United States Patent [19]
`Brackett et al.
`
`l|ll||lllllllllll|||||lllllllELlllLlllglglllllllllllllllllllllllllllll
`
`[11] Patent Number:
`[45] Date of Patent:
`
`5,550,818
`Aug. 27, 1996
`
`[54]
`
`[75]
`
`SYSTEM FOR WAVELENGTH DIVISION
`MULTIPLEXING/ASYNCHRONOUS
`TRANSFER MODE SWITCHING FOR
`NETWORK COMMUNICATION
`
`Inventors: Charles A. Brackett, Mendham;
`Gee-Kung Chang, Holmdel;
`Muhammed Z. Iqbal, Tinton Falls, all
`of N].
`
`[73]
`
`Assignee: Bell Communications Research, Inc.,
`Monistown, N.J.
`
`[22]
`[51]
`[52]
`
`[58]
`
`[56]
`
`Appl. No.: 308,313
`Filed:
`Sep. 19, 1994
`
`Int. Cl.6 ......................... .. H04] 14/02; H04L 12/433
`US. Cl. ................... .. 370160; 370/85.12; 370/85.14;
`359/123; 359/124; 359/139; 359/341
`Field of Search ................................... .. 359/124, 139,
`359/118, 123, 127, 137; 370/85.14, 60.1,
`85.5, 85.11, 85.15,110.1, 85.12
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,734,907
`4,821,255
`
`3/1988 Turner ..................................... .. 370/60
`4/1989 Kobinski
`359/128
`
`4,829,227
`
`5/1989 Turner . . . . . . . . .
`
`. . . . .. 370/60
`
`4,849,968
`
`7/1989 Turner . . . . .
`
`. . . . .. 370/60
`
`4,901,309
`2/1990 Turner . . . . .
`5,077,727 12/1991 Suzuki .......... ..
`5,111,323
`5/1992 Tanaka et al. ..
`
`. . . . .. 370/60
`359/123
`359/139
`
`5,175,777 12/1992 Bottle . . . . . . . . . . . . . .
`
`. . . . .. 385/17
`
`5,179,551
`5,179,556
`5,214,527
`
`1/1993 Turner . . . . .
`1/1993 Turner ........... ..
`5/1993 Chang etal.
`
`. . . . .. 370/60
`370/94.1
`359/189
`
`5,229,991
`
`7/1993 Turner . . . . . . . . . . . . .
`
`. . . . .. 370/60
`
`5,260,935 11/1993 Turner . . . . . . . . . . . . . . . . .
`
`. . . . .. 370/60
`
`3591139
`4/1994 Brackett et a1.
`5,303,078
`.. 359/125
`5,369,516 11/1994 Uchida .......... ..
`.. 359/341
`5,392,154 211995 Chang etal
`5,452,115
`9/1995 Tornioka ............................... .. 359/123
`
`OTHER PUBLICATIONS
`Brackett, Photonics in Switching, “Multiwavelength Switch
`ing and Interconnection Networks,” vol. II, 1993.
`Lawton, Lightwave, “DARPA builds optical switch,” pp. 1,
`16, 18, 20, May 1993.
`A Scalable Multiwavelength Multihop Optical Network: A
`Proposal for Research on All-Optical Networks, Journal of
`Lightwave Technology, May/Jun. 1993, vol. 11, pp.
`736—753.
`
`Primary Examiner-Melvin Marcelo
`Assistant Examiner—Melissa Kay Carman
`Attorney, Agent, or Firm-Leonard Charles Suchyta; James
`W. Falk
`
`ABSTRACT
`
`[57]
`The present invention is directed to a system for the wave
`length division multiplexing/asynchronous transfer mode
`(WDM/ATM) operation of high-capacity optical communi—
`cation networks. The optical components of the network can
`transport vast amounts of information, while the ATM-based
`electronics provides data processing, and information dis
`tribution. The capacity of the communications network to
`recon?gure and rearrange itself is maximized through wave—
`length translation of its data signals using a limited set of
`?xed-wavelength channels. The system incorporates an opti
`cal ?ber communication network ring, or several optical
`?ber communication network rings that are connected to
`each other, through which data signals are transmitted and
`received. Optical WDM cross-connecting switch devices
`4a-4e connect adjacent optical ?ber rings 3a, 3b to each
`other, and control the routing of the data signals into and out
`of the optical ?ber n'ngs 3a, 3b. Access node circuits 2a—2d
`connected to the WDM cross-connecting switch devices
`4a—4d can access the data signals in the optical ?ber rings
`3a, 312. Each of the access node circuits 2a-2d can then route
`the data signals to individual user stations 5a—5h connected
`to it. A network controller 8 con?gures the WDM cross
`connecting switch devices 4a-4e through their correspond
`ing local node controllers 7.
