(12) United States Patent
`Jin et al.
`
`US006256430B1
`
`(10) Patent No.: US 6,256,430 B1
`(45) Date of Patent: Jul. 3, 2001
`
`(54) OPTICAl, CROSSCONNECT SYSTEM
`COMPRISING RECONFIGURABI,E IAGHT-
`REFLECTING DEVICES
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`(75) Inventors:
`
`Sungho Jin, Millinglon; Neal Henry
`Thorsten, Lebanon, both of NJ (US)
`
`(73) Assignee:
`
`Agere Systems Inc., Miami Lakes, FL
`(US)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/197,800
`
`(22) Filed:
`
`Nov. 23, 1998
`
`(51)
`
`Int. Clo7 ....................................................... G02B 6/26
`
`(52) U.S. Cl ................................... 385/18; 385/17; 385/37
`
`(58) Field of Search .................................. 385/16, 17, 18,
`385/20, 21, 22, 23, 37
`
`5,042,889 * 8/1991 Bel~zoni ................................. 385/’16
`5,581,643 * 12/1996 Wu ......................................... 385/’18
`5,974,207 * 10/1999 Aksyuk el al ......................... 385/24
`5,999,546 * 12/1999 Espindola et al ...................... 385/’37
`5,999,671 * 12/1999 Jin et al ................................. 385/’37
`
`¯ cited by examiner
`
`Primary Examiner~’rank G. Font
`Assistant Exammer~ang H. Nguyen
`(74) Attorne); Agent, or Firm~owenstein Sandler PC
`
`(57) ABSTRACT
`
`In accordance with the invention, an optical switching
`device comprises a light-rellecting mirror containing a mag-
`netic component coupled to a substrate. One or more pro-
`grammable magnets are provided for moving the mirror by
`interacting with the magnetic component. The program-
`mablc magnets move the mirrors bctwccn or among sclcctcd
`positions and then maintain the mirror position without
`continuous power. Exemplary cross connects and 2x2
`switches are described.
`
`9 Clailns, 6 Drawing Sheets
`
`10
`
`~14C
`
`-15
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-1
`
`

`

`U.S. Patent
`US. Patent
`
`ju~. 3, 2001
`Jul. 3, 2001
`
`Sheet 1 of 6
`Sheet 1 0f 6
`
`US 6,256,430 B1
`Us 6,256,430 B1
`
`
`
`I0
`
`Petitioner Ciena Corp. et al.
`Petitioner Ciena Corp. et al.
`Exhibit 10242
`Exhibit 1024-2
`
`

`

`U.S. Patent
`US. Patent
`
`Jul. 3, 2001
`JuL 3, 2001
`
`Sheet 2 0f 6
`Sheet 2 of 6
`
`US 6,256,430 B1
`US 6,256,430 B1
`
`H(OHI»)
`
`H(0Hs)
`
`M(ORa)
`
`FIG.20
`
`FIG.28
`
`FIG.2A
`
`Petitioner Ciena Corp. et al.
`Petitioner Ciena Corp. et al.
`Exhibit 102443
`Exhibit 1024-3
`
`

`

`U.S. Patent
`
`~uL 3, 2001
`
`Sheet 3 of 6
`
`US 6,256,430 BI
`
`FIG.
`
`3__O OA <~ lOB
`12"~’ ~"-13 ,Ill’
`
`~"" 14D ~’" 14E
`
`’~ IOD ’~ tOE
`"" 12
`
`~14D’ ~’-I4E’
`
`FIG. 4A
`
`4O
`
`’li
`
`41A 41B 41C 410
`
`L
`
`__/42B
`
`j_i-42A
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-4
`
`

`

`U.S. Patent
`
`jui. 3, 2001
`
`Sheet 4 of 6
`
`US 6,256,430 B1
`
`FIG. 4B
`
`FIG. 5
`
`50
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-5
`
`

`

`U.S. Patent
`
`jura. 3, 2001
`
`Sheet 5 of 6
`
`US 6,256,430 B1
`
`FIG.
`
`GO
`
`10
`
`FIBER A (INPUT)
`
`FIBER C (OUTPUT)
`
`FIBER B IOUTPUTI
`
`FIBER O IINPUTI
`
`FIG. GB
`
`FIBER A
`
`FIBER B
`
`\
`
`FIBER C
`
`FIBER O
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-6
`
`

`

`U.S. Patent
`
`JuL 3, 2001
`
`Sheet 6 of 6
`
`US 6,256,430 B1
`
`FIG. 7
`
`lO
`
`FIBER A
`(INPUT]
`
`FIBER C
`(INPUT)
`
`10
`
`FIBER D
`(OUTPUT)
`
`FIBER B
`IOUTPUT)
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-7
`
`

