WO2001009653A1 - Opto-mechanical valve and valve array for fiber-optic communication - Google Patents
Opto-mechanical valve and valve array for fiber-optic communication Download PDFInfo
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- WO2001009653A1 WO2001009653A1 PCT/IL2000/000425 IL0000425W WO0109653A1 WO 2001009653 A1 WO2001009653 A1 WO 2001009653A1 IL 0000425 W IL0000425 W IL 0000425W WO 0109653 A1 WO0109653 A1 WO 0109653A1
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- electrode
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- ing
- switching
- movable
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/3564—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
- G02B6/358—Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/264—Optical coupling means with optical elements between opposed fibre ends which perform a function other than beam splitting
- G02B6/266—Optical coupling means with optical elements between opposed fibre ends which perform a function other than beam splitting the optical element being an attenuator
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/351—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
- G02B6/3512—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being reflective, e.g. mirror
- G02B6/3514—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being reflective, e.g. mirror the reflective optical element moving along a line so as to translate into and out of the beam path, i.e. across the beam path
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/351—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements
- G02B6/353—Optical coupling means having switching means involving stationary waveguides with moving interposed optical elements the optical element being a shutter, baffle, beam dump or opaque element
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/354—Switching arrangements, i.e. number of input/output ports and interconnection types
- G02B6/3554—3D constellations, i.e. with switching elements and switched beams located in a volume
- G02B6/3556—NxM switch, i.e. regular arrays of switches elements of matrix type constellation
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/3564—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
- G02B6/3568—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details characterised by the actuating force
- G02B6/357—Electrostatic force
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/35—Optical coupling means having switching means
- G02B6/3564—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
- G02B6/3584—Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
- G02B6/4228—Passive alignment, i.e. without a detection of the degree of coupling or the position of the elements
- G02B6/423—Passive alignment, i.e. without a detection of the degree of coupling or the position of the elements using guiding surfaces for the alignment
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/0036—Switches making use of microelectromechanical systems [MEMS]
- H01H2001/0084—Switches making use of microelectromechanical systems [MEMS] with perpendicular movement of the movable contact relative to the substrate
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0007—Construction
- H04Q2011/0026—Construction using free space propagation (e.g. lenses, mirrors)
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0007—Construction
- H04Q2011/0026—Construction using free space propagation (e.g. lenses, mirrors)
- H04Q2011/003—Construction using free space propagation (e.g. lenses, mirrors) using switches based on microelectro-mechanical systems [MEMS]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0052—Interconnection of switches
- H04Q2011/0056—Clos
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/0001—Selecting arrangements for multiplex systems using optical switching
- H04Q11/0005—Switch and router aspects
- H04Q2011/0052—Interconnection of switches
- H04Q2011/0058—Crossbar; Matrix
Definitions
- the present invention relates to sw itching in optical netw orks, such as optical communications networks to an optomechanical es general K
- An essential component of an ⁇ communications sy stem is a sw itch to enable signal routing
- Various types of devices are used for optical sw itching Some transform the optical signal into the electrical domain, w hei e sw itching is done, and then retransform back to the optical domain
- Others use integrated optics to perform sw itching, using materials such as lithium niobate
- These devices are relat ⁇ expensive, their minimum size is limited the pln sics of optical e-guides. the ⁇ are strong! ⁇ dependent on w ax elength. and the ⁇ siiffei from cross-talk and signal attenuation
- Micro-mechanical switches are not wavelength dependent and can be very compact Signal loss occurs mainly at the input from and output into the fibers, which is about the same as for other switching technologies
- a niicro-electromechdincal optical switch using a able mirror constiucted on the surface of a substrate and oriented at 45° to the ra ⁇ 's direction is presented The switch either intercepts a light and teflects the ra ⁇ into a changed direction or allows the ra ⁇ to transit unimpeded This switch is situated on.
- NxN switch that can route aiu of its N inputs to ain of its N outputs, is simple to realize There is no interference among the N inputs, since hght-ra ⁇ paths cross without interaction (Hecht J . "Optical s itching promises cure for telecommunications log-jam”. Laser Focus World. Septembei 1998.
- the task is main! ⁇ the production of tin ⁇ mirrors to use as switches in these arra ⁇ s
- Micro-machined devices are capable of fulfilling the task, provided that the micro-machining produces optical-grade mirrors in order to reduce losses Actuation needs to be fast, simple, and allow reproducible and accurate alignment of the beam inputs and outputs as the mirrors bend the ra ⁇
- the ability to deplov laige arrays of mirrois is an essential feature of the s ⁇ stem All of these affect switching losses and utility
- Pre ious art devices, although ingenious were not able to achieve all of these requirements togethei See, for example Toshivoshi H el al "Electrostatic maco-torsion mirrors for an optical-switch matrix".
- a device that can separate a multi-wavelength beam into a bundle of parallel single wave- length ra ⁇ s and recombine them is also disclosed
- an optical switch for switching a light rav including (a) a substantial planar substrate having a portion that is transparent to the light rav (b) a switching element having at least one ieflective surface substantiallv parallel to the substrate, and (c) a mechanism for moving the s itching element in a direction parallel to the substrate between (l) a first position wherein the light ra ⁇ traverses the transparent portion of the substrate and ( ⁇ ) a second position wherein the light ra ⁇ is blocked from travel sing the transparent portion of the substrate and reflected b ⁇ the reflective surface
- the mechanism includes (i) a first rigid element ha ing two ends, the first end of the first iigid element being flexibK connected to a fixed point, (u) a second ngid element ha ing two ends, the second end of the first rigid element being flexibK connected to the first end of the second ngid element and (in) a tensile elastic element connecting the first end of the fust i igid element to the second end of the second rigid element so that the distance between the first end and the second end when the elastic element is m a relaxed state is less than the sum of the distance between the ends of the first rigid element and the distance between the ends of the second rigid element, both the rigid elements being constrained to be movable onlv in a plane parallel to the substrate
- the mechanism includes (i) a fust element ha ing two ends (u) a second element having two ends the first end of the first element being flexibK connected to the first end of the second element, (in) a third element having two ends, the second end of the second element being fiexiblv connected to the first end of the third element (iv) a fourth element having two ends, the second end of the thud element being flexibK connected to the first end of the fourth element, (v ) two fixed anchor points a second the end of the fust element being fiexiblv connected to the first anchoi point and the second end ol the touith clement being flexibK connected to the second anchoi point and ( v i ) a tensi le elastic mechanism toi maintaining the mechanism toi mov mg the sw itching element in eithei of tw o stable states, al l the elements being consti amed to be
- the tensile elastic mechanism includes (a) a tensi le elastic element connecting the second end of the second element to the first anchor point so that the distance between the second end and the first anchor point when the elastic element is in a relaxed state is less than the sum of the distance between the ends of the first element and the distance between the ends of the second element, and (b) a tensile elastic element connecting the first end of the third element to the second anchor point so that the distance between the first end and the second anchor point w hen the elastic element is in a lelaxed state is less than the sum of a distance betw een the ends of the third element and the distance betw een the ends of the fourth element
