(12) United States Patent
`Jin et al.
`
`US006256430B1
`(10) Patent N0.:
`US 6,256,430 B1
`(45) Date of Patent:
`Jul. 3, 2001
`
`(54) OPTICAL CROSSCONNECT SYSTEM
`COMPRISING RECONFIGURABLE LIGHT-
`REFLECTING DEVICES
`
`(56)
`
`References Cited
`Us PATENT DOCUMENTS
`
`
`
`(75) Inventors: Sungho Jin, Millington; Neal Henry Thorsten, Lebanon, both of NJ (Us)
`
`(73) AssigneeZ Agere Systems Inc” Miami Lakes, FL
`(US)
`
`.
`
`_
`
`( * ) Notlce-
`
`_
`
`_
`
`_
`
`_
`
`sutbletct_m artly ((iilsglalmeéi thf fiermgf “g1;
`pa en is ex en e or a Jus e un er
`U.S.C. 154(b) by 0 days.
`
`(21) APPL N05 09/197,800
`(22) Filed;
`Nov_ 23, 1998
`
`(51) Int C17
`.
`.
`
`..................................................... ..
`_
`_
`(52) US. Cl. ................................ .. 385/18, 385/17, 385/37
`
`G02B 6/26
`
`(58) Field of Search ................................ .. 385/16, 17, 18,
`385/20, 21, 22, 23, 37
`
`5,042,889 * 8/1991 BenZOni ............................... .. 385/16
`
`5,581,643 * 12/1996 5,974,207 * 10/1999 Aksyuk et a1. ...................... .. 385/24
`
`5,999,546 * 12/1999 Espindola et a1. ................... .. 385/37
`5,999,671 * 12/1999 Jin et a1. .............................. .. 385/37
`* cited by examiner
`Primary Examiner—Frank G. Font
`Assistant Examiner—Sang H. Nguyen
`(74) Attorney, Agent, or Firm—LoWenstein Sandler PC
`(57)
`ABSTRACT
`In accordance With the invention, an optical switching
`device comprises a light-re?ecting mirror containing a mag
`netic component coupled to a substrate. Qne or more pro
`grammable magnets are provided for moving the mirror by
`interacting With the magnetic component. The program
`mable magnets move the mirrors between or among Selected
`positions and then maintain the mirror position Without
`Continuous power‘ Exemplary Cross Connects and 2X2
`'t h
`d
`'b d.
`SW“: 65 are 656“ e
`9 Claims, 6 Drawing Sheets
`
`.llllll'
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-1
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 1 6f 6
`
`US 6,256,430 B1
`
`12
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-2
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 2 6f 6
`
`US 6,256,430 B1
`
`um 6am
`
`2 m2 =
`
`mm 6H1
`
`3 x2 2
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-3
`
`

`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-4
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 4 6f 6
`
`US 6,256,430 B1
`
`FIG. 48
`
`07428
`
`42A
`
`_
`
`I
`
`_
`
`‘
`
`[IV/420
`
`I
`
`I
`I
`
`4'
`
`I
`
`I
`I
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-5
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 5 6f 6
`
`US 6,256,430 B1
`
`FIG. 5A
`
`/\
`
`[1]
`
`l--~
`
`10
`
`FIBER C (OUTPUT)
`
`---->|
`
`\
`
`1-5»
`
`|<I~
`
`FIBERB (INPUT)
`
`FIBER A (INPUT)
`
`FIBER B (OUTPUT)
`
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`y 6%
`
`5
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`FIG. 5B
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`
`10
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`
`FIBER A
`
`\
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`FIBER c
`
`—>|
`
`T- — — - - - - - - - - - - - - - - - - - ">T
`
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`FIBER B
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`FIBER B
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`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-6
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 6 6f 6
`
`US 6,256,430 B1
`
`FIG. 7
`
`I " Q
`
`FIBER A
`(INPUT)
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-7
`
`

`
`US 6,256,430 B1
`
`1
`OPTICAL CROSSCONNECT SYSTEM
`COMPRISING RECONFIGURABLE LIGHT
`REFLECTING DEVICES
`
`FIELD OF THE INVENTION
`This invention pertains to improved optical switches for
`altering light transmission paths, and, in particular, to mag
`netically programmable and latchable optical sWitches.
