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`USUIJ6069719A
`
`[19]
`United States Patent
`|ll] Patent Number:
`6,069,719
`|451 Date of Patent: May 30, 2000
`Mizrahi
`
`
`
`[54I DYNAMICALLY RECONFICURABLE
`OPTICAL ADD-Iii“)? MUlJl'll’LEXERS FOR
`WUM OI'I‘ICAL COMM UNICA'I'ION
`SYSTEM 5
`
`75]
`
`Inventor: Vlctm‘ Mum“. Columbia, Mr].
`
`73] Assignee: Cienzl Corporation, Linlhicum, Md.
`
`2|] Appl. No: 088023810
`
`
`
`22|
`
`51]
`52
`
`58|
`
`56]
`
`l-‘iled:
`
`Jul. 30. 1997
`
`
`Int. Cl.7
`U.S. C].
`
`HIMJ Him.
`359(124; 359t'127; 359.5128;
`359F130
`Field of Search ..................................... 359t'124, 12?,
`359-128. 139. 130. [31; 38553?
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`........
`.. 350t128
`3:100? Fourier eta].
`lt'1998 Alexander el al.
`359.62?
`
`2t'19‘l8 Alexander et al.
`350330
`
`.........
`531998 ilantel or al.
`35931.3(!
`
`(1319‘th Setter et ul.
`..
`35mm
`
`7,-‘10‘18 Stidhar ..........
`.. 3593130
`OTHER PU Bi .1 CATIONS
`
`S,el2.8t]5
`5312.932
`5.71.3.0?!)
`5,748.815
`S.‘t‘bU,§i34
`SJTSJIS
`
`Kitayama, K. —1; "Suharrier Mutliplexing Based Signaling
`and Acces‘ea Control
`in Optical FDM Networks"; pp.
`1996-3002; Telecommunications Conference. Singapore.
`Nov. 14—16. 1995. vol. 3, Nov. [995.
`'l'achikawa. Y,. cl a|.: “Arrayed—WavGuide Grating Multi-
`plexer with loop—Back Optical Palhs and its Applications";
`pp. Wit—984; Journal of l..ightwave 'l'echnology, vol. 14. N0.
`6, Jun. 1996.
`Beer, 1.; "Pholonische Transportnelze”; pp. 2(L24; Techi
`nischc Rundschau Transfer, vol. 88, No. 14, Apr. I996.
`Chawki, M. J., el 31.; "Evaluation 01' an Optical Boosled
`Addt'[)rop Multiplexer UBADM including Circuiators and
`[tiber Grating Filters"; pp. tit—50; Proceedings of the Euro-
`pean Conference on Optical ('.'ommunication, vol. I, Sep.
`1995.
`Notification of Transmittai of The [nlemational Search
`Report or The Declaration, 6 pages.
`
`t’rt’tttttnr EJ‘ttttttncr—Dttniel J. Wu
`Assistant Exatttt'tter—John 'l'weel. Jr.
`Attorney, Agent. or Finn—David L. 50112; Margaret Burke
`
`[STI
`
`ABSTRACT
`
`In an optical add-"drop multiplexer, an optical switch is
`coupled to one or more outpuls from a demultiplexer.
`Accordingly, a dropped oplieal channel can be switched
`between a receiver optical path for directing [he dropped
`uplical signal to an optical receiver and between a combiner
`oplical path [or ruuling the dropped optical channel back
`towards the optical transmission path. optionally passing the
`dropped optical channel
`through a
`remndulalor.
`Alternatively, the optical switch routes the dropped nplieal
`channel towards an optical receiver while permitting a new
`optical channel to be routed to add port of the static add-drop
`multiplexer.
`
`10 Claims, 5 Drawing Sheets
`
`'l‘oba, 1L, el 31.: "An Optical {BM—Based Self—l [caling Ring
`Network Employing Arrayed WaveGuide Grating Fillers
`and El)]7A‘s with Level Equalizers"; pp. 800—813; [EEE
`Journal on Selected Areas in Communications, vol. 14, No.
`5. Jun. 1996.
`'l‘oba, 11., ct a1.; "Demonstration of Optical FDM Based
`Self—Healing
`Ring Network
`Employing
`Arrayed—
`WaveGuide—Gralling ADM Filters
`and EFDAS"; pp.
`263-266; Optical Communication (EC, Fireman Sep. 25—29.
`1994] vol. I. No. CONF. 20, Sep. 1994.
`
`
`
`JDS UNIPHASE CORPORATION
`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 1
`Exhibit 1016, Page 1
`
`

