Optical Interferometric Pressure Sensor Based on a Buckled Beam With Low-Temperature Cross-Sensitivity

This paper reports a novel optical interferometric sensor based on a buckled beam for pressure measurements with low-temperature dependence. The working principle of the pressure sensor involves a pressure transfer mechanism and a displacement transfer mechanism. The principal sensor structure consists of an optical fiber, a gold-coated steel beam, and a steel sheet with a thickness of 0.8 mm. The optical fiber endface and the center part of the buckled beam form a Fabry-Perot interferometer. When the sensor is subjected to an external pressure, the steel sheet will deflect, resulting in an axial displacement of the prebuckled beam. The axial displacement will be further transferred and amplified to a vertical deflection at the center of the buckled beam, leading to a relatively large change in the Fabry-Perot cavity length. Based on this buckled beam structure, the pressure measurement sensitivity of the novel sensor is improved. Moreover, the sensitivity could be flexibly adjusted through the modification of the initial setting of the buckled beam. In our prototype sensor, a pressure sensitivity of 169 nm/kPa was realized with a low-temperature dependence of 0.022 kPa/degrees C. The stability of the sensor was also investigated. This cost-effective and easy-to-manufacture sensor is believed to be an excellent candidate for monitoring the environmental pressure in various fields.