Miniature surface-mountable Fabry–Perot pressure sensor constructed with a 45° angled fiber

We present a surface-mountable miniature Fabry-Perot (FP) pressure sensor that utilizes the total internal reflection at a 45 degrees angled fiber end face to steer the optical axis by 90 degrees . By using the fiber as a waveguide, as well as a natural mask in photolithography, an FP cavity is constructed on the sidewall of the fiber. A polymer-metal composite diaphragm is employed as the pressure transducer. The sensor exhibits a good linearity over the pressure range of 1.9-14.2 psi, with a sensitivity of 0.009 microm/psi and a hysteresis of 2.7%. This sensor is expected to impact many fronts that require reliable static pressure measurements of fluids.