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By considering the instrument as a complex operator on the incident electric field, a model to calculate secondary fringes of the Field-widened, Achromatic, Temperature-compensated Wind Imaging Interferometer (FATWindII) has been built. The distribution of secondary fringes on a charge coupled device detector has been plotted. The effects of secondary fringes on inversion errors of temperature and wind velocity have been presented. The results show that antireflection coating on the air/glass interface cannot meet the accuracy requirement of FATWindII. A theoretical method for calculating the optimal wedge angles of compensating glasses is derived to suppress the secondary fringes while preserving the primary ones. By adopting both methods, coating with antireflection film and shaping wedge compensating glasses, the relative intensity of secondary fringes is reduced to below 2.5% and the inversion errors of temperature and wind velocity introduced by the effects of secondary fringes can be minimized to about 0.05 K and 0.045 ms(-1), respectively.

For direct detection Mie Doppler wind lidar, the method of use Fabry-Perot interferometer as a dynamic Doppler shift discriminator is proposed and investigated theoretically. For the highest measuring sensitivity part of the FPI transmission curves is utilized to measure any possible laser Doppler shift, its measuring accuracy is very high. With no loss of this significant superiority, any actual wind speed range requirement can be met by repeating this way in a measurement. The simulations for different atmosphere conditions prove that this method is more suitable for wind measurement of higher part troposphere than previous.