Research Of Absolute Distance Measurement System Of Semiconductor Laser Linear Frequency Modulation

Absolute distance measurement has a broad application prospect in the field of industrial manufacturing,and it is also one of the important research directions in the field of precision measurement.Due to its strong anti-jamming capability and simple measurement signal processing,laser frequency modulation ranging technology has gradually become a research hotspot in recent years.The semiconductor laser has the advantages of small package size,long service life,fast frequency tuning speed,and high cost performance,it is an ideal tunable light source.This paper studies the absolute distance measurement technology based on semiconductor laser linear frequency modulationThis paper analyzes and verifies the principle of the absolute distance measurement of semiconductor laser linear frequency modulation.Based on the measurement principle,an absolute distance measurement system is built and a distance measurement experiment is carried out.According to the wavelength tuning characteristics of the selected semiconductor laser,a semiconductor laser frequency modulation drive circuit was designed to implement the laser linear frequency modulation.Designs an absolute distance measurement scheme and sets up an optical interference system.The beat frequency signal was obtained,and the beat frequency signals at different measured distances were collected and processed,and the linear relationship between the laser beat frequency and the measured distance was established.The distance measurement experiment was conducted,and the main factors affecting the resolution of the system ranging were analyzed and studied by experiment.Experiments show that the absolute frequency measurement system of the linear frequency modulation of semiconductor laser designed in this paper can measure absolute frequency by measuring the frequency of the beat frequency signal.With the laser selected in this paper,the range resolution is 0.24mm in the range of 130mm.The ranging range mainly depends on the degree of collimation of the laser beam.Increasing the modulation bandwidth and the tuning frequency of the laser frequency modulation can significantly improve the resolution of the distance measurement.