`
`22 Claims, 11 Drawing Sheets
`
`Advanced Media Exhibit 2018, pg. 1
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`US. Patent
`
`Aug. 27, 1996
`
`Sheet 1 of 11
`
`5,550,818
`
`an
`
`w)
`
`mmril?sa mmmE E
`
`v w w
`
`w
`
`w
`
`aw.
`
`<@
`
`M
`
`
`
`woOZ mmmuud.
`
`
`
`0.07 W82 38%
`
`
`
`ZOTEPm mmm:
`
`
`
`woOz 3604
`
`mmljomhzou N w
`
`
`
`M392 mmmuuq
`
`Advanced Media Exhibit 2018, pg. 2
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`Advanced Media Exhibit 2018, pg. 3
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`Advanced Media Exhibit 2018, pg. 4
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`US. Patent
`
`Aug. 27, 1996
`
`Sheet 4 0f 11
`
`5,550,818
`
`2w
`
`$ a 362%?
`
`
`
`85:26 N.. N
`
`E
`
`NR
`
`
`
`
`
`MR .52 20>)
`
`5i 203
`
`Advanced Media Exhibit 2018, pg. 5
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`US. Patent
`
`Aug. 27, 1996
`
`Sheet 5 of 11
`
`5,550,818
`
`TRANSMITTING
`
`:0 ‘III
`
`A
`
`C l
`
`h 4
`2 1A
`
`i \A
`
`2 1A A 7A \A
`
`G b c d 2 2 2 2
`
`O .l 2 3 4.
`
`2 .\A i
`
`2 1A 3
`
`d 4 3 l.
`
`2 1A ‘.A 1Q \A
`
`3 b.
`
`.)A
`
`F761". 44
`
`@Z_>_wumm
`
`CROSS ' CONNECT MODU LE
`
`40
`
`4d
`
`T00
`
`b m
`
`nlv
`c
`
`d w
`\A
`4.
`
`F/G. 4B
`
`Advanced Media Exhibit 2018, pg. 6
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`US. Patent
`
`Aug. 27, 1996
`
`Sheet 6 of 11
`
`5,550,818
`
`Advanced Media Exhibit 2018, pg. 7
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`US. Patent
`
`Aug. 27, 1996
`
`Sheet 7 of 11
`
`5,550,818
`
`TO cRoss-coNNecT .
`MODULES 4c,4d
`
`TO CROSS'CUNNECT
`Q‘ MODULES 40,4b
`
`M76
`
`‘
`TO CR
`MODU
`
`T
`
`0’
`‘CONNECT . §:§’. T0 CROSS-CON T
`4C,4d
`.
`MODULES 40,
`—* I"
`""
`Q; 14
`
`A2
`M
`
`Advanced Media Exhibit 2018, pg. 8
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`US. Patent
`
`Aug. 27, 1996
`
`Sheet 8 of 11
`
`5,550,818
`
`TRANSMITTING
`2b
`2c
`
`20
`
`20
`
`2b
`
`A1
`
`4 A
`
`A2
`
`F/G. 6A
`
`CROSS“ CONNECT SWITCH NO.
`
`4 I
`.D
`I.