`
`BACKGROUND OF THE INVENTION
`In modern lightWave telecommunication systems such as
`Wavelength-division-multiplexed (WDM) optical ?ber
`systems, it is often necessary to sWitch the path of trans
`mitted light. A number of different approaches have been
`utiliZed. SWitching has been effected by mechanical move
`ment of optical ?bers (see P. G. Hale et al., Electronic Lett.,
`vol. 12, p. 388,1976, and Y. Ohmori et al.,Appl. Optics, vol.
`17, p. 3531, 1978). SWitching can also be based Faraday
`rotation (see M. Shirasaki et al., Appl. Optics, Vol. 23, p.
`3271, 1984).
`SWitching based on re?ecting mirrors is particularly
`attractive for communication systems but has not yet
`achieved its potential. (see Tanaka et a/. US. Pat. No.
`4,498,730, L. Y. Lin et al, IEEE Photonics Technology Lett.,
`Vol. 10, p. 525,1998, R. A. Miller et al., Optical Eng., Vol.
`36, p. 1399, 1997, and by J. W. Judy et al., Sensors and
`Actuators, Vol. A53, p. 392, 1996). SWitches using re?ecting
`mirrors are convenient in that they use free-space light
`transmission and are potentially expandable to a large-scale
`optical crossconnect system. They typically employ
`electrostatic, pieZoelectric or electromagnetic actuation
`means to move or rotate the mirrors and alter the light paths.
`The problem With these devices is that they either require the
`use of continuous application of poWer to maintain the
`shifted mirror position or their position is unstable. For
`example electrostatic devices are prone to charge build up
`and leakage, and hence are very sensitive to environment.
`Accordingly there is a need for latchable optical sWitches in
`Which poWer is not required once the light path is shifted to
`a desired direction and for Which the latched position is
`stably maintained.
`
`SUMMARY OF THE INVENTION
`In accordance With the invention, an optical sWitching
`device comprises a light-re?ecting mirror containing a mag
`netic component movably coupled to a substrate. One or
`more programmable magnets are provided for moving the
`mirror by interacting With the magnetic component. The
`programmable magnets move the mirrors betWeen or among
`selected positions and then maintain the mirror position
`Without continuous poWer. Exemplary cross connects and
`2x2 sWitches are described.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The advantages, nature and additional features of the
`invention Will appear more fully upon consideration of the
`illustrative embodiments described in the accompanying
`draWings. In the draWings:
`FIG. 1 schematically illustrates an exemplary, three
`dimensionally programmable and latchable optical sWitch;
`FIGS. 2(a)—(c) a graphical representations, useful in
`understanding the invention, of mag tiZati M (or correspond
`ing mirror displacement 6 vs applied ?eld curves for a
`latchable magnet;
`FIG. 3 schematically illustrates a cross-sectional vieW of
`programmable, free-space, optical sWitch With a plurality of
`light re?ecting mirrors;
`
`1O
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`2
`FIGS. 4(a) and 4(b)illustrate a programmable and latch
`able optical cross connect system in tWo and three dimen
`sions respectively;
`FIG. 5 illustrates an alternative programmable and latch
`able optical sWitch;
`FIGS. 6(a)and 6(b) schematically illustrate a program
`mable and latchable 2><2 optical sWitch; and
`FIG. 7 illustrates an alternative 2><2 optical sWitch.
`It is to be understood that these draWings are for purposes
`of illustrating the concepts of the invention and are not to
`scale. The same reference numerals are used to designate
`similar elements throughout the draWings.
`DETAILED DESCRIPTION
`Referring to the draWings, FIG. 1 schematically illustrates
`an exemplary programmable and latchable, light-re?ecting
`sWitch 9 comprising a mirror 10 including a magnetiZable
`component 11. The mirror is movably coupled to substrate
`12 by a movable support 13, and one or more programmable
`and latchable magnets 14 (here three magnets: 14A, 14B,
`and 14C) are provided for controlling the mirror position.
`Each programmable magnet 14 comprises a magnet com
`ponent 15 and a controlling solenoid 16. The mirror 10
`changes the path of an incoming light signal, e.g., a beam
`from a laser or a Waveguide, toWard a desired output
`direction, such as to a speci?c Waveguide channel, an optical
`ampli?er or a photodetector.
`The mirror 10 can be completely re?ective (e.g., made
`With a thick metallic coating on a substrate) or semi
`transparent (e.g., made With a thin coating on a transparent
`substrate) alloWing a part of the incoming light signal to pass
`and propagate straight. The mirrors can be macroscopic or
`microscopic in siZe depending on speci?c applications. They
`can be made by micromachining similar to the fabrication of
`microelectromechanical systems (MEMs). Each mirror is
`made magnetiZable, either by attaching (e.g., epoxying) or
`depositing (as by sputtering or electroplating) at least one
`magnetiZable component 11 on a portion of the front or
`backside surface of the mirror 10.
