit and scope of the present invention.
[0170] Software embodiments of example aspects described herein may
be provided as a computer program product, or software, that may
include an article of manufacture on a machine-accessible,
computer-readable, and/or machine-readable medium (memory) having
instructions. The instructions on the machine-accessible,
computer-readable and/or machine-readable medium may be used to
program a computer system or other electronic device. The
machine-readable medium may include, but is not limited to, floppy
diskettes, optical disks, CD-ROMs, and magneto-optical disks or
other types of media/machine-readable medium suitable for storing
or transmitting electronic instructions. The techniques described
herein are not limited to any particular software configuration.
They may find applicability in any computing or processing
environment. The terms "machine-accessible medium",
"computer-readable medium", "machine-readable medium", or "memory"
used herein shall include any medium that is capable of storing,
encoding, or transmitting a sequence of instructions for execution
by the machine and that cause the machine to perform any one of the
procedures described herein. Furthermore, it is common in the art
to speak of software, in one form or another (e.g., program,
procedure, process, application, module, unit, logic, and so on) as
taking an action or causing a result. Such expressions are merely a
shorthand way of stating that the execution of the software by a
processing system causes the processor to perform an action to
produce a result. In other embodiments, functions performed by
software can instead be performed by hardcoded modules, and thus
the invention is not limited only for use with stored software
programs. Indeed, the numbered parts of the above-identified
procedures represented in the drawings may be representative of
operations performed by one or more respective modules, wherein
each module may include software, hardware, or a combination
thereof.
[0171] In addition, it should be understood that the figures
illustrated in the attachments, which highlight the functionality
and advantages of the present invention, are presented for example
purposes only. The architecture of the example aspect of the
present invention is sufficiently flexible and configurable, such
that it may be utilized (and navigated) in ways other than that
shown in the accompanying figures.
[0172] Although example aspects herein have been described in
certain specific example embodiments, many additional modifications
and variations would be apparent to those skilled in the art. It is
therefore to be understood that the various example embodiments
herein may be practiced otherwise than as specifically described.
Thus, the present example embodiments, again, should be considered
in all respects as illustrative and not restrictive.
* * * * *