`
`4 I
`d I
`
`1% O I
`
`M I O
`
`% I O
`
`xhozm?m><>>
`
`2 3
`
`P76‘. 65
`
`Advanced Media Exhibit 2018, pg. 9
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`US. Patent
`
`Aug. 27, 1996
`
`Sheet 9 0f 11
`
`5,550,818
`
`
`
`wQOz mmmuo<
`
`OP
`
`om
`
`mQOZ m u< O
`UN
`
`3/ Q NM) Z 111%
`All
`
`3
`
`Kllii; ,
`
`3
`
`E»
`
`1:
`
`v Q K
`NK
`
`m 3%
`
`UN
`
`OP
`
`
`
`mOOz wwwuu<
`
`Advanced Media Exhibit 2018, pg. 10
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`Advanced Media Exhibit 2018, pg. 11
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`Advanced Media Exhibit 2018, pg. 12
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`5,550,818
`
`1
`SYSTEM FOR WAVELENGTH DIVISION
`MULTIPLEXING/ASYNCHRONOUS
`TRANSFER MODE SWITCHING FOR
`NETWORK COMMUNICATION
`
`GOVERNMENT RIGHTS
`
`The invention was made with government support under
`Agreement No. MDA972~92-H-O0l0 awarded by DARPA.
`The government has certain rights in the invention.
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The invention relates to a system for controlling the
`operation of high capacity communication networks that use
`?ber optic technology. Speci?cally, the invention relates to
`controlling the routing of data signals to a large number of
`users at different wavelengths using wavelength-selection,
`space-division optical cross-connecting switch devices, and
`asynchronous transfer mode (ATM) switches.
`2. Related Art
`High-speed, high-capacity optical communication sys
`terns are being developed. U.S. high-technology companies
`are developing the “Information Super Highway.” This
`“Information Super Highway” is envisioned to be a com
`munication system that adapts various types of user data
`services. For example, the system is designed to accommo
`date diiferent types of data including voice, data, still-image,
`and live-video/voice multicast transmissions to a large num
`ber of users. The system may send the data in “burst”
`transmissions between individual users and/or between
`regions. Individual users may access the system through a
`local area network using desktop computers. Different
`regions of the country may access the system through wide
`area networks.
`In the “Super Highway” or in any future network, user
`tra?ic patterns will likely evolve and usage is expected to
`rapidly increase along with more complex services. As the
`“Super Highway” or network expands, the system’s ability
`to adapt to the expansion may be severely taxed. In other
`words, problems may occur if the “Super Highway” or
`network is unable to adapt to the changing tra?ic patterns
`without degrading its service to its current users.
`The challenge facing the telecommunications industry is
`designing a network that can allocate and manage a growing
`data transmission capacity that is capable of incorporating
`new users and new equipment while serving its current
`users. The industry also faces the challenge of designing the
`network to be capable of recon?guring itself for an optimum
`level of e?iciency. To meet the operating requirements for
`various types of data communication, the “Information
`Super Highway” and any similar future networks must be
`designed to recon?gure themselves relatively quickly and
`e?iciently.
`
`15
`
`25
`
`35
`
`45
`
`50
`
`55
`
`SUMMARY OF THE INVENTION
`
`A main object of the present invention is to provide a
`system for high-capacity optical communication networks
`that can transport vast amounts of information, while pro
`viding e?icient data processing and information distribution.
`Another object of the present invention is to maximize the
`capacity of a communications network to recon?gure and
`rearrange itself where the network uses wavelength trans
`lation of its data signals and a limited set of ?xed-wave
`length channels.
`
`65
`
`2
`Consequently, a further object of the present invention is
`to provide a system using both wavelength division multi
`plexing (WDM) and asynchronous transfer mode (ATM)
`switching for high-capacity, optical communication net
`works.
`In order to achieve the above objects, the present inven
`tion encompasses a system that comprises an optical ?ber
`communication network ring, or several optical ?ber com
`munication network rings that are connected to each other,
`through which data signals are transmitted and received.
`Optical WDM cross-connecting switch devices connect
`adjacent optical ?ber rings to each other, and control the
`routing of the data signals into and out of the optical ?ber
`rings. Access node circuits connected to the WDM cross
`connecting switch devices can access the data signals in the
`optical ?ber rings. Each of the access node circuits can then
`route the data signals to individual user stations connected to
`it. A network controller con?gures the WDM cross-connect
`ing switch devices through their corresponding local node
`controllers.