- the first element and the fourth element are elastic beams, the second element and the third element are rigid, the first element is rigid) ⁇ connected to the first anchor point, and the fourth element is rigid! ⁇ connected to the second anchor point
- a hinge including (a) a housing hav ing a flat w all, (b) an element free to rol l w ithin the housing and hav ing a connector that protrudes bev ond the housing (c) a mechanism for ui ging the reliable element against the wall as the element rolls w ithin the housing so as to maintain rolling contact between the element and the w all
- the present invention furthei includes (d) a restoimg mechanism for returning the rollable element to contact with the wall in case of loss of contact
- the iestormg mechanism includes (a) two flexible cables (i) the first end of the first cable being operational! ⁇ connected to but electrical! ⁇ insulated from the housing, (n) the first end of the second cable being operational! ⁇ connected to but electrical! ⁇ insulated from the housing, (in) the second end of the first cabie being operationall ⁇ connected to but electricalK insulated from the tollable element, and (iv) the second end of the second cable being operationall ⁇ connected to but eleetiicalK insulated from the tollable element, (b) two electiodes tor resetting the tollable element in place (i) a first the electiode being situated opposite the first cable on a side avvav from the rollable element, and (n) the second electrode being situated opposite the second cable on a side awa ⁇ from the rollable element, (c) a mechanism for charging the electrodes, and (d) a mechanism for charging the cables
- the cables in the restoring mechanism (a) the cables aie slack while the rollable element is in contact with the wall, and (b) at least one cable is taut when the rollable element loses contact ith the wall
- a tiavelling wave actuator for moving an ob
- the tiavelling wave actuator furthei includes (d) a substrate whereupon the elastic membrane is deposited
- the mechanism for generating a tiavelling wave includes (i) a pliualilv ot electiode pans cquallv spaced along and stiaddlmg the niembianc and (n) toi each a lespective alternating electrical powei supplv
- an actuator for moving an element comprising (a) a stationai ⁇ support for the element, (b) a deflectable support for the element opeiative to (i) ⁇ aise the element from the stationary support (n) advance the element in a requned direction ot motion, (in) deposit the element upon the stationar ⁇ support and (iv) return to a starting position thereof
- the stationai v support includes a clustei of fingers the cluster being sufficient to support the element
- the deflectable movable support includes at least one clustei of fingers, each clustei being sufficient to support the element
- an emergenc ⁇ holding device for a movable switching element including (a) a buckled beam having (i) a first stable configuration concave tow aids the switching element and (n) a second tense configuration, concave towaids the switching element wheiefiom it lelieved the beam lelaxes to the first stable configuiation and ( b) a flexible snap stiaddlmg the sw itching element the snap being (i) attached at a ilrst end thereof to a centei ot the beam and perpendiculai theieto and ( ⁇ u anchoi ed at a second end thereof at a fixed point, so that at the concave stable configuration the strap constrains the switching element
- the flexible strap is electrical! ⁇ conductive
- the dev ice further comprising (c) an electiode placed opposite the strap
- a mechanism for lateral realignment of a free movable element with respect to a rectilinear motion path thereof comprising (a) two alignment pads on opposite sides of the element, (b) a mechanism for bringing the pads into contact with the movable element, thereb ⁇ nudging the element to the laterallv aligned position and (c) a mechanism for retracting the pads from contact
- the realignment mechanism further includes (d) two walls situated on opposite sides of the movable element and outside the alignment pads and (e) elastic elements attaching each alignment pad to the nearer wall
- the realignment mechanism further includes (d) two walls situated on opposite sides of the movable element and outside the alignment pads, each wall including an electrode, and (e) elastic elements attaching each alignment pad to the nearer side of the movable element
- a mechanism for continuous iateral realignment ot a free movable element with respect to a motion path thereof including (a) a stationaiv electiode ad
- the realignment mechanism includes (d) a second stationary electrode adjacent to and clear of the path, (i) King in a same plane as and clear of the first stationary electrode, (n) opposed to the first stationary electrode with respect to the motion path and (in) at least partial! ⁇ overlapped by the movable electrode so that a gap remains therebetween and (e) a mechanism for electrostatically charging the second stationarv electrode the resulting electrostatic force between the electiodes acting to maintain the element in the motion path
- the charge on the movable electrode is of opposite poia ⁇ ty to the chaige on the stationarv electiodes
- each electrode is an isosceles triangle, an axis of S ⁇ mmetry whereof is oriented perpendicular to the motion path
- a method ot moving an object including the steps of (a) urging the object to be in contact with an elastic membrane while (b) generating a traveling wave in the membrane
- a method of moving an element including the steps of (a) providing (i) a stationaiy support for the element, and (n) a deflectable support for the element, and (b) cyclically operating the deflectable support to (i) laise the element fiom the stationaiv support (n) advance the element in a lequired diieetion ot motion (in) deposit the element upon the stationaiv support and (iv) lettiin to a starting position theieot
- a method of holding an electiostaticalK supported switching element in the event of cessation of a supply of power to the switching element including the steps of (a) providing a flexible strap straddling the switching element and having a first configuration wherein the stiap constrains the switching element and a second configuration wherein the switching element is free from the constraint and (b) maintaining the strap in the second configuration only while power is supplied
- a method of laterally realigning a free movable element in a direction perpendicular to a rectilinear motion path thereof including the steps ot (a) providing a realignment mechanism including two movable alignment pads on opposite sides of the element (b) bringing the pads into contact ith the movable element theieby nudging the element to the rectilineal motion path and (c) retracting the pads
- a method of continuouslv laterally realigning a free movable element with respect to a motion path thereof comprising the steps of (a) providing (i) a stationary electrode adiacent to and clear of the path (u) a second. movable electrode attached to the element, at least partially overlapping the stationary electrode and constrained to remain parallel to the stationary electrode so that a gap remains therebetween and (in) a mechanism for electrostatically charging the electiodes and (b) electrostatically charging the electrodes
- the method includes the furthei steps of (c) pioviding (i) a second stationarv electrode adiacent to and clear ot the path King in a same plane as and clear of first the stationarv electrode opposed to the fust stationary electrode with respect to the motion path, and at least partially overlapped b ⁇ the movable electrode so that a gap remains therebetween and (u) a mechanism for electrostatically charging the second stationaiy electrode
- the method includes the furthei step of chaiging the second stationaiy electiode with a polantv the same as the charge on the fust stationaiv electiode Accoiding to a iuithci mbodiment ot the piesent invention the method includes th fuithci step of charging the movable electiode with a polantv the same as the chaige on the stationarv electrodes
- the method includes the further 5 step of charging the movable electrode with a polantv opposite to the charge on the stationary electrodes
- a method of fabricating a micro-device 10 hav ing a high-qualitv smooth mirror surface comprising the steps of (a) polishing a substrate suiface to a required smoothness (h) depositing mirror material on the substrate and (c) lemoving a supeifluous part ot the substrate adiacent to a surface ot the miiror
