Investigation of CO2 measurement of ZIF-8-based F–P interferometric optical fiber sensor

Abstract

In this paper, a set of ZIF-8 (Zeolitic Imidazolate Framework-8)-based Fabry-Perot (F–P) interferometric optical fiber sensor was designed to measure the carbon dioxide gas with different concentrations. The optical path difference of our sensing element was mainly caused by the F–P cavity filled with ZIF-8 instead of gas cavity. We analyzed the operating principle and verified the feasibility of the sensor. We gave the exact relation between the concentration of carbon dioxide and each parameter of the F–P cavity. The experimental results show that the spectrum will be red-shifted with the increase of the adsorption of carbon dioxide by ZIF-8 at a certain concentration of carbon dioxide. In addition, after applying Fourier transform to the spectrum, the frequency spectrum displayed two main peaks which changed to the lager value with the increase of concentration of carbon dioxide. The sensor has linear wavelength and phase sensitivities with the concentration of carbon dioxide under 5 × 104 ppm. Besides, the response time becomes shorter as the concentration of carbon dioxide decreases. To sum up, we presented a fiber optic gas sensor that is both simple to manufacture and has high selectivity, making it an effective method for measuring carbon dioxide.