`One particular feature of the invention is that each cross
`connecting device incorporates l) a demultiplexer circuit for
`demultiplexing the data signals into several wavelength
`separated data signals, 2) a wavelength-selection, space
`division switch for each of the wavelength-separated data
`signals, and 3) a multiplexer circuit for multiplexing the
`wavelength~separated data signals together into the data
`signals transmitted through the network. Each of the wave
`length-selection, space-division switches is con?gured in
`either a BAR state or a CROSS state. The BAR state allows
`the switch to simply conduct its corresponding wavelength
`separated data signal bypassing the access node circuit
`connected to the cross-connecting device. The CROSS state
`of the switch diverts the wavelength~separated data signal to
`the access node circuit, and allows a wavelength-separated
`data signal from the access node circuit to be inputted into
`the multiplexer.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The invention is better understood by reading the follow
`ing Detailed Description of the Preferred Embodiments with
`reference to the accompanying drawing ?gures, in which
`like reference numerals-refer to like elements throughout,
`and in which:
`FIG. 1 illustrates a system diagram showing the general
`network architecture of a preferred embodiment of the
`present invention;
`FIG. 2A shows a system diagram for a general embodi~
`ment of a 2X2 WDM cross-connect module applicable to the
`network architecture of the present invention;
`FIG. 2B illustrates the circuit structure of the 2x2 WDM
`cross-connect module shown in FIG. 2A;
`FIG. 3 shows a system diagram of a speci?c embodiment
`of the 2X2 cross-connect module incorporated into the
`network architecture of the present invention shown in FIG.
`1;
`FIG. 4A illustrates a cross-reference chart showing
`example wavelength assignments for the 2X2 WDM cross
`connect module of the present invention;
`FIG. 4B illustrates a cross-reference chart showing
`example switch con?gurations for the wavelength-selection,
`space-division switches in the 2X2 WDM cross-connect
`modules having the wavelength assignments of FIG. 4A;
`FIGS. 5A, 5B and 5C together show a graphical repre
`sentation of the cross»connections outlined in the cross
`reference charts from FIGS. 4A and 4B;
`
`Advanced Media Exhibit 2018, pg. 13
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`5,550,818
`
`3
`FIG. 6A shows a second cross-reference chart of example
`wavelength assignments for the 2X2 WDM cross-connect
`module of the present invention;
`FIG. 6B shows a second cross-reference chart of example
`switch con?gurations for the wavelength-selection, space
`division switches in the 2X2 WDM cross-connect modules
`having the wavelength assignments of FIG. 6A;
`FIGS. 7A, 7B and 7C together show a graphical repre
`sentation of the cross-connections outlined in the cross
`reference charts from FIGS. 6A and 6B;
`FIG. 8 is a system diagram for a 4X4 WDM cross-connect
`module applicable to the network architecture of the present
`invention;
`FIG. 9 is a system block diagram of an access node
`structure that is incorporated into the network architecture of
`the present invention shown in FIG. 1; and
`FIGS. 10A and 10B show examples of optical ampli?er
`circuits used for bi-directional transmission of data signals.
`
`10
`
`15
`
`25
`
`30
`
`4
`among multiple wavelength division multiplexing (WDM)
`optical ?ber rings, and connected to their corresponding
`WDM optical ?ber rings by WDM cross-connect modules.
`The optical ?ber rings themselves are connected by addi
`tional WDM cross-connect modules. In both embodiments,
`the network access nodes each incorporate multi-wave
`length transmitter arrays to communicate with the network.
`Signals from individual user stations connected to the access
`nodes enter the network using the multi-wavelength trans
`mitter arrays. A user station connected to an access node
`may be, among others, an individual user terminal such as a
`PC, a local area network (LAN) having its own plurality of
`users, or even a supercomputer.
`In the present invention, scalability is achieved by re
`using a limited number of wavelengths to create “hand-to
`hand” single-hop connections between the WDM cross
`connect modules as will be explained below. Within the
`WDM cross-connect modules, these single hop connections
`are then connected using ATM switches to perform wave
`length translation and bu?rering, thereby creating a multi
`hop network. This multi-hop network provides connectivity
`among many users, and results in a network of very high
`capacity that may be recon?gured with minimum informa
`tion ?ow interruption and maximum utilization of the net
`work bandwidth.
