Electrostatic actuated mems for precision AC voltage references
The purpose of this paper is to present results on the design of electrostatic actuated micro- electromechanical systems (MEMS) aiming at developing AC voltage references through mechanical-electrical transduction for electrical metrology and more generally for miniaturized instrumentation. Several test MEMS architectures (targeted AC voltages from 10 V up to 100 V) for the vertical motion have been designed and are under fabrication by an epitaxial silicon on insulator (SOI) surface micromachining process with the aim to investigate the potentialities of the different structures with respect to the geometrical dispersion, the strain sensitivity and the electrical stability.
Advantages of alternative actuating signal for MEMS actuators
In this paper, we report the different advantages of using AC actuating signal for driving MEMS actuators. The study is based upon micro-mirror devices used in scanning or digital mode. In scanning mode, an AC signal can be used to overcome difficulties induced by the high voltages required in electrostatic systems by taking advantage of the double rectifying effect of electrostatic actuation within a second order system. On the other hand, when the pull-in effect is used, charge injection occurs after a long time in the deflected position except when the landing electrodes are electro-statically separated from the control electrodes. An AC signal also eliminates charge injection particularly if a bipolar signal is used. Long term experiments have demonstrated the reliability of such a signal command to avoid injection of electric charges.
Dynamic optical filtering in DWDM systems using the DMD
Summary form only given. We describe applications of the Texas Instruments Digital Micromirror Device (DMD) as a high efficiency spatial light modulator for dynamic optical filtering and switching in Dense Wavelength Division Multiplexed (DWDM) optical networks. Whereas the DMD has found wide acceptance as a spatial light modulator in video display applications, the present paper describes applications of the DMD to DWDM signal processing. The DMD is shown in this work to behave as a 2-dimensional switched blazed gating when modulating coherent light. In addition, the efficiency of fiber coupling will be shown to depend on the amplitude of the overlap integral between the modulated field and the mode of the output. Hence, the efficiency of the fiber coupling depends not only on the amplitude of the fields, but on how well they are matched in phase. The DMD is very suitable to digital processing of optical networking signals where it can be used as a series of parallel optical switches (e.g. 400-l/spl times/2 switches). A very useful optical platform combines the DMD with a dispersive element such as a gating or a prism. DWDM signals are first dispersed and impinge onto the DMD, which is then used as a reflective adaptive slit. The DMD selectively routes specific wavelengths back into one of two optical paths or ports. Using this general configuration of the DMD as an adaptive optical slit, we have demonstrated several network functions including digital optical equalization, optical add drop multiplexing and optical performance monitoring. In this presentation, we will describe these applications of the DMD as well as describe system performance attributes (insertion loss, polarization dependent loss, group delay and power penalty) as they pertain to the DMD structure and DMD based optical signal processing.