全光纤M-Z干涉仪的高灵敏度与大动态范围多普勒激光雷达风场探测技术

多普勒测风激光雷达是大气风场探测的重要手段之一。通过检测风速导致的大气后向散射谱的多普勒频移从而实现风速的探测。由于受鉴频器本身特性的影响，高灵敏度与大动态范围的探测一直是大气风场探测的难点。提出采用双光纤Mach-Zehnder干涉仪(FMZI)作为多普勒激光雷达的鉴频器件，设计两路不同动态范围及风速探测灵敏度的FMZI鉴频器同时对大气回波信号进行鉴频。采用小光程差(13.7 cm)、大动态范围(±100 m·s-1)鉴频光路FMZI-2对风速区间进行定位，大光程差(74.8 cm)、高探测灵敏度(2.62%/(m·s-1))的鉴频光路FMZI-1进行风速精细探测，从而实现大动态范围高灵敏度的风场探测。利用标准大气模型对不同参数条件下的系统灵敏度、系统探测的信噪比及风速误差进行仿真分析。结果表明，该系统可以实现±100 m·s-1大动态范围内风速误差小于1 m·s-1的大气风场探测，为大动态范围高灵敏度测风激光雷达的发展进行了有益的探索。

Doppler Lidar with High Sensitivity and Large Dynamic Range for Atmospheric Wind Measurement

Doppler wind Lidar is an important method for atmospheric wind measurement .The Doppler frequency shift of backscattering spectrum due to the wind is detected fro m the transmissions of frequency discrimination .High sensitivity and large dynamic range measurement is difficult for atmospheric wind measurement because of the limitationof frequency discriminator characteristic .In this paper,a frequency discriminator constructed with Dual fiber Mach-Zehnder interferometer is propose d .Two fiber Mach-Zehnder interferometers with different atmospheric wind detection dynamic range and sensitivity are designed and used to measure Doppler frequency shift at the same time .The optical path difference of FMZI-2 is 137 cm which can realize large dynamic range wind measurement (±100 m·s-1) and the optical path difference of FMZI-1is designed to be 748 cm which c an realize high sensitivity detection .Moreover,the absolute wind velocity of FMZI-1 channel can be corrected by the measurement result of FMZI-2 channel .Thus the high sensitivity and large dynamic range wind detection can be realize d .The sensitivity,SNR and wind error of two channels are simulated and analy zed for different parameters .The results indicate that the system can realize the wind error less than 1 m·s-1 for large dynamic range(±100 m·s-1) wind velocity,which is a beneficial exploration for high sensitivity and large dynamic range Doppler wind lidar .