光源线宽和脉宽对激光测风雷达测量精度的影响  

Influence of linewidth and pulse width on lidar measurement accuracy

作　　者：李强[1] 贾豫东[1] 李琛 LI Qiang;JIA Yu-dong;LI Chen(School of Instrument Science and Opto-Electronics Engineering,Beijing Information Science & Technology University,Beijing 100192,China;Academy of Opto-Electronics Chinese Academy of Sciences,Beijing 100094,China)

机构地区：[1]北京信息科技大学仪器科学与光电工程学院,北京100192 [2]中科院光电研究院,北京100094

出　　处：《激光与红外》2020年第11期1308-1312,共5页Laser & Infrared

基　　金：中国科学院战略性先导科技专项项目(A类)(No.XDA17010401);促进高校内涵发展-研究生科技创新项目-光电学院(No.5121911049)资助。

摘　　要：激光线宽和脉冲宽度是激光测风雷达测量精度重要的影响因素。本文分析了风速测量精度的影响因素,理论推导了激光线宽与信噪比关系,以及脉宽引起的功率谱展宽。数值分析表明,线宽增加引起的信噪比下降和脉冲宽度引起的谱线展宽都会导致风速测量精度下降。脉冲累计发数在10000的条件下,相干测风激光雷达系统脉冲宽度和信噪比分别为100 ns、-35 dB或激光线宽小于45 kHz,时,风速测量精度优于0.5 m/s。减小线宽和增加脉冲宽度,可以增加风速测量精度。在相同信噪比条件下,较宽的脉冲宽度的风速测量精度更高。Pulse width and laser linewidth are important factors in the accuracy of laser wind radar measurement.This paper analyzes the influencing factors of the lower limit of wind speed measurement accuracy,and theoretically deduces the relationship between laser linewidth and signal-to-noise ratio,and the power spectrum broadening caused by pulse width.Numerical analysis shows that the decrease of signal-to-noise ratio caused by the increase of line width and the broadening of the line caused by pulse width can lead to the decrease of wind speed measurement accuracy.The pulse width and signal-to-noise ratio of the coherent wind lidar system with the cumulative number of pulses is 10000,100 ns,-35 dB,the laser linewidth is less than 45 kHz,and the wind speed measurement accuracy is better than 0.5 m/s.Reducing the line width and increasing the pulse width can slow down the signal-to-noise ratio.With the same signal-to-noise ratio,a wider pulse width is more accurate for wind speed measurement.

关 键 词：激光线宽 脉冲宽度 风速测量精度 激光测风雷达 

分 类 号：TN249[电子电信—物理电子学]