`The movable support 13 betWeen the mirror 10 and the
`substrate 12 is prepared in such a Way that the mirror is
`three-dimensionally movable. The support can alloW tilting,
`rotating, sliding, or tWisting displacement of the mirror
`light-re?ecting plane. The support 13 can be a mechanical
`hinge, a spring, a ball and socket, or a resilient member such
`as an elastically compliant extension of the substrate.
`At least one programmable and latchable magnet is pro
`vided in the vicinity of each mirror 10. The programmable
`magnet typically consists of an elongated magnet 15 With
`speci?c desired magnetiZation and demagnetiZation
`characteristics, and a solenoid 16 comprising a Winding
`surrounding the magnet. The solenoid can be a pre-made
`Winding on a bobin, insulated Wires directly Wound around
`the magnet 15, or a thin, lithographically-de?ned thin ?lm
`conductor pattern helically placed around the magnet (With
`a thin insulating layer placed betWeen the conductor and the
`magnet). The solenoid 16, upon passing a predetermined
`amount of electrical current, supplies a magnetic ?eld Which
`is then ampli?ed by the elongated magnet 15. In operation,
`the magnetic ?eld from each of the programmable magnets
`14A, 14B, 14C attracts or repels the mirror through mag
`netostatic interaction With the magnetiZable component 11
`placed on the mirror.
`FIGS. 2(a)—(c) are graphical illustrations useful in under
`standing the programmable and latching behavior of the
`sWitch. They shoW M-H magnetic hysteresis loop charac
`teristics.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-8
`
`

`
`US 6,256,430 B1
`
`10
`
`15
`
`25
`
`35
`
`3
`FIG. 2(a) illustrates a “square” hysteresis loop. With
`magnets exhibiting a square hysteresis loop, one can make
`bistable devices that sWitch betWeen tWo magnetization
`levels, e.g., a mirror position corresponding to Zero magnetic
`force and a saturation displacement position achieved With
`the maximum magnetic force. The Zero magnetic force is
`achieved by applying an AC or DC demagnetiZing ?eld. The
`saturation displacement is achieved by a DC pulse current
`sufficient to saturate the magnets. HoWever, for continuous
`tuning of the mirror position in any x, y or Z direction, the
`square loop characteristic is not alWays desirable as the steep
`side of the curve in FIG. 2(a) can pose a control problem
`When a certain intermediate ?ber displacement (6) is desired.
`FIG. 2(b) illustrates a skeWed hysteresis loop. For ease of
`control, the M-H and 6-H loop can be skeWed as shoWn in
`FIG. 2(b). This is achieved by increasing the selfdemagne
`tiZing ?eld of the magnets e.g., by either increasing effective
`diameter of the magnet, reducing the length (and thus
`decreasing the magnet length-to-diameter aspect ratio), or
`by subdividing the magnet length With inserted gaps
`betWeen divided magnet parts. The optimal skeWing of the
`loop is as illustrated in FIG. 2(b), i.e., the remanent mag
`netiZation or the remanent mirror displacement When the
`applied ?eld is removed is still essentially the same as the
`saturation value (at least 90%), and the onset ?eld of rapid
`decrease of M or 6 When the ?eld is reversed is near Zero
`?eld and preferably in the range of 150% the coercive force,
`even more preferably in the range of 110% of the coercive
`force
`The desired degree of skeWing of the loop is
`preferably a maximum loop shift by 50%—150% of Hc.
`FIG. 2(C) illustrates an excessively skeWed hysteresis
`loop. An excessive skeWing of the M-H or 6-H loop is not
`desirable as this causes a deterioration of the latchability of
`the ?ber displacement. Such a deterioration in latchable
`displacement is indicated by arroWs in FIG. 2(C).
`For applied magnetic ?elds of H1 and H2, the correspond
`ing magnetiZation is latchably retained after the ?eld is
`removed, and the corresponding displacement of the mirror
`position, 61 and 62, is also latchably retained. Therefore the
`device can be operated after actuation Without continuous
`poWer. The degree of mirror displacement is altered and
`latched by changing the magnetiZation in the programmable
`magnets. This can be achieved by either increasing the
`applied ?eld or by demagnetiZing ?rst and remagnetiZing to
`a neW ?eld level. For example, to shift from 61 to 62 an
`applied ?eld of H2 is used. To shift the mirror position from
`62 back to 61, a reverse polarity magnetic ?eld is utiliZed.
