Optimization of multi-longitudinal-mode incoherent doppler wind lidar with quadri-channel mach–zehnder interferometer

Multi-longitudinal-mode (MLM) high-spectral-resolution lidar is a new concept of incoherent Doppler wind lidar (IDWL), which can avoid the complex techniques of seed injection as well as the high requirement of frequency stabilization and frequency locking. To achieve high-precision atmospheric wind measurement, an optimized design is performed for the MLM IDWL, which utilizes a free-running MLM laser as the excitation light source and a quadri-channel Mach-Zehnder interferometer (QMZI) as the spectral discriminator. Based on the partial coherence theory of quasi-monochromatic light interference, the data inversion algorithms for MLM IDWL are simplified, and the performance evaluation parameters for MLM IDWL are analyzed. Furthermore, using the control variable method, the key parameters of MLM IDWL are optimized by discussing its performance evaluation parameters in the condition of aerosol Mie scattering or molecular Rayleigh scattering, respectively. The simulation experiments of wind measurement with the optimal key parameters prove that the MLM IDWL can realize the atmospheric wind measurement with an accuracy of 0.3 m/s in the low-altitude environments using aerosol Mie scattering echo signals and with an accuracy of 3.0 m/s in the high-altitude environments using molecular Rayleigh scattering echo signals.