Dual-comb Absolute Distance Measurement System Based On All Polarization-maintaining Femtosecond Fiber Lasers

Based on the background of spaceborne instruments such as synthetic aperture radar(SAR)and distributed intersatellite instruments such as satellite flying formations,this paper develops a range finder with high accuracy,high update rate,high integration and high stability for large-scale industrial and aerospace industries.Femtosecond laser has been widely concerned since it was first used in ranging light source in 2000 because of its ultra-high temporal and spatial resolution.In this paper,based on the principle of space engineering application,the selection of laser source is discussed,and a femtosecond two-comb range finder system is built.The main contents of this paper are as follows:1.The methods and progress of femtosecond laser ranging at home and abroad are discussed,and the advantages and disadvantages of each method in practical engineering applications are summarized.2.Two main components of the dual-comb range finder system are summarized:femtosecond laser source and sampling mode.In the femtosecond laser part,three commonly used mode-locked femtosecond lasers are introduced in detail and their advantages and disadvantages as ranging light sources are analyzed.Two different sampling methods are introduced,and their advantages and disadvantages are analyzed.Finally,several factors affecting ranging accuracy and how to improve them are briefly analyzed..3.A new type of all polarization maintaining fiber ring mirror "9" cavity laser is introduced in detail,its principle is analyzed,the components and functions of its components are analyzed by matrix,and a new type of laser is built to measure its output parameters.4.Based on a new type of fiber laser,a two-comb range finder system suitable for engineering application is built,and the experimental research of absolute distance measurement under large-scale distance is carried out in the National Institute of Metrology.Compared with the standard interferometer,the high-precision ranging results with residual error(+2um)in 65 m range and standard deviation less than 2um in 1s gate time are achieved.5.The absolute distance measurement of moving antenna target in simulated spaceborne environment is carried out by using the built two-comb range finder system,and the classical motion state curve is measured and analyzed in detail.