Abstract: 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.

Abstract: Methods and apparatus for varying and measuring the position of a micromachined electrostatic actuator using a pulse width modulated (PWM) pulse train are disclosed. One or more voltage pulses are applied to the actuator. In each of the pulses, a voltage changes from a first state to a second state and remains in the second state for a time tpulse before returning to the first state. The position of the actuator may be varied by varying the time &Dgr;tpulse. A position of the actuator may be determined by measuring a capacitance of the actuator when the voltage changes state, whether the time t is varied or not. An apparatus for varying the position of a MEMS device may include a pulse width modulation generator coupled to the MEMS device an integrator coupled to the MEMS device and an analog-to-digital converter coupled to the integrator. The integrator may measure a charge transferred during a transition of a pulse from the pulse generator.

Abstract: A method for rotating a combdriven device about an axis uses applied bias force along with applied voltage between first and second comb fingers to controllably rotate the device about one or two axis. One mode of the present invention includes measuring the position of a rotating element and providing feedback to control the angular position thereof by changing bias force and/or drive voltage. The present invention can be employed with prior-art staggered combdrives, single layer self-aligned combdriven devices, and in a broad range of applications in optical telecommunication switching, video, biomedical, inertial sensors, and in storage magnetic disk drives.

Abstract: Rotating devices including actuators and position sensors that employ combdrives are described. One design of a combdrive fabricated from a single layer is provided such that, in a nominal state, the two sets of comb fingers are substantially interdigitated according to a predetermined engagement. A rotating element may be attached to a rotatable flexure disposed along an axis and coupled to the comb fingers along with a biasing element attached to the rotating element to cause the comb fingers along with the rotating element to undergo a controlled angular displacement from the initial engagement and in response to feedback from sensing the position of the movable or rotating element. A voltage may be applied between comb fingers to cause the rotating element to undergo further rotation about the axis in a predetermined manner.

Abstract: 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.

Abstract: A microelectromechanical systems (MEMS) element, MEMS optical switch and MEMS fabrication method are described. The MEMS element comprises a crystalline and moveable element is moveably attached to the substrate. The moveable element includes a perpendicular portion oriented substantially perpendicular to a plane of the substrate. The crystal structure of the perpendicular portion and substrate are substantially similar. The moveable element moveable is moveably attached to the substrate for motion substantially constrained to a plane oriented substantially perpendicular to a plane of the substrate. In at least one position, a part of a perpendicular portion of the moveable element projects beyond a surface of the substrate. The moveable element may be retained in place by a latch. The perpendicular portion may be formed substantially perpendicular portion to the substrate. An array of such structures can be implemented to work as an optical switch.

Abstract: 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.

Abstract: A beam steering module and switching system. The steering module is composed of a N×M array of single axis mirrors able to rotate about a particular axis (X-axis), a second N×M array of single axis mirrors able to rotate about an axis orthogonal to that of the first N×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.

Abstract: An apparatus and method for aligning one or more optical fibers is disclosed. The apparatus includes a carrier having one or more through holes and one or more plugs, each of which is sized to be received in one or more of the three or more through holes. The carrier is adapted to receive one or more waveguides. The waveguides may be aligned by inserting a plug into each of one or more through holes in a carrier; attaching a waveguide to the carrier; aligning the carrier to align the one or more waveguides with respect to an optical device attached to a substrate; and tacking one or more of the plugs to the substrate to maintain the alignment of the waveguides with respect to the optical device.

Abstract: 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.

Abstract: Methods and apparatus for varying and measuring the position of a micromachined electrostatic actuator using a pulse width modulated (PWM) pulse train are disclosed. One or more voltage pulses are applied to the actuator. In each of the pulses, a voltage changes from a first state to a second state and remains in the second state for a time tpulse before returning to the first state. The position of the actuator may be varied by varying the time &Dgr;tpulse. A position of the actuator may be determined by measuring a capacitance of the actuator when the voltage changes state, whether the time t is varied or not. An apparatus for varying the position of a MEMS device may include a pulse width modulation generator coupled to the MEMS device an integrator coupled to the MEMS device and an analog-to-digital converter coupled to the integrator. The integrator may measure a charge transferred during a transition of a pulse from the pulse generator.

Abstract: An enclosure for sealing a MEMS optical device, a MEMS apparatus, a MEMS module, and a method for switching optical signals are disclosed. The enclosure includes one or more sidewalls and an optical element hermetically sealed to at least one of the sidewalls. Suitable optical elements include windows, lenses and lens arrays. The enclosure may be evacuated to improve the performance of the MEMS device enclosed within it. The MEMS apparatus includes a MEMS device enclosed by an enclosure of the type described above. The MEMS device may include a substrate and the enclosure may be bonded to the substrate. Alternatively, the MEMS device may include a substrate attached to a mount and the enclosure may be bonded to the mount. The MEMS module includes a mount and a MEMS device attached to the mount. One or more optical fibers are attached to the mount proximate the MEMS device. An enclosure, attached to the mount encloses the MEMS device. The fibers are located outside the enclosure.

Abstract: A gas pulse is used to actuate the movable part (e.g. a rotatable mirror) of a MEMS device. The MEMS device generally comprises a substrate and one or more movable elements coupled to the substrate and means for pneumatic actuation of at least one of the one or more movable elements. The MEMS device may be in the form of an NXN optical crossbar switch. Pneumatic actuation eliminates the need for magnetic pads and electromagnets along with the disadvantages associated with MEMS devices having these components. Such pneumatic actuation may be incorporated into a MEMS optical switch having a substrate and one or more rotatable mirrors coupled for rotation with respect to the substrate.

Abstract: For any optically interconnected assembly, the packaging tasks include alignment of one or multiple optical devices, and attachment of aligned modules to a common substrate. The concept disclosed here is a packaging method to assemble pre-aligned optical modules on a common structure called motherboard. The apparatus consists of two components: device carrier or motherboard with openings on the sides and adjustable plugs in the form of pins or balls. The method and apparatus utilize plugs as connection bridges between device carriers and motherboard, allowing solid contacts and a rigid aligned structure among modules. The direct benefits include relaxation of dimensional tolerances on parts and elimination of the need for high-precision spacers.

Abstract: Rotating devices including actuators and position sensors that employ combdrives are described. One design of a combdrive fabricated from a single layer is provided such that, in a nominal state, the two sets of comb fingers are substantially interdigitated according to a predetermined engagement. A rotating element may be attached to a rotatable flexure disposed along an axis and coupled to the comb fingers along with a biasing element attached to the rotating element to cause the comb fingers along with the rotating element to undergo a controlled angular displacement from the initial engagement and in response to feedback from sensing the position of the movable or rotating element. A voltage may be applied between comb fingers to cause the rotating element to undergo further rotation about the axis in a predetermined manner.