`

`US 6,256,430 B1
`
`1
`OPTICAL CROSSCONNECT SYSTEM
`COMPRISING RECONFIGURABLE I,IGHT-
`REFLECTING DEVICES
`
`FIELD OF TIIE 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
`
`2
`FIGS. 4(a) and 4(b)illustrate a prograrnmable and latch-
`able optical cross connect system in two and three dimen-
`sions respectively;
`FIG. 5 illustrates an alternative programmable and latch-
`s able optical switch;
`FIGS. 6(a)aod 6(b) schematically illustrate a program-
`mablc and latchable 2x2 optical switch; and
`FIG. 7 illustrates an alternative 2x2 optical switch.
`It is to be understood that these drawings are for purposes
`10 of illustrating the concepts of the invention and are not to
`scale. The same reference numerals are used to designate
`similar clcmcnts throughout thc drawings.
`
`In modern lightwave telecommunication systems such as
`wavelength-division-multiplexed (WDM) optical fiber
`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- 15
`meat of optical fibers (see R G. Hale et al., Ek, ctronic 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., App!. Optics, Vol. 23, p.
`3271, 1984). 20
`Switching based on rellecting mirrors is particularly
`attractive for communication systems but has not yet
`achieved its potential. (see Tanaka et a/. U.S. Pat. No.
`4,498,730, L. Y. Lin et al, IEEE Photonics Technology Lett.,
`Vol. 10, p. 525,1998, R. A. Miller et al., OpticMEng., Vol. 25
`36, p. 1399, 1997, and by J. W. Judy et al., Sensors and
`Actuators, Vol. A53, p. 392, 1996). Switches nsing reflecting
`mirrors are convenient in that they use flee-space light
`transmission and are potentially expandable to a large-scale
`optical crossconnect system. They typically employ 30
`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 continuons application of power to maintain the
`shifted mirror position or their position is unstable. For 35
`example electrostatic devices are prone to charge build up
`and leakage, and hence are very sensitive to enviromnent.
`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 4r~
`stably maintained.
`
`SUMMARY OF THE INVENTION
`
`In accordance with the invention, an optical switching
`device cmnprises a light-reflecring mirror containing a mag- 45
`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 5~
`without continuous power. Exemplary cross connects and
`2x2 switches are described.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The advantages, nature and additional features of the 55
`invention will appear more fully upon consideration of the
`illi~strative embodiments described in the accompanying
`drawings. In the drawings:
`FIG. 1 schcmatically illustrates an exemplary, three-
`dimensionally programmable and latchable optical switch; 6~
`FIGS. 2(a)-(c) a graphical representations, useful in
`understanding the invcntion, of mag tizati M (or correspond-
`ing mirror displacement ~ vs applied field carves for a
`latchable magnet;
`FIG. 3 schematically illustrates a cross-sectional view of 65
`programmable, free-space, optical switch with a plurality of
`light reflecling mirrors;
`
`DETAILED DESCRIPTION
`
`Referring to the drawings, FIG. 1 schematically illustrates
`an exemplary programmable and latchable, light-reflecting
`switch 9 comprising a mirror 10 including a magnctizablc
`component 11. The mirror is movably conpled to sttbstrate
`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 cmn-
`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, snch as to a specific waveguide channel, an optical
`amplilier or a photodetector.
`The mirror 10 can be completely reflective (c.g., made
`with a thick metallic coating on a snbstrate) 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 specific applications. They
`can be made by micromachining similar to the fabrication of
`microclcctromcchanical 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-reflecting plane. The support 13 can be a mechanical
`hinge, a spring, a ball and socket, or a resilient mcmbcr 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
`specific 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-defined thin film
`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 field which
`is then amplified by the elongated magnet 15. In operation,
`the magnetic field from each of the programmable magnets
`14A, 14B, 14C attracts or repels the mirror through mag-
`nctostatic interaction with thc magnctizablc 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
`
`3
`FIG. 2(a) illustrates a "square" hysteresis loop. With
`magnets exhibiting a square hysteresis loop, one c,’m 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 maxinrum nragnetic force. Tire zero nragnetic force is
`achicvcd by applying an AC or DC dcmagnctizing field. 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 dircction, the
`square loop charactcristic is not always dcsirablc as the steep
`side of the curve in FIG. 2(a) can pose a control problem
`when a certain intermediate fiber displacement (~5) is desired.
`FIG. 2(b) illustrates a skewed hystcrcsis loop. For case 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 field of the magnets e.g., by either increasing effective
`diameter of the nragnet, reducing the length (and thus
`decreasing the magnet length-to-diameter aspect ratio), or
`by subdividing the magnet length with inserted gaps
`between dividcd magnet parts. Thc optimal skcwing of the
`loop is as illustrated in FIG. 2(b), i.e., the remanent mag-
`netization or the remanent mirror displacement when the
