共查询到20条相似文献,搜索用时 156 毫秒
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提出并实验验证了一个四通道的基于啁啾光栅的连续可调光控延时系统,该系统适合于频率达10 GHz的相控阵天线的波束形成及扫描,使用一种基于啁啾光栅的延时网络和一种新型的波长等间隔增大或减小的多波长可调谐线性腔光纤激光器.光纤激光器的等波长间隔,通过相等增量的作用力挤压或拉伸激光谐振器中固定在一个有机塑料盘上成一定的角度相邻的布拉格光栅来调谐.光控延时是通过被调制光在一个线性啁啾光栅的不同位置反射而实现,波长等间隔激光可获得等间隔的延时. 相似文献
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啁啾光纤光栅是用于偏振模色散补偿的重要光无源器件。本文对基于两个啁啾光纤光栅的偏振模色散补偿系统进行了分析。重点分析了啁啾光纤光栅的一阶啁啾系数c1和两个光栅之间的有效折射率差△n变化对系统补偿特性的影响,并进行了数值仿真。 相似文献
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啁啾长周期光纤光栅的滤波特性研究 总被引:1,自引:0,他引:1
基于光纤光栅耦合模理论,采用传输矩阵法对啁啾长周期光纤光栅的啁啾系数和光栅参量(光栅长度、光栅周期和折变量)对其滤波特性的影响进行分析。当啁啾系数处于-0.000008~-0.0004 nm/cm范围内时,可用于宽带带阻滤波器。当啁啾系数处于-0.05~-1 nm/cm范围内时,可用于多通道窄带滤波器。为啁啾光纤光栅滤波器的优化设计提供理论依据。 相似文献
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本文用传输矩阵法分析了啁啾Bragg光纤光栅的反射谱特性及时延特性,同时给出了用142mm长相位掩模板和扩束技术研制的色散补偿线性啁啾Bragg光纤光栅的反射谱特性及传输实验结果.实验研制的线性啁啾Bragg光纤光栅样品带宽为0.56~0.84nm,可实现对普通光纤色散补偿100km以上. 相似文献
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在以基于光纤布喇格光栅( F B G) 传感器的基础上,介绍了啁啾光纤光栅( C F G) 的光学特性和基于啁啾光纤光栅的光栅内传感的概念以及在此基础上实现传感的途径 相似文献
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Tunable Chirped Fiber Grating Based Variable Time-Delay Network for Phased-Array Antenna Beamforming
Jianliang Yang Yunqi Liu Swee Chuan Tjin Nam Quoc Ngo 《Journal of Infrared, Millimeter and Terahertz Waves》2003,24(4):593-601
In this paper, we present a photonics continuous beamforming system for optically controlled phased-array antenna based on a tunable fiber ring laser source and a novel variable true-time delay network consisting of one single-mode fiber delay line and four tunable chirped grating delay lines. The chirp rate of each chirped grating is tuned by bending a uniform fiber Bragg grating (FBG) bonded at a slant onto the lateral surface of a simply supported beam. This kind of variable true-time delay network can provide five-channel time-delayed signals that can be fed to an antenna array to achieve continuously beam scanning. The proposed true-time-delay unit with 5-element phased array steerer is suitable for phased-array antenna beamforming at frequencies up to 12 GHz. 相似文献
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Jianliang Yang Yunqi Liu Sweechuan Tjin Jianping Yao 《Journal of Infrared, Millimeter and Terahertz Waves》2002,23(8):1241-1250
A photonics true-time-delay system for phased array antenna beam steering employing a novel tunable chirped fiber grating delay line and a multi-wavelength erbium-doped fiber ring laser source based on a sampled grating filter is proposed. The tunable chirped fiber grating, which act as a continuous time-delay element, is achieved by bending a uniform fiber Bragg grating bonded at a slant onto the lateral surface of a simply supported beam. This technique allows the dynamic control of the chirp rate and spectral width of the grating without center wavelength shift. By adjusting the chirp rate of the fiber grating via bend strain, this kind of tunable chirped fiber grating could achieve very low and adjustable delay times, therefore provides higher angle resolution for scanning microwave beam, even the wavelengths of laser source are fixed and un-tunable. The true-time-delay system using proposed tunable chirped fiber grating delay element and sampled grating based laser source is constructed and demonstrated experimentally. 相似文献
