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Optical Engineering

Suppression of span in sealed microcavity Fabry–Perot pressure sensors
Author(s): Shivam Mishra; Balasubramaniam Rajappa; Sudhir Chandra
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Paper Abstract

Optical microelectromechanical system pressure sensors working on the principle of extrinsic Fabry–Perot (FP) interferometer are designed and fabricated for pressure range of 1-bar absolute. Anodic bonding of silicon with glass is performed under atmospheric pressure to form FP cavity. This process results in entrapment of gas in the sealed microcavity. The effect of trapped gas is investigated on sensor characteristics. A closed-loop solution is derived for the deflection of the diaphragm of a sealed microcavity pressure sensor. Phenomenon of “suppression of span” is brought out. The sensors are tested using white light interferometry technique. The residual pressure of the trapped gas is estimated from the experiments. The developed model has been used to estimate the deflection sensitivity of the free diaphragm and the extent of suppression of span after bonding.

Paper Details

Date Published: 6 January 2017
PDF: 9 pages
Opt. Eng. 56(1) 016105 doi: 10.1117/1.OE.56.1.016105
Published in: Optical Engineering Volume 56, Issue 1
Show Author Affiliations
Shivam Mishra, Homi Bhabha National Institute (India)
Bhabha Atomic Research Ctr. (India)
Balasubramaniam Rajappa, Homi Bhabha National Institute (India)
Bhabha Atomic Research Ctr. (India)
Sudhir Chandra, Bennett Univ. (India)

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