At present, for methane detection machines, there are mainly on-line gas detectors using non-dispersive infrared mode, and Catalytic Combustion Methane detectors. These instruments can not quantitatively correct the cross-interference of background gases such as water. At the same time, it is necessary to prevent dust from polluting the optical windows of the analyzer. Therefore, before gas analysis, the sampling probe must be used to sample the process gas that needs to be analyzed. After removing dust and moisture from the sample gas through a complex pretreatment system, the sample gas is sent to the gas analysis instrument for gas analysis. These gas analysis systems often have many defects, such as: the gas sampling and pretreatment system can not meet the requirements of the analysis instrument, which results in the instrument being easily damaged and dimensional. The maintenance and repair cycle is short, the maintenance workload of sampling and pretreatment system is large and expensive, and the response time of the system is slow, which can not fully meet the requirements of real-time control of industrial processes. Both infrared methane detector and Catalytic Combustion Methane Detector have some inherent defects, which have become the bottleneck for enterprises to realize process control automation, but also restrict the development and application of gas detector.

TDLAS technology is essentially a spectral absorption technology. The concentration of gas can be obtained by analyzing the selective absorption of laser by gas. It differs from traditional infrared absorption technology in that the spectral width of semiconductor lasers is much smaller than that of gas absorption lines. The absorption wavelength of gas molecules is independent of the external temperature and pressure, and the wavelength absorption characteristics of different gas molecules are not interfered with each other, so that it is not affected by ambient temperature and humidity, and not by interfering gas.