`The magnitude of the ?eld is selected so that the magneti
`Zation is reduced to the level corresponding to the displace
`ment 61. When this ?eld is removed the displacement 61 is
`latched. For magnetiZation of the magnets using a solenoid,
`a pulse ?eld (a pulse current in the solenoid) can conve
`niently be used for high-speed, loW-poWer operation. The
`desired duration or speed of the pulse ?eld is typically in the
`range of 10—10_6 seconds, preferably 10—10_4 seconds. The
`shape of the current pulse applied can be sinusoidal, rect
`angular or irregular.
`The preferred programmable magnet materials for the
`latchable mirror devices are those Whose magnetic proper
`ties are modi?able by a pulse magnetic ?eld. Some examples
`of suitable magnets are Fe—Cr—Co, Fe—Al—Ni—Co
`(Alnico), Cu—Ni—Fe (Cunife), and Co—Fe—V
`(Vicalloy). The desired range of the coercivity for the
`programmable magnet is typically beloW 500 Oe and pref
`erably beloW 100 Oe for the ease of programming by
`remagnetiZation using solenoid pulse ?eld. The coercivity is
`typically above 10 Oe and preferably above 30 Oe for
`
`45
`
`55
`
`65
`
`4
`maintaining the stability of the remanent magnetiZation and
`also for stability against demagnetiZation due to stray mag
`netic ?elds. For satisfactory latchability of the shifted mirror
`position When the ?eld is removed, the programmable
`magnet should preferably have a parallelogram-shaped mag
`netiZation hysteresis loop With the squareness ratio (de?ned
`as a ratio of remanent magnetiZation/saturation
`magnetization) of at least 0.85, preferably at least 0.90, even
`more preferably at least 0.95. For ease of control, the loop
`is desirably skeWed by at least 50% of Hc. Mechanically
`ductile and easily formable or machineable magnet alloys
`such as Fe—Cr—Co, Cu—Ni—Fe, Co—Fe—V are particu
`larly desirable for shaping into desired rod-like geometry
`shoWn in FIG. 1. Stable permanent magnets With high
`coercive forces (e.g., Hc>1000 Oe), such as Sm—Co,
`Nd—Fe—B ,or Ba ferrite, are less desirable (unless modi
`?ed to exhibit loWer coercive forces) because of the dif?
`culty in reprogramming the remanent magnetiZation using
`desirably loW magnetic ?eld.
`Apreferred magnet material is Fe—28%Cr—7%Co alloy
`Which is deformation aged to yield a M-H loop With HC of
`70 Oe. The M-H loop is skeWed by about 60 Oe, producing
`a M-H loop similar to FIG. 2(b).
`The number of programmable magnets 14A, 14B, 14C
`can be one, tWo, three or even more than three, depending
`on the nature of the device and the required degree of
`freedom for mirror repositioning. In general, three program
`mable magnets or more are preferred in order to provide a
`three dimensional degree of freedom in the movement of the
`mirror. HoWever, use of spring components or tWo
`dimensional con?nement of mirror movement can reduce
`the number of programmable magnets.
`A feedback system (not shoWn) can optionally be utiliZed
`to control the precise mirror position shift. Positional infor
`mation can be used to activate additional, incremental, or
`reduced pulse current to one or more of the solenoids so as
`to obtain a revised latchable magnetiZation level and mirror
`position. This feedback and adjustment process can be
`repeated a number of times, if necessary, until the desired
`mirror position or angle is achieved.
`The optical sWitch can also be utiliZed for intentional
`misalignment of light so as to completely cut off the optical
`information from the light path (basically serving as an
`on-off sWitch). It can also be used to partially misalign the
`paths to provide a desired level of signal intensity to
`receiving optical path (thus serving as a latchable
`attenuator). The performance of the sWitch as a latchable
`attenuator depends on the control provided by the program
`mable and latchable magnets.