`One example of the implementation of the present inven~
`tion is illustrated in FIG. 1. As shown, in an optical network
`1, a plurality of network access nodes 2a—2d are distributed
`. between a plurality of adjacent, interconnected WDM opti
`cal ?ber rings 3a, 3b joined by at least one WDM cross
`connect module 4e. In this embodiment, four access nodes
`and two optical ?ber rings are used. The access nodes 2a-2d
`are then each connected to the WDM optical ?ber rings 3a,
`312 also through a WDM cross-connect module. In this
`example, with four access nodes 2a-2d, four 2X2 WDM
`cross-connect modules 4a—4a' are employed. User stations
`5a-5h are distributed among the access nodes 2a-2d and
`access the ?ber rings 3a, 3b through the access nodes 2a—2d.
`Optical ?ber ampli?ers 6 are employed within the individual
`?ber rings 3a, 3b to compensate for component insertion
`losses and ?ber transmission losses in the signals transmitted
`through the ?ber rings 3a, 312. A suitable optical ?ber
`ampli?er is an erbium-doped type. As shown, ampli?ers 6
`may be located at the outputs of the WDM cross-connect
`modules 4a—4e.
`FIGS. 2A and 2B illustrate the structure and operation of
`a general 2X2 embodiment of the WDM cross-connect
`module 4. In this general embodiment of the WDM cross
`connect module, each cross-connect module 4a—4e incor
`porates a WDM demultiplexer 9, a plurality of 2X2 wave
`length-selection, space-division switches 10a-10d, and a
`WDM multiplexer 11. An optical ?ber ampli?er 6 may be
`connected to the output of each WDM cross-connect module
`to amplify the multiplexed signals for transmission through
`the optical ?ber rings 3a, 3b as shown in FIG. 1.
`Up to four separate wavelengths can be multiplexed and
`transmitted through the WDM cross-connect modules
`4a—4d. In operation, the WDM multiplexed input signals
`27»; are ?rst inputted into the demultiplexer 9 to separate the
`multiplexed input signals Z7ts into four parallel input signals
`in different wavelengths X1, X2, 13, L4. The four parallel
`input signals K1, 7V2, 23, k4 are then inputted into corre
`sponding wavelength-selection, space-division switches
`10a-10d. Each of the wavelength-selection, space-division
`switches 10a-10d as con?gured by the WDM cross-connect
`module’s local controller 7 either routes selected wave
`lengths to bypass a corresponding access node 2a-2d or
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`In describing preferred embodiments of the present inven
`tion illustrated in the drawings, speci?c terminology is used
`for the sake of clarity. However, the invention is not intended
`to be limited to the speci?c terminology so selected, and it
`is to be understood that each speci?c element includes all
`technical equivalents that operate in a similar manner to
`accomplish a similar purpose.
`A paper by Charles A. Brackett, et al., “A Scalable
`Multi-wavelength Multi-hop Optical Network: A Proposal
`for Research on All-Optical Networks”, Journal of Light
`wave Technology, Volume 11, No. 5/6 (May/June 1993) is
`incorporated herein by reference. In that paper, an architec
`tural approach for very high capacity wide area optical
`networks is described. That proposed architecture uses
`wavelength-selective, wavelength-routing, wavelength-divi
`sion-multiplexing (WDM) cross-connects and multi-wave
`length transceivers. The proposed architecture is scalable in
`the number of network users, in the geographical range of
`coverage, and in the aggregate network capacity it can
`accommodate. Scalability as de?ned in the Brackett et al.
`article is the ability of a network (e.g., a communications
`network) to add one or more access stations to its current
`number of users in order to offer service to a given popu
`lation size of users spread over a given service domain.
`In the proposed architecture, a user is connected to a
`network through an access station equipped with a limited
`number of optical transmitters and receivers (transceivers),
`each operating on a di?erent wavelength. With that ?xed set
`of transceivers, data communication channels are estab
`lished between access stations through an optical intercon
`nect system. This interconnect system is intended to be
`wavelength-selective
`and
`electronically-controllable,
`thereby permitting clear communication between selected
`access stations using a limited set of wavelengths. At the
`same time, the interconnect system permits that limited set
`of wavelengths to be re-used by the other access stations.
