A New Diaphragm Material for Optical Fibre Fabry-Perot Pressure Sensor

Abstract

Fibre optic Fabry-Perot interferometric pressure sensors have proved many orders of excellent measurements system, but they suffer from limitations in sensitivity and resolution caused by the trade-off in designing the sensor when very thin diaphragm is needed. By reducing the diaphragm thickness increases the deflection range, but reduces the diaphragm strength and therefore increases the risk of mechanical failure. The pressure sensor has been designed and its fabrication process using MEMS techniques is explained. This paper proposes a new diaphragm material for the fibre optic Fabry-Perot pressure sensor. Using a Polydimethylsiloxane (PDMS), the limitation on sensor resolution and sensitivity are overcome. The goal of this research is to design and analyze the PDMS diaphragm to enhance the consistency and sustainability of fibre optic FabryPerot pressure sensor for medical measurements which require a minimum resolution of ~1 mmHg over all the physiological pressure range (~300 mmHg) [1,2]. Comparisons of theoretical and simulation with Coventor Ware simulator on mechanical part of the pressure sensor are made. Also, an explanation viewing the sensor's diaphragm stability is provided.

Fiber optic Fabry–Perot pressure sensor based on lensed fiber and polymeric diaphragm

“…Most of Fabry-Perot fiber interferometer for pressure measurement usually employs two reflecting flat-surfaces separated by a cavity, an end face of optical fiber and a reflecting diaphragm surface. For the pressure measurement, various types of diaphragms have been used, including those fabricated from polymer materials (silicon, SU8), metal and even optical fiber, according to their mechanical properties and applications [9][10][11][12][13][14][15][16][17]. The loaded pressure can be estimated by detecting the interference signal when pressure deforms the diaphragm.…”

“…The Fabry-Perot sensors have drawn much interest owing to their advantages, such as dimensional compactness, high sensitivity, applicability in harsh environments, low cost, easy handling and alignment, immunity to electromagnetic interference (EMI) and multiplexing capability [1][2][3][4][5][6][7][8][9]. In particular, the Fabry-Perot sensors for the pressure measurement have a remarkable attention in a many applications such as medical, automotive, aerospace, gas and oil industries [9][10][11][12][13][14][15][16][17]. Most of Fabry-Perot fiber interferometer for pressure measurement usually employs two reflecting flat-surfaces separated by a cavity, an end face of optical fiber and a reflecting diaphragm surface.…”