采用可调谐激光器提高光纤延迟线精度的研究

为了提高一种3bit可变光纤延迟线的延时精度,提出一种采用可调谐激光器作为系统光源的技术,利用光纤的材料色散特性即光纤的折射率随传输波长变化而改变的特点,来改变延时光纤中信号存储的时间,从而达到提高光纤延迟线延时精度的目的。仿真结果表明,采用该种技术的光纤延迟线系统,平均延时误差从4.1ps下降到了1.3ps,延时精度得到了显著提高。     

相位调制平行光延迟器的微波高精度测量

提出了一种新的相位调制平行光延迟器,使用双电极马赫-曾德尔调制器进行高精度测量微波信号到达角及等效到达时间差,建立了一个理论模型来分析系统的测量精度监控。空间时延测量转换成两个微波信号之间的相移,精度监测的结果显示,对从5°~165°相移的测量误差小于3.1°,具有重要的应用价值。     

基于偏振态变化时延估计的分布式光纤传感系统

提出一种基于偏振态（SOP）变化时延差估计的分布式光纤传感系统。本系统采用两个直流光信号在传感光纤中双向注入,振动会对正向和逆向光造成SOP变化,在各自的尾端利用起偏器检测SOP变化并转换为光强信息。两路信号间的时延差表明了振动的位置信息。对时延差形成的原因进行了理论分析,并阐明利用互相关算法计算该时延差并进行分布式传...     

A high precision low dropout regulator with nested feedback loops

A high precision low dropout regulator (LDO) with nested feedback loops is proposed in this paper. By nesting a zero-tracking compensation loop inside of the negative feedback loop comprising an error amplifier, the independence of off-chip capacitor and effective series resistance (ESR) is ensured for different load currents and operating voltages. This circuit is designed and fabricated using a standard CMOS process. The die area is a . The measurement results show that the total error of the output voltage caused by line and load variations is less than ±3% in low quiescent current (Iddq) or low voltage scenarios. Besides, the smallest dropout of the LDO, 0.11 V, while the output current is 165 mA, the output load is and 20 in parallel.     

基于SDH网络的高精度授时研究

针对目前基于数字同步体系(SDH)网络的长距离时 频同步精度不高、不易与现有网络相融合等问题,提出了一种采 用桥接测量方式拓展SDH网络无源双向比对授时距离的新方法。分析了桥接测量法的中间站 时延测量误差。搭建了220km的4节点SDH实验网络,通过桥接测量法 跨越两个 SDH网元设备,利用桥接站时延数据的测量结果对终端时钟实施伺服控制,使其跟踪于 主站时钟。授时 系统的同步误差峰-峰值为965ps,均方差为117.7ps。实验结果表明,使用桥接测量和时钟伺服技术不但能有 效拓展授时距离,而且能在SDH网络终端再生与基准时钟高度同步的时间频率信号,达到较 高的授时精度水平。     

An integrated high resolution CMOS timing generator based on anarray of delay locked loops

This paper describes the architecture and performance of a new high resolution timing generator used as a building block for time-to-digital converters (TDC) and clock alignment functions. The timing generator is implemented as an array of delay locked loops. This architecture enables a timing generator with subgate delay resolution to be implemented in a standard digital CMOS process. The TDC function is implemented by storing the state of the timing generator signals in an asynchronous pipeline buffer when a hit signal is asserted. The clock alignment function is obtained by selecting one of the timing generator signals as an output clock. The proposed timing generator has been mapped into a 1.0 μm CMOS process and an r.m.s. error of the time taps of 48 ps has been measured with a bin size of 0.15 ns. Used as a TDC device, an r.m.s. error of 76 ps has been obtained, A short overview of the basic principles of major TDC and timing generator architectures is given to compare the merits of the proposed scheme to other alternatives     

基于高双折射光纤环镜的可调谐光滤波器

为了得到具有全光纤结构和中心波长可调谐的光滤波器,采用3阶高双折射光纤环镜,提出了一种电磁力的悬臂调谐单元构成的新型可调谐光滤波器,对环镜传输过程和悬臂调谐单元原理进行了理论分析,通过控制悬臂调谐单元的输入电流,实现了滤波器通带的调谐。结果表明,该滤波器具有调谐灵活、输出光谱精细等特点,可应用于不同波长光波的选频输出。     

高精度倒车雷达系统设计

采用超声波测距原理,由装置于车尾保险扛上的探头发送超声波,遇到障碍物,产生回波信号,传感器接收到回波信号后经控制器进行数据处理,从而计算出车体与障碍物之间的距离,判断出障碍物的位置,再由1602显示器和蜂鸣器声发出警示信号,从而使驾驶者倒车时不至于撞上障碍物。基于此,计划自主设计开发一种主要用于售后市场的、结构简单、制作方便、成本低廉的倒车雷达。     

高精度超声倒车雷达的设计

为解决超声倒车雷达指向性不足和存在探测盲区的缺点,设计使用步进电动机驱动小波束角超声传感器做扇形扫描探测的办法.设计中使用步距角为7.2°的步进电动机驱动波束角为5°的超声传感器在每一个步进角度上进行测距.结合测距的角度和测得的距离就可得到准确的障碍物位置信息.并且,由于传感器的有效探测角度大于电机的步进角度,所以每一...     

