(12) United States Patent
`Jin et al.
`
`([10) Patent N0.:
`(45) Date of Patent:
`
`US 6,256,430 B1
`Jul. 3, 2001
`
`US006256430B1
`
`OPTICAL CROSSCONNECT SYSTEM
`COMPRISING RJLCONFIGLJRABLE LlGH’l‘-
`REFLECTING DEVICES
`
`Inventors: Sungho Jin, Millingtou; Neal Henry
`Thorsten, Lebanon, both of NJ (US)
`
`Assignee: Agere Systems lnc., Miami Lakes, FL
`(US)
`
`.
`.
`.
`.
`Sub]eCt.IO any dlsclalmer’. the term of this
`patent is extended or adjusted under 35
`L'.S.C. 154(b) by 0 days.
`
`APPL N0‘: 09/1979800
`Ffled:
`N0“ 23’ 1998
`
`Int. CL7
`
`G02B 6/26
`
`U.S. Cl. ........................ .. 385/18, 385/17; 385/37
`
`Field of Search
`
`385/16, 17, 18,
`385/20, 21, 2 23, 37
`
`(56)
`
`References Cited
`U_5_ PATENT DOCUMENTS
`VI‘
`8/1 99 1
`5,042,889
`*
`5.5814343 * 12/1995
`5.974907
`10/1999
`5,999,546 * 12/1999
`
`* 12/1999
`52999767]
`* cited by cxamincr
`Primary Examiner—Frank G. Font
`Assistant Exrzminer—Sang II. Nguyen
`(74) Attorney, Agent, or FL'rm—Lowcnstcin Sandlcr PC
`(57)
`ABSTRACT
`In accordance with the invention, an optical switching
`device comprises a light-reflecting 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-
`mable 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.
`
`9 Claims, 6 Drawing Sheets
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-1
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 1 of6
`
`US 6,256,430 B1
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-2
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 2 of6
`
`US 6,256,430 B1
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-3
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 3 of6
`
`US 6,256,430 B1
`
`FIG. 3
`
`41A
`
`41B
`
`41C
`
`41D
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-4
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 4 of6
`
`US 6,256,430 B1
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-5
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 5 of6
`
`US 6,256,430 B1
`
`FIBER A (INPUT)
`
`_
`
`FIBER C
`
`(OUTPUT)
`
`FIBER B IOUTPUH
`
`'
`
`FIBER D (INPUT)
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-6
`
`

`
`U.S. Patent
`
`Jul. 3, 2001
`
`Sheet 6 of6
`
`US 6,256,430 B1
`
`E
`
`\ \ x \
`FIBER A .
`
`(INPUT)
`
`FIG. 7
`
`14
`
`11
`
`,
`
`1
`
`/
`
`I
`
`/1
`
`I
`
`I
`
`1
`
`1
`
`,
`
`I
`
`I
`
`\
`
`‘\
`
`\
`
`\
`
`\
`\\\\
`
`\ \
`
`‘
`
`x
`
`\
`
`\
`
`\
`
`s
`
`\
`
`\
`\
`\
`I \\
`1
`\\
`\
`\
`V
`
`;
`
`-
`
`(OUTPUT)
`
`/
`
`FIBER B
`muwun
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-7
`
`

`
`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
`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 elfected by mechanical move-
`ment of optical fibers (see P. G. Hale et al., Electronic Left,
`vol. 12, p. 3388,1976, 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 reflecting 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 Photurtics Techrtolugv Lett.,
`Vol. 10, p. 7725,1998, 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 refiectirig
`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—reflecting 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.
`BRIJJI’ DJ.'SCRIPTl()N OF TIIE DRAWINGS
`
`The advantages, nature and additional features of the H
`invention will appear more fully upon consideration of the
`illustrative embodiments described in the accompanying
`drawings. In the drawings:
`three-
`FIG. 1 schematically illustrates an exemplary,
`dimensionally programmable and latchable optical switch;
`FIGS. 2(c1)—(c) a graphical representations, useful
`in
`understanding the invention, of mag tizati M (or correspond-
`ing mirror displacement 5 vs applied field curves for a
`latchable magnet;
`FIG. 3 schematically illustrates a cross-sectioiial view of
`programmable, free-space, optical switch with a plurality of
`light reflecting mirrors;
`
`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 2x2 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, 1ight—reflecting
`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 specific waveguide channel, an optical
`amplifier or a photodetector.
`The mirror 10 can be completely reflective (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 specific applications. They
`can be made by micromachining similar to the fabrication of
`microeleetromechanical 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 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
`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 lielically 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-
`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 1020-8
`
`

