Buckled Beam based Optical Interferometric Pressure Sensor with Low Temperature Cross-Sensitivity

A novel optical fiber extrinsic Fabry-Perot interferometer pressure sensor with low temperature cross-sensitivity is presented. The Fabry-Perot is formed by the endface of an optical fiber and the center part of a buckled beam. The working principle of the sensor involves a pressure transfer and displacement transfer and amplification mechanism based on a buckled beam. When the sensor is subjected to an external pressure, the sheet steel will deflect, resulting in an axial displacement of the buckled beam. The buckled beam will experience a deflection, and the deflection at the midpoint of the beam is one order of magnitude larger than the deflection of the sheet steel. So, a relatively large change in the cavity length can be obtained. Compared with the traditional diaphragm based pressure sensors, the sensitivity of our sensor was improved by one order of magnitude, and the temperature-pressure cross-sensitivity was found to be as low as 22 Pa/°C