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 (712), and attachement of aligned modules to a common substrate (702). The concept disclosed here is a packaging method to assemble pre-aligned optical modules (712) on a common structure called motherboard (702). The apparatus consists of two components: device carrier (704) or motherboard (702) with openings on the sides and adjustable plugs (706) in the form of pins or balls. The method and apparatus utilize plugs (706) as connection bridges between device carriers (704) and motherboard (702), allowing solid contacts and a rigid aligned structure among modules (712). The direct benefits include relaxation of dimensional tolerances on parts and elimination of the need for high-precision spacers.
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. Optical signals may be coupled between the fibers and the MEMS device within the enclosure through an optical elements in the sidewall. The optical switching method proceeds by reducing a pressure of an atmosphere proximate the MEMS optical device and moving at least one of the optical elements from a first position to a second position. The optical element deflects an optical signal when it is in the second position.
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:
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 nulltpulse. 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. The integrator may include an amplifier, an integrator capacitor, a hold capacitor, a compensation voltage generator and three switches. The hold capacitor and integrator capacitor may be coupled to a MEMS device. The integrator capacitor, hold capacitor, and compensation voltage generator may be selectively coupled to the amplifier by two of the switches. The MEMS device and hold capacitor may be selectively coupled to ground by a third switch.
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. Alternatively, a time-vary biasing force may be exerted on the rotating element, causing the first comb fingers along with the rotating element to undergo further rotation about the axis in a predetermined manner. The combdriven device can serve as both rotating actuators and position sensor. By arranging two such combdrives in a gimbaled structure bi-axial rotating actuators and position sensors may be constructed. The combdrive devices of the present invention can be employed in a broad range of applications, including biomedical devices, optical devices for tracking and display, telecommunication devices such as fiber-optic switches, inertial sensors, and magnetic disk drives.
Abstract:
Disclosed is an apparatus and method for detecting whether rotatable MEMS elements are in the "on" or "off" position. Embodiments of the invention have application in devices switches that employ mirrors that move between an "on" or "off" position, wherein they reflect light from an input fiber into an output fiber in the "on" position, and allow the light to pass in the "off" 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 "on" or "off" 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 positions 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.
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 is reduced within the block, and beam spreading and diffraction are reduced. For switch connections that have a long optical path, a long optical path through the block is required. The dimensions of the block must be designed according to the path length differences of the different switch connections. Optionally, a prism is used instead of the stairstep block. In this case, the optical fibers must be aligned at an angle to the switch. Furthermore, a series of small optical deflectors can be used instead of the stairstep structure.
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 (702, 712) are substantially interdigitated according to a predetermined engagement. A rotating element (700) may be attached to a rotatable flexure (711) 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 (780) 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. Alternatively, a time-vary biasing force may be exerted on the rotating element, causing the first comb fingers along with the rotating element to undergo further rotation about the axis in a predetermined manner. The combdriven device can serve as both rotating actuators and position sensor. By arranging two such combdrives in a gimballed structure bi-axial rotating actuators and position sensors may be constructed. The combdrive devices of the present invention can be employed in a broad range of applications, including biomedical services, optical devices for tracking and display, telecommunication devices such as fiber-optic switches, inertial sensors, and magnetic disk drives.
Abstract:
A beam steering module and switching system. The steering module is composed of an NxM array of single axis mirrors able to rotate about a particular axis (X-axis), a second NxM array of single axis mirrors able to rotate about an axis orthogonal to that of the first NxM 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.