Research On Broadband Linearly Modulated High-power Laser Source

Laser radar can not only obtain the information of laser reflectivity of target surface, but also can obtain the three-dimensional information of the object. Therefore, laser radar technology whether in civil or military has important application value, and at the same time, it also is an important way to complement other detection. To realize miniaturization, high frequency and high precision frame, many countries begin the study of laser radar imaging technology with focal plane. Frequency modulation/continuous wave (FM/cw) nonscanning imaging radar system is a laser based 4D imaging sensor with the characteristics of high speed, high frame-rate and high ranging accuracy. In the laser radar system, the characteristic of modulation of the light determines the accuracy of distance from imaging, and the power of the laser source decides the imaging range. Therefore, the source of linear chirp modulated amplitude with high power output is a key component of this radar system. It has special significance to produce a laser source with good modulation and high power.The paper analyses the basic principle and characteristics of modulation method. Combining research status with actual conditions adopted the way that connecting a seed laser source with high precision, high frequency sweep of bandwidth to a fiber amplifier. We made a linear chirp amplitude and 18W peak power laser source with high sweep frequency modulation bandwidth and high sweep accuracy to meet the requirements of the radar system. I analysed the requirements of the source on all parts and performed numerical simulation. I used modern methods to optimize the time-frequency analysis of linear sweep frequency signal processing. We built the test system for seed source and fiber amplifiers.In the experiment, according to theoretical analysis of the sourcesin and the optimization of linear sweep frequency signal processing methods, I designed the test system of the laser modulator and the laser source of the seed source and the fiber amplifier, and completed each device testing. In the linear area of the laser modulator, we can modulate the laser strength linearly by electricity signal. Studyed and tested the modulation of electro-absorption modulator seed source and M-Z Lithium Niobate electro-optic modulator seed source. We also studied the amplification of the fiber amplifier to the optical signals. I performed FM/cw detection experiment and prepared for outfield experiment. I finished this experiment and study of the light source.