`

`US. Patent
`
`May 30, 2000
`
`Sheet 1 of S
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`JDS UNIPHASE CORPORATION
`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 2
`Exhibit 1016, Page 2
`
`
`

`

`US. Patent
`
`May 30, 2000
`
`Sheet 2 0f5
`
`6,069,719
`
`No:
`
`JDS UNIPHASE CORPORATION
`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 3
`Exhibit 1016, Page 3
`
`

`

`US. Patent
`
`May 30, 2000
`
`Sheet 3 of S
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`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 4
`Exhibit 1016, Page 4
`
`
`
`
`

`

`US. Patent
`
`May 30, 2000
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`Sheet 4 of S
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`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 5
`Exhibit 1016, Page 5
`
`
`
`

`

`US. Patent
`
`May 30, 2000
`
`Sheet 5 of 5
`
`6,069,719
`
`0|,_COMBMER90
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`JDS UNIPHASE CORPORATION
`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 6
`Exhibit 1016, Page 6
`
`

`

`6,069,719
`
`1
`DYNAMICAILY RECONFIGURABLE
`OPTICAI..ADD-DROP MULTIPLEXERS FOR
`WDM OPTICAL COMMUNICATION
`SYSTEMS
`
`FIELD OF THE INVENTION
`
`The invention relates to optical add-drop multiplexers
`and. more particularly, to optical add—drop multiplexers for
`wavelength division multiplexed optical communication
`systems which are dynamically reconfigurable for transfer—
`ring selected optical channels between optical paths within
`the optical system.
`BAt'IKGROUNI) 013 T] [E INVENTION
`
`Wavelength division multiplexing (WUM) is one tech—
`nique used to increase the capacity of optical communica-
`tion systems. The expression “optical communication
`system," as used herein, relates to any system which uses
`optical signals to convey information across an optical
`waveguiding medium. Such optical systems include, but are
`not limited to, telecommunications systems, cable television
`systems, and local area networks (LANs), Optical systems
`are described in Gowar, Ed. Optical Cortrrrtrrrricarr'rm
`Systems, (Prentice Hall, NY) c.
`I993,
`the disclosure of
`which is incorporated herein by reference. A wavelength
`division multiplexed optical communication system
`employs plural optical channels, each channel being
`assigned a particular channel wavelength.
`In a WDM
`system, optical channels are generated, multiplexed to form
`an optical signal comprised of the individual optical
`channels, transmitted over a waveguide. and demulliplexed
`such that each channel wavelength is individually routed to
`a designated receiver. Through the use of optical amplifiers,
`such as doped fiber amplifiers, plural optical channels are
`directly amplified simultaneously, facilitating the use of
`wavelength division multiplexing in long-distance optical
`systems.
`In many applications, such as optical LANs, cable tele-
`vision subscriber systems, and telecommunications
`networks, there is a need to route one or more channels of
`a multiplexed optical signal to difiercnt destinations. Such
`routing occurs when optical channels are sent to or with—
`drawn front an optical transmission line e.g., for sending
`optical channels between a terminal and an optical bus or
`rattling long distance telecommunications traffic to indi—
`vidual cities. Additionally, optical routing must be suff-
`cienlly flexible to enable a variety of system configurations,
`permitting optical signal paths to be reconfigured in
`response to changing traffic pattern requirements. Thus.
`there is a need in the art for flexible and efiectiv'e optical
`routing to enable practical implementation of wavelength
`division multiplexed optical communication systems.
`SUMMARY OF THE INVENTION
`
`invention provides a reconfigurable optical
`'lhe present
`add—drop multiplexer For a wavelength division multiplexed
`optical communication system. The reconfigurable add—drop
`multiplexer includes a static optical add-drop multiplexer
`including an input port for receiving optical signals from an
