光通信网络检测领域光频域反射方法的运用实践探析

随着科技的发展,通信领域的发展是我们所关注的。在光通信网络检测领域使用光频域反射方法是很有必要的。文章主要阐述了光频域反射检测的运用原理和现状以及对光频域反射方法在光通信网络监测领域中的应用。     

光频域反射在光通信网络检测中应用分析

光频域反射计(OFDR)相对于光时域反射计(OTDR)而言,其动态范围与空间分辨率无制约关系,可以在不损失动态范围的情况下获得高的空间分辨率,因而可以被广泛应用于光纤传输特性检测和集成光路诊断等领域.本文分析了OFDR在光通信网络检测中的基本原理、OFDR相对于OTDR的优点,并讨论了限制OFDR使用的各种因素和目前的发展现状.     

基于窄带光纤激光器的光频域反射计研究

光频域反射计(OFDR)是一种强大的光通信网络检测工具,能对光纤中微弱反射进行探测、定位和量化,利用这种特性可以实现对光纤长度的高精度测量。主要介绍了OFDR的工作原理,对OFDR系统的空间分辨率的限制因素进行了讨论,理论分析了空间分辨率与光频调谐范围之间的关系,以及光源非线性扫频对光纤长度测量结果的影响。利用测试干涉仪和辅助干涉仪实现了对光纤的高精度、高空间分辨率的长度测量。     

二维光子晶体偏振分束器的优化设计北大核心

为解决二维光子晶体在光束调整和光束偏转中的应用,采用有限时域差分法和完全匹配层吸收边界条件,通过在结构中引入消反层,从理论上实现基于二维光子晶体的偏振分束器。优化计算表明,通过随光频的改变调节消反层参数,可以实现TE模超过95%的光发生透射,TM模超过95%的光发生反射,从而使TM模与TE模分离。引入消反层的偏振分束器具有尺寸小、透射率高、分束角大和偏振分束率高等优点,在高密度集成光通信系统中有广泛的应用。     

脉冲参量对时间门控光频域反射仪性能的影响

为了对时间门控光频域反射仪系统参量设置进行优化,采用光脉冲压缩原理搭建了时间门控光频域反射仪试验系统,进行了理论分析与实验验证,取得了仿真与实验数据.结果表明,当探测光脉冲信号的峰值功率和本振光信号功率不变时,系统信噪比只与啁啾率相关,且与其成反比;当扫频范围保持80MHz不变时,系统相位噪声随脉宽增加呈现先减小后增大...     

基于超高Q值氟化镁晶体微腔的克尔光频梳产生研究

克尔光频梳具有等距分布的梳状光谱结构,在精密测量、光钟、相干光通信、微波和光学任意波产生、光谱学及天文光谱仪校准等方面有着重要的应用。首先,微腔光频梳与其他光频梳系统相比,具有集成性高、体积小、功耗低的优势,大大扩展了光频梳的应用;其次,通过超精密加工方法制备了品质因子Q值达到了4.8×107的氟化镁微腔,并且得到了干净规律、排列规则的谐振谱,自由频率范围为9.73 GHz,为产生低重复频率光频梳提供了条件;最后,根据实验结果结合Lugiato-Lefever方程分析了氟化镁微腔光频梳的产生过程,研究了泵浦功率对光频梳的影响,通过调整失谐参数得到了孤子态光频梳。并且通过色散调控优化了微腔的光场模式,为产生具有超光滑光谱的孤子光频梳创造了先决条件,提升了光频梳性能。     

布里渊散射分布式光纤传感器

介绍了基于布里渊分布式光纤传感器的进展和发展趋势,以及应用后向布里渊散射测量光纤温度／应变的基本原理。介绍了基于光时域反射仪发展起来的BOTDR（布里渊光时域反射）、BOTDA（布里渊光时域分析）及BOFDA（布里渊光频域分析）分布式光纤传感器的原理及各种实施方案,并指出还存在的问题。     

高分辨率光频域反射计的发展和应用

光频域反射计(OFDR)是一种高分辨率测量仪器,其动态范围大,可应用于各种范围的测量.目前,在国外,OFDR技术已被广泛应用于各个领域,而国内关于这方面的研究和文章还不多.本文介绍了OFDR的基本原理和关键技术.同时,介绍了OFDR在国外的应用和发展现状.     

浅议高分辨率光频域反射计的发展及优点

光频域反射计(OFDR)作为高分辨率测量仪器的主要代表性产品之一,具有动态范围大,测量范围光等优点,被广泛使用于我国的光纤故障监测中,同时也为我国光纤领域的发展和建设提供了有利的保障。文章在分析OFDR技术的基本原理和光源调制方式之后,总结了此项技术的发展现状及优点,以供各位读者参考。     

一种新颖的光通信方式-光频多路复用载波通信

本文根据某些文献报导,首先将光频多路复用(OFDM)载波通信与波分复用(WDM)和相干光通信作了简单的比较,然后对其工作原理和解复用的关键器件——光纤法布里-珀罗(OFFP)调谐滤波器作了说明,最后以两个实验网络阐明其实现过程,指出所具有的通信潜力和广泛的应用前景。     

Calibration of optical modulators by optical down-conversion

A new method for the calibration of intensity modulators and modulated laser diodes at millimeter-wave frequencies is presented. The method uses an integrated-optic modulator as both a mixer and a frequency doubler. To demonstrate the measurement technique an intensity modulator is calibrated over the band 26.5-40 GHz. The measurement system employs no components exceeding 20 GHz (excluding the RF generator), and with relatively minor modifications measurements in excess of 60 GHz are feasible     

光网络中的动态可重构的光分插复用技术

动态可重构的光分插复用器(ROADM)在光通信网络与传感网络中有重要的应用,而且是对目前正在使用的非重构的光网络升级的核心技术之一.超大规模、高可靠性的传感器网络对可重构的OADM需求尤其迫切.结合本课题组承担的863项目的研究成果,对该技术进行介绍.     

