Experimetal Research On1550nm Coherent Wind Lidar

In this thesis, for the coherent wind measurement lidar using optical fiber as thereceiver, the relationship between the parameters of the optical system and the impacton the receiving energy of the system were studied. And the impact on coherentdetection of fixed focal length of the optical system at different target range wasanalyzed. Then related experiment was done. Finally, the impact of the detection relatedto monostatic and the impact of different detecting distances were analyzed. The maincontents of this paper are shown as below.Firstly, the wind detection principle of lidar and the basic principle of coherentdetection were introduced, the establishment of signal-to-noise ratio and energyequation of the laser radar were done. And the advantages and disadvantages of thedifferent style antennas were discussed. Then, the object-image locations and sizes wereanalyzed by using geometrical optics.Then, the relationship between the parameters of the transmitting and the receivingsystems of the wind lidar were discussed. And the requirements of the optical systemwere discussed when using fiber as receiver. In the system using polarization splittingprism and quarter-wave plate, the working principle of the polarization isolation systemwas analyzed. And the similarities and differences of space beam combiner and fiberbeam combiner were compared. Then the location and size of the minimum spot inreceiving optical system was studied at different detection distances, and the receivingenergy and the receiving efficiency of the optical fiber were analyzed. The diameter, therelative aperture, the optical fiber numerical aperture and the fiber receiving efficiencyof the receiving optical system were discussed as mutual constraints. Then in ZEMAX,the receiving system model was established to validate the above analysis.Finally, coherent wind lidar experiment was done, the echo signal of hard targetfrom0to90meter distance was tested, and the experimental analysis of the impact ofmonostatic optical system for detection was done. Then, the impact on detection whenchanging the focal length and aperture of the receiving system was analyzed with theexperiment, and the above theories were verified.