Investigation of miniature fiber optic surface-mountable Fabry-Perot pressure sensor built on 45° angled fiber

摘要

We present a surface-mountable miniature Fabry-Perot (FP) pressure sensor that exploits a polished 45° angled fiber end face to swerve the optical axis by 90°. Optical analysis of the sensor system is performed based in ABCD method in terms of intensity of the beams reflected from each mirror and visibility of the sensor compared to conventional sensor system. One unique feature of the surface-mountable sensor is its embeddability with minimum intrusiveness to the system. By using the fiber as a waveguide, as well as an inherent mask for the photolithography, a self-aligned FP cavity is constructed. A polymer-metal composite diaphragm is employed as a deflection diaphragm for pressure sensing which enables achieving higher sensitivity and low-cost fabrication over silicon diaphragm. The sensor exhibits a good linearity over the designed pressure range. A fiber Bragg grating is embedded in the vicinity of the pressure sensor to measure the local temperature around the pressure sensor. A method of compensating the temperature effect on pressure sensing was discussed. This sensor is expected to impact many fronts where temperature effect should be considered to perform reliable and accurate pressure measurement with minimum intrusiveness.