Reducing Brownian Motion in an Electrostatically Tunable MEMS Laser

Huber, Dorit; Corredoura, P.; Lester, S.; Robbins, V. M.; Kamas, L.A.

doi:10.1109/jmems.2004.836290

Cited by 15 publications

(8 citation statements)

References 9 publications

(15 reference statements)

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“…The contour and size of the rigid electrode are the same as those for sensors with silicon diaphragms; resources limited fabricating multiple templates. The response shows a decrease in sensitivity with pressure, the probable effect of a value of , instead of 2.0 in (11). Fig.…”

Section: Resultsmentioning

confidence: 89%

“…[11], [12]. The high sensitivity and force of sensors and actuators with contoured electrodes allow them to operate with stiffer electrodes and etch-released structures to reduce Brownian motion.…”

Section: Electrostatic Forcementioning

confidence: 99%

“…The general form (11) provides a good approximation for a variety of designs. It is shown in Appendix-B that exponent in (11) for a sensor with a pretensioned membrane under uniform pressure.…”

Section: E Electrode Contourmentioning

confidence: 99%

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Capacitive transducers with curved electrodes

McIntosh

Mauger²,

Patterson

2006

IEEE Sensors J.

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The design, performance, and potential applications are described for capacitive transducers with curved electrodes. A curved electrode governs the deflection of a compliant electrode under applied stress. A dielectric film on one electrode provides a variable region of fixed electrode spacing. The sensitivity and linear dynamic range of the transducers are higher and wider than devices with parallel electrodes. An electrical advantage is obtained from the permittivity of the dielectric film and a mechanical advantage from its thinness. Transducers have been constructed with silicon diaphragms that bend and polymer membranes that stretch in response to uniform pressure. The silicon sensors measured dynamic pressure changes over a linear range of 125 dB. An 885% change in capacitance was obtained for a sensor with a thin silicon diaphragm. Sensors with polycarbonate membranes demonstrated the ability of a low-cost transducer to measure pressure, fluid flow, displacement, and tilt. An active capacitive bridge circuit was developed to linearly measure capacitance changes up to 1000% and to control electrostatic actuators by force-balanced feedback. Methods and materials to construct microscale transducers are discussed along with the performance limitations of electrostatic actuation.Index Terms-Capacitive transducer, curved electrode, electret transducer, electrostatic actuator, force-balanced feedback, nullbalanced bridge (NBB), ultrasound transducer.

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Section: Resultsmentioning

confidence: 89%

Section: Electrostatic Forcementioning

confidence: 99%

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Capacitive transducers with curved electrodes

McIntosh

Mauger²,

Patterson

2006

IEEE Sensors J.

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“…1 introduces pitfalls when applied to MEMS-VCSELs. This is because MEMS-VCSELs experience linewidth broadening when measured over long time scales, due to thermally-induced Brownian motion of the suspended membrane [15–17]. Thermal noise in MEMS has been well studied, as it is often the limiting noise source in vibrational MEMS sensors [19, 20].…”

Section: Coherence Length Measurementmentioning

confidence: 99%

“…The noise force, f n , is replaced by the value calculated using the equipartition theorem [15]. This becomes an approximation since the frequencies being integrated are now limited to ω ≥ ω k ; only those frequencies fast enough to be captured by the measurement time window, τ k , where τ k = (2π/ω k ) .…”

Section: Coherence Length Measurementmentioning

confidence: 99%

Wideband Electrically Pumped 1050-nm MEMS-Tunable VCSEL for Ophthalmic Imaging

John

Burgner

Potsaid

et al. 2015

J. Lightwave Technol.

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In this paper, we present a 1050 nm electrically-pumped micro-electro-mechanically-tunable vertical-cavity-surface-emitting-laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost & complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over 6 mm × 6 mm & 3 mm × 3 mm fields to show retinal vasculature and capillary structure near the fovea. These results demonstrate the feasibility of electrically pumped MEMS-VCSELs in ophthalmic instrumentation, the largest clinical application of OCT. In addition, we estimate that the 3 dB coherence length in air is 225 meters ± 51 meters, far greater than required for ophthalmic SS-OCT and suggestive of other distance ranging applications.

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Theory and experimental verification of micro switch group sensor (MSGS)

Nishiyama

Ward

Al-Dadah

2007

Physica Status Solidi (a)

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Due to the development of micro system technology (MST), mechanical structures of micro or nanometer dimension can be achieved. Devices in such small dimensions inevitably tend to be affected by Brownian motion and the errors caused by tolerance of fabrication, which decreases the accuracy of sensors. Micro Switch Group Sensor (MSGS) is a new type of sensor system which works by exploiting the stochastic features of noise and randomness within an array of switches. In this paper, the theory of MSGS is introduced. In the experimental work, the theory is verified with three noise affected switches using electronically generated noise. From the analysis, the theory is developed and it is shown that the behaviour of output signals agrees with the theory. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Reducing Brownian Motion in an Electrostatically Tunable MEMS Laser

Cited by 15 publications

References 9 publications

Capacitive transducers with curved electrodes

Capacitive transducers with curved electrodes

Wideband Electrically Pumped 1050-nm MEMS-Tunable VCSEL for Ophthalmic Imaging

Theory and experimental verification of micro switch group sensor (MSGS)

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