Research on image encryption based on Erbium-doped fiber laser system with optical delay feedback

A novel image encryption algorithm that based on Erbium-doped fiber laser with an optical delay feedback (ODF-EDFL) system is proposed in this paper. First, by the dynamic analysis of this system, two different chaotic sequences are generated. Meanwhile, the statistic characteristic is verified on this chaotic sequence. On this basis, the image encryption algorithm is designed by using this chaotic sequence: the gray value of the original image is substituted with the chaotic sequence at beginning; then the space array of the image's pixel is mixed up by using both two chaotic sequences. The experimental results show that the proposed method can encrypt digital images quickly and effectively.     

光纤延迟线编/解码器的研究

在光码分多址（ＣＤＭＡ）通信中,光延迟线编／解码器是实现全光编／解码的关键技术．本文对并行结构的光纤延迟线编／编码器的原理及构造方法进行了分析,并给出相应的实验结果。     

A 5 bit fiber delay line based on magneto-optic switch

In order to fulfill the reliability requirements in field application, the high reliability magneto-optic (MO) switches are used to realize an optical true time delay (OTTD) line. This paper first analyzes the characteristics of MO switch, then the topologies of OTTD are analyzed. Latter, two key supporting aspects are put forward, including measuring method and integrated structure design. In this article, we present and demonstrate a 5 bit optical fiber delay line (FDL) based on MO switches and fiber. The FDL exhibits the maximal delay error of 2.98 ps in 32 states.     

X波段光纤延迟线光纤分系统的设计与实现

光路部分是光纤延迟线信号延迟的主要组成部分, 为了降低光学损耗、提高系统性能 、精简优化组成结构,提出了一种X波段光纤延迟线光纤分系统的设计方案。首先进行系统 整体结构设计,结合光纤的膨胀效应及改进后的马库塞公式,建立了光纤的弯曲半径模型并 进行分析计算。然后依据计算结果,针对光纤长度及实际生产精度等对光路部分的主体结构 进行了设计与实现、对绕制光纤的传输特性进行了理论分析及计算。最后,将光纤分系统放 入系统整体结构 中,利用矢量网络分析仪对系统的传输性能进行了测试分析,结果表明,光 纤的插入损耗在－38.56 dB到－39 dB之间、 幅度平坦度≤±1.5 dB、温度漂移时的增益变化幅 度小于±1dB,系统性能稳定、工作可靠,基本满足光纤延迟线信号传输的指标及误差范围 。     

基于高非线性光纤中SBS效应的慢光系统

实验研究了高非线性光纤(HNLF)中受激布里渊散射(SBS)的阈值、增益谱、放大特性及其慢光特性,并与普通单模光纤(SMF)进行了对比分析。测量实验表明,HNLF在线宽100MHz的泵浦激光作用下,SBS的阈值为60mW,增益带宽为150MHz,获得的最大慢光延迟量将近15ns,延迟谱与增益谱较好对应。对基于SBS的未来全光通信系统中的高性能光延迟线或全光缓存器具有重要的参考价值。     

Optical delay lines based on optical filters

Optical delay lines have some important applications, notably in optical communication systems and in phased arrays. These devices are based on the concept of optical group delay, which, in turn, can be understood as the property of an optical filter. Optical filters are well-understood devices and, in particular, their dispersive properties determine the group delay response. We review these dispersive properties and point out some of the inherent tradeoffs involved in generating large group delay. Fiber Bragg gratings and recent results on optical all-pass filters are used as examples     

A high-resolution compact optical true-time delay beamformer using fiber Bragg grating and highly dispersive fiber

A high resolution optical true-time delay (OTTD) beamformer constructed by fiber Bragg grating (FBG) and highly dispersive fiber (HDF) is presented. It can produce the true time delay with the resolution of 1 ps. Besides the proposed system has compact structure and light weight even when a large number of antenna elements are present in a practical antenna array, this is because the used FBG fibers and HDFs are short and independent of the antenna element number. Theoretical analysis and numerical simulations are made. Proof-of-concept experiment results that demonstrate the feasibility of the system are presented.     

基于双光纤耦合的微深孔测量方法

为了解决微深孔的精密测量问题,介绍了一种基于双光纤耦合原理的微深孔测量方法.该方法属于瞄准触发式测量方法,通过双光纤耦合器及显微物镜将光纤传感器触测头在微深孔内的微小位移量转变为CCD图像捕捉系统的横向位移量,利用图像空间定位算法得到CCD上的光斑中心位置.由CCD上光斑能量中心位置与传感器触测点在空间位置的一一对应关系即可得出传感器触测头在孔内部与孔壁的接触状况,从而实现对被测孔测量时的高精度瞄准.光纤传感器瞄准后将发出信号给测量长装置,如双频激光干涉仪,以实现对微深孔的精密测量.最后运用该方法对直径为0.2 mm、深2.0 mm深盲孔的直径进行了测量,其测量结果的重复不确定度优于0.4 μm.同时运用该方法对直径为0.3 mm、深110 mm的微深孔的圆柱度进行了测量.