- a method ot fabricating a micro-device having a high-qualitv smooth mirror surface comprising the steps ot (a) depositing a ID saciificial laver on the substrate, (b) polishing a surface ot the saciificial laver to a required smoothness, (c) patterning the sacrificial layer to provide toi auxiliary elements (d) depositing mirror material on the polished surface ot the sacrificial layer (e) depositing the auxiliary elements on the patterned portion ot the sacrificial lavei and (f) removing the saciificial layei 0 Accoiding to anothei embodiment ot the present invention the method further includes the step ot (g) remov ing a superfluous part ot the substrate
- a method of fabricating an envelope-actuated micro-device having a high-quality smooth minor surface including the steps of (a) providing a first substrate, (b) depositing an electrode on the first substrate, (c) i depositing a first sacrificial layer on the electrode and the first substrate (d) polishing a surface of the first sacrificial laver to a required smoothness (e) patterning the first sacrificial laver to provide for a first set of auxiliary elements (f) depositing mirror material on the polished surface ot the first saciificial laver and (g) depositing the auxiliary elements on the patterned portion of the first saciificial layer
- the method includes the furthei step ot (h) pi v iding a second electiode Accoiding to anothei embodiment ot the piesent invention
- the method of pioviding the second electrode is effected bv the furthei steps ol (i) depositing a second sacrificial lay et on the muioi material, (n) patterning the second sacrificial la ei to piovide tor the second electrode and a second set of auxiliary elements, and (in) depositing the second electrode and the second set of auxiliary elements on the patterned portion of the second sacrificial layer
- the method of pro iding the second electrode is effected b ⁇ the further steps of (i) providing a second substrate, (u) depositing the second electrode on the second substrate, (in) aligning the second electrode opposite the micro-device as fabricated on the first substrate, and (iv) bonding the second substrate to the first substrate
- the method includes the further step ot (h) lemoving the fust sacrificial layer
- the method includes the furthei step of (h) removing a superfluous part of the substrate
- a mechanism foi providing a strictly non-blocking switching configuration comprising two coupled substantial! ⁇ identical t ⁇ -cube complex switching arra ⁇ s (a) each capable of switching an ⁇ input element to an ⁇ output element (b) the first arra ⁇ being capable of allowing an ⁇ input element to transit unsw itched to a corresponding input of the second arra ⁇ . and (c) the second ana ⁇ being capable of allowing anv output element from the first arra ⁇ to transit unsw itched to a coiiespondmg output of the second aira ⁇
- a method ot strictly non-blocking switching including the steps of (a) providing two coupled substantially identical t ⁇ -cube complex switching arrays (i) each capable of switching any input element to any output element (n) the first array being capable of allowing any input element to transit unsw itched to a corresponding input of the second array, and (in) the second array being capable of allowing anv output element tiom the first array to transit unsw itched to a coiiespondmg output ot the second airay. and (b) operating the switching arrays coupled in parallel
- FIG 1 shows the general switch lav out and basic switching motions
- FIG. 3 shows basic switching actions
- Figure 4 illustrates how a switch can direct two parallel inputs to separate outlets, by operating a switching element entirelv ithin an optical! ⁇ active zone
- Figure 7 illustrates the use of magnetic actuation
- Figure 9 show s further examples of bistable beam supports
- Figure 10 presents a representation of the use of bistable beams ith a micro-mechanical switching element
- Figure 12 presents a more complex application of a t ⁇ ctionless joint
- Figure 13 shows a resetting mechanism in the event of power failure
- Figure 14 illustrates travelling-wave actuation
- Figure 1 sho s the mechanism of finger actuation
- Figure 16 shows a variation on finger actuation
- Figure 17 presents a mechanism foi securing a movable element in the event of povvei failure
- Figure 20 shows how electrostatic forces can maintain alignment
- Figure 22 shows some basic switching actions with two crossed ra ⁇ s
- Figure 23 presents a two variations of a basic 2D switch arra ⁇
- Figure 24 shows a schematic view of multi-layer s itch arra ⁇
- Figures 25 illustrate 3D switching methods involving two or more multi-layer switch arra ⁇ s. including a partialK blocking configuration, a Clos architecture (non-blocking) configuration, and a strictly -non-blocking configuration:
- Figure 26 shows a wavelength-separation/recombiner de ice
- FIG. 27 illustrates basic switch fabrication processes
- Figure 28 shows fabrication stages of a 3D sw itch arra ⁇ :
- Figure 29 shows an isometric view of a 3D arrav cube.
- the wave valve of the present invention is intended to be used in fibei -optic communications to overcome the above-mentioned shortcomings ot previous art although other applications can be envisioned It emplo ⁇ s mirrors to perform the switching Mirrois have the advantage of being substantialK insensitive to wavelength
- the active environment is air. some other gas or a vacuum This is a non-blocking environment, i e it allows ra ⁇ s to cross unimpeded Thus there is no cross-talk and almost no attenuation b ⁇ the medium Most losses occur during light transfer from and into the fiber at the switch/fiber interfaces Losses also arise from beam spieadmg but use of collimatmg lenses and short distances can reduce these
- the miirois should be small to allow fast lesponse and compactness
- the mirrors are geneialK cro-machined and in order to reduce losses, are designed to be of optical grade Actuation should prov ide reproducible and accurate alignment of the beam inputs and outputs while the mirror bends the ra ⁇
- Actuation should prov ide reproducible and accurate alignment of the beam inputs and outputs while the mirror bends the ra ⁇
- the ability to form large a ⁇ ra ⁇ s is an essential requirement ot the svstem All these requirements letlect on switch loss and utility
- Prior art devices although ingenious were not able to fulfil all these lequiiements together [Toshivoshi H et al Electrostatic micro toision mirrors tor an optical switch matrix " . Journal of Miaoelectiomechanical stems vol 5 No 4 page 231 December 1996, and Marxei C et al Vertical mirrors fabricated bv deep reactive ion etching for fiber optic switching applications vol 6 No 3 page
- the valve consists of a flat mirror 1 situated above on. inside oi below and paiallel to a siibsliate 2
- the substrate Mnroi 1 mav move to ditteient positions in i plane 3 pat al lei lo i siiitace ot substrate 2 either substantial cuiv ilinearlv as in a pendulum-like motion 5 in Tigiue lc oi in a substantiallv rectilinear motion in anv direction such as 6 or 6A in Figure Id or in some combination of these
- motion is generallv parallel or normal to a base line 7 ( Figure 2) that separates an opaque zone 8 of substrate 2 wherethrough light 10 cannot pass from a transparent zone 9 wherethrough light 10 can pass and wherein switching takes place
- Zone 9 mav be transparent because the material of substrate 2, which is present in zone 8 is absent in zone 9 or
- Figuie 3 Mirror element 1 is located opposite an opaque zone 38 ot substrate 2 while light 10 tiansits unobstructed through a tiansparent zone 39
- the svstem is in an OI 1 state 1A as shown in Figure 3a
- Mirror 1 is movable rectilinearK parallel to substrate 2 to a position opposite zone 39, as shown bv double-headed arrow 36 to an ON state IB ( Figure 3c d)
- mirror 1 While mirror 1 is in OFF state 1 A light 10 can pass from one side 39 A of surface 3 to anothei side 39B
- minor 1 is movable along a line ot motion 46 which lies entirelv opposite a transparent part 49 of plane 3 and bv so doing simultaneouslv exchanges blocking and non-blocking states in different parts of zone 49
- Mirror suspension and actuation elements are placed opposite another opaque zone 48 of plane 3
- FIG. 4c shows that light from 10A passes to exit 10B while in blocking state 41B light is reflected to an alternate output 10C
- either position of mirror 1 can be designated as ON or OH (Figuie 4e 0
- On actuating switch 1 these states leverse and input rav 10 IA is in an OFF
- the valve consists of mirror 1 which is movable parallel to surface 3 and may be in at least two rest positions Mirror 1 reflects light at one position and allows its passage at another position Any appropriate force may be applied to induce a desired change in mirror position
- actuation methods are available thermal (bimetallic strips), magnetic, piezoelectric mechanical and electrostatic actuation and methods that lelv on shape memorv allovs (SMA) aie a few of many known in the art
- a miuoi is supported by flexible beams that are actuated bv attraction to or repulsion from static cuived electrodes
- a preferred embodiment employs electrostatic actuation
- Different schemes of electrostatic actuation can be used among them a comb-drive mechanism (Hirano T et al. "Design Fabrication, and operation of submicron-gap comb-d ⁇ ve microactuators”. Journal oj Microelecti omechumcul stems, vol 1 No 1.
