摘要
为减小差分吸收相干激光雷达(DIAL)中偏振衰落对回波信号功率反演精度影响,研究了偏振分集技术(PDT)在相干DIAL中的作用,构建了利用STM32控制的双光束切换DIAL实验装置。依托构建的装置,利用平衡探测,分别采用PDT和一般外差探测完成多组次实验,应用单频检测方法得到20m光程下吸收气体不同浓度下相干中频信号的振幅值,并由此求解出on光和off光回波信号功率。对回波信号功率值差分信息与由HITRAN得到的参考差分信息比较发现:应用PDT能使探测分辨率提高4倍,对应到2km距离内,可以探测到3.5×10-6ppm的CO2浓度变化,满足了气候研究所需的优于1%的精度要求,验证了PDT消除偏振衰落以及提高相干DIAL分辨精度的作用。
To reduce the impact of polarization-induced fading in coherent differential absorption lidar（DIAL）,the basic principle of polarization diversity technology（PDT）is studied in a coherent lidar system.A dual-wavelength switching DIAL system controlled by STM32 is performed.Based on the system,many groups of experiments with balanced detection are conducted using PDT and normal heterodyne detection respectively,and the amplitudes of intermediate frequency（IF）are acquired in different concentrations in an optical path of 20 m with single frequency detection.And the return power of on light and off light could be solved from these amplitudes of IF.By comparing the differential information of the return signal power with the reference differential value acquired from the HITRAN database,it is indicated that the minimum concentration the system could detect with PDT is improved by 4times than those without PDT,and thus a variation of 3.5mg/L of CO2 concentration could be identified corresponding to a range of 2km,which could meet the need of climate research with the requirement of verifying the concentration change of better than 1%.The effects of PDT on eliminating polarization-induced fading and improving the resolution of DIAL detection are verified,which is important to the research of DIAL.
出处
《光电子．激光》
EI
CAS
CSCD
北大核心
2015年第3期541-547,共7页
Journal of Optoelectronics·Laser
基金
国家自然科学基金(61271353)
安徽省自然科学基金(1308085QF123)
脉冲功率激光技术国家重点实验室主任基金资助项目
关键词
偏振分集技术(PDT)
平衡探测
差分吸收
相干激光雷达
大气CO2浓度
polarization diversity technology（PDT）
balanced detection
differential absorption
coherent lidar
atmospheric CO2 concentration
