Research on Optical Fiber Methane Gas Sensor of Spectral Absorption Type

Based on the methane spectral absorption characteristic and difference absorption technology, a method of detecting methane concentration is presented. Taking distributed feedback (DFB) laser as the light source, the light with central wavelength 1650 nm is be divided into two-way by beam splitter, and one beam passes the methane gas in a gas cell, the other directly passes another reference gas cell. The useful light signal is converted in to electric signal by hardware circuit. The relation ship between concentration and voltage is obtained by virtual instrument software processing the voltage signal, and the experimental result accord with the actual methane concentration. At last, the factors influencing on the experimental detecting resolution are analyzed. The results of the experiments show that the real time detection and monitor of the methane gas can be completed in this system.