Study Of High-speed,Large-bandwidth And Linear Frequency Modulated Laser Ranging Based On Semiconductor Laser

In 1960,the distance measurement enters the era of distance measurement which based on the laser technology after the birth of the first ruby laser.The laser technology in military field and civilian field has obtained fast development and widely application because of the laser with high brightness,good monochromaticity,and better in direction and coherence.Compared with the other ranging method,the laser ranging has the advantages of long measuring distance,high ranging precision and high ranging resolution.In general,the laser ranging method contains pulse laser ranging technology,phase laser ranging technology and linear frequency modulated laser ranging technology and so on.Wherein,the early application of pulse laser ranging technology has a lower ranging precision because of the measuring frequency error,however,this technology is suit for the long distance measurement and the lower ranging precision which is required because the peak power of laser pulse is very high.Compared with the pulse laser ranging technology,the phase laser ranging technology has a higher ranging precision but the measuring distance is shorter than pulse laser ranging technology,what's more,this system has a complex structure so that it is suit for the short distance and high-precision measurement.Therefore,the linear frequency modulated laser ranging technology with high ranging precision,fast measuring speed and the ranging precision is irrelevant to the distance so that the linear frequency modulated laser ranging technology has beco me a hot research area.This paper have a study on the linear frequency modulated laser ranging technology which based on the tunable semiconductor laser.First of all,we analyze the relevant theory of the linear frequency modulated laser ranging technolo gy,o n this basis,we built a set of all-fiber linear frequency modulated laser ranging syste m on the basis of the theory of linear frequency modulated laser ranging,and then have a experiment study on the linear frequency modulated laser ranging technolo gy.The main job of this paper are as follows:1)We have a research on laser ranging method,and then analyze the advantages and disadvantages of each kind of the laser ranging method;2)We have a research on the tunable laser which using for laser ranging,an d then analyze the advantages and disadvantages of each kind of tuning method;3)We have a study on the working principle of current tuning semiconductor laser,and analyze the rate equation of the conversion relationship between injection current and photon in the process of current tuning semiconductor laser and then solve the steady-state solution of this rate equation;analyze the line-width characteristics of the laser source of this laser ranging system,and introduce the measurement method of laser 's line-width and then analyze the advantages and disadvantages of each kind of measurement method;4)We analyze the time-domain characteristic and frequency-domain characteristic of the beat frequency signal between transmitting signal and echo signal of the linear frequency modulated laser ranging system,and then analyze the influence factor on ranging resolution of linear frequency modulated laser ranging system;5)We built a set of all-fiber linear frequency modulated laser ranging syste m according to the theory of linear frequency modulated laser ranging,we have a study on the every parameter of the linear frequency modulated laser ranging,and then get the relationship between the ranging precision and the object's distance,the modulated bandwidth and the modulated speed.