`In one embodiment, the present invention is directed to an
`optical communications network that incorporates a plural
`ity of network access nodes connected to a wavelength
`division multiplexing (WDM) optical ?ber ring through
`WDM cross-connect modules.
`In second, preferred embodiment, the present invention is
`directed to an optical communications network that incor
`porates a plurality of network access nodes distributed
`
`35
`
`45
`
`60
`
`65
`
`Advanced Media Exhibit 2018, pg. 14
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`5,550,818
`
`15
`
`20
`
`25
`
`5
`routes the selected wavelengths to be diverted to the corre
`sponding access node. In the WDM cross-connect module
`illustrated in FIG 2A, the input signals 7t, and L, are routed
`to bypass the corresponding access node through the WDM
`cross-connect module, while the input signals )2, K3 are
`diverted to the access node for processing by an ATM switch
`in the access node. For example, the input signals may be
`sent to designated user stations 5a—5h which may be con
`nected to that access node, or bypass through as being
`designated for other access nodes in the network.
`The input signals 2., and 24 as illustrated in FIG. 2A pass
`through the WDM cross-connect module, but may be
`diverted in another WDM cross~connect module con?gured
`to route those input signals to the ATM switch in its access
`node. This is an example of a multi-hop connection, or of a
`local train information carrier in operation, both of which
`will be explained below.
`Signals from the user stations 7t‘: connected to the ATM
`switch of the access node connected to the WDM cross
`connect module shown in FIG. 2A can also be routed by the
`ATM switch into the wavelength-selection, space-division
`switches 10a—10d corresponding to their selected wave—
`lengths In this case, the signals X2 and X3 are routed into the
`switches that correspond to their wavelengths Four parallel
`output signals X1, X2, X3, 7V4 are then be multiplexed
`together as 21's and outputted from the WDM cross-connect
`module to the ?ber rings 3a, 3b.
`An example of how the WDM cross-connect modules
`4a—4e may be constructed is shown in FIG. 2B. As shown,
`the multiplexed input signals are inputted into the WDM
`cross-connect module through a FC/PC optical ?ber bulk
`head connector into the demultiplexer 9 (JDS Fitel Product
`No. WD5555XGKC2 thin-?lm demultiplexer) for separa
`tion into the four parallel input signals X1, X2, 7L3, A4. The
`input signals are then inputted into the wavelength-selection,
`space-division switches 10a—10d which consist of JDS Fitel
`Product No. SR22A400FP discrete wavelength-selection,
`space-division switches Output signals N1, N2, 763, M, from
`the discrete switches are multiplexed by the multiplexer 11
`(JDS Product No. WD5555YGKC2 thin-?lm multiplexer)
`into the multiplexed output signals
`In operation, each of the discrete wavelength-selection,
`space-division switches 10a-10d is con?gured to operate in
`either a BAR state or a CROSS state. In the BAR state, an
`input signal it,‘ is inputted into terminal T1 and outputted
`from terminal T2 to the access node of the WDM cross
`connect module An output signal N" from the access node is
`routed into terminal T3 and out through terminal T4 to the
`multiplexer. In the CROSS state, an input signal 7t” is
`inputted into terminal T1 and outputted from terminal T4 as
`an output signal X" to the multiplexer
`The BAR or CROSS state of each of the discrete switches
`10a-10d is determined by the input of an external signal
`(eg.,0 to 5 volts) to the terminal B/C. The local node
`controller 7 of the WDM cross-connect module incorporat
`ing the discrete switches 10-10d sets the state of the terminal
`B/C based on the commands from the network controller 8
`interpreting the preselected routing tables. Table 1 below
`shown lists the operating characteristics of an example 2X2
`WDM cross-connect module constructed from the above
`described components. As shown, the wavelength-selective
`
`6
`
`TABLE I-continued
`
`110 Fiber Type
`Fiber Connector Type
`Output Channel Passband
`
`Optical Crosstalk Between
`Channels at the Center of
`Adjacent Channels
`Output Channel Intensity
`Variation
`Insertion Loss
`
`Re?ection Tapping
`Port Eff.