- Overlapping finger 51 and comb 52 form a capacitor ( Figure 5b)
- the attractive force between the movable and static fingers is
- ⁇ 0 is the permitttv ity of the vacuum
- an electrical potential, //cov is width ot the finger
- ⁇ is the overlapping length of the finger in the direction ot advance thereof
- g is the gap between the movable finger and each static finger
- the disclosed actuator has an envelope-like configuration in which mirror / finger (movable electrode) 51 may enter or exit envelope (static actuating electiode) 52
- envelope static actuating electiode
- f igui e ! at least tw o actuat ing electi odes ai e placed in a w av that one set 52A actuates to an ON position w hile anothei set 52B.
- C actuates to an OFF position
- Actuation can be made bistable if the actuated min or is supported by buckled beams ( see below ) a snap action to each position of the mirror lesults
- bistabil ity employs electrostatic snap (pull-in) action
- An actuated element is attracted to and held by an electrically isolated electrode at an end of its motion From the equations above, force exerted is given by
- the force can be incieased furthei by using a more complex profile than a straight line (57 Figure 5c) that the electrode crosses, thereby increasing the rate ot area change
- This line can be designed, for example, to be circular (57B. Figure 5e), and the force increases correspondingly Alternativ ely, or additionally , the leading edge of electrode 51 may be similarly enlarged
- Another embodiment increases the profile by using an ev en more complex geometrical form
- a form might be an irregular fo ⁇ n such as a fractal line designed for the application
- the use of a fractal torm can increase the actuating force by the ratio of its rate of area change to that of a straight-line profile
- FIG. 6 Another electrostatic actuation method is presented in Figure 6, in w hich the post-fix A or B refers respectively to v ariant embodiments
- One or more flexible beams 67A or 67B support a mirror 61
- One point of the beam(s) 68A or 68B is fixed in close proximity to a circular segment stator 69A or 69B attached to a substrate 62
- These stators and beams are conductiv e and respectiv elv chargeable w ith opposite polarity Beam 67A or 67B and stator 69 or 69B, respectiv ely , aie separated by insulators 65A or 65B from each other along an entire circular segment of stator 69A or 69B or at least, at points w here contact may otherw ise occur, so as to prev ent a short circuit ( Figure 6a. b. c. and d)
- stator 694 (B) and mov able beam 67A (B) sets charges of opposite polarities on stator 69.4 (B) and beam 674 (B). so that the latter is atti acted to the foi mei as c lose as pei m itted bv the insulation ( Figuie 6b 6d) Remov ing the potential dit tei ence a llow s beam 674 ( B) to l etui n to the oi igin l shape thereof Since a ti ee end of beam 67A (B) is connected to mirroi 61.
- stator 69A moves mirror 61 A (B) a distance L in a direction indicated by double-headed arrow s 66A (B)
- This method is especially useful w hen actuating elements 67A (B), 68A (B), and 69A (B) are completely w ithin substrate 62 A (B) w ith mirror 61 being entirely opposite transparent zone 63.
- stator 69A (B) is preferably approximately L If stator 69B is a quadrant of a circle, the height should approximate the circle radius and have a value of L
- v alv e s itch uses magnetic forces Magnetic fields can pi oduce greater toi ces and consequently faster sw itching
- a disadv antage is the largei ov ei all v olume of the dev ice, ev en though the sw itching mechanism, itself has the same dimensions w hatev ei the actuation mechanism
- a magnetic field. B is necessary at the svv itch
- the field can be produced by conducting loops around each sw itch, b ⁇ a permanent magnet, or by an electromagnet with similar field
- mirror 71 is supported b ⁇ beams 77A and 77B These beams are preferably made from buckled beams, to produce bistable operation, and are conductiv e or include a conducting la ei w herethrough an electric current I may be passed Interaction w ith the magnetic field induces a lateral force F on the beams The magnetic field is aligned so that current I actuates mirror 71 to a new position ( Figure 7a) Re eising current I l ev ei ses foi ce F and returns mn ror 71 to an original position ( Figuie 7b) Highei field v alues o ⁇ highei cui rents pi oduce sti oiigei toi ces and tastei sw itching Bistable support
- each buckled beam, 77A and 77B is a v ariation of a bistable buckled element w ith a bistable, snap mechanical action
- the basic principle of the buckled beam is shown in Figure 8a
- a beam 80 has intrinsic elasticity and its length is greater than a distance between anchor points 81 and 82 If a lateral force F be applied to beam 80 as know n from standard texts, the beam snaps from a stable state 80 to another stable state 80'
- Figures 8b, c. and d. App of this principle are illustrated in Figures 8b, c. and d. in which like reference numerals refer to like parts throughout the figures of the drawing It is to be understood that the descriptions below ai e illustrative, and are not intended to restrict the present inv ention to the specific details set forth below
- the dev ice of Figure 8b is bistable, analogous to the buckled beam, and the components are correspondingly numbered
- the beam includes rigid elements. 80A and 8 ⁇ B flexibly connected at respective ends 80A ( and 80B
- a second stable configuration of this element is represented by the dashed lines denoted by 804' and 80B' This device, like that in Figure 8a.
- bistable building block ⁇ snap element that has two static configui at ions is show n in 1 igui e 8c Rigid elements 80A and 80B ai e flexibly connected at ends 80A, and 80B, l espectiv ely 80B and 80C ai e flexibly connected at ends 80B 2 and 80C 2 respectiv ely , at a point 84. and 80C and 80D are flexibK connected at ends 80C
- FIG. 9d Another embodiment employs an elastic beam as part or all of the elastic members of the device to produce the elasticity , as show n in Figure 9d
- anchor points 82 and 82A rigidly hold ful ly or partially elastic members 80A and 80D at ends 80A 2 and 80D 2 respectiv ely Al l other members remain as in the prev ious example
- Figure 9e show s a partially actuated state of this embodiment, showing elastic members 80A and 80D bent, allow ing the tr ansit of point 84 to a new stable state, as before
- joint 84. oi anv other point oi beam in the dev ice is attached to something that one w ishes to mov e
- o ⁇ nt 84. can be l eplaced w ith or attached to a usable element, such as a mirror, as show n in Figuie 10.