`optical transmission path in a wavelength division t'nulti—
`plexed optical communication system, a drop port for rout—
`ing optical channels to be removed front an optical trans-
`mission palh, an add port for receiving optical channels to be
`added to an optical
`transmission path, and wavelength
`selecting means [or selecting at least one optical channel to
`be dropped from the optical transmission path.
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`An optical path communicating with the drop port
`includes an optical demulliplexer having an input port for
`receiving the dropped optical channels and plural demulti—
`plexer output ports for separately outputting optical chan—
`nels. Alternatively, the demultiplexer can be omitted it only
`one optical channel is to be dropped. Plural demultiplexer
`optical paths optically communicate with the optical dcmul—
`tiplexer for receiving each of the dropped optical channeLs.
`Similarly, an optical path optically communicates with the
`add port of the static add-drop multiplexer. The add optical
`path includes an optical combiner or multiplexer having
`plural combiner input ports communicating with plural
`combiner optical paths [or receiving optical channcls to be
`added to the optical transmission path and an output port for
`outputting a combined optical signal comprising the optical
`channels received from the combiner input ports.
`An optical switch positioned in one or more of the
`demultiplexer optical paths permiLs switching of a dropped
`optical channel between a receiver optical path for directing
`the dropped optical signal to an optical receiver and between
`a combiner optical path for routing the dropped optical
`channel back towards the optical transmission path, option~
`ally passing the dropped optical channel through a remodu~
`lator. Alternatively, the optical switch routes the dropped
`optical channel towards an optical receiver while permitting
`a new optical channel to be routed to add port of the static
`add—drop multiplexer.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 schematically depicts a reconfigurable add-drop
`multiplexer aocording to the present invention;
`l-‘1G.2 schematically depicts a static add-drop multiplexer
`for use with the reconfigurable add-drop multiplexer of FIG.
`I;
`
`FIG. 3 schematically depicts a reconfigurable add-drop
`multiplexer according to a further embodiment of the
`present invention;
`FIG. 4 schematically depicts a reconfigurable add-drop
`multiplexer according to a further embodiment of the
`present invention; and
`FIG. 5 schematically depicLs a remodulalor.
`[)E'I‘AJILD DESCRIPI'ION
`
`in which like
`Turning now to the drawings in detail,
`numerals indicate the same or similar elements, FIG. 1
`dcpicLs a reconfigurable add-drop multiplexer 10 according
`to the present
`invention. Reconfigurable add-drop multi-
`plexer 10 is interposed in optical
`transmission path 12.
`Transmission path 12 is typically a single mode optical fiber
`that
`forms the principal
`transmission medium of an
`N—channel wavelength division multiplexed optical system
`where N is a whole number greater than or equal
`to 2.
`Exemplary values for N are 4, 8, 16, and 32 or more optical
`channels. WDM optical systems suitable for the application
`of the present invention are described in commonly-assigned
`U.S. Pat. No. 5,504,609, the disclosure of which is incor—
`porated by reference herein.
`Reconfigurable add-drop multiplexer 10 includes static
`add—drop multiplexer 14 for removing and inserting optical
`channels into optical transmission path 12. "l‘he expression
`"static” as used to describe add-drop multiplexer 14 refers to
`the fact
`that
`the channels dropped by multiplexer 14 are
`fixed, and are not remotely reconfigurable. An exemplary
`add—drop multiplexer for use as static add—drop multiplexer
`14 is depicted in FIG. 2. Add-drop multiplexer 14 comprises
`
`JDS UNIPHASE CORPORATION
`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 7
`Exhibit 1016, Page 7
`
`

