基于窄带FBG的宽带可调谐双啁啾微波信号生成  

Wideband Tunable Dual-Chirp Microwave Signal Generation Based on A Narrowband FBG

作　　者：白嘉诚 卢冰 张佳昕 白一凡 郭鹏星 Bai Jiacheng;Lu Bing;Zhang Jiaxin;Bai Yifan;Guo Pengxing(School of Communications and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,China;Institute of Intelligent Communications and Network Security,Chongqing University of Posts and Telecommunications,Chongqing 400065,China)

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065 [2]重庆邮电大学智能通信与网络安全研究院,重庆400065

出　　处：《中国激光》2025年第1期139-149,共11页Chinese Journal of Lasers

基　　金：国家自然科学基金(62001072,12104078);国家自然科学基金区域联合基金(U22A2018)。

摘　　要：基于光纤布拉格光栅(FBG)提出了一种光子学辅助的宽带可调谐双啁啾微波信号生成方案,并通过实验对该方案进行了验证。在所提方案中,光源产生的连续光载波经过马赫-曾德尔调制器(MZM)时被射频信号调制。当MZM工作在最大偏置点时,通过合理设置射频信号的调制指数,可以产生0阶和±2阶光边带。随后,该光信号进入3 dB带宽为17.5 GHz的FBG中实现±2阶光边带和光载波的分离,其中,透射的±2阶光边带进入另一个MZM中被基带啁啾微波信号调制,调制输出的光信号与FBG反射的光载波耦合并进入光电探测器中,生成载频二倍频、带宽二倍频的双啁啾微波信号。实验中产生了中心频率调谐范围为16~28 GHz、带宽为1 GHz、时间带宽积为1000的双啁啾微波信号。所提方案具有系统结构简单、频率调谐范围大的优势,并且产生的啁啾微波信号具有良好的旁瓣抑制能力和脉冲压缩性能。Objective In radar systems,single-chirped waveforms are susceptible to the range-Doppler coupling effect in high-speed moving target detection,which limits the performance of radar target tracking and detection.To overcome the influence of the range-Doppler coupling effect,a dual-chirp microwave waveform is proposed.Recently,electro-optic external modulation-based techniques have become the main schemes adopted in microwave photonic signal generation systems,as they can generate high carrier frequency and large time-bandwidth product(TBWP)dual-chirp signals;however,these schemes face problems such as system complexity(e.g.,using complex devices such as dual-polarization quadrature phase shift keying modulators),implementation difficulty(e.g.,requiring cutting of parabolic signals,power amplification,and other complex processing),and high cost(e.g.,using swept-frequency lasers).Therefore,photonic-assisted wideband dual-chirp microwave signal generation with a large TBWP comprising a fiber Bragg grating(FBG)is proposed and demonstrated experimentally.The scheme generates a high-carrier-frequency,large-bandwidth dual-chirp microwave signal using a simple and low-cost system,and the generated signal exhibits good sidelobe suppression and pulse compression performance.Additionally,this scheme has the advantages of a wide frequency tuning range and tunable signal parameters.It is expected to provide a stable and reliable signal source for future radar systems,with a high joint range-velocity resolution.Methods The wideband dual-chirp microwave signal generation system based on FBG is mainly composed of a laser diode(LD),Mach-Zehnder modulator(MZM),optical circulator,FBG,optical coupler(OC),and photodetector(PD).First,a continuous optical carrier signal from the LD is sent to the first MZM biased at the maximum transmission point(MATP).Subsequently,the±2nd-order optical sidebands and optical carriers are generated by controlling the power of the radio frequency(RF)signal.The modulated output optical signal passes throu

关 键 词：微波光子 雷达系统 光纤布拉格光栅 双啁啾微波信号 大时间带宽积 

分 类 号：O436[机械工程—光学工程]