基于OPO激光器探测低空CO2激光雷达系统性能研究

Research on performance of lidar detecting CO_2 in low space based on OPO laser

阐述了差分吸收激光雷达探测低空CO2浓度的原理,分析了系统的信噪比,对一种DS系列的OPO激光器用于探测低空CO2进行了仿真。激光脉冲能量为2mJ,重复频率为10KHz,5×104(5Sec)个脉冲积累,探测器采用InGaAs/InP-APD,量子效率大于10%,得出结论:不考虑背景噪声情况下(夜间工作),在高度10km处信噪比约为10:1,因此夜间可探测10km以下的CO2浓度;考虑背景噪声情况下(白天工作),采用1.5nm的窄带滤波器,在高度6.7km处信噪比约为10:1,因此白天可探测6.7km以下的CO2浓度。从仿真结果看,该系统探测距离远,所需积累时间短,有利于激光雷达探测低空CO2性能的提高。

The principle of detecting thickness of CO2 in low space by DIAL is expatiated. And the SNR（ signal to noise ratio） of the system is analyzed. With the simutation experiments of a kind of OPO lidar of DS series, whose pulse power is 2mJ, repetition rate is 10KHz and accumulation pulse number is 5 ×10^4 （5sec）, some conclusions are drawn as follows： Without regard to the background noise（work at night）, SNR at the 10km is near 10：1 so that thickness of CO2 can be detected below 10km. If with regard to the background noise（work in daylight）, SNR at 6.7km is near 10：1 with 1.5nm narrow- band filter so that thickness of CO2 can be detected below 6.7km. From the results of simulation, it can be seen that this system can detect with long distance and little accumulation time, which can enhance the performance of detecting CO2 in low space by lidar.