全光纤分光转动拉曼测温激光雷达探测性能优化

Optimization of all-fiber spectroscopic rotational Raman lidar for profiling temperature

采用光纤Bragg光栅的耦合模理论和转动拉曼激光雷达的温度反演算法,优化全光纤分光转动拉曼测温激光雷达系统的探测性能。以光纤Bragg光栅高斯型谱为基础,构建以光纤Bragg光栅为核心的全光纤分光系统的参数优化模型,以1.5km高度处大气温度的统计误差为优化目标进行仿真分析,得到光纤Bragg光栅的中心波长和半峰值带宽的优化值;为了使均匀光纤Bragg光栅的光谱旁瓣与大气分子的纯转动拉曼谱线匹配,局部优化光纤Bragg光栅的Bragg波长、平均折射率变化和光栅长度等结构参数,以构建光纤Bragg光栅加工系统及设置初始加工参数。结合望远镜耦合效率的仿真结果,分析了全光纤分光转动拉曼激光雷达的探测性能。仿真结果表明,全光纤分光转动拉曼激光雷达系统在高度1.5km处的统计温度误差可达1.3K。

Performance of all-fiber spectroscopic rotational Raman lidar ts opttmtzect by using me coupled-mode theory of fiber Bragg grating and retrieval temperature algorithm in the rotational Raman lidar. The optimization model of all-fiber spectroscopic filter with fiber Bragg grating is constructed on the basis of Gaussian-type spectra of fiber gragg grating. The simulation analysis is made with statistical error of the atmospheric temperature at the 1.5 km height as the optimiza- tion goal to obtain optimum central wavelength and full width at half maximum of fiber Bragg grating. These configuration parameters of fiber Bragg gratings including Bragg wavelength, av- erage refractive index, and grating length are locally optimized to match the spectral side-lobes of uniform fiber Bragg gratings with pure rotational Raman spectral lines of atmospheric molecules. These will bring some advantages to construct the fabrication system and to configure the initial parameters of fiber Bragg gratings. The performance of all-fiber spectroscopic rotational Raman lidar is simulated by combining the simulative coupling efficiency of telescope. Simulative results show that this all-fiber spectroscopic rotational Raman lidar possesses 1.3 K statistical error of temperature at 1.5 km height.