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采用无色散特性的模拟或数字移相器会导致天线波束指向随频率发生变化,即相控阵天线的孔径效应。工程上一般在子阵级别上采用色散特性的实时延迟线拓展相控阵天线瞬时带宽,但是子阵级延时量化误差会产生周期性栅瓣,导致天线副瓣性能恶化。文中提出在通道(或多通道收发组件)上设置小位延迟线、与子阵级大位延时线叠加使用,消除或改善子阵级延时误差造成的性能恶化。结合X波段有源二维阵列天线,对单元级、子阵级、子阵+单元两级三种情况进行了仿真。仿真结果表明,子阵+单元两级延时方法在扩展相控阵天线瞬时带宽的同时,能明显改善相控阵天线的副瓣特性,且具有较强的工程可实现性。 相似文献
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The authors have demonstrated an optical fibre grating based delay line which produces time delays in increments as small as 31 ps. The device could provide a true time delay component for a phased array antenna 相似文献
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《Optical Fiber Technology》2000,6(2):91-108
Methods for wideband photonic signal processing using fiber delay lines and Bragg grating sampling elements are described. These processors provide new capabilities for the realization of high time-bandwidth operation and high resolution performance. Multiple wavelength techniques with discrete and chirped Bragg gratings are described, which have high capacity signal processing functions using dense parallel signal processing techniques. Both fixed and tunable or reconfigurable processors using wavelength control to change the sampling time are discussed. A range of grating-based signal processors, including high Q microwave filtering, frequency discriminators, widely tunable filters, fast and adaptive signal correlators, and true-time delay beamforming in phased array antennas are described. 相似文献
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微环作为一种典型的平面光波导回路,具有结构紧凑、性能可靠等特点,而用其制成的波导延时芯片集成度高、体积小,与其他光延时器件相比,更适合于贴近阵面安装。因此提出了一种基于阵元级微环延时、子阵级光纤延时的宽带相控阵天线系统,并在均匀线阵的情况下,对所提天线系统进行了数学建模和性能仿真。由仿真结果可知,与一般的阵元级移相、子阵级光纤延时的相控阵系统相比,所提系统能够更有效地满足电子对抗宽带宽角扫描的需求。 相似文献
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光实时延时技术与相控阵技术的融合,解决了传统相控阵雷达的瞬时大带宽受限和波束偏斜问题.文中给出了光实时延时技术的思想,讨论了光实时延时技术出现的背景.分析了应用于光实时延时技术中的光纤光栅的原理,着重讨论了均匀光纤光栅和线性啁啾光栅,分别给出了基于两种光纤光栅的光实时延时的技术方案,在此基础上,讨论了受控于应变和温度的光纤光栅在光实时延时技术中的应用.最后讨论了一些技术上存在的问题.Abstract: Optical true time delay technology (OTTD) is the key technology for phase array antennas (PAA).By using OTTD,the beam squint and the restriction of instantaneous bandwidth are resolved.The principles of OTTD are given,the emergence background of OTTD is discussed.The theory of fiber Bragg grating(FBG) used in OTTD is analyzed,especially on uniform fiber bragg grating and linear chirped fiber Bragg grating.Two OTTD schemes based on FBG is presented,then some new kinds of FBG used in OTTD are discussed.Some technique hurdles are analyzed as well. 相似文献
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光控相控阵雷达中的真延时技术 总被引:2,自引:0,他引:2
在介绍光控相控阵雷达相对于传统相控阵雷达的优势所在及其发展历程的基础上,阐述了光控相控阵雷达工作的基本原理和实现光控相控阵雷达的手段——真延时。介绍了现阶段国内外实现真延时的方法,通过归纳将真延时结构分为两类,具体分析了两类结构中各种真延时结构的组成、实现方法、工作原理以及现阶段运用在光控相控阵雷达中能够达到的性能指标。 相似文献