`applied lield is removed is still essentially the same as the
`saturation value (at least 90%), and the onset field of rapid
`decrease of M or 6 when the field is reversed is near zero
`field and preferably in the range of -+50% the coercive force,
`even morc prcfcrably in the rangc of _+10% of thc cocrcivc
`force (He). 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 skcwcd hystcrcsis
`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 fiber displacement. Such a deterioration in latchable
`displacement is indicated by arrows in FIG. 2(c).
`For applied magnetic fields of H1 and Ha, the correspond-
`ing magnetization is latchably retained after the lield 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 field or by demagnetizing first and remagnetizing to
`a new field level. For example, to shift from 61 to 62 an
`applied field of H: is used. To shift the mirror position front
`62 back to 6~, a reverse polarity magnetic field is utilized.
`The magnitude of the field is selected so that the magneti-
`zation is reduced to the level corresponding to the displace-
`ment 6~. When this field is removed the displacement 6~ is
`latched, l~or magnetization of the magnets using a solenoid,
`a pulse field (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 field is typically in the
`range of 10-10 ~’ seconds, preferably 10-10 4 seconds. The
`shape of the mlrrent 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 modifiable by a pulse magnetic field. Some examples
`of suitable magnets are Fe Cr~Co, Fe@N~Co
`(Alnico), Cu--Ni--l~e (Cunife), and Co--l~’e--V
`(Vicalloy). Tire 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 field. The coercivity is
`typically above 10 Oe and preferably above 30 Oe for
`
`4
`maintaining the stability of the remanent magnetization and
`also for stability against demagnetization due to stray mag-
`netic fields. For satisfactory latchability of the shifted mirror
`position whcn the field is removed, the programmable
`5 magnet should preferably have a parallelogram-shaped m ag-
`netization hysteresis loop with the squareness ratio (defined
`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 skcwcd by at lcast 50% of Hc. Mechanically
`ductile and casily formablc or machincablc magnet alloys
`such asFe Cr Co, Cu Ni Fe, Co Fe~areparticu-
`larly desirable for shaping into desired rod-like geometry
`shown in FIG. 1. Stable permanent magnets with high
`15 coercive forces (e.g., Hc>1000 Oe), such as Sin--Co,
`Nd--Fe--B ,or Ba ferrite, are less desirable (unless modi-
`ficd to exhibit lowcr coercivc forces) because of the diffi-
`cuhy in reprogramming the remanent magnetization using
`desirably low magnetic field.
`~ Apreferred magnet material is Fe--28%Cr--7%Co alloy
`which is deformation aged to yield a M-H loop with H~ of
`70 Oe. The M-H loop is skewed by about 60 Oe, producing
`a M-II loop similar to FIG. 2(b).
`The nnmbcr of programmable magncts 14A, 14B, 14C
`~s can be one, Iwo, 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 urore are preferred in order to provide a
`three dimensional degree of freedom in the movement of the
`30 mirror. IIowever, use of spring components or two-
`
`dimcnsional confincmcnt of mirror movement can reduce
`the number of programmable magnets.
`A feedback system (not shown) can optionally be utilized
`35 to control the precise mirror position shift. Positional infor-
`mation can be used to activate additional, incremental, or
`rcduccd pulse currcnt to onc or morc of the solcnoids so as
`to obtain a revised latchable magnetization level and mirror
`position. This feedback and adjustment process can be
`40 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
`45 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). Thc pcrformancc of the switch as a latchablc
`attenuator dcpcnds on the control provided by thc program-
`50 mane and latchable magnets.
`The magnetic conrponent 11 attached or deposited on the
`mirror (preferably on the backside) can be made of a
`permanent magnct material such as Nd--Fc--B, Sm--Co,
`A1--Ni--Co, Fe--Cr--Co or Ba--ferrite. Alternatively, the
`55 magnetic component can be made of a soft magnetic mate-
`rial such as Ni~e (permalloy), Si-steel or metglas mate-
`rial. If a permanent magnet material is employed, magnetic
`attraction to as well as magnetic repulsion frona the pro-
`grammable magnet can be utilized to induce a two-way
`6~ movcmcnt 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
`~5 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
`
`10
`
`right but also with some torsional displacement allowing the
`mirror to take a different light-reflecting 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- s
`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-reflecting angle. Thus the mirror can take up many
`different reflecting angles in three dimensions.
`FIG. 3 is a schcmatic cross-sectional vicw of a two
`dimensional array of programmable opfical switches. An
`array 30 of light-reflecting mirrors 10A, 10B, . . . are
`mounted on a common substrate 12 such as a silicon
`substrate. An array 31A of progranamable magnets 14A,
`14B,..., at 1cast onc magnet for each mirror (and preferably ~5
`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 fine 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 :0
`such magnet arrays, one as the upper array 31A and the other
`as the lower array 31B (magnets 14A’, 14B’, . . . ) beneath
`the substrale are pre-assembled, brought close to the snb-
