光纤通信系统与LWC—1型光纤通信实验装置

一、引言光纤通信是70年代发展起来的新兴技术,是未来信息社会的一项基础技术。光纤通信系统中包含了光调制、光解调和光电转换等多项技术,还包括对光导纤维的传光原理、物理特性的研究等等多方面的知识。因此,把这项新技术内容纳入教学中以便扩大学生的知识面,使学生对高科技领域之一的光纤通信技术的基本原理有一个初步的了解是基础教学的重要任务。为了达到上述目的,我们对实际工程上比较复杂的光纤通讯     

光纤通信系统中偏振模色散自适应补偿实验研究

成功地研制了光纤通信系统偏振模色散的自适应补偿实验系统.实验中采用特定频率分量功率取样作为反馈信号,采用一种名为PSO(Particle Swarm Optimization)的优化方法作为反馈控制算法.偏振模色散的补偿量达30 ps,自动跟踪补偿时间为1～2 s,实现了准实时自动跟踪补偿.     

全光纤通信系统中的偏振激光器

报道了一种简单、实用的解决全光通信中的光源偏振问题的方法,并通过实验对偏振环形腔光纤激光器与没有偏振措施的普通环形腔激光器进行了比较,观察到了清晰的眼图.     

贝尔实验室的光纤通信实验传输距离超过两万公里

贝尔实验室在美国圣迭戈举行的 1991年光纤通信会议(OFC’91)上报道了新的一轮Hero实验.在这些实验中,他们实现了传输距离超过两万公里的超高速光纤传输,其重大意义是不言而喻的,因为地球上任何两地之间的距离都不超过两万公里. 在美国新泽西州Holmdel贝尔实验室的N.S.Bergano等人完成了两个实验:在一个实验中,光信号以2.4 Gb/s的数据传送速率传输了21000km 多;在另一个实验中,光信号以5Gb/s 的数据传送速率传输了9000km.他们在这两个实验中让光信号反复通过一个循环圈.这个循环圈包括四个10dB的掺铒光纤放大器和三段变色散光纤,每段长…     

光传输网络管理的实验教学研究

本文介绍了光传输网络管理实验的基本方法与操作过程,与传统的实验相比,更加有效与实用,克服了传统实验的局限性,取得了较好的效果。     

基于OptiSystem的光纤通信实验项目的设计

采用OptiSystem仿真软件在计算机上对光纤通信实验进行模拟设计,学生通过自主搭建实验教学实例和修改传输系统参数,对观测的实验结果进行测试和分析,能够让学生更好地理解光纤传输过程,掌握光纤通信的理论知识。通过该实验的设计,激发了学生对光纤通信课程的学习兴趣,培养了学生的主动性和创新性,为今后进一步研究光纤通信打好理论分析基础。     

波分复用器在光纤通信中的应用

在光纤通信领域中使用波分复用技术，可以极大地提高网络的传输容量及速率，是解决现代通信技术带宽危机的有效方法．本文介绍了波分复用（WDM）器件的特性，并以双路双向光纤通信为例说明应用WDM技术的优势．     

环太平洋光纤通信进展

自从１９８９年第一个跨太平洋海底光缆通信系统ＴＰＣ－３投入运营以来，环太平洋光纤通信网迅速发展，许多重要的新技术，如光纤放大器技术，色散位移纤，光孤子通信技术和波分复用光纤通信技术，正在或将要在通信网中应用。     

光纤通信光开关的物理基础

光开关是光交换系统的基本元件，也是一种基本的控光器件，本文综述了目前光纤通信中所研究和开发的光通信开关器件的物理原理，并给出各类光开关的阈值条件和典型参量。     

光纤通信光开关的物理基础(续)

3.2　定向耦合器电光开关定向耦合器电光开关是在电光材料 (如L i Nb O3、化合物半导体、有机聚合物 )的衬底上制作 1对条形波导和 1对电极构成 ,如图 5所示 .当不加电压时 ,它是 1个具有 2条波导和 4个端口的定向耦合器 .一般称 1 -3和 2 -4为直通臂 ,1 -4和 2 -3为交叉臂 .图 5　定向耦合器型光开关假设两波导的耦合较弱 ,各自保持独立存在时的场分布和传输系数 ,耦合的影响只表现在场的振幅随耦合长度的变化 .设两波导中的复数振幅分别为 E1(z)和 E2 (z) ,相位常量是β1和 β2 ,其变化规律可用一阶微分方程组表示 [3]d E1(z)dz =-ik12…     