`

`6,069,719
`
`3
`an optical circulator 20 having first, second, and third optical
`circulator ports 22, 24, and 26. respectively. Optical circu-
`lator 20 is configured such that optical signals which enter
`circulator port 22 exit through circulator port 24 and optical
`signals which enter circulator port 24 exit through circulator
`port 26.
`Optical transmission path 12 optically communicates with
`first circulator port 22. The expression "optically commu-
`nicates" as used herein, refers to any connection, coupling,
`link, or the like, by which optical signals carried by one
`optical system element are imparted to the "communicating"
`element. Such "optically communicating” devices are not
`necessarily directly connected to one another, but may be
`separated by intermediate optical components or devices. In
`an exemplary embodiment, optical transmission path 12 is a
`single mode optical fiber which forms the principal Irans-
`mission medium for a wavelength division multiplexed
`optical communication system.
`A second transmission path 50 optically communicates
`with second circulator port 24. Positioned within optical
`transmission path 5|] is an optical filter 4|]. In the depicted
`embodiment, tiller 40 comprises a set of four fiber Bragg
`gratings, 42, 44. 46, and 48 respectively corresponding to
`wavelengths of 1.5,
`11-,
`it.» and 1....
`In an exemplary
`embodiment, }.,.<l\.’-<l.,,<1.ylo avoid problems associated with
`transmission through radiation mode loss regions of adjacent
`gratings. Although gratings are employed as an exemplary
`optical filter. it is understood that any optical device capable
`ol'sclectirtg the desired optical channels can be employed as
`lilter 40.
`A third optical transmission path 28 optically communi-
`cates with third optical circulator port 26. Optical transmis—
`sion path 28 receives optical signals which are reflected by
`optical filter 40 back towards second circulator port 24.
`Optical coupler 30 is used to couple optical signals to be
`added to an optical transmission system. Optical coupler 30
`is selected from any optical device which combines optical
`signals I'rom plural
`input pork; and places the combined
`optical signal onto an output port. Typically,
`the optical
`signals from two input ports are equally combined and
`placed on the output path although the two input paths can
`be combined in various ratios {e.g., T0230, 80:20, etc.)
`depending upon the needs of the optical system (cg, when
`desiring to equalize signal strength from two optical paths).
`Exemplary optical couplers are 1X2 fused fiber oplical
`splitters, commercially available from Corning and Gould,
`used to combine signals rather than split the signals. Optical
`coupler3tl includes first input port 32, second input port 36,
`and output port 34. First inpul port 32 optically communi-
`cates with optical transmission path 50 for receiving those
`optical signals output by optical circulator port 24 which are
`not dropped by optical filter 40, i.e., the "through" optical
`signals.
`A fourth optical transmission path 39 optically commu—
`nicates with second coupler input port 36 for adding optical
`signals to the through optical signals received by first
`coupler input port 32. Because coupler 30 combines the
`optical signals from input ports 32 and 36, the optical signals
`which are added vial transmission path 39 do not contact
`optical filter 40 but are directly combined with the signals
`from first
`input port 32 and output
`through port 34.
`Consequently, an arbitrary number of optical channels may
`be added to the optical system;
`the wavelengths of the
`optical channels do not need to correspond to the wave-
`lengths of the channels dropped by optical filter 40.
`Optical
`transmission path 12,
`i.e.,
`the primary optical
`transmission path of the WDM optical system, optically
`
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`communicates with coupler output port 34 for receiving the
