Onix Microsystems, Inc.

Analog Devices,inc.

Other

Silicon Light Machines Corporation

Orix Microsystems, Inc.

Michael J Daneman

Behrang Behin

Meng-Hsiung Kiang

Satinderpall S Pannu

Timothy E Beerling

Murali Chaparala

Gary M Zalewski

Boris Kobrin

Kam Y Lau

Chuang-Chia Lin

Scott D Dalton

Kam-Yin Lau

Mark W Chang

Stephen Panyko

Bryan P Staker

David Horsley

James A Hunter

Akira Tomita

Franklin Joseph Wall

David Thomas Amm

Robert A Conant

David Lerner

An optical cross-connect switch comprises a base (), a flap () and one or more electrically conductive landing pads () connected to the flap (). The flap () has a bottom portion that is movably coupled to the base () such that the flap () is movable with respect to a plane of the base () from a first orientation to a second orientation. The one or more landing pads () are electrically isolated from the flap () and electrically coupled to be equipotential with a landing surface.

Optical cross-connect system

A grating light valve has with a plurality of spaced reflective ribbons are spatially arranged over a substrate with reflective surfaces. The grating light valve is configured to optimized the conditions for constructive and destructive interference with an incident light source having a wavelength &#x3bb;. The grating light valve preferably has a set of movable active ribbons alternating between the set of stationary bias ribbons. The active ribbons and the bias ribbons are spatially separated over the substrate surface such that reflective regions of the substrate surface correspond to the spaces between the ribbons. The ribbons and reflective regions of the substrate optically and geometrically optimized for to generate the conditions for constrictive and destructive interference with the incident light source. Accordingly, ribbons of the active ribbons are configured with reflective cross sections that are is approximately equal to the sum of the diffraction cross sections of the bias ribbons and the reflective regions of the substrate. In operation, active ribbons are moved by a multiple of &#x3bb;/4 to switch between the conditions for constructive and destructive interference.

High contrast grating light valve type device

A beam steering module comprised of a mirror stack array in close proximity to a collimator array controllably steers photons along two axis and in a direction substantially less than 90 degrees to the collimator orientation. Several configurations of the module are described using single and double axis mirror rotation and relay optics. Optical telecommunications switches are shown using modules coupled to each other along flat and curved surfaces, with and without use of fold mirror and enabling a plurality of configuration options including photodetector optical power monitoring schemes that require no external power taps.

Three dimensional optical switches and beam steering modules

MEMS structures may be formed on a substrate by forming a series trenches filled with etch-stop material in the device layer, followed by an isotropic etch of the device material stopping on the etch-stop material. This approach provides a controlled release method where the exact timing of the isotropic release etch becomes non-critical. Further, using this method, structures with significant topology may be fabricated while keeping the wafer topology to a minimum during processing until the very end of the process. Using the method of this invention, features with large topology may be formed while keeping the wafer topology to a minimum until the very end of the process.

Fabrication and controlled release of structures using etch-stop trenches

A microelectromechanical (MEMS) apparatus has a base and a flap with a portion coupled to the base so that the flap may move out of the plane of the base between first and second position. The base may have a cavity with largely vertical sidewalls that contact a portion of the flap when the flap is in the second position Electrodes may be placed on the vertical sidewalls and electrically isolated from the base to provide electrostatic clamping of the flap to the sidewall. The base may be made from a substrate portion of a silicon-on-insulator (SOI) wafer and the flap defined from a device layer of the SOI wafer. The flap may be connected to the base by one or more flexures such as torsional beams. An array of one or more of such structures may be used to form an optical switch.

MEMS mirrors with precision clamping mechanism

An optical microelectromechanical system (MEMS) device and a method for making it are disclosed. The device generally includes a substrate with two or more device dies attached to the substrate. Each device die includes one or more MEMS optical elements. A common clamping die is attached to the device dies such that each MEMS optical element aligns with a corresponding clamping surface on the common clamping die. The single larger clamping die, which covers all the elements on the smaller device dies, forces mirrors contained thereon to register accurately, in the 'ON' state. Such a device may be made by attaching two or more device dies to a substrate, and attaching a common clamping die to the two or more device dies. The device dies may be attached to the substrate before attaching the common clamping die to the device dies. Alternatively, the common clamping die may be attached to the device dies before the device dies are attached to the substrate. High yields may be achieved since simple semiconductor process may be used to fabricate the larger clamping die.

Tiling of optical MEMS devices

A two-dimensional scanner consists of a rotatable gimbal structure with vertical electrostatic comb-drive actuators and sensors. The scanner's two axes of rotation may be controlled independently by activating two sets of vertical comb-drive actuators. The first set of vertical comb-drive actuator is positioned in between a outer frame of the gimbal structure and the base, and the second set of vertical comb-drive actuator is positioned in between the inner part of the gimbal structure and the outer frame of the gimbal structure. The inner part of the gimbal structure may include a reflective surface, and the device may be used as a mirror. Furthermore, the capacitance of the vertical comb-drives may be measured to monitor the angular position of the mirror, and the capacitive position-monitoring signal may be used to implement closed-loop feedback control of the mirror angle. The two-dimensional scanner may be fabricated in a semiconductor process. Two-dimensional scanners may be used to produce fiber-optic switches.

