▎ 摘　　要

NOVELTY - The invention claims a gas sensor based on double-layer graphene doped TiO2, comprising an ASE broadband light source (1), a gas sensing chamber (2), a spectrum analyzer (3), a demodulation module (4), a PC machine (5). The invention patent uses the double-layer graphene doped TiO2 coated on the surface of 19 core optical fibre, the gas sensing chamber into the gas to be detected, when the gas to be detected contains SO2 gas, because the SO2 gas will change the refractive index of 19 core optical fibre, the light path of the reflected light is changed so that the spectrum curve is moved, realizing the detection of SO2 gas. the light beam output by the 19-core optical fibre enters the spectrum analyzer and then enters the demodulation module, finally processing on the PC machine, reaching the purpose of digitization, at the same time, detecting the result in real time. The invention can detect whether there is SO2 gas in real time and can be output on the PC machine, it realizes the digital detection, it is convenient and fast and accurate.