`combined optical signal
`front
`the first and second input
`pons. It is emphasized that the static add-drop multiplexer of
`FIG. 2 is merely exemplary. Any add—drop multiplexer
`which can select the desired optical channels can he used in
`the reconfigurable add-drop multiplexers of the present
`invention. For example, an add drop multiplexer based on
`interference filters commercially available from Dieon and
`JDS Fitel, for example, may also be used. Further exemplary
`add-drop multiplexers are described in commonly-assigned
`US. patent applicalion Ser. No. tJéltISZEflS'F. filed Mar. 27.
`1996 and (B,-'759.965. filed Dec. 2. I996. [he disclosures of
`which are incorporated by reference herein.
`Returning to the reconfigurable add-drop multiplexer of
`FIG. 1, optical path 28, which receives [he dropped optical
`channeLs, optically communicates with demultiplexer input
`port 62 of optical demultiplexer 60 for separating the
`dropped optical channels into individual optical channels to
`be individually routed to separate output paths 64 through
`output ports 63. Optical demultiplexer can be selected from
`any optical device or system which can take a combined
`optical signal and separate individual optical channels there~
`from.
`[Exemplary optical dernultiplexcrs include planar
`waveguide devices such as arrayed waveguide gratings
`(AWG) or other routers, as well as passive optical splitters
`combined with gratings-based selectors (see, for example,
`the receiving system grating selectors of US. Pat. No.
`5,504,609, incorporated herein by reference).
`Typically, the dropped optical channel will be routed to
`optical receiver 80, either directly or after being transmitted
`through another branch of the same or another optical
`system. However,
`if it
`is desired that
`the optical channel
`remain on the optical
`transmission path 12,
`the optical
`channel can be routed to an optical path leading to the add
`port of static add-drop multiplexer 14. Optical switch 70
`permits the selection of either optical path for the appropri-
`ate routing of the dropped optical signal. Optical switch 7“
`may be an SRIEAU—ZUNC 1:2 optical switch commercially
`available from J DS-liite]. However, it is understood that the
`depicted optical switches are exemplary. Other electrome-
`chanical optical switches as well as electro—optic and
`therththic switches having a variety of switching eon—
`ligurations can also be employed in the reconfigurable
`add-drop multiplexers of the present invention. Exemplary
`optical switches attd switclt configurations enable the selec-
`tion of dilIerenl optical path in fewer than 50 milliseconds,
`with times of fewer than 15 milliseconds or even less than
`1 millisecond being preferred.
`To optionally enable the reconfigurable adddmp multi—
`plexers of the present
`invention to be dynamically
`reconfigurable, the optical switches can be externally con-
`trolled through control signals carried by a service channel,
`2.“, on optical transmission path [2, as shown in FIG. I.
`The service channel is fed, via optical demultiplexer 60, to
`a circuit such as a service channel modem 93 where it is
`converted to an electrical signal used to direct switch
`controller circuit 95. If the service chanttel carries informa-
`tion for receipt by other service channel modems coupled to
`optical communication path [2, service channel modem 93
`retransmits the service channel, 1“}, to optical communi-
`cation path 12 via combiner 90. While this technique for
`controlling the optical switching is exemplary, it is under
`stood that any method for controlling the optical switches is
`within the scope of the present invention.
`()ptical channels to he added to optical transmission path
`12 enter static add—drop multiplexer 14 through input port
`36. input port 36 optically communicates with add optical
`
`JDS UNIPHASE CORPORATION
`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 8
`Exhibit 1016, Page 8
`
`