`
`US 6,256,430 Bl
`
`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 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 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 fiber displacement (6) is desired.
`FIG. 2(b) illustrates a skewed hysteresis loop. For ease of
`control, the M-H and 5-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 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 field is removed is still essentially the same as the
`saturation value (at least 90%), and the onset field of rapid
`decrease of M or 5 when the field is reversed is near zero
`field and preferably in the range of 150% the coercive force,
`even more preferably in the range of 210% of the coercive
`force (He). The desired degree of skewing of the loop is
`preferably a maximum loop shift by 50%—150% of He.
`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 latehability 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 H2, the correspond-
`ing magnetization is latchably retained after the field is
`removed, and the corresponding displacement of the mirror
`position, 31 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 52 an
`applied field of H2 is used. To shift the mirror position from
`62 back to 61, 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 51. When this field is removed the displacement 51 is ,
`latched. For magnetization ofthe 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 10-106 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 modifiable by a pulse magnetic field. 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 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 latehability of the shifted mirror
`position when the field is removed,
`the programmable
`magnet should preferably have a parallelogram-shaped mag-
`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 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—Il ,or Ila ferrite, are less desirable (unless modi-
`fied to exhibit lower coercive forces) because of the diffi—
`ctdty 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-II loop with IIC of
`70 Oe. The M—II loop is skewed by about 60 Oe, producing
`a M-H loop similar to FIG. 2(1)).
`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 confinement 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 ea11 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 011 the backside) can be made of a
`permanent magnet material such as Nd—l'e—J3, 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—l"e (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.
`the mirror 10 can take a 45
`As exemplary operation,
`degree inclined angle as the default position in the absence
`of actuation of any of the three programmable magnets l4A,
`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 1020-9
`
`

`
`US 6,256,430 Bl
`
`5
`right but also with some torsional displaceriierit 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 riiagriet 14C. If the program-
`mable magnets 14A and 14B are unevenly magnetized at the
`same time 14C is magnetized, the downward mirror r11ove-
`ment will occur with some angle twist, giving rise to a varied
`light-refiectirig angle. Thus the riiirror can take 11p many
`different reflecting 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-reflecting riiirrors 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 fine wire, and the respective solenoids
`can be either wound directly on the magnetwire 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—balaneing force, only one set of magnet
`arrays, either 31A or 31B, may be used for mirror reoon-
`figuration.
`shows a two-dimensional optical cross connect
`FIG.
`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 sotirces 41 A, 41D ,
`.
`.
`. such as lasers, fibers, planar
`wave guides, amplifiers, are sent into the optical switching
`cross connect 40, and are reflected 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 reflected 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 [low can be the ,
`opposite of what
`is shown in FIG. 4(1)) for additional
`flexibility of light tralfic control.
`FIG. 5 schematically illustrates an alternative program-
`mable and latchable optical switch 50. An optical input line
`41 (eg., fiber, 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 reflected 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 flat
`geometry and can be magnetically tilted, rotated or twisted
`so that the optical signal is reflected to a desired transmission
`line.
`
`>
`
`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 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. 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 magnetically
`arranged,
`the switch may operate as a reflectiori mode
`optical connection of fiber A to fiber B and fiber D to fiber
`C Alternatively as illustrated in FIG. 6(1)), the switch may
`operate as a transmission mode connection of fiberAto 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.
`Fiber B and llbcr C are positioned slightly olT-centered to
`accommodate the mirror thickness for a refiective-iiiode,
`beam connection of fiber A to B and fiber 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 fiberAto D and fiber C to B. One or
`more light focusing lenses (or mirrors) may be utilized to
`move the beam from the input fiber (1 toward the output fiber
`B.
`
`It is to be understood that the above-described embodi-
`ments are illustrative of only a few of many possible specific
`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-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
`component to move said mirror between a first position
`reflecting light from said input path to said output path
`and at least a second position reflecting light from saie
`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 optica
`input path comprises an optical fiber.
`3. The switching device of claim 1 wherein said at leas
`one optical input path comprises a plurality of optical fibers.
`4. The switching device of claim 1 wherein said at leas
`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 suppor
`member.
`6. The switching device of claim 1 wherein said secone
`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 leas
`one optical output path comprises a first output path and a
`second output path and said mirror in the said seconc
`position reflects light from said input path to said seconc
`output path.
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-10
`
`

`
`US 6,256,430 B1
`
`7
`8. An optical crosseonneet 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 reflecting mirrors, each mirror including
`a magnetic component and movahly mounted on a
`substrate, and,
`[or each mirror, one or more
`programmable, latehable magnets for moving said mir-
`ror by interaction with said magnetic component,
`whereby the position of the mirror can be controlled 10
`without continuous power.
`
`8
`9. T11e cross connect switching device of claim 8 wherein:
`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 n1irr0rs e0n1prises 21 two
`.
`.
`.
`.
`dlmcnsmnal array of Sam H11H0r5~
`
`Petitioner Ciena Corp. et al.
`Exhibit 1020-11