分析了光纤Mach-Zehnder干涉仪作为鉴频器的多普勒激光雷达风速探测灵敏度及动态范围与光程差的关系.当光纤Mach-Zehnder干涉仪光程差从0.1 m变化到1.5 m时, 对应风速探测范围从±199.5 m/s变化到±13.3 m/s.光程差为0.45 m时, 风速变化1 m/s对应的最高灵敏度为2.15%.光程差误差将导致风速反演误差.当光程差为0.145 9 m和1.088 9 m时, 1 nm的光程差误差将导致反演风速误差分别为1.028 m/s 和 0.138 m/s.应用激光波长调谐的方法得到光纤Mach-Zehnder干涉仪的透过率曲线, 由自由光谱范围精确确定了光程差的值.应用此干涉仪作为鉴频器的激光雷达完成了实际风速探测, 反演风速与相干探测风速具有较好的一致性, 证明了校准探测的正确性.

The wind measuring sensitivity and dynamic range for Fiber Mach-Zehnder Interferometer (FMZI) based Doppler lidar are analyzed. The detection dynamic range is ±199.5 m/s and ±13.3 m/s for 0.1 m and 1.5 m Optical Path Difference (OPD). The optimal sensitivity is 2.15% with the change of wind speed of 1 m/s, corresponding to an optimal OPD of 0.45 m. The OPD error will result in retrieval wind velocity error. When the OPD is equal to 0.145 9 m or 1.088 9 m, the retrieval wind velocity error is 1.028 m/s or 0.138 m/s for 1 nm OPD error. We employed laser wavelength tuning method to determine the OPD of FMZI. The experiment has been implemented to calibrate OPD. This interferometer is used as a frequency discriminator in the lidar to detect the actual wind speed. The inversion of the wind speed is in good agreement with the coherent detection of the wind speed, which proves the correctness of the calibration detection.