针对0.5%VOL以下的低浓度甲烷气体，设计了一种基于近红外可调谐半导体激光吸收光谱的光学式甲烷气体传感器.调谐激光器扫描甲烷气体位于1 653.72 nm处的吸收谱线，采用一次谐波“峰-平比”对气体浓度进行测量.该方案能够有效地消除激光器光强波动和其它同类光功率波动所带来的影响，通过标定后的测试实验表明传感器测量准确度可达0.02%VOL.

To the methane gas with the concentration lower than 0.5%VOL,an optical methane gas sensor was designed based on near infrared tunable diode laser absorption spectroscopy.The methane gas absorption spectroscopy of 1 653.72 nm was scanned by tunable laser,and the gas concentration was measured by using the first harmonic PAPR.The proposed can effectively eliminate the influences caused by light intensity fluctuation of the laser and other kindred light power fluctuations,and the test results show that the precision of this kind of sensor can be 0.02%VOL.