Two-dimensional gimbaled scanning actuator with vertical electrostatic comb-drive for actuation and/or sensing

A method is disclosed for operating a MEMS device having a flap that is movable with respect to a base. The method includes applying a force to the flap to move the flap at least partially out of contact with an underlying base. Means for applying such a biasing force may be incorporated into a microelectromechanical (MEMS) apparatus having a base and a flap with a portion coupled to the base so that the flap may move out of the plane of the base between first and second position. The base may have a cavity with largely vertical sidewalls that contact a portion of the flap when the flap is in the second position Electrodes may be placed on the vertical sidewalls and electrically isolated from the base to provide electrostatic clamping of the flap to the sidewall. The base may be made from a substrate portion of a silicon-on-insulator (SOI) wafer and the flap defined from a device layer of the SOI wafer. The flap may be connected to the base by one or more flexures such as torsional beams. An array of one or more of such structures may be used to form an optical switch.

Use of applied force to improve MEMS switch performance

Disclosed is an apparatus and method for detecting whether rotatable MEMS elements are in the &ldquo;on&rdquo; or &ldquo;off&rdquo; position. Embodiments of the invention have application in devices switches that employ mirrors that move between an &ldquo;on&rdquo; or &ldquo;off&rdquo; position, wherein they reflect light from an input fiber into an output fiber in the &ldquo;on&rdquo; position, and allow the light to pass in the &ldquo;off&rdquo; position. Electrodes are positioned in the device such that the mirrors are close to, and therefor capacitively coupled to, a different electrode depending on whether they are in the &ldquo;on&rdquo; or &ldquo;off&rdquo; position. This invention is especially useful for switches that already employ electrodes for electrostatic clamping of mirrors in one or more positions, since those same electrodes can be used both to electrostatically clamp the mirrors and to sense their position. The method described in this invention comprises sensing of the capacitance between the mirrors and the one or more electrodes used to clamp the mirrors in its one or more position in order to detect which of the positions the mirrors are clamped in. Furthermore, the magnitude of the capacitances can be monitored to detect improper clamping.

Capacitive sensing scheme for digital control state detection in optical switches

A device having a landing pad structure on an underside of a device and method for fabricating same. The device is formed from a device layer with at least one landing pad protruding from an underside thereof. The landing pad is attached to the device layer by a plug passing through an opening in the device layer. The device may be attached to the device layer by one or more compliant flexures, which allow the device to rotate in and out of a plane defined by the device layer. The landing pads are fabricated by forming one or more vias through the device layer. An underlying sacrificial layer is then partially etched to form one or more depressions at locations corresponding to locations of the vias in the device layer. The vias and depressions are then filled with a landing pad material to form a structure having one or more landing pads protruding from an underside of the device layer. The sacrificial layer is subsequently removed to release the device. Particular embodiments of both methods may be applied to fabricating microelectromechanical systems (MEMS) especially MEMS mirrors. The various embodiments are well suited to use with silicon on insulator (SOI) substrates.

Mechanical landing pad formed on the underside of a MEMS device

A MEMS device with a flap having one or more conductive landing areas electrically isolated from the flap and electrically coupled to a landing surface to reduce stiction. The device may be formed from a device layer of a silicon-on-insulator (SOI) substrate with conductive landing pads fabricated by forming one or more vias through the device layer, an underlying sacrificial layer etched to form one or more depressions at locations corresponding the vias and filled with a conductive landing pad material to form a structure having one or more electrically isolated landing pad areas on an underside of the device layer. A method for operating a MEMs device in an equipotential stiction reduction mode is also provided.

Conductive equipotential landing pads formed on the underside of a MEMS device

A method and apparatus for maintaining the state of a MEMS device in the event of a power failure are disclosed. The apparatus and method may be used with a MEMS device generally having one or more MEMS elements moveably coupled to a substrate that uses electrostatic clamping force to sustain the state of the MEMS element. According to the method, a capacitive or other charge-storing circuit is coupled between a clamping surface and an electrical ground. During normal operation, a clamping voltage is applied between the clamping surface and at least one MEMS element to retain the at least one MEMS element against the clamping surface. In the event of a power failure, the source of the clamping voltage and other circuit paths to ground are isolated from the clamping surface. The charge-storing circuit maintains an electric charge on the clamping surface. Leaky circuit paths to ground may be isolated from the clamping surface by an isolator element configured to electrically isolate the clamping surface in the event of a power failure. The isolator element may include an opto-isolator or a low leakage diode.

Maintaining the state of a MEMS device in the event of a power failure

A beam steering module and switching system. The steering module is composed of a N&times;M array of single axis mirrors able to rotate about a particular axis (X-axis), a second N&times;M array of single axis mirrors able to rotate about an axis orthogonal to that of the first N&times;M array of mirrors (Y-axis), and a relay lens designed to image the first mirror array onto the second mirror array such that the beam angle may be controlled in both the X and Y-axis by adjusting the angle of the appropriate mirrors in the X and Y mirror arrays. Two steering modules may be combined to form a switching system. With two such steering modules, it is possible to completely determine, at the plane of the output fiber array, the position and angle of an optical beam emerging from any of the input fibers.

Apparatus and method for 2-dimensional steered-beam NxM optical switch using single-axis mirror arrays

An optical crossbar switch having refractive or reflective components for equalizing beam spreading and diffraction in all the connections. The optical fibers or waveguides coupled to the switch are not staggered, but are parallel as in a conventional fiber array. The refractive component is disposed between the switch and the input optical fibers. Preferably, a similar refractive component is disposed between the output optical fibers and the switch. The refractive component can be a stairstep block made of glass, silicon or silica. Light from each input fiber travels through a well-defined thickness of the stairstep block. Since the block has a refractive index greater than the surrounding atmosphere, the wavelength in reduced within the block, and beam spreading and diffraction are reduced.

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Pacifica, CA, United States of America

Michael J Daneman