`Polarization Sensitivity
`Temperature Sensitivity
`
`7t, = 1554 nm
`14 = 1558 nm
`C -SMF
`PC -PC
`1.0 nm ($0.1 dB)
`2.0 nm (il.0 dB)
`—30 dB (max)
`
`0.5 dB (max)
`
`4.0 dB
`
`10%
`
`0.1 dB
`0.025 nm/“C.
`
`selective and wavelength routing functions of the discrete
`switches have set the center wavelengths to be within i0.l
`nm of 1546, 1550, 1554 and 1558 nm. Among other features,
`the crosstalk between channels was measured to be —30 dB
`maximum. The switch’s temperature sensitivity was mea
`sured to be 0.025 nml° C. The maximum ?ber-to-?ber
`insertion loss was 4.0 dB.
`In the general embodiment of the present invention dis
`cussed above, FIG. 2A illustrates the input signals X1, 79, A3,
`2.4 being transmitted to the access node in parallel. As shown
`in FIGS. 1 and 3, the input signals may alternatively be
`transmitted to the access node in a multiplexed form. In FIG.
`3, a speci?c embodiment of the present invention comprises
`a WDM cross-connect module 4a—4e having parallel~con
`nected demultiplexers and multiplexers. Each cross-connect
`module 4a—4e incorporates WDM demultiplexers 9a, 9b, the
`2x2
`wavelength~selection,
`space-division
`switches
`Illa-10d, and WDM multiplexers 11a, 11b.
`In this speci?c embodiment, four separate wavelengths
`also may be multiplexed and transmitted through the WDM
`cross-connect modules 4a—4e. In operation, the WDM mul
`tiplexed input signals 2X, are ?rst inputted into the ?rst
`demultiplexer 9a to separate the multiplexed input signals
`27L: into four parallel input signals 7L1, K2, K3, 7L4 in diiferent
`wavelengths. The four parallel input signals 2.1, L2, 23, k4 are
`then inputted into a corresponding wavelength-selection,
`space—division switch 10a—10d. Each of the wavelength~
`selection, space-division switches 10a-10d as con?gured by
`the WDM cross-connect module’s local node controller 7
`either bypasses selected wavelengths through, or diverts the
`selected wavelengths to the second multiplexer 111;. The
`second multiplexer 11b then multiplexes the input signals
`for transmission to the ATM switches of the corresponding
`access node 2a-2d. In the WDM cross-connect module
`illustrated in FIG. 3, the input signal 7», is routed to bypass
`through the WDM cross~connect module, while the input
`signals X2, 23, and A4 are diverted to the second multiplexer
`11b for transmission to the corresponding access node and
`then for processing by the ATM switch. As an example, the
`input signals may be sent to their designated user stations
`5a-5h which may be connected to that access node, or
`bypass through for routing to a ditferent access node.
`Multiplexed signals from the user stations NJ connected to
`the access node of the WDM cross-connect module may also
`be routed by the ATM switch into the second demultiplexer
`9b to the wavelength-selection, space-division switches
`10a—10d corresponding to their selected wavelengths. The
`parallel output signals 762, N3, 7d,, are then multiplexed
`together along with the signal 7», through the ?rst multi
`plexer and outputted from the WDM cross-connect module
`to the ?ber rings 3a, 3b.
`
`35
`
`45
`
`TABLE I
`
`Wavelength Channels
`
`7», = 1546 nm
`
`65
`
`Advanced Media Exhibit 2018, pg. 15
`Mercedes-Benz v. Advanced Media
`IPR2016-01255
`
`

`
`5,550,818
`
`7
`The structure of the WDM cross-connect module illus
`trated in FIG. 3 is also applicable to the WDM cross-connect
`module 4e that is used to interconnect the optical ?ber rings
`3a, 312. Like the other WDM cross-connect modules, the
`con?guration of the module 4e is determined by which
`wavelengths need to be passed through to remain within the
`same ?ber ring and which wavelengths should be diverted to
`the other connecting optical ?ber ring. Examples of con
`?gurations for passing speci?c wavelengths originating
`from one optical ?ber ring to the other interconnecting ?ber
`ring will be set forth below.
