DFB半导体激光器线性调频技术研究

发布时间：2018-05-12 03:13

本文选题：线性调频连续波 + DFB　；参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：线性调频连续波(LFMCW,Linear Frequency Modulated Continuous Wave)激光器雷达测距技术是一种非接触式、高精度、高效率、无盲区的大尺寸绝对距离测量技术。其测距原理要求必须有一个高调频线性度的可调谐激光器,而实际中的可调谐激光器都存在固有的调频非线性,差拍信号的频谱会因此出现展宽,测距的分辨率和精度会受到严重影响。本文主要围绕DFB激光器的线性调频技术研究,简要说明了DFB激光器注入电流调频原理及调频非线性产生的原因。对调频非线性的影响进行了理论分析和仿真。测试了激光器的静态调频参数,设计并搭建了DFB激光器的动态调频特性测试系统对DFB激光器的动态调频特性进行了测试,实现结果表明DFB激光器调频带宽随调制频率的增加而减小,并分析了这种现象产生的原因。从理论上推导了基于软件的非线性校正迭代算法模型,并搭建了非线性软件校正系统进行了实验,很大程度上降低了DFB激光器的调频非线性,而且这种方法也适用于其他类型的电流注入式调谐激光器。另外这种校正方法也可以实现对激光器调频速率的改变。对基于光电锁相环的DFB激光器线性调频系统进行了分析、仿真、电路设计以及等效模型的测试。使用DFB激光器作为调频源进行调频连续波干涉测距,对激光器未经校正和经过校正后的测距重复性精度进行了对比分析,实验结果表明经过校正后的测距精度提高了29.26倍。但是由于激光器功率的波动、扫频的拐点效应、系统中的噪声的影响,以及设计的非线性开环校正方法本身存在的问题,经过非线性校正后激光器仍残余不小的非线性。
[Abstract]:LFM CW LFMCW linear Frequency Modulated Continuous Wave) laser radar ranging technology is a non-contact, high precision, high efficiency, no blind area large size absolute distance measurement technology. The principle of ranging requires that there must be a tunable laser with high frequency modulation linearity. In practice, the tunable laser has inherent frequency nonlinearity, and the spectrum of the beat signal will be widened. The resolution and accuracy of ranging will be seriously affected. This paper mainly focuses on the study of linear frequency modulation (LFM) technology of DFB laser, and briefly explains the principle of injection current frequency modulation of DFB laser and the cause of frequency modulation nonlinearity. The influence of frequency modulation nonlinearity is theoretically analyzed and simulated. The static frequency modulation parameters of the laser are tested, and the dynamic frequency modulation characteristic of DFB laser is designed and built. The dynamic frequency modulation characteristic of DFB laser is tested. The results show that the frequency modulation bandwidth of DFB laser decreases with the increase of modulation frequency, and the causes of this phenomenon are analyzed. In this paper, the iterative algorithm model of nonlinear correction based on software is derived theoretically, and the nonlinear software correction system is built for experiment, which greatly reduces the frequency modulation nonlinearity of DFB laser. This method is also suitable for other types of current-injection tunable lasers. In addition, the frequency modulation rate of the laser can be changed by this correction method. The linear frequency modulation (LFM) system of DFB laser based on optoelectronic PLL is analyzed, simulated, circuit design and equivalent model test are presented. DFB laser is used as frequency modulation source for frequency modulation CW interferometric ranging. The repeatability accuracy of uncorrected and corrected ranging is compared and analyzed. The experimental results show that the corrected ranging accuracy is 29.26 times higher. However, due to the fluctuation of laser power, the inflexion effect of frequency sweep, the influence of noise in the system, and the problems of the designed nonlinear open-loop correction method, the laser still remains a large amount of nonlinearity after nonlinear correction.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248.4

【参考文献】