- w hich depicts a double application of the arrangement in Figure 9c and is labeled to show corresponding components, the duplicate part of the mechanism being labeled with primed numbers In this figure.
- 84 represents a usable element Another possible application is as a sw itch in which different connections are made in each state of the bistable dev ice
- frictionless hinges are adv antageous Dv namic f ⁇ ction is normallv a cause of w ear, suppression of which is especiallv important tor micromachines.
- w here lubi icants are not general! ⁇ usable For this l eason.
- pin joints are usuallv replaced bv spnal sjiiings wheie Luge movement is lequued
- Anothti tvjie of hinge is
- the hinge in Figure I 1 includes a c ⁇ lmd ⁇ cal roller 111 from which protrudes a radial aim 112 the movable element thus formed being in contact with a surface 114 contained within a housing 113 Arm 112 protrudes out of housing 113
- Large static friction between roller 111 and surface 114 as 111 rolls on 114 means that no slippage occurs during the rolling This requires that contact be maintained at all times between roller 111 and surface 114 this is termed 'rolling contact " and is achieved b ⁇ the action of a normal force F urging contact between roller 111 and surface 114
- Force F ma ⁇ include electrostatic and magnetic forces Through rolling contact rollei 111 ma ⁇ move between position lllAand position 11 IB and, consequent! ⁇ , anri 112 moves between position 112A and position 112B
- the whole airangement fo ⁇ s a dvnamicallv frictionless hinge with center of rotation at a point 115 which is not the centei of r llei 111 and with
- This hinge can be emploved more than once in an implementation, as illustrated in Figure 1
- the result enables translation of a movable part 122 relative to a stationary housing 113 in directions 127+ and 127-
- a normal force is needed to maintain contact between rotor 112 and housing 113 and between rotor 112 and movable part 122 which rotor 112 connects
- different types of force ma ⁇ be used including magnetic and electrostatic forces
- a magnetic force movable part 122 and stationary housing 113 of the hinge include permanent magnets or electromagnets
- electrostatic attraction be emploved a thin insulating laver 123 is deposited to cover at least all of the possible contact surfaces of the hinge so as to prevent a short circuit as shown in Figure 12
- An electrostatic potential is applied between rotor 112 and embedded electrodes 125a and 125b The potential is provided b ⁇ direct connection of the electrodes to a power suppl ⁇ or through electrostatic induction, electrodes 125a and
- Figure 13 shows views of the device of Figure 1 1 from within the plane of Figure 1 1 . and relevant parts are similarly numbered.
- Part of a housing 1 13 in contact with a rotor 11 1 is viewed schematically from the plane of motion of protruding part 112. While power is supplied, both elements are in contact but for a separating, insulating layer 123. as described before.
- Flexible, loose conductive cables 131A and 131B are anchored to either side of housing 113.
- masts 130A and 130B, emerging from either side of housing 1 13, are used to illustrate this.
- Masts 130A and 130B also electrically insulate cables 131 A and 131B from housing 113.
- Insulation 133 may be also prov ided for cables 131 A and 131 B from rotor 111 as is also a means 134A and 134B of electrical K charging the cables.
- Resetting electrodes 132A and 132B are situated to the sides of the hinge, outside cables 131 A and 131 B and prov ided with respectiv e means 135A and 135B of being electrostatically charged. In normal operation, cables 131.4 and 131 B are relaxed. When power fails, the attraction between rotor 111 and housing 113 ceases and rotor 111 falls until checked by one taut cable, in this case 131 A.
- a v oltage 135A is applied to electrode 132A and an opposite voltage 134A to cable 1314 so that electrode 132A attracts cable 131A.
- a v oltage 135B is appl ied to electrode 132B and an opposite voltage 134B to cable 131B so that electrode 132B attracts cable 131B.
- the resultant tensing of cables 131A and 131B returns rotor 1 11 to a w orking position, as show n in Figure 13c.
- a standing w ave 140 is induced in an elastic material 141 situated on a substrate 142 by any method that can cause a modification of the dimensions of elastic membrane 141.
- the modification method which mav affect the time constant of standing w ave 140.
- mav be thermal, piezoelectric, magnetic, or electrostat ic.
- electrostatic actuation is used.
- An osci l lating ⁇ oltage 144 is applied acioss a pan ot electi odes 143 placed in substiate 142 and abov e elastic material 141.
- mov able element 148 is made of magnetic material, as are the surrounding parts of elastic membrane 141 or substrate 142 B ⁇ opposite! ⁇ magnetizing 148 and 141 and/or 142.
- an attractiv e normal force holds mov able element 148 against elastic membrane 141 ev en against grav ity , and induces friction that w il l permit the functioning of the dev ice
- electrostatic attraction between mov able element 148 and the stationary part of the dev ice produces a force that induces the static friction that enables the actuator to function
- This enhancement permits the functioning of the device in any orientation, without rei ing on gravity or springs or other elements that may produce dynamic friction and wear or require the use of bearings that are difficult to fabricate at micro-dimensions
- This kind of actuator in the optical cross-connect, the afoiementioned mirror and mov able part is an innov ativ e
- the electromagnetic attraction of the previous paragi aph is caused to v ary cyclically so as to induce a required travelling wav e in the membrane
- the membi ane is select iv elv heated bv heatei 149 in Figure 14(d ) to cause periodic deformation so as to induce a l eqiured ti av elling w av e in the membi ane
- piezoelect ⁇ cal ly deformable device 149 in Figure 14(d) is caused to change dimensions in contact w ith the membrane to cause periodic selectiv e deformation therein so as to induce a required travelling wav e in the membrane
- the design ( Figuie 1 5a) is based on c lusters of supporting fingers 153 each c lustei being sufficient to support a movable element 152
- Fingers 153 can have v arious configiuations. such as cantilevers protruding from a side wall or posts protruding from a substrate 151 Although the illustration shows the finger tips aligned in a straight line, this is not an essential requii ement of the inv ention Movable element 152 rests on supporting fingei s 153
- An appropriate movable element 152 for this application is an actuatable minor
- the supporting surfaces of fingers 153 are generally located abov e the plane of substrate 151
- a working cy cle is illustrated in Figures 15b - 15e and starts w hen a first cluster of supporting fingers 153B.
- D moves aw ay from substrate 151 bearing mov able element 152 At this stage.
- a second clustei of supporting fingers 153A, C is stationarv and thus out of contact w ith mov able element 152
- first cluster ot supporting fingei s 153B D mov es lateral ly in a required direction of motion to a new position and lowers so that second cluster 153A C now supports mov able element 152
- D then moves laterally in an opposite direction from the first motion thereof and returns, without touching movable element 152. to a starting position thereof while second cluster 153A.
