Designing and manufacturing of the laboratory optical fiber sensor for detection of the gas pressure by Fabry-Perot method and the investigation of the effect of the polymer material on its sensitivity.

In this paper, design and fabrication of Fabry-Perot optical fiber sensors with a coating of polyurethane, Soft PVC and Rigid PVC with the same thickness of 300 μm and a cavity length of 0.1 mm was introduced for the pressure gas and the effect of these three polymeric materials on the sensitivity of gas pressure sensors was investigated. The above sensors have been tested at a constant laboratory temperature and have been compared with each other. To perform gas pressure tests, two gases of oxygen and nitrogen in the pressure range of 10 to 50mbar have been used. The sensitivity of the sensor with the coated polyurethane for oxygen and nitrogen gas is 0.438 and 0.392 nm/bar, respectively, the sensor coated with soft PVC has the sensitivity of 0.311 and 0.224 nm/bar, for oxygen and nitrogen gas respectively, and the sensors with rigid PVC coated for oxygen and nitrogen gas has the sensitivities of 0.298 and 0.186 nm/mm, respectively. The results show that the sensor made with polyurethane coating is more sensitive than the other sensors.