`The setting up or con?guration of the WDM cross
`connect modules is controlled by predetermined routing
`tables that designate the wavelength distribution and allo
`cation of the WDM cross-connect modules. In the ?eld of
`optical communication systems, the rule of connectivity for
`wavelength-division-multiplexing states that in any optical
`path, each wavelength carries a data stream originated from
`only a single source. In implementing this general rule, the
`following predetermined routing rules are translated into the
`routing tables:
`1. The number of single-hop connections is maximized.
`2. Single-hop connections are implemented for the long
`est loop paths.
`3. One wavelength channel is assigned as the multi-hop,
`local train information carrier.
`All three of the above rules are not necessarily applied
`simultaneously. Rather, Rule No. l and Rule No. 3 are
`applied together so that the con?guration of the cross
`connect modules will maximize data ?ow or bandwidth
`usage in and out of each cross-connect module, while
`maintaining the capability of adding new users anywhere in
`the network without interrupting the established connections
`of current users.
`Rule No. 2 is only applied in con?guring the cross—
`connect modules when users require a clear channel (single~
`hop) connection to deliver data with maximum security and
`minimum system delay or latency. Such requirements are
`satis?ed by using a long optical path.
`All three rules can only be satis?ed simultaneously when
`a su?iciently large number of wavelength channels is avail
`able to connect all the nodes together in a system. However,
`in any system using a limited number of wavelengths, such
`connections are extremely di?icult to implement.
`FIG. 4A shows an example routing table of the wave
`length assignments for the optical connections, and FIG. 4B
`is an example routing table listing the corresponding wave
`length-selection, space-division switch settings for FIG. 4A
`to control each wavelength transmitted through the 2><2
`WDM cross-connect modules 4a—4d. In FIG. 4A, the access
`nodes identi?ed horizontally across the top of the table
`designate the transmitting access nodes, while those along
`the left vertical side designate the receiving access nodes.
`The values in the table itself designate the signal represen
`tative of a speci?c wavelength that a transmitting access
`node uses to connect with a particular receiving access node.
`For example, access node 2a uses 11 to transmit back into
`itself, and A2110 transmit to access node 2b. Also, access node
`2a uses 23 to transmit to access node 20, and 2.4 to transmit
`to access node 2d. Transmissions from one access node to
`another can even be through more than one input signal. For
`example, access node 2b can transmit to access node 2a via
`A? or 23. Transmission from, for example, access node 2b to
`access node 2d directly requires a multi-hop connection (as
`denoted by “*”).
`In FIG. 4B, the WDM cross-connect modules 4a-4e
`designated horizontally across the top of the table are
`
`55
`
`60
`
`65
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`45
`
`50
`
`8
`cross-referenced with the wavelength signals 7q—7t4. The
`wavelength signals 11-24 correspond to the wavelength
`selection, space-division switches 10a-10d, respectively.
`The values in the table represent the state of the correspond
`ing wavelength-selection, space-division switches as being
`either a BAR state “0” or a CROSS state “1” as de?ned
`above. For example, in the WDM cross-connect module 4a,
`the wavelength-selection, space-division switch 10a operat
`ing with wavelength signal 7H is in a BAR state, While the
`wavelength-selection, space-division switch 101] operating
`with wavelength signal 7», is in a CROSS state.
`FIGS. 5A—5C illustrate how data signals are transmitted
`using the cross-connections outlined in FIGS. 4A and 4B by
`representing each of the different wavelengths as individual
`circuit paths. In particular, FIG. 5A shows the circuit paths
`for data signals at the different wavelengths routed through
`cross-connect modules 4a and 4b, while FIG. 5C shows the
`circuit paths for data signals routed through cross-connect
`modules 40 and 4d. FIG. 5B shows circuit paths for data
`signals routed through cross-connect module 4e that connect
`the optical ?ber rings 3a, 3b.
`As shown in FIG. 5A—5C, if a limited number of wave
`lengths are used (in this case, four), users operating through
`the access nodes 2a-2d cannot be fully connected by single
`hop optical paths, as discussed above. Rather, multi-hop
`paths are needed to establish connections among all of the
`users. As indicated in FIG. 4A, two multi-hop connections
`(marked with “*”) are necessary for the operation of the
`system.
`In FIG. 4B, inpu