中功率Ku波段光纤延迟线

介绍了光纤延迟线的工作原理.详细叙述了中功率Ku波段光纤延迟线的研制过程,其中包括:光发射模块、光接收模块、低噪声前置放大器、中功率线性放大器的研制及整个系统链路的设计链接调试等.最后给出了中功率Ku波段光纤延迟线的测试结果.     

光纤延迟线应用研究动态

对目前正成为研究热点的光纤延迟线(FDL)进行了原理和结构特点的分析,总结了光纤延迟线的分类,对光纤延迟线的3个重要应用领域作了详细的跟踪研究.在光纤传感与光学测量领域,分析了激光器线宽测试系统、晶体双折射参数测量系统、光相干层析成像(OCT)测镀系统及光相关光谱术(OCS)测量系统,指出了光纤延迟线在这些系统中的丰要作用及参数设置;存光纤通信领域,从原理和系统结构上莺点分析了高速脉冲串发生器、光缓存器及光编/解码器,指出了目前存在的问题;在微波光子学领域,详细分析了多频光振荡器、微波光纤延迟线、光A/D转换器及光信号相关处理器.指出了关于光纤延迟线技术的最新研究方向主要足提高延时精度、实现连续可调、减小插入损耗和提高工程可靠性.解决这些问题是光纤延迟线实用化的关键所在.     

基于微波光子学的光载超宽带信号产生和传输技术

光载超宽带技术因兼具超宽带信号大带宽、传输速率高等优点和光纤传输的远距离传输、损耗小等优势而在近年来备受关注。文章提出一种基于微波光子技术产生超宽带(UWB)信号的系统,该方案基于非线性PM-IM转换,产生一阶超宽带信号,然后又用平衡光电探测器(BPD)和光延迟线构建延迟线滤波器对其进行一阶差分,产生了符合美国联邦通信委员会(FCC)掩膜要求的二阶超宽带信号。系统最终产生的二阶超宽带信号的频谱具有大约5.4 GHz的中心频率和4.3 GHz的10 dB带宽。另外,还提出了一种基于直接序列-二进制相移键控调制(DS-BPSK),并使用卷积编码进行信道编码,然后使用啁啾布拉格光栅对信号进行色散补偿的信号处理技术。通过Opti-system软件进行仿真验证,在前向纠错门限为3.8×10^-3时,接收机灵敏度提升了约5.5 dBm,有效降低了误码率,提升了光载超宽带系统的传输性能。     

光纤技术在雷达中的应用

光纤技术、光电子器件和微波集成电路技术的发展，为光纤微波模拟信号传输开辟了道路。本文介绍了微波光纤链路和光纤延迟线及其在雷达和电子战方面的应用。     

光分组交换网络中光纤延迟线缓存技术

光分组交换网是全光网络发展的必然趋势.然而,光分组交换网络发展的瓶颈是光缓存技术.目前,在光域比较现实的还是采用光纤延迟线(FDL)作光缓存.重点研究了光纤延迟线光缓存技术,对FDL光缓存技术进行了深入的分析和归纳,并对每一种光纤延迟线光缓存调度策略的优缺点都进行了细致的分析.最后指出了光纤延迟线光缓存技术的未来研究重点和发展方向.     

超宽带微波近场目标探测成像实验系统

基于超宽带脉冲源和高性能采样示波器,配以自行研发的超宽带收/发组合探头、脉冲触发与数据采集控制模块,研制了一套超宽带微波近场成像实验系统.实验系统中采用了结构紧凑的超宽带收/发组合探头,易于实现系统校准和数据采样.通过改变探头的位置,采集多组在不同发射角度下的目标回波信号,对其进行信号预处理,去除直达波等环境因素影响,利用微波共焦成像算法进行目标成像.对嵌于聚氯乙烯泡沫中直径为10mm的片状金属目标的成像结果表明,本成像系统能给出目标大小和位置等信息,所使用成像方案具有较高的可行性,为下一步研制应用于早期乳腺癌检测的超宽带微波成像系统奠定了基础.     

X波段可编程光钎传输微波延迟系统

介绍了X波段可编程光纤传输微波延迟系统的基本工作原理及系统组成。叙述了该系统的研制过程,包括:光发射模块、光接收模块和光纤延迟链路的设计。微波延迟系统具有低插入损耗、低延迟相关损耗,输出幅度稳定,快速延迟切换速度(<0.5 ms)等优点以及单板机编程和计算机控制界面。该延迟系统传输微波频率范围:9~11 GHz,延迟时间范围为1.013 3~1.646 7μs,延迟精度为0.5 ns,延迟时间可以在1.013 3~1.646 7μs范围内步进调节,延迟时间控制实现了计算机控制。     

基于BAW微波延迟线的雷达距离标定模块研制

针对目前雷达距离零点标定存在的问题,提出了一种基于声体波微波延迟线构成的雷达距离标定模块的方案,以及在设计上降低声体波(BAW)微波延迟线插入损耗,增长延迟时间,扩展工作频率范围的方法,并以此研制了一种能用于多种雷达的通用距离标定模块。实际测试结果表明,基于声体波微波延迟线构成的雷达距离标定模块测试精度高、对场地要求低,可广泛用于雷达生产和维修。     

微波光纤延迟线技术研究

介绍了微波光纤延迟线的原理和特点，并对微波光纤延迟线的性能（灵敏度，动态范围等）进行了详细的分析计算，当前，微波光纤延迟线已实用化程度，可广泛应用于雷达和电子对抗领域。     

