Experimental study of diaphragm thickness effect on the sensitivity of the gas pressure sensor based on Fabry-Perot optical fiber

In this paper, the performance of a high-sensitivity, low-cost, low-dimensional Fabry-Perot based fiber-optic sensor for measuring argon gas pressure is reported. A Fabry-Perot sensor probe with an air cavity, length of 1.25 mm and suitable diaphragm with different thicknesses has been investigated in order to achieve the optimal thickness. The ultimate goal is to achieve a diaphragm that detects and measures gas pressures below 80 millibars. A PVC layer was used as second Fabry-Perot plate of the sensor,The sensing experimental arrangement for measuring gas pressure was provided in the laboratory. The effect of gas pressure as well as diaphragm thickness as an important parameter on the sensitivity of gas pressure sensor was investigated. Diaphragm thicknesses of 42, 56 and 70 μm and cavities with a length of 1.25 mm were investigated at different pressures of argon gas. The results showed that the best sensitivity with a value of 0.035 nm / mbar is related to the sensor with a diaphragm thickness of 42 μm.