`The magnetic component 11 attached or deposited on the
`mirror (preferably on the backside) can be made of a
`permanent magnet material such as Nd—Fe—B, Sm—Co,
`Al—Ni—Co, Fe—Cr—Co or Ba—ferrite. Alternatively, the
`magnetic component can be made of a soft magnetic mate
`rial such as Ni—Fe (permalloy), Si-steel or metglas mate
`rial. If a permanent magnet material is employed, magnetic
`attraction to as Well as magnetic repulsion from the pro
`grammable magnet can be utiliZed to induce a tWo-Way
`movement of the mirror.
`As exemplary operation, the mirror 10 can take a 45
`degree inclined angle as the default position in the absence
`of actuation of any of the three programmable magnets 14A,
`14B, 14C. If the programmable and latchable magnets 14A
`and 14B are evenly magnetiZed, the mirror Will be magneti
`cally attracted and bend toWard right to be more upright. If
`they are unequally magnetiZed, the mirror Will bend to the
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-9
`
`

`
`US 6,256,430 B1
`
`5
`right but also With some torsional displacement allowing the
`mirror to take a different light-re?ecting angle. If only the
`programmable magnet 14C is actuated, the mirror Will bend
`doWnWard, the degree of Which is controlled by the latchable
`magnetiZation induced in the magnet 14C. If the program
`mable magnets 14A and 14B are unevenly magnetiZed at the
`same time 14C is magnetiZed, the doWnWard mirror move
`ment Will occur With some angle tWist, giving rise to a varied
`light-re?ecting angle. Thus the mirror can take up many
`different re?ecting angles in three dimensions.
`FIG. 3 is a schematic cross-sectional vieW of a tWo
`dimensional array of programmable optical sWitches. An
`array 30 of light-re?ecting mirrors 10A, 10B, .
`.
`. are
`mounted on a common substrate 12 such as a silicon
`substrate. An array 31A of programmable magnets 14A,
`14B, .
`.
`. , at least one magnet for each mirror (and preferably
`three magnets for each mirror if a three-dimensional control
`is desired), are mounted on separate holders 32. The magnets
`can be as small as a ?ne Wire, and the respective solenoids
`can be either Wound directly on the magnet Wire or pre-made
`and slipped onto the Wire. In a preferred embodiment, tWo
`such magnet arrays, one as the upper array 31A and the other
`as the loWer array 31B (magnets 14A‘, 14B‘, .
`.
`. ) beneath
`the substrate are pre-assembled, brought close to the sub
`strate 12, and aligned for ease of device construction.
`Alternatively, utiliZing mirror supports 13 having spring
`force for counter-balancing force, only one set of magnet
`arrays, either 31A or 31B, may be used for mirror recon
`?guration.
`FIG. 4(a) shoWs a tWo-dimensional optical cross connect
`40 comprising an array of optical input paths 41A, 41B , .
`.
`. ,
`an array of output paths 42A, 42B ,
`.
`.
`. and an array of
`programmable, latchable mirrors 10 similar to FIG. 1. Typi
`cally the inputs and outputs are respective linear arrays and
`the mirrors are disposed in a tWo-dimensional array. The
`programmable magnets are not shoWn for simplicity of
`description. The input optical signals from various input
`light sources 41A, 41B ,
`.
`.
`. such as lasers, ?bers, planar
`Wave guides, ampli?ers, are sent into the optical sWitching
`cross connect 40, and are re?ected by programmable and
`latchable mirrors 10 toWard desired output signal lines 42A,
`42B , .
`.
`. Light focusing lenses (not shoWn) may optionally
`be utiliZed for improved optical coupling to the receiving
`lines.
`FIG. 4b shoWs an analogous three-dimensional cross
`connect. The arrangement of input and output lines com
`bined With magnetically programmable mirrors 10 conve
`niently alloWs the optical signals to be re?ected to any of the
`siX faces of a cube-shaped crossconnect system for three
`dimensional, high-capacity optical routing. The crosscon
`nect system can be optionally designed to be reversible in
`that the direction of the optical signal ?oW can be the
`opposite of What is shoWn in FIG. 4(b) for additional
`?exibility of light traffic control.
`FIG. 5 schematically illustrates an alternative program
`mable and latchable optical sWitch 50. An optical input line
`41 (e.g., ?ber, planar Waveguide, laser, etc) can be arranged
`in an essentially parallel manner together With output lines
`42A, 42B. Each line is tipped With a focusing lens 51.