- the supporting elements can be made of piezoelectric material and. bv applying suitable v oltages, these piezoelectric beams may be bent in the horizontal and v ertical directions. B controlling the timing and duration of these voltages it is possible to produce the required motion of the supporting element and rotate its extremity in clockw ise or anticlockwise motions to advance or regress the movable part. Since static friction is necessary for the functioning of the device, as in the travelling wave option, the same method of holding and application of the normal force by using electrostatic or magnetic forces is used here.
- a simpler variation of this actuator uses only one set of supporting fingers at each step, as show n in Figure 16.
- a movable element 162 is supported by actuated fingers 163A.B.C w hile being mov ed, as prev iously explained, and. while actuated fingers 163A.B.C return to an original position thereof, element 162 rests on stationary posts 164A.B. Again, main cv cles are needed to achiev e a required lateral displacement.
- buckl ing element 173 is triggered by apply ing a suitable force in d ordei to make element 173 snap to anothei stable point 173B as show n in Figure 17c d
- flexible element 172 is tensed as show n in Figure 17c.d, and thus holds tree element 171 in position In oi der to al low element 171 to mov e, element 172 is disengaged by an electrode 175.
- Another aligning option has the same lay out as in Figure 1 8 but acts through electrostatic attraction betw een element 184 and elements 183a and 183b
- One possibility is to connect element 184 to one polarity and elements 183a and 183b to an opposite polarity of a pow ei supply
- Another, preferred embodiment is to apply opposite polarity charges to elements 183a and 183b.
- mov able element 184 contains spring parts 182 that support aligning elements 183a and 183b
- opposite electrostatic charges are applied to electrodes 185a and 185d, w hich are located at surrounding walls 181a and 181 b As before, these charges induce opposite charges in respectiv e elements 183a and 183b w hich are attracted to respective walls 181a and 181b
- Balanced springs 182 act to align element 184, as before
- Electrodes ma ⁇ be tailored to produce different dependencies of the electiostatic force on the o erlap distance B ⁇ combining these forms complicated actuation effects even including accelerations and decelerations can be achieved
- Another use ot this concept is in the stabilization of electrostatic actuators such as in the envelope-type actuator B ⁇ placing shaped electiodes in opposition it is possible to stabilize the movable central electiode and prevent it from sticking to a side electiode as a lesult ot the inherent mstabilitv ot this actuator Valve Array
- the single valve disclosed above is capable of switching light ravs Switching is possible between a single input and two outputs or two inputs into one output
- the disclosed switch ( Figure 22) can incorporate prior art optical devices such as MEMS (Micro-Electro Mechanical Svstems) switches (eg mirrors) liquid crvstals and electro-optics
- Input 236B is howev er, sw itched to output 237C via path ⁇ b ⁇ reflecting at the back ot actuated mirror 238.
- input 236C is sw itched to output 237B ⁇ ⁇ a path ⁇ bv reflecting at mii ioi 238
- This description l efers to mirroi s as the actuatable elements but as alreadv mentioned other sw itching elements hav ing similar capabilities ma ⁇ be utilized
- More elaborate effects may be obtained by placing actuatable mirrors at the arra ⁇ diagonal, instead of a fixed mirror
- the two half-arrav s ma ⁇ work independent! ⁇ but it part of the reflecting bisecting element is sw itchable it is possible for part of the ra ⁇ s to transit from one arra ⁇ to another
- FIG. 24a An embodiment of this more elaborate device is presented schematicalK in Figure 24a
- three virtual switching planes, a, b, and c. each having the capability of the arra ⁇ s described in Figure 23a or 23b, are utilized
- These virtual switching planes are, in effect, stacked, with corresponding elements vertical! ⁇ above one another
- Each virtual switching plane operates either independent! ⁇ of the other virtual planes or in conjunction therewith
- these planes are not mereK stacked, but mav be mutual! ⁇ coupled, to achieve more efficient switching, in a smaller volume than is possible using prior art switch a ⁇ ra ⁇ s
- Inputs 241 consist of stacked rows, denoted b ⁇ a, b. c. and vertical columns denoted b ⁇ I, II III Outputs.242, are similar! ⁇ denoted
- the switch ma ⁇ be regarded as comprising a two-dimensional input arrav to a three-dimensional switch, leading to a two-dimensional output arra ⁇ (The previous! ⁇ described device had a one-dimensional input arra ⁇ to a two-dimensional switch, leading to a one-dimensional output arra ⁇ )
- an eas ⁇ fabrication method is described below Those skilled in the art mav find other fabrication possibilities
- Other types ot switches bevond the preferred embodiments presented here, mav be tabiicated bv the methodtourednted in the following A le g alization ot this aiiangement is shown in I iguie 24b whcie a eut-awav view ot c ⁇ two-lavei anav having tour switches
- FIG. 24b can also illustrate the smallest realization of the half-array switch illustrated schematicalK in Figure 23b
- Bl and B4 are fixed, mirrors A3 and B3 are absent, and mirrors A2 and B2 are actuatable. as befoie. and also reflective on both sides Light paths bevond mirrors 41 44 Bl and B4 aie no longer possible As in the pievious paragraph theie is no intei action between the two laveis
- FIG. 24 Another use of the 3D switching matrix shown in Figure 24 is in compact switching of a large ntimbei of inputs
- the mam purpose ot this use is the reduction both of a ra ⁇ path-length and the number of switches necerney compared with a square switching array
- a 2D input matnx is utilized as aus plane a, b. and t consists of a non-blocking anav
- Such an anav can be legarded as an opeiatoi that tianstoinis the input ⁇ ow 241 la, 241 llu.241 Ilia at plane a to output row . 242 la. 242 Hit, 242 Ilia, at plane a. and so on for the other planes. Since each plane is isolated from neighboring planes, the only possible operator action is to change a column index. /. //. /// between input and output.
- FIG. 25c depicts a tri-cube complex sw itching array: a matrix of input beams 255 enters cube 256A, wherein switching occurs, and the rays emerge as an output matrix 255'.
- Matrix 255' enters cube 256B, which is a cube similar to, but with the switching planes thereof rotated w ith respect to cube 256A. and emerges as transformed matrix 255".
- a third cube 256C is used to make a final transformation of ray matrix 255" into output matrix 255'". Cube 256C is. again, rotated with respect to prev ious cube 256B.