`

`6,069,719
`
`5
`path 39 in which is positioned optical combiner 90. Optical
`combiner 90.
`including, for example. a passive optical
`element such as a fused fiber coupler, or a multiplexer which
`routes wavelengths, receives optical channels to be added to
`the wavelength division multiplexed optic system through
`combiner input ports 92. Combiner input ports 92 commu-
`nicate with combiner optical paths 94 which carry the
`optical channel[s) to be added. In the configuration of FIG.
`1, the optical channel to be added is the same as the optical
`channel dropped by the static arid-drop multiplexer. Other
`optical paths 94 can communicate with optical transmitters,
`rcmodttlators. or other dropped optical channels for carrying
`optical channels to he added to the optical system. The
`depicted optical switch can be interposed in any or all of the
`remaining "drop" optical paths. The optical channels to he
`added can have any optical channel wavelength as long as
`that wavelength is not occupied by a “through" channel
`passed by static add-drop multiplexer 14. Moreover.
`the
`channels to he added and dropped can be changed or
`reconfigured without affecting the through channels.
`In the configuration of FIG. 3, a dropped optical channel
`to be added back into the optical system is first routed
`through an optical remodulator lllll. As seen in FIG. 5,
`optical remodulator 100 includes an optoelectronic element,
`such as photodetector 502, for receiving a dropped optical
`channel and outputting a corresponding electrical signal
`which includes the information from the optical channel.
`The electrical signal is supplied to a drive circuit 501, which.
`in turn, supplies a modulating circuit to external modulator
`503. An optical source, such as semiconductor laser 594,
`continuously emits light which is modulated by external
`modulator 503,
`a Mach—Zehnder
`interferometer,
`for
`example, in accordance with the electrical signal. The modu-
`lated light is next output to combiner 90.
`Exemplary remodulators for use with the present inven-
`tion are described in US. Pat. No. 5.504.609. incomorated
`by reference above. The configuration shown in FIG. 3
`advantageously regenerates the signal and readily accom-
`plishes wavelength translation.
`Although an external modulation scheme is illustrated in
`FIG. 5. it directly modulated scheme is within the scope of
`the present invention whereby a modulated optical output is
`generated by directly turning laser 504 on and off.
`Preferably. the power level of the optical signal is adjusted
`so that all the channels carried by optical transmission path
`12 have substantially the same power level,
`i.e., "power
`balaneing" is achieved. Moreover. in the embodiments illus-
`trated in FIGS. 1 and 3, an optical amplifier 91, including an
`erbium doped fiber, for example, can be provided at
`the
`output of static addt’drop multiplexer 14to amplify signals
`carried on optical transmission path 12. Alternatively, opti—
`cal amplifier 91 can be provided at the input of addidrop
`multiplexer 14.
`In the configuration of FIG. 4, a 2:2 bypass optical switch
`110, for example, an SREBAS-EONC commercially avail-
`able from IDS-liitel, permits the dropped optical channel to
`be routed to optical receiver 80. An optical channel to be
`added is generated by optical transmitter 120 and mapped to
`a channel wavelength within the channel plan of the WDM
`optical system through remodulator 100.
`In this
`embodiment, a dropped channel to be rc-routed to the optical
`transmission path is passed through the rcmodulator, as in
`the previous embodiment.
`While the foregoing invention has been described in terms
`of the embodimean discussed above, numerous variations
`are possible, Accordingly, modifications and changes such
`
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`as those suggested above, but not limited thereto, are con-
`sidered to be within the scope of following claims.
`What is claimed is:
`l. A reconfigurable optical add—drop multiplexer for a
`wavelength division multiplexed optical communication
`system comprising:
`a static optical add-drop multiplexer including an input
`port for receiving optical signals from an optical trans-
`mission path in a wavelength division multiplexed
`optical communication system, a drop port for routing
`optical channels to be removed from an optical trans-
`mission path. an add port for receiving optical channels
`to be added to an optical transmission path, wavelength
`selecting means for selecting optical channels to he
`dropped from the optical transmission path, an output
`port supplying at least ones of said optical channels not
`selected by said selecting means. and a continuous
`optical path coupling said input port and said output
`purl;
`an optical path optically communicating with the drop
`port having positioned therein an optical demulliplexer
`having a demultiplexer input port
`for receiving the
`dropped optical channels and plural demultiplexer out-
`put ports for separately outputting optical channels;
`plural demultiplexcr optical paths optically communicat-
`ing with the optical dentultiplexcr for receiving each of
`the dropped optical channels;
`an optical path optically communicating with the add port
`having positioned therein an optical combiner having
`plural combiner input ports for receiving optical chan—
`nets to be added to the optical transmission path and an
`output port for outputting a combined optical signal
`comprising the optical channels received from the
`combiner input porLs;
`at least one optical receiving path configured to route a
`dropped optical channel to an optical receiver;
`plural combiner optical paths optically communicating
`with the optical combiner for carrying optical channels
`to be added to the optical transmission path;
`optical switching means optically communicating with a
`demultiplexer optical path and with a combiner optical
`path and with an optical receiving means, the optical
`switching means configured to switch a dropped optical
`channel
`from the demultiplexcr optical path to the
`combiner optical path or to switch a dropped optical
`channel
`from the demultiplexer optical path to the
`optical receiving means.
`add—drop multiplexer as
`2.. A reconfigurable optical
`recited in claim 1 further comprising an optical remodulator
`positioned in the contbiner optical path optically communi-
`cating with the optical switching means, the optical remodu-
`lator comprising:
`an optoelectronic element for receiving a dropped optical
`channel and outputting a corresponding electrical sig-
`nal which includes the information from the optical
`channel;
`an optical source for emitting an optical signal at an
`optical channel wavelength; and
`means for modulating the optical source with information
`front the electrical signal output by the optoelectronic
`element to create an output signal including the infor-
`mation from the dropped optical channel;
`a remodulator output port optically communicating with
`the combiner optical path for placing the output signal
`onto the combiner optical path.
`
`JDS UNIPHASE CORPORATION
`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 9
`Exhibit 1016, Page 9
`
`