`Alternatively, each of the output lines 42A, 42B can be
`positioned at appropriately tilted orientation so as to receive
`the re?ected light signal directly in line With the output line
`orientation, With a minimal use of light focusing lenses. The
`magnetic tuning and latching of the mirror 10 alloWs the
`input beam to be selectively rerouted to one of the output
`lines. The mirror 10 can be an isolated body With a ?at
`geometry and can be magnetically tilted, rotated or tWisted
`so that the optical signal is re?ected to a desired transmission
`line.
`
`10
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`6
`Alternatively one can employ a cylinder con?guration
`With a ?at-end mirror surface positioned at a tilted angle
`With respect to the cylinder axis, With the cylinder magneti
`cally rotated around its aXis so that the re?ected beam is
`directed to one of the circularly arranged transmission lines
`around the input line.
`FIG. 6(a) shoWs a 2x2 optical sWitch 60 (programmable
`magnets not shoWn). The sWitch 60 comprises at least tWo
`pairs of aligned optical paths, e.g. ?bers A and C form one
`aligned pair and ?bers B and D, the other. The sWitch
`controls transmission among a plurality of ?ber paths A, B,
`C, D. Depending on hoW the 4 mirrors 10 are magnetically
`arranged, the sWitch may operate as a re?ection mode
`optical connection of ?ber A to ?ber B and ?ber D to ?ber
`C Alternatively as illustrated in FIG. 6(b), the sWitch may
`operate as a transmission mode connection of ?ber Ato ?ber
`C and ?ber D to ?ber B.
`FIG. 7 illustrates an alternative 2>2 optical sWitch 70
`comprising only one magnetically programmable mirror 10.
`Fiber B and ?ber C are positioned slightly off-centered to
`accommodate the mirror thickness for a re?ective-mode,
`beam connection of ?ber A to B and ?ber C to D. This
`displacement also prevents the collision of the tWo light
`beams When the mirror 10 (dashed sketched) is displaced out
`of the beam paths and the sWitch is operated in a
`transmission-mode,beam connection. Transmission mode
`provides connection of ?ber Ato D and ?ber C to B. One or
`more light focusing lenses (or mirrors) may be utiliZed to
`move the beam from the input ?ber C toWard the output ?ber
`B.
`It is to be understood that the above-described embodi
`ments are illustrative of only a feW of many possible speci?c
`embodiments Which can represent applications of the inven
`tion. Numerous and varied other arrangements can be made
`by those skilled in the art Without departing from the spirit
`and scope of the invention.
`What is claimed:
`1. An optical sWitching device comprising:
`at least one optical input path;
`at least one optical output path; and
`disposed betWeen said input path and said output path, an
`optical sWitch comprising a light-re?ecting mirror
`including a magnetic component, said mirror movably
`coupled to a substrate, and at least one programmable,
`latchable magnet for interacting With said magnetic
`component to move said mirror betWeen a ?rst position
`re?ecting light from said input path to said output path
`and at least a second position re?ecting light from said
`input path aWay from said output path, said program
`mable magnet maintaining said mirror positions With
`out continuous poWer.
`2. The sWitching device of claim 1 Wherein said optical
`input path comprises an optical ?ber.
`3. The sWitching device of claim 1 Wherein said at least
`one optical input path comprises a plurality of optical ?bers.
`4. The sWitching device of claim 1 Wherein said at least
`one optical input path comprises a plurality of optical ?bers.
`5. The sWitching device of claim 1 Wherein said mirror is
`movably coupled to said substrate by a resilient support
`member.
`6. The sWitching device of claim 1 Wherein said second
`position is misaligned With said optical output path to
`attenuate the signal to said output path.
`7. The sWitching device of claim 1 Wherein said at least
`one optical output path comprises a ?rst output path and a
`second output path and said mirror in the said second
`position re?ects light from said input path to said second
`output path.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-10
`
`

`
`US 6,256,430 B1
`
`7
`8. An optical crossconnect switching device comprising:
`an array of optical input paths;
`an array of optical output paths;
`disposed betWeen said input and output path arrays, an
`array of light re?ecting mirrors, each mirror including
`a magnetic component and movably mounted on a
`substrate, and, for each mirror, one or more
`programmable, latchable magnets for moving said mir
`ror by interaction With said magnetic component,
`Whereby the position of the mirror can be controlled
`Without continuous power.
`
`10
`
`8
`9. The cross connect sWitching device of claim 8 Wherein:
`said array of optical input paths comprises a linear array
`of optical ?bers;
`said array of optical output paths comprises a linear array
`of optical ?bers; and
`said array of light re?ecting mirrors comprises a tWo
`dimensional array of said mirrors.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-11