`strate 12, and aligned for ease of device construction.
`Alternatively, utilizing mirror supports 13 having spring :s
`force for counter-balancing force, only one set of magnet
`arrays, either 31A or 31B, may be used for mirror recon-
`figuration.
`FIG. 4(a) shows a two-dimensional optical cross connect
`411 comprising an array of optical input paths 41A, 41B,..., 30
`an array of output paths 42A, 42B , . . . and an array of
`programmable, latchable mirrors 10 similar to FIG. 1. Typi-
`cafly 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 35
`light sources 41A, 41B , . . . such as lasers, fibers, planar
`wave guides, amplifiers, are sent into the optical switching
`cross connect 411, and are reflected by programmable and
`latchable mirrors 111 loward desired outpnl signal lines 42A,
`42B, ... Light focusing lenses (not shown) may optionally 40
`bc utilized for improved optical coupling to the receiving
`
`FIG. 4b shows an analogous three-dimensional cross
`connect. The arrangement of input and output lines com-
`bincd with magnctically programmablc mirrors 10 convc- 4s
`niently allows the optical signals to be reflected to any of the
`six faces of a cube-shaped crossconnect system for three-
`dimensional, high-capacity optical routing. The crosscon-
`nect syslem can be opfionally designed lo be reversible in
`thai the direcfion of lhe oplical signal flow can be the 50
`opposite of what is shown in lqG. 4(b) for additional
`flexibility of light traffic control.
`FIG. 8 schemafically ilh~strates an alternative program-
`mable and latchable optical switch 811. An optical input line
`41 (e.g., liber, planar waveguide, laser, etc) can be arranged 5s
`in an essentially parallel manner together with output lines
`42A, 42B. Each line is tipped with a focusing lens 81.
`Alternatively, each of the output lines 42A, 42B can be
`positioned at appropriately tilted orientation so as to receive
`the reflected light signal direclly in line with the outpul 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 111 can be an isolated body with a flat
`geometry and can be magnetically tilted, rotated or txvisted 65
`so that the optical signal is reflected to a desired transmission
`
`6
`Alternatively one can employ a cylinder configuration
`with a flat-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 reflected beam is
`directed lo 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. fibers A and C form one
`aligned pair and fibers B and D, the other. The switch
`controls transmission among a plurality of fiber paths A, B,
`C, D. Depending on how the 4 mirrors 10 are magneficafly
`arranged, the switch may operate as a reflection mode
`optical connection of fiber A to fiber B and fiber D to fiber
`C Alternatively as illustrated in FIG. 6(b), the switch may
`operate as a transmission mode connection of fiber A to fiber
`C and fiber D to fiber B.
`FIG. 7 illustrates an alternative 2>2 optical switch 70
`comprising only one magnetically programmable mirror 10.
`Fibcr B and fiber C are positioncd slightly off-centcrcd to
`accommodate the mirror thickness for a reflective-mode,
`beam connection of fiber A to B and fiber C to D. This
`displacement also prevents the collision of lhe 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 fiber A to D and fiber C to B. One or
`more light focusing lenses (or mirrors) may be utilized to
`move the beam frmn the input fiber C toward the output fiber
`B.
`It is to be understood that the above-described embodi-
`ments are iflnslrative of only a few of many possible specific
`embodinaents 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 scopc of the invention.
`What is claimed:
`1. An optical switching device comprising:
`at least onc 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-reflecting mirror
`including a magnetic component, said mirror movably
`coupled to a substrate, and at least one programmable,
`latchable magnet for interacting with said magnetic
`componcnt to move said mirror between a first position
`reflecting lighr from said inpnl path to said outpnl path
`and at least a second position reflecting 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 compriscs an optical fiber.
`3. The swilching device of claim 1 wherein said at least
`one optical input path comprises a plurality of optical fibers.
`4. l’he switching device of claim 1 wherein said at least
`one optical input path comprises a plurality of optical fibers.
`5. The switching device of claim 1 wherein said mirror is
`movably coupled to said substrate by a resilient support
`member.
`6. The swilching 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 first output path and a
`second output path and said mirror in the said second
`position reflects light from said input path to said second
`onlput path.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-10
`
`

`

`US 6,256,430 t31
`
`8. An optical crossconnect switching device comprising:
`an array of optical input paths;
`an array of optical output paths;
`disposed bctwccn said input and output path arrays, an
`array of light reflecting 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.
`
`9. The cross connect switching device of claim 8 xvherein:
`
`said array of optical input paths comprises a linear array
`of optical fibers;
`
`said array of optical output paths comprises a linear array
`of optical fibers; and
`
`said array of light reflecting mirrors comprises a txvo
`dimensional array of said mirrors.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1024-11
`
`