测风激光雷达光学参量对相干效率的影响

Influence of optical parameters of wind LiDAR on coherent efficiency

为了研究光学参量如何影响测风激光雷达相干效率的问题,结合理论推导与实验验证进行了研究。基于光场叠加理论,讨论了本振光束腰、光纤耦合器芯径、光学系统像差对系统相干效率的影响;开展大气湍流影响实验,测量了不同光学参量的系统在典型天气条件下的信噪比。结果表明,光瞳口径为100 mm、F数为2时,最优束腰半径为3.3μm,最佳匹配接收光纤芯径为9μm,光学系统波像差均方根值应不大于0.06λ;在强湍流作用下,当能见度小于5 km时,雷达探测距离降低60%。此研究对光学参量的优化具有重要参考意义。

By combining theoretical derivation and experimental verification,research was conducted on how optical parameters affected the coherence efficiency of wind light detection and ranging(LiDAR).According to the superposition principle of optical fields,the influence of local oscillator waist and fiber coupler diameter and optical aberrations on coherent efficiency was discussed.Experiment of atmospheric turbulence effect was conducted,and the system signal-to-noise ratio with different optical parameters was measured under typical weather conditions.The consequence indicate that if the pupil aperture and F number are 100 mm and 2,the optimal beam waist and receive fiber diameter are 3.3μm and 9μm,and root mean square of the optical wavefront aberration is less than 0.06λ.Under strong turbulence,when the visibility is less than 5 km,the radar detection distance decreases by 60%.It has special significance for optimizing optical parameters to promote the study.