The Absorption Line-Shapes Recovery Research Of Gas Detection System Based On TDLAS

The technology of tunable diode laser absorption spectroscopy is widely used in gas detection field. At present, the detection of poisonous and harmful gas in the environment is the foundation of the haze governance, so the application of this technology has great prospects for development. The application of this technology effectively enhances the precision of gas detection products, which is of great significance to the production and environment monitoring. A great many of related products have been put into use, but the product itself still has a lot space to improve the product precision. Considering from the establishment of the theoretical model, the determine of many parameter values which influence theoretical model is worth analyzing and discussing, parameter in model of theory need to be corrected, and recovery the line shape. The value makes it suitable for the application of gas detection system, which is to show one of methods to improve the accuracy. Therefore, being proposed in this paper, we take a method without current under the condition of modulation, and adopt measures based on actual test, to correct parameter in the theory model.This paper introduces the basic theory of the gas detection based on TDLAS technology, the test gas is the methane, we use the methane gas detection device as the primary test system, and determine the center of the methane gas detection wavelength value of1.65um, and set the specific temperature according to the profile of the laser using in the methane gas detection device, and apply an sawtooth current to the laser, then, get the modulation the actual absorption line shape. This paper also discussed the theoretical model of the influence of some parameters on the absorption lines shape. According to the comparison of actual measured data and the theoretical value, analysis of the main parameters affecting the model, think of the range of parameters at the same time, to determine the value of the parameter in the model.According to the actual need, the related theory model was established, and designed a kind of lines shape correction method under the condition of non-modulation. Results show that the linear revised parameters according to the actual absorption, applied to the test system much better, realized the improvement of the precision of the products.