- Each sw itching matrix consists of a I Ox 10 ⁇ 1 cube, with 1000 sw itches - a total ot i()()0 switches I he longest optical path lor a switch se
- Figure 25b is illustrated an equivalent switch array complex to that of Figure 25a this time using the half-array 3D switching matrix of Figure 24b wherein theie are fixed mirrors along a diagonal of each matrix instead of that of Figure 24a In this case a 100x100 switch requires only 1350 s itches not including the 100 fixed s itches, along the diagonal
- Figures 24b and 25a can be configured with switches such as the switch illustrated in Figures 22c and 22d providing the option of placing the arrays in switching states in which some or all input rays traverse the array without being leflected
- switches such as the switch illustrated in Figures 22c and 22d providing the option of placing the arrays in switching states in which some or all input rays traverse the array without being leflected
- ⁇ 3D matiix need not be cubic and an input arrav may be. for example 10x10 10x3 etc. provided that a following. rotated 3D matrix has a matching number of rows and columns
- two planes of 3x3 arrays are needed The second cube then needs three planes of 2x2 arrays
- any kind of sw itch may be mcoi poi ated into the design, but sw itches including mirrors have many adv antages and are a preferred embodiment It is also emphasized that, although ray s are show n as entering and exiting normal to a block, other angles of incidence and output can be designed tor. depending on v arious considerations pertaining to the required final sw itching arrangements
- the 3D matrix need not be cubic and the input array may be toi example 10x4. 10x3, etc prov ided that the rotated 3D matrix has a corresponding number of rows and columns
- the input array may be toi example 10x4. 10x3, etc prov ided that the rotated 3D matrix has a corresponding number of rows and columns
- two planes ot 3 x3 array s are needed
- the follow ing cube w ill need three planes of 2x2 array s
- Another embodiment includes the addition of a wavelength demultiplexing/multiplexing svstem to the above methods for use of the disclosed switch in WDM (wavelength division multiplexing)
- information is transmitted through optical fiber encoded within a group of different wavelengths
- a wavelength de-multipiexing and multiplexing device is necessarv to separate the different wavelengths at the entrance to a switch arrav and attei piocessmg oi use to recombine these wavelengths Ravs introduced into the desuibed switch aie pieteiablv paiallel to one anothei
- a device that can accomplish this is presented
- the device used ( Figure 26) includes two parallel reflection gratings. 261 and 262 with respective diffracting sui faces that face each othei and with rulings also parallel
- the distance between the sej>a ⁇ ated wavelength ravs is detei mined bv paiameteis including the distance d between parallel giat gs 261 and 262 and the pitch ot the grating tulings
- a collimated input beam 263 emerging from a fiber is incident on a surface of first reflection grating 261 at a predetermined angle ⁇
- a simple mirror would reflect this beam at the same angle with respect to a normal to the surface of the mirror
- a grating however reflects different wavelengths ( ⁇
- the switch presented can thus be used for diverting input rays of different wavelengths from a plurality of inputs to a plurality of outputs
- the primary use is in communications Together with the wavelength separation and combination device presented, the switch is applicable to WDM
- Other applications such as optical computation, etc. are also possible
- the three-dimensional arrays described in the present invention may be fabricated using pnor art technologies, such as conventional macro-, meso- and micro-machining techniques
- the fabrication methods include photo-hthographv deposition and etching all methods commonly used in iniuoelectroiiics and micro-machining These methods may however be uneconomical or impiacticai Therefore, the scope ot the present invention includes an innovative method of fabiicating these arrays, which enhances the advantages thereof
- 3D arrays are produced using 2D fabrication methods and stacking to obtain the desired 3D switching array, such as an optical cross-connect (OXC)
- OXC optical cross-connect
- the basic device is fabricated on top of a wafer surface, in contrast to previous art. where the mirrors aie etched into or elected upon a substrate
- the mirrois which require substantially perfect suiface quahtv flatness and paiallelism take advantage ot high-qualitv substiates pi epai ed lor the mac oelecti onic s industr v Substi ates ot v anous dimensions thicknesses materials and surface piepai ations ai e av ai lable
- the dev ice can be prepaied on any kind of material and the fabrication procedure is independent of substrate material While the substrate material has no effect on the sw itches apart from surface preparation and phy sical dimensions it is possible to take adv antage of a substrate's properties
- electronic circuitry may be integrated into the substrate or optical fibers may be set therein, in which case advantage can be taken of features such as the cry stallographic planes of the substrate material, as in silicon
- the fabrication techniques introduced here may be useful for other applications and not pist for mirrors or sw itches as in the disclosed inv ention
- the dev ice is like a silhouette If a device should require any out-of-plane structure the elements prepared at the surface hav e to be raised In many cases this is not a problem but when dealing w ith tree-space array s for optical sw itching this introduces sev ere restrictions
- the principal deficiencv is the impossibility of truly positioning the mirrors (a v ariation of 0 1 degree is enough to spoil the usefulness of the dev ice)
- Another aspect is mirror quality , mirror smoothness affects signal loss When dealing w ith large array s ot mn rors and especially in 3 D configurations, this becomes a disqual ify ing factor
- Mirror material 271 generally a metal such as aluminum, is deposited on substrate 272 and patterned using standard methods such as lithography Generally , mirror 271 is produced on top of substrate 272 at a zone 273 w here substrate material ev entually w i l l be remov ed so that a rav may pass through (Figure 27b)
- a sacrificial layer 274 is deposited on top of substrate 272, patterned if necessary to allow the deposition of subsequent layers that must jieneti ate sacrific ial lav u 274 to i each substrate 272 and polished pnoi to deposition and patterning ot m iu oi 271 As w el l as min or 271 supporting beams 275 arc deposited and [ patterned abov e and thi ough sacrificial lav ei 274 Supporting beams 275 can be made ot anv material in main cases thev are made of metal oi otherw ise include conductiv e mate ⁇ al Supporting beams 275 ai e fabricated attached to mirror 271 and substrate 272 The numbei and configuration of supporting beams 275 depend on the application
- Electrodes conducting lines and the like as well as the above-mentioned supporting beams 275 are referred to collectiv elv herein as auxiliary elements
- an electrode 276 is deposited on substrate 272 and covered bv a sacrificial layer 274
- the above-mentioned steps for fabrication of mirror 271 are carried out on top thereof
- a second electrode of the env elope can be produced in one of sev eral wav s
- mirror 271 is cov ered bv a second saci ificial lav er 274A
- Second lav er 2744 is patterned and cov ered bv a second env elope electrode 277 which is also patterned
- remov ing sacrificial lav ers the envelope is formed and mirror 271 is released
- FIG. 27h Another possibility is depositing and patterning a second env elope electrode 277 on another side of substrate 272 oi as illustrated in Figure 27g on another substrate 272A Bv aligning and bringing togethei a mirror side of substrate 272 and a second-electrode side of substrate 272A and bonding an envelope is formed (Figure 27h) Bonding is done bv one of the known wafer-bonding methods such as fusion bonding anodic bonding or other bonding methods Spacers and electrical connection paths are deposited and patterned as required prior to alignment and bonding In the case of curv ed electrode actuation, the m irror can be processed directly on a w ater surface at a ray trav erse zone.
- Supporting beams are deposited and patterned on top of the mirror, as prev iously explained. It is possible to deposit material for the static curved electrode and to do the patterning simultaneously, fol lowed by insulation deposition and patterning over the static electrode. Etching the sacrificial layer and corresponding substrate area releases the mov able elements.
- the supporting beams may act also as conducting lines, and there is no need for further fabrication steps.
- the mirror and beams are fabricated and released, as described above.
- a sw itch array requires more elaborate methods than single-switch fabrication.
- the disclosed method is designed to facilitate accurate construction of a 3D cubic arra ⁇ . Sw itches are made on wafers in row s and a number of wafers are bonded each on top of another, but displaced lateral! ⁇ , to produce a 3D array.
