基于电光调制和线性调频去斜的微波光子测距研究

RESEARCH ON MICROWAVE PHOTONIC RANGING BASED ON ELECTRO-OPTIC MODULATION AND LINEAR FREQUENCY MODULATION DE-CHIRP

传统的电磁测距受到电子学瓶颈的局限,难以进一步提升工作带宽,导致系统的测距精度受限。本文提出了一种基于电光调制和线性调频去斜的微波光子测距方法,利用马赫-曾德尔调制器获取±1阶调制光边带,通过光电探测产生二倍频的宽带线性调频发射信号,可有效提升系统的距离分辨率;在接收端采用线性调频去斜接收的方法,通过探测中频信号的频率反演获得目标距离信息,可极大地降低对后续模数转换器采样速率的要求。该研究将电光调制、光电探测等基础知识实际应用到微波光子测距中,与科学前沿有机结合,有助于拓展教学内容、提升教学深度,有利于培养学生的科学素养和实践能力。

The traditional electromagnetic ranging is limited by the bottleneck of electronics,and it is difficult to improve the working bandwidth further,leading to the finite accuracy of system.In this paper,a microwave photonic ranging method based on electro-optic modulation and linear frequency modulation de-chirp is proposed.Mach-Zehnder modulator(MZM)is used to obtain the±1 order modulated sidebands,and the linear frequency modulation(LFM)emission signal with doubled frequency is generated by photoelectric detector,which can effectively improve the range resolution of the system.In the receiver,the linear frequency modulation de-chirp is applied to obtain the target distance via the frequency of the acquired IF signal.Therefore,the requirement on the sampling rate of the subsequent analog-digital converter(ADC)can be greatly reduced.The basic knowledge about electro-optic modulation and photoelectric detection is applied to microwave photon ranging,combining with the scientific frontier.This is helpful to expand the teaching content,enhance the depth of teaching,and cultivate students’scientific literacy and practical capability.