一种用于测量应变及光损耗分布的高性能OTDR

我们研制出了一种新型的ＯＴＤＲ，它是ＢＯＴＤＲ和ＣＯＴＤＲ的组合，可用于测量沿光纤长度方向的应用及光损耗分布。这种新型ＯＴＤＲ不仅有可能降低光网络系统的维护费用，而且可用来判断大型建筑内的光网络故障。     

用于光纤和光缆生产环境的新型OTDR测试方法

目前光纤和光缆制造商希望能用一台多波长ＯＴＤＲ对光纤和光缆的部分性能进行试验和测量。借助多波长ＯＴＤＲ，可以计算的光纤测试性能有：衰减谱、光纤均匀性和后向散射均匀性。     

光缆长度的精确测量

光纤精确长度的测量是光缆日常维护工作中一个重要手段。本文就如何精确的测量光缆长度及怎样正确使用ＯＴＤＲ仪表以减小测量误差等问题做了介绍。     

光缆长度的精确测量

光纤精确长度的测量是光缆日常维护工作中的一个重要手段。本文就如何精确的测量光缆长度及怎样正确使用ＯＴＤＲ仪表以减小测量误差等问题做了介绍。     

OTDR在光纤线路中的两种基本应用

光时域反射仪（简称ＯＴＤＲ）在光纤线路中，用于监测光缆接续点损耗和光缆故障定位，非常简便、快速，掌握其正确的操作方法，可避免产生误差。１ＯＴＤＲ的使用原理无论哪一种型号的ＯＴＤＲ，其测试原理都是：往光纤中传输光脉冲时，由于在光纤中散射了微量光，返回光...     

德国W＆G公司推出全新OTDR光时域反射仪

德国Ｗ＆Ｇ公司推出全新ＯＴＤＲ光时域反射仪这种新的ＯＴＤＲ测试仪表，一改传统设计，将笔记本ＰＣ与分体式的主机箱结为一体，便携、方便，具有高分辨率和宽动态范围。这种设计有苦干优越性。如在新工程的安装中，光纤通路测量结果可以用笔记本ＰＣ进行记录和处理，也...     

德国W＆G公司推出全新的OTDR光时域反射仪

德国Ｗ＆Ｇ公司推出全新的ＯＴＤＲ光时域反射仪这种新的ＯＴＤＲ测试仪表，一改传统设计，将笔记本ＰＣ与分体式的主机箱结为一体，便携，高分辨率和宽动态范围。这种设计有若干优越性，能获取广泛的不同结果，如在工程安装中，光纤通路测量结果可以用笔记本ＰＣ进行记录...     

布里渊散射在光纤拉伸应变分布测量中的应用

论述了布里渊散射测量光纤拉伸应变的原理,对近年来布里渊光时域反射计法（ＢＯＴＤＲ）和布里渊光时域分析技术（ＢＯＴＤＡ）的研究概况进行了评述,并提出了这些技术尚存的问题和可能的解决办法。     

使用OTDR应注意的几个问题

使用ＯＴＤＲ应注意的几个问题四川省长途线路局技术维护工程处目前在光纤接续过程中主要使用的监测仪表是ＯＴＤＲ（光时域反射仪）。这种仪表具有测试简便、迅速、测试距离准确、测试结果与真实值较接近的优点，是目前普遍使用作光特性测试及光纤接续损耗测试的工具。下...     

使用OTDR应注意的几点问题

本文通过对ＯＴＤＲ在光缆线路测量中出现的常见现象的分析，说明了使用ＯＴＤＲ应注意的几点问题，并指出在新型光纤网络中对ＯＴＤＲ的特殊要求，从而提高了我们的工作效率和处理事件的能力。     

Optical time domain reflectometry on optical amplifier systems

The use of optical time-domain reflectometry (OTDR) on long-span fiber transmission systems containing in-line optical amplifiers is discussed. Having identified the specific requirements for OTDR equipment, measurements were carried out on systems of up to 300 km in length, containing three semiconductor laser amplifiers. The results demonstrate that OTDR can be used not only for fault location on fiber links several hundred kilometers in length but also as an alternative to standard system supervisory techniques, thus providing the potential for minimizing the hardware in the optical amplifier stages of future long-span fiber optic transmission systems     

Fiber-optic reflection measurements using OCWR and OTDR techniques

A method for determining the backscatter and reflection responses of an optical fiber and reflector to an arbitrary input is developed. Two cases are specifically considered: a continuous-wave input and a rectangular pulse input. From the rectangular pulse input response, the equation is derived for computing the reflectance of a discrete component from an optical time-domain reflectometer (OTDR) measurement. Precautions are given for accurately performing reflectance measurements using an OTDR. Two methods are presented for determining the backscatter level of the fiber type under test, and its importance in reflection measurements is shown     

A novel in-service measurement technique using the same wavelength band as SCM signals

This paper proposes a new technique for measuring in-service optical fibers, that uses an optical time domain reflectometer (OTDR). The feature of the proposed technique is that the OTDR light is in the same wavelength band as the video signal, which is distributed by using the subcarrier multiplexing (SCM) technique. In a 40-channel SCM system operating at a signal wavelength of 1.558 /spl mu/m, we show that the required video quality can be maintained, by using the proposed OTDR operating in the 1.55 /spl mu/m band, even though the measured fiber is in service and the OTDR light enters an optical receiver. Moreover, we clarify the conditions for undertaking measurements, without the need for optical filters designed to prevent OTDR light from degrading the SCM signal quality.     

