基于光子学的线性调频微波信号产生技术进展(特邀)  

Progress in Photonics-Based Linear Frequency-Modulated Microwave Signal Generation Technology(Invited)

作　　者：邵帅 杨四刚[1,2] 陈宏伟 陈明华[1,2] Shao Shuai;Yang Sigang;Chen Hongwei;Chen Minghua(Department of Electronic Engineering,Tsinghua University,Beijing 100084,China;Beijing National Research Center for Information Science and Technology,Beijing 100084,China)

机构地区：[1]清华大学电子工程系,北京100084 [2]北京信息科学与技术国家研究中心,北京100084

出　　处：《光学学报》2024年第15期507-521,共15页Acta Optica Sinica

基　　金：国家重点研发计划(2021YFB2800800)。

摘　　要：线性调频(LFM)信号以其具备大时间带宽积的优势已成为现代雷达系统中最为常用的波形之一。因受限于电子瓶颈,传统电学器件在产生高频、大带宽的信号方面已面临诸多挑战。相比之下,微波光子技术以其具有大可用带宽、低损耗、高灵活度等优势现已成为最为可行的替代方案之一。本文首先综述了现有基于微波光子技术产生线性调频微波信号的方案,之后介绍了本课题组提出的一种基于锁相同步光源的信号产生方案。通过构建同步锁相环路实现了直流光源与扫频光源的实时锁定,拍频后实现了低相位噪声和高相参的信号产生。此外,本课题组所提出的信号产生方案还可实现中心频率、带宽和周期的灵活调节,产生的信号可以分别覆盖L至Ka波段。Significance Modern radar systems play crucial roles across various applications including imaging,high-resolution remote sensing,and surveillance.Among radar modulation schemes,linear frequency-modulated(LFM)waveform radar stands out due to its capability to maintain expansive instantaneous bandwidth and high power concurrently.Furthermore,its distinctive dechirp reception technique simplifies data acquisition and processing at the receiver end,requiring only a low-speed analog-to-digital converter(ADC)with a sampling rate below 1 GSa/s,thereby facilitating swift and potentially real-time operations.However,the electrical generation of LFM signals has encountered limitations.Multistage frequency upconversion introduces considerable in-band distortion and temporal jitter,constraining practical applications.Recent strides in microwave photonics technologies have consequently fostered various photonics-based LFM signal generation techniques.These approaches capitalize on photonics’distinct advantages,such as ultra-wide bandwidth,flat response,and immunity to electromagnetic interference.They have been substantiated through experimental validation.Progress The frequency-to-time mapping method(Fig.1)shapes a short optical pulse using a spectral shaper and then maps it using a dispersion element.Once the components are selected,the generated LFM signal typically has a fixed center frequency and bandwidth,with a time-bandwidth product(TBWP)of approximately 100.Microwave photonic frequency multiplication(Fig.2)and spectrum stitching(Fig.4)methods significantly enhance TBWP.These techniques involve either multiplying narrow-band intermediate frequency LFM(IF-LFM)signals or seamlessly stitching them together in the optical domain to create a wideband signal.However,these methods typically struggle to generate signals across a one-octave frequency range and require additional control loops to maintain phase continuity at stitching points.Additionally,the Fourier domain mode-locked optoelectronic oscillator(FDML-OEO)(Fig.

关 键 词：微波光子学 线性调频信号 半导体激光器 光锁相环 

分 类 号：O436[机械工程—光学工程]