- the fabrication is exemplified by mirrors, although other sw itching elements can be used instead and formed into a 3D-matrix dev ice. This fabrication method can be applied to other devices that can take advantage of the planarity of the w afers and the 3D configuration of the completed dev ice.
- Single sw itches 281 are produced, as described prev iously. in rows 283, on a surface 282 of a substrate.
- These sw itches are also arranged in groups 285 of regularly spaced columns 284. each group being separated from a neighboring group by an empty column 286 at the same column spacing.
- the first group of our example consists of one column of four row s ( 1 4). separated by an empty column from a second group consisting of tw o columns of four rows (2x4) followed by another empty column.
- the a ⁇ angement continues w ith successiv e gun ⁇ s o! 3*4 and 4x4 to tonn a set
- An entire watei mav be cov eied w ith such sets Foi oui example at least sev en such sets are required
- the mass is accuiatelv diced. pi eferably parallel to columns 287 and rows 288 ot the mirror arrav . along dashed lines 280 A cubic arra ⁇ of mirrors results This arra ⁇ is further packaged b ⁇ aligning w ith input and output fibers It is possible to align two or more such cubes and to rotate one w ith respect to another so that a 3D-sw itching device, as explained before, is produced
- a finished dev ice is represented in Figure 29 There, a finished cube can be seen w ith aligned substrates 291 bonded at interfaces 294
- the input and output ports for the ra ⁇ s in the case of an optical sw itch, are represented interchangeably b ⁇ 292 and 293
- the switch presented can be used for switching input rays of different wavelengths from numerous input paths to numerous output paths It is primarily intended for use in communications Together with the wavelength separation and re-combination device disclosed above, it is applicable to WDM Othei applications, such as in optical computation, etc. will be evident
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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CA002379936A CA2379936A1 (en) | 1999-07-20 | 2000-07-19 | Opto-mechanical valve and valve array for fiber-optic communication |
AU60121/00A AU6012100A (en) | 1999-07-20 | 2000-07-19 | Opto-mechanical valve and valve array for fiber-optic communication |
IL14752100A IL147521A0 (en) | 1999-07-20 | 2000-07-19 | Opto-mechanical valve and valve array for fiber-optic communication |
GB0201261A GB2367906A (en) | 1999-07-20 | 2000-07-19 | Opto-mechanical valve and valve array for fiber-optic communication |
Applications Claiming Priority (8)
Application Number | Priority Date | Filing Date | Title |
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US14462899P | 1999-07-20 | 1999-07-20 | |
US60/144,628 | 1999-07-20 | ||
US17049499P | 1999-12-13 | 1999-12-13 | |
US17049299P | 1999-12-13 | 1999-12-13 | |
US17048299P | 1999-12-13 | 1999-12-13 | |
US60/170,482 | 1999-12-13 | ||
US60/170,492 | 1999-12-13 | ||
US60/170,494 | 1999-12-13 |
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WO2001009653A1 true WO2001009653A1 (en) | 2001-02-08 |
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---|---|---|---|
PCT/IL2000/000425 WO2001009653A1 (en) | 1999-07-20 | 2000-07-19 | Opto-mechanical valve and valve array for fiber-optic communication |
Country Status (5)
Country | Link |
---|---|
AU (1) | AU6012100A (en) |
CA (1) | CA2379936A1 (en) |
GB (1) | GB2367906A (en) |
IL (1) | IL147521A0 (en) |
WO (1) | WO2001009653A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6647164B1 (en) | 2000-10-31 | 2003-11-11 | 3M Innovative Properties Company | Gimbaled micro-mirror positionable by thermal actuators |
EP1388743A2 (en) * | 2002-08-09 | 2004-02-11 | Sumitomo Electric Industries, Ltd. | Optical switch, optical add/drop apparatus, optical transmission system, and method of producing optical switch |
US6711318B2 (en) | 2001-01-29 | 2004-03-23 | 3M Innovative Properties Company | Optical switch based on rotating vertical micro-mirror |
US6718084B1 (en) | 2001-05-10 | 2004-04-06 | Axsun Technologies, Inc. | Integrated optical line card protection module |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4703215A (en) * | 1986-03-13 | 1987-10-27 | Aisan Kogyo Kabushiki Kaisha | Stacked piezoelectric ceramics displacement magnifying device |
US5479064A (en) * | 1993-02-28 | 1995-12-26 | Nec Corporation | Piezoelectric actuator with a displacement enlarging feature |
US5742712A (en) * | 1996-10-08 | 1998-04-21 | E-Tek Dynamics, Inc. | Efficient electromechanical optical switches |
US5943454A (en) * | 1997-08-15 | 1999-08-24 | Lucent Technologies, Inc. | Freespace optical bypass-exchange switch |
-
2000
- 2000-07-19 IL IL14752100A patent/IL147521A0/en unknown
- 2000-07-19 CA CA002379936A patent/CA2379936A1/en not_active Abandoned
- 2000-07-19 GB GB0201261A patent/GB2367906A/en not_active Withdrawn
- 2000-07-19 WO PCT/IL2000/000425 patent/WO2001009653A1/en active Application Filing
- 2000-07-19 AU AU60121/00A patent/AU6012100A/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4703215A (en) * | 1986-03-13 | 1987-10-27 | Aisan Kogyo Kabushiki Kaisha | Stacked piezoelectric ceramics displacement magnifying device |
US5479064A (en) * | 1993-02-28 | 1995-12-26 | Nec Corporation | Piezoelectric actuator with a displacement enlarging feature |
US5742712A (en) * | 1996-10-08 | 1998-04-21 | E-Tek Dynamics, Inc. | Efficient electromechanical optical switches |
US5943454A (en) * | 1997-08-15 | 1999-08-24 | Lucent Technologies, Inc. | Freespace optical bypass-exchange switch |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6647164B1 (en) | 2000-10-31 | 2003-11-11 | 3M Innovative Properties Company | Gimbaled micro-mirror positionable by thermal actuators |
US6711318B2 (en) | 2001-01-29 | 2004-03-23 | 3M Innovative Properties Company | Optical switch based on rotating vertical micro-mirror |
US6718084B1 (en) | 2001-05-10 | 2004-04-06 | Axsun Technologies, Inc. | Integrated optical line card protection module |
EP1388743A2 (en) * | 2002-08-09 | 2004-02-11 | Sumitomo Electric Industries, Ltd. | Optical switch, optical add/drop apparatus, optical transmission system, and method of producing optical switch |
EP1388743A3 (en) * | 2002-08-09 | 2004-08-11 | Sumitomo Electric Industries, Ltd. | Optical switch, optical add/drop apparatus, optical transmission system, and method of producing optical switch |
US6931172B2 (en) | 2002-08-09 | 2005-08-16 | Sumitomo Electric Industries, Ltd. | Optical switch, optical add/drop apparatus, optical transmission system, and method of producing optical switch |
Also Published As
Publication number | Publication date |
---|---|
AU6012100A (en) | 2001-02-19 |
GB0201261D0 (en) | 2002-03-06 |
GB2367906A (en) | 2002-04-17 |
IL147521A0 (en) | 2002-08-14 |
CA2379936A1 (en) | 2001-02-08 |
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