Low-noise optical receiver for high-speed optical transmission

This paper describes the design of a low-noise optical receiver using Si bipolar transistors for high-speed optical transmission. The conventional common emitter-common collector circuit (CE-CC pair) and Darlingtou circuit (transimpedance amplifiers with parallel feedback) are studied. Optimal CE-CC pair collector-biasing current for attaining minimum noise current with a 400-MHz bandwidth is 2.7 mA, and less than 1.2 mA for the Darlington circuit. It is confirmed that the Darlington circuit is better than the CE-CC pair in signal-to-noise ratio by about 1.5 dB. The low-noise Darlington optical receiver with a Ge-avalanche photodiode has achieved an optical sensitivity of -41 dBm for a 400 Mbit/s RZ pulse with a bit error rate of 10^-10. This is a 2.5-dB improvement in optical sensitivity over that of the conventional CE-CC receiver.     

Coherent optical tapping using semiconductor optical amplifier

Semiconductor optical amplifiers are attractive not only as optical repeaters but also as functional devices, since carrier density modulation in amplifiers causes a nonlinear phenomenon. Utilizing the effect of the carrier density modulation on the semiconductor optical amplifier junction voltage, a coherent optical tapping is proposed for signal monitoring or control signal extraction. A 155 Mb/s FSK (frequency shift keying) signal tapping was realized with a simple configuration using heterodyne single-filter detection with -24.4 dBm sensitivity. Many applications for this coherent optical tapping are discussed, and basic characteristics for frequency-selective tapping from FDM (frequency division multiplexing) signals and optical amplifier gain control are examined     

利用光学微分预处理的强度光学相关

本文把采用菲涅耳全息滤波器的强度光学相关识别系统与光学微分预处理系统相结合,通过对输入图像进行边缘增强预处理,强度相关器的鉴别能力得到了改善。给出了理论分析和实验演示的结果。     

Nonlinear optical glasses for ultrafast optical switches

In this paper we report degenerate four-wave-mixing measurements of the nonlinear coefficient of rutile and a number of optical glasses at 1.06 μm. We define a figure of merit which measures the suitability of a material for nonlinear waveguide switches and show that the best glasses have figures of merit substantially higher than any other material. We include a brief discussion of the types of switching elements that could be made with these materials.     

Low-noise optical receiver for high-speed optical transmission

This paper describes the design of a low-noise optical receiver using Si bipolar transistors for high-speed optical transmission. The conventional common emitter-common collector circuit (CE-CC pair) and Darlington circuit (transimpedance amplifiers with parallel feedback) are studied. Optimal CE-CC pair collector-biasing current for attaining minimum noise current with a 400-MHz bandwidth is 2.7 mA, and less than 1.2 mA for the Darlington circuit. It is confirmed that the Darlington circuit is better than the CE-CC pair in signal-to-noise ratio by about 1.5 dB. The low-noise Darlington optical receiver with a Ge-avalanche photodiode has achieved an optical sensitiyity of -41 dBm for a 400 Mbit/s RZ pulse with a bit error rate of 10^-10. This is a 2.5-dB improvement in optical sensitivity over that of the conventional CE-CC receiver.     

集成光学声光光通道监测仪的研究

在集成声光可调谐滤波器(IAOTF)的基础上,提出了一种新型的集成光学波导型声光光通道监测仪(OCM).介绍了该OCM的工作原理及其基本结构,对它的插入损耗、响应时间、波长范围、波长分辨率和波长精度等性能指标进行了分析与计算,并对制成的集成光学声光OCM进行了实验研究.理论分析和实验结果表明,该OCM能够对密集波分复用(DWDM)系统多路光信道的工作波长和功率同时进行监测,其插入损耗小于3 dB,响应时间小于7μs,波长监测范嗣达174 nm,波长分辨率可达0.3 nm、波长精度可达±30 pm.     

全光通信中的光开关技术

光开关是实现全光交换的核心器件,光开关的研究已成为全光通信领域研究的焦点。本文首先对光开关的原理进行归纳,总结光开关的应用范围。对传统机械式光开关、微电子机械式光开关、热光开关进行了进一步地划分,分析了它们的结构形式和性能特点。设计了光开关性能评价指标体系,对常见的4种光开关进行了定性与定量对比,指出不同类型光开关的优点和不足之处。最后依据全光通信网的发展趋势,指出大容量、高速、透明、低损耗是光开关的重点发展方向。     

Fusion splicing between optical circuits and optical fibres

Splicing between an optical fibre and a planar deposited silica waveguide was performed by using a CO2 laser as a heat source. The average splicing loss of 30 samples between a multimode graded-index fibre and a deposited silica waveguide was 0.18 dB. Reflection from the joining point disappeared by the fusion splicing.