Performance comparison of Fabry-Perot and Mach-Zehnder interferometers for Doppler lidar based on double-edge technique

Compared with dual-channel Fabry-Perot interferometer (DFPI), dual-channel Mach-Zehnder interferometer (DMZI) is a new frequency discriminator for Doppler wind lidar based on double-edge detection. The double-edge frequency discrimination systems based on DFPI and DMZI in the wind lidar system are designed, respectively, and the detection principle is analyzed theoretically. Under certain simulation conditions, performances such as line-of-sight (LOS) wind velocity measurement sensitivities, signal-to-noise ratios (SNR) and LOS wind velocity measurement errors of both DFPI and DMZI systems are simulated and compared based on the U.S. standard atmospheric model. The simulation results show that for 1064 nm aerosol system, the LOS wind velocity measurement sensitivity of the DMZI system is lower than that of DFPI system and the error is higher than that of DFPI system with the same dynamic wind velocity measurement range. Nevertheless, for 355 nm atmospheric molecular system, DMZI system provides a factor of 1.33 times lower error in the LOS wind velocity than that of DFPI with an altitude of 30 km and the LOS wind velocity of 200 m/s. Furthermore, in the LOS wind velocity range of -200 m/s +200 m/s, the measurement error of DMZI system hardly increases with the increasing of wind speed. Therefore, the results of this study not only provide guidance for the selection of discriminators, but also provide theoretical support for the application of DMZI in the double-edge detection of atmospheric molecular lidar.