光纤微波延迟线在逆合成孔径雷达中的应用

由激光二极管组件，波导调制器，光纤传输线，高速接收二极管组件和偏置网络为核心组成的光纤微波延迟线系统是逆合成孔径雷达中信号处理的重要手段，文章介绍光纤微波延迟线系统设计，性能测试分析，展望今后发展前景。     

基于光传输的精密标准延时模块设计

该文在分析了基于光传输的延时系统原理的基础上,介绍了精密标准延时模块的组成。对模块的发射、传输、接收和放大等组成部分进行了理论分析和实际设计,重点讲述了光纤链路及逻辑控制的设计和实现。介绍了该模块时延特性测试系统的组成和搭建,并通过矢量网络分析仪对设计完成的光延时模块实物进行标准延时测试,分析对比测试结果,得出测量误差,并分析误差原因。该模块的实现为某系统的自校准提供了标准延时参考,同时可作为便捷有效的溯源手段。     

Tunable microwave photonic filter based on a fiber ring and erbium-doped fiber amplifier

The tunable microwave photonic filter based on a fiber ring and erbium-doped fiber amplifier （EDFA） was proposed. By introducing a section of erbium-doped fiber （EDF） into the fiber ring, the loss of the signal can be compensated by the EDFA gain through adjusting the pump power. This can largely increase the number of the effective sampling taps, and then improve the performance of the microwave photonic filter notably. When the pump power was set to be 42.7 roW, a microwave bandpass filter with the 3-dB bandwidth of 0.15 MHz, the Q factor up to 100 and extinction ratio up to 20 dB was achieved. By employing a tunable optical delay line in the above fiber ring, a tunable microwave photonic filter has been realized through tuning the length of the optical delay line. The proposed tunable microwave photonic filter can fred great applications in microwave signal processing and ROF system.     

Recent progress in optical amplifiers

State of the art optical amplifier technologies are reviewed focusing on research at ntt. The following developments will be described : an erbium-doped silica fiber with a very high gain coefficient of 11.0 dB/mW, a very small (volume : 36 cc) fiber amplifier module pumped by a 980 nm InGaAs laser diode, an Er-doped fiber amplifier pumped by an AlGalnP visible laser diode, praseodymium-doped fluoride glass fiber amplifiers operating in 1300 nm band, silica-based erbiumdoped planar lightwave circuit amplifiers, and their applications in various optical transmission and measurement systems. The future trends in the optical amplifier research are also described.     

Mining the optical bandwidth for a terabit per second

A significant part of optical-fiber capacity can be tapped now that optical amplifiers can boost many high-speed channels simultaneously. The erbium-doped optical fiber amplifier opened the floodgates to wide-bandwidth, all-optical schemes for multiplexing many wavelengths. Until the advent of the erbium-doped fiber amplifier, no practical all-optical amplifier existed. Optical signals were instead regenerated electronically to overcome the attenuation inherent in the silica fiber as well as other losses due to optical components along the line     

多抽头宽带光纤延迟线的设计与分析

提出一种具有实用价值的步进延迟可调的多抽头宽带光纤延迟线。首先简要介绍了光纤延迟线的优点、工作原理和基本结构,分析了光纤延迟线的增益、带宽、动态范围和失真指标,着重分析了多抽头宽带光纤延迟线的光纤分配网络的设计和实现。最后对设计的多抽头宽带光纤延迟线进行了测试,给出了测试方法和测试结果,并将它同国际、国内其他同类产品做了对比,描述了它的应用前景和应用领域。     

Generation and wavelength switching of picosecond pulses by optically modulating a semiconductor optical amplifier in a fiber laser with optical delay line

A novel actively mode-locked fiber laser having a semiconductor optical amplifier playing the roles of both a gain element and an optically controlled mode-locker and eight cascaded fiber Bragg gratings playing the role of the wavelength selecting element is proposed and demonstrated. Stable amplitude equalized pulse trains with a pulsewidth about 43 ps at 2.5 GHz have been obtained by injecting optical control signals into the laser. Wavelength switching among eight wavelengths is achieved by merely tuning an intracavity optical delay line. This all-optical generation and wavelength-switching scheme should be useful in applications where picosecond pulse trains at high repetition rates are desired.     

Analysis of a novel optical fiber interferometer with common modecompensation

An optical fiber interferometer formed when the unused output of a fiber Mach-Zehnder interferometer is fed back through a length of fiber to the unused input port is discussed. For sensor applications, the resulting optical circuit combines many features of a Mach-Zehnder with the high measured sensitivity of a resonant fiber recirculating delay line. This analysis shows that suitable choice of path lengths preserves high measurand sensitivity, yet it permits complete common-mode compensation in which the effects of all perturbations which uniformly affect the interferometer vanish     

Bidirectional optical amplifier for time transfer using bidirectional WDM transmission

In this letter, we propose a bidirectional optical amplification scheme for fiber-optic time transfer based on bidirectional wavelength-division multiplexing (WDM) transmission. The proposed scheme employs single unidirectional erbium-doped fiber amplifier (Uni-EDFA) for commercial optical networks to implement bidirectional optical amplification. Since including isolators, the effect of backscattering due to the accumulated amplification can be efficiently suppressed by the proposed amplifier. The proposed scheme is validated over different length fiber links in laboratory. Experimental results show that the proposed amplifier can support fiber-optic time transfer over several thousands of kilometers with an additional bidirectional delay difference fluctuation at picosecond magnitude.     

传输序列干涉型光纤传感阵列

本文提出了一种新型干涉型光纤传感器复用系统。传感阵列部分采用光纤环路延迟线序列,并通过接收端的补偿干涉仪实现干涉效应和信号检测。具有结构简单、系统光功率利用率高、损耗低及高灵敏度、低串话等优点,适于大型传感器阵列应用。