A two fiber Bragg grating gas leakage detection sensor

In this paper, a new optical fiber gas sensor bases on the two fiber array. There is a sensor on the every fiber. It reduces the temperature disturbance. Every fiber system can also provide quantitative data about pipeline leakage rate based on the optical fiber self heating effect. The optical energy leaking out from the fibre is absorbed by the metallic coating,which raises the temperature and alter the grating pitch of the fibre Bragg grating(FBG).When gas leaking out from the pipeline blow on the fibre grating,its temperature changes accordingly. The gas leaking velocity can be controlled by monitoring the change of resonance wavelength. The validity of this grating gas leakage detection sensor has been experimentally proved by means of controlling the velocity of CH₄.