相比于使用DFB边发射激光器，采用VCSEL激光器作为检测光源的TDLAS激光气体检测系统，具有功耗低的优点。针对低功率下的TDLAS气体检测信号特点，结合VCSEL激光光源调制特性，自主开发了VCSEL激光器驱动模块、信号采集及处理模块，采用波长调制光谱(WMS)技术研制出了一套低功率甲烷(CH₄)气体检测系统。选择了1653.7 nm附近CH₄分子的吸收峰作为吸收谱线，采用锁相放大器提取二次谐波(2f)信号。实验研究了不同浓度的CH₄检测的响应情况，记录2f信号的峰峰值并进行线性拟合，线性度为0.999 8。该检测系统在50 ~ 500 ppmv范围内，检测精度优于10%，检测下限为10 ppmv。对250 ppmv的CH₄持续检测10 h，数值波动小于±2.4%。引入Allan偏差分析，初始积分时间为1 s时，Allan偏差为9.9 ppmv；积分时间达到359 s时，Allan偏差为0.06 ppmv，表征了系统良好的稳定度。

Compared with the DFB laser, the TDLAS laser gas detecting system using the VCSEL laser as the detecting light source has the advantage of low power consumption. According to the characteristic of the low power TDLAS gas detection signal, combined with the characteristics of modulation VCSEL laser source, a laser driver, signal acquisition and processing were designed, and a low-power TDLAS methane (CH₄) gas detector based on WMS was designed. The absorption peak of CH₄ molecule near 1653.7 nm was selected as the absorption line, and the second harmonic (2f) signal was extracted by a lock-in amplifier. The response of different concentrations of CH₄ detection was studied experimentally, and the 2f signal's amplitude was recorded and linearly fitted. The results show that the CH₄ concentration has a good linear relationship with its 2f signal's amplitude, and the linearity is 0.9998. Accuracy of the detection system is better than 10% in the range of 50 - 500 ppmv, and the detection limit is 10 ppmv. With the long-term detection of 250 ppmv of CH₄ for 10 h, the fluctuations are less than ± 2.4%. Allan deviation analysis was introduced. When the initial integration time was 1 s, the Allan deviation was 9.9 ppmv. When the integration time reached 359 s, the Allan deviation was 0.06 ppmv, which indicated the good stability of the system.