Receiving characteristics analysis of large dynamic range based on four-optic coherent mixing

Abstract Aiming at the problem that the maximum measurement speed of conventional laser coherent detection is limited, a four-optical coherent mixing large dynamic range Doppler measurement method is proposed. The speed measurement range of this method is nearly doubled, and the speed measurement of high-speed and ultra-high-speed targets can be achieved. The SNR is a key reference quantity for the four-light coherent mixing performance. Therefore, a theoretical analysis was carried out from the spatial coherence length, receiving aperture, and mismatch angle. Through theoretical and simulation analysis, the optimal relationship between the aperture coherence length and the receiving aperture is obtained.