Optical time domain reflectometry in optical transmission linescontaining in-line Er-doped fiber amplifiers

Optical time domain reflectometry (OTDR) in an optical transmission line containing in-line Er-doped fiber amplifiers is investigated. The proposed Er-doped fiber amplifiers are based on optical circulators, which support both OTDR and digital signal transmission. The measurable limit of OTDR fault location in optical transmission lines containing in-line amplifiers is discussed. Fault location and 1.8-Gb/s digital signal transmission are demonstrated in a 316.9 km, optical transmission line constructed with three in-line Er-doped fiber amplifiers     

High-accurate fault location technology using FSK-ASK probebackscattering reflectometry in optical amplifier submarine transmissionsystems

This paper proposes a new modulation format for optical time domain reflectometry (OTDR) to eliminate optical surge and improve OTDR performance in optical amplifier submarine transmission systems. The modulation format, FSK-ASK, uses a short high-power probe pulse and a long dummy pulse. Thanks to the slow gain dynamics of erbium-doped fiber amplifiers, both pulses experience an identical gain, equal to the loss of a span, so that the probe pulse maintains its high power and does not develop into an optical surge. Fault location experiments verify a theoretical prediction that FSK-ASK improves the signal-to-noise ratio (SNR) of OTDR by an amount as large as the power ratio of the probe to dummy signal. They also confirm the elimination of the optical surge caused by conventional OTDR using a solitary probe pulse. An FSK-ASK OTDR is applied in a commercial submarine amplifier transmission system which has a total transmission length of 890 km and a repeater spacing of 90 km. These field trial results show that subtle fiber anomalies can be located, with a spatial resolution of 1 km, along the entire length of the amplifier transmission system from a terminal end     

光纤布里渊温度和应变同时传感系统性能分析

采用基于朗道比的微波外差检测技术的布里渊光时域反射传感系统,获得布里渊散射信号的频移和强度,可以精确地测量沿光纤长度的分布式温度和应变信息。此方法在同一条光纤线路上分别测量光纤的布里渊散射和瑞利散射,且使用布里渊频谱扫描对信号进行处理。给出了这种传感方案的实验系统,并在理论推导的基础上对其性能进行了分析,该传感系统可以获得1℃的温度分辨率和100uε的应变分辨率。     

Low-cost high-resolution time-domain reflectometry for monitoringthe range of reflective points

A new OTDR technique to interrogate the range of reflective markers in an optical fiber (or an electrical cable) is presented. The technique has been developed to monitor strain in sections of a fiber over gauge lengths of several meters. Signal-to-noise analysis shows that current OTDR systems do not fully exploit the spatial resolution theoretically available. The available resolution is explored with a new OTDR technique     

OTDR in optical transmission systems using Er-doped fiber amplifiers containing optical circulators

Fault location in optical amplifier transmission systems is described. Optical time-domain reflectometry (OTDR) cannot be used for an optical transmission line containing traditional Er-doped fiber amplifiers (EDFAs) because they contain optical isolators. The authors propose an OTDR scheme that uses new EDFAs containing optical circulators and return transmission lines. The new EDFAs support both OTDR and digital signal transmission. A 280.9 km transmission line containing three of the proposed EDFAs was constructed and tested. Experimental results demonstrated the feasibility of OTDR fault location and 1.8-Gb/s digital signal transmission.<>     

基于双向OTDR测试的光传输网实时监测系统

基于现有的光信号处理技术、网络技术以及OTDR等设备设计并实现光传输网实时监测系统,提出基于双向OTDR测试来解决OTDR在长距离测量光缆线路时动态范围受限的问题,同时结合采用GIS等技术开发的光缆线路管理系统(FMMIS),进行对光传输网络的实时监测,实现了光纤中断故障的自动精确定位。     

1.5-μm-band optical time domain reflectometer for single-modeoptical fiber using a P2O5-highly-doped fiberRaman laser

A wide-dynamic-range 1.5-μm-band optical time-domain reflectometer (OTDR) for single-mode optical fibers using a P₂O₅-highly-doped fiber Raman laser light source and a cooled Ge-p-i-n photodiode is realized for the first time. The stimulated-Raman-scattering properties of P₂O₅-doped single-mode fiber are investigated. Using this fiber and an Nd:YAG laser operating at 1.32 μm, a high-power light pulse at 1.59 μm is generated with high efficiency. Using the stimulated-Raman-scattering light as the light source and a high-sensitivity optical receiver, a 1.5-μm-band OTDR having a one-way dynamic range of 35 dB is realized