Based on the principle of methane gas spectral absorption

a high-precision dual wave-length single optical path detection system for methane gas volume fraction

which use multiple re-incidence optical resonant cavity as methane gas absorption chamber is designed.Multiple reflections of light rays in the gas absorbing chamber increase optical path length of the absorption with methane gas

which greatly improves the detection precision

and because the distribution characteristics of scattered light points

so that the system also has a good characteristics of loose heat

which does not cause heat accumulation.It is benefit to the heat elimination of methane gas absorption chamber.It is verified by experiment

the system has very high precision and reliability.It provides a new way for the design of high precision methane sensors.