`

`6,069,719
`
`7
`3. Arecontlgttrahle optical add-drop multiplexer in accor-
`dance with claim 2. wherein a wavelength of said dropped
`optical channel is dill'erent than a wavelength of said output
`signal.
`4. A reconfigurable optical add-drop ntultiplexer as
`recited in claim 2 further comprising an optical transmitter
`for transmitting an optical signal to be supplied to the optical
`remodulator.
`5. A reconfigurable optical addxlrop multiplexer. com-
`prising:
`a static addt'drop multiplexer having an input port receiv-
`ing a first pluralityr of wavelength division multiplexed
`channels, a drop pon, an add port, an output port
`outputting a second plurality of wavelength division
`multiplexed channels, a continuous optical path cou-
`pling said input port
`to said output port. said static
`addr’drop multiplexer outputting at least one of said lirst
`plurality of wavelength division multiplexed channels
`through said drop port; and
`an optical switch coupled to said drop port, said switch
`selectively supplying said at
`least one of said first
`plurality of wavelength division multiplexod channels
`to one of an opto-clectronic receiver and said add port.
`said at least one ol‘said plurality of wavelength division
`multiplexed channels being supplied through said out—
`put port of said static addidrop multiplexer as one of
`said second plurality of wavelength division multi-
`plexed channels when said optical switch supplies said
`at least one of said first plurality of wavelength division
`multiplexed channels to said add port.
`6. Arcconligurahlc optical add-drop multiplexer in accor-
`dance with claim 4. wherein said input port also receives a
`service channel carrying control signals, said service chan-
`nel being output through said drop port, said reconfigurable
`optical add-drop multiplexer further comprising:
`a service channel modem circuit coupled to said drop port,
`said service channel modem generating an electrical
`control signal in response to said service channel; and
`a switch controller circuit coupled to said optical switch
`and configured to receive said electrical control signal.
`said switch controller circuit controlling said optical
`switch in accordance with said electrical control signal.
`7. An optical device comprising:
`a static addt'drop multiplexer having an input port receiv-
`ing a first plurality of wavelength division multiplexed
`channels, a drop port. an add port, an output port
`
`llil
`
`[5
`
`3L]
`
`Lu'2:
`
`4o
`
`45
`
`8
`outputting a second plurality ot’ wavelength division
`multiplexed channels. a continuous optical path cou-
`pIing said input port
`to said output port. said static
`addt’drop multiplexcroutputling at least one ol'said Iirsl
`plurality of wavelength division multiplexed channels
`through said drop port;
`an optical switch coupled to said drop port. said switch
`selectively supplying said at
`least one of said first
`plurality of wavelength division multiplexed channels
`to one of an opto—clectronic receiver and said add porlI
`said at least one ofsaid plurality of wavelength division
`multiplexed channels being supplied through said out-
`put port of said static addt’drop multiplexer as one of
`said second plurality of wavelength division multi-
`plexed channels when said optical switch supplies said
`at least one of said Iirst plurality of wavelength division
`multiplexed channels to said add port; and
`an optical amplifier coupled to said output port for ampli-
`fying said second plurality of wavelength division
`multiplexed channels.
`8. An optical device in accordance with claim 6, wherein
`said optical amplifier comprises an erbium doped liber.
`9. A reconfigurable optical add-drop multiplexer as
`recited in claim 5 further comprising an optical remodulator
`coupled to said optical switch and said add port, the optical
`rernodulalor comprising:
`an optoelectronic element for receiving a dropped channel
`from said first plurality of wavelength division multi—
`plexed channels and outputting a corresponding elec—
`trical signal which includes the information from the
`dropped channel;
`an optical source For emitting an optical signal at an
`optical channel wavelength: and
`means for modulating the optical source with information
`from the electrical signal output by the optoelectronic
`element to create an output signal including the infor—
`mation from the dropped optical channel;
`an output port optically communicating with the add port
`for supplying the output signal as one of said second
`plurality of wavelength division multiplexed channels.
`[I]. A reconfigurable optical add-drop multiplexer
`in
`accordance with claim 9, wherein a wavelength of said
`dropped optical channel
`is dilferent than a wavelength of
`said output signal.
`
`JDS UNIPHASE CORPORATION
`JDS UNIPHASE CORPORATION
`Exhibit 1016, Page 10
`Exhibit 1016, Page 10
`
`