光纤通信光开关的物理基础(续)

4　热光开关热光开关和电光开关的结构可以相同 ,但是产生开关效应的机理不同 .这里的热光效应是指通过电流加热的方法 ,使介质的温度变化 ,导致光在介质中传播的折射率和相位发生改变的物理效应 .折射率随温度的变化关系为n(T) =n0 +Δn(T) =n0 + n TΔT=n0 +αΔT(6 9)式中 n0 为温度变化之前的折射率 ,ΔT为温度的变化 ,α为热光系数 ,它与材料的种类有关 .表 3是几种材料的热光系数 .表 3　几种材料的热光系数材料 α/ (10 - 4K- 1 )L i Nb O30 .0 4 3Si 2Si O2 1.1聚合物 1　　Δn将引起相位变化为Δφ=2 πΔn L/ λ0 =2 παL…     

Bit-rate adaptive optical performance monitoring method for fiber communication systems

A novel bit-rate adaptive method, by varying the optical sampling rates alternatively, is proposed in this paper for optical performance monitoring. Firstly, the theoretical model and the differential software-synchronized algorithm are developed. Then, the results verify that different channel bit-rate can be estimated with high precision irrespective of the modulation formats and signal distortion caused by chromatic dispersion and nonlinearity along the fiber link. Employing the proposed bit-rate adaptive method, the eye diagrams and Q values of 10 Gbit/s, 40 Gbit/s and even higher bit-rate signal can be monitored by a single optical performance monitoring system without any prior knowledge about bit-rate or signal period. The method we propose in this paper has the advantage that different channel bit-rates can be adaptively estimated and the differential software-synchronized algorithm is much simpler.     

An optical receiver for eight-level data communication over step index plastic optical fiber

An optical receiver with automatic-gain-control transimpedance amplifier, linear post amplifier and linear line driver suitable for multilevel signals is presented. A large-diameter photodiode (400 μm) with an antireflection coating optimized for red light was integrated. These features enable the presented optical receiver to be a promising plastic optical fiber receiver. An error free (<10⁻⁸) 400 Mbit/s data rate over 50 m PMMA-step index plastic optical fiber (1 mm diameter) is achieved with eight-level pulse amplitude modulation (8-PAM).     

Placement of hybrid optical amplifier in fiber optical communication systems

In this paper, we investigated the post-, pre- and symmetrical power compensation methods for a different position of hybrid optical amplifier RAMAN–EDFA in fiber link. The effect of increase in signal input power for three power compensation methods is compared in terms of bit error rate, eye closure penalty and output received power. It is found that the post power compensation method is superior to pre- and symmetrical power compensation methods. Further, the effect of variation in length of the standard single mode fiber and dispersion-compensated fiber for three power compensation configurations has also been observed. We observed that RAMAN–EDFA as post power compensation method provides least bit error rate (10^?40) and high output power (12 dBm) at ?15 dBm signal input power at fiber link.     

Arbitrary waveform generation for pre-compensation in optical fiber communication systems

The powerful capabilities of electronic digital signal processing and digital-to-analog conversion for implementing waveform generation in an optical transmitter are illustrated by considering pre-compensation for optical filtering, fiber dispersion, and nonlinear modulation dynamics.     

Optical fibers and fiber dispersion compensators for high-speed optical communication

In order to meet the requirements necessary for advanced optical fiber transmission schemes that enable larger transmission capacity, higher efficiency and/or lower transmission costs per bit, optical fiber technologies are still evolving toward ultimate performance. Recent developmental activities have realized a number of improved performance optical fibers, such as ultra-low loss or ultra-low nonlinearity fibers and various types of dispersion-modified fibers. Fiber-based dispersion compensators or dispersion compensating fibers have also become one of the most essential optical components that support high-speed large capacity optical transmission. Very recently, the dispersion compensating fibers have further evolved into dispersion-managed optical transmission lines, which are now being actually deployed in transoceanic submarine optical cable networks.     

新世纪的非线笥光纤光孤子通信

全面地论述了非线性光纤光孤子通信的发展以及跨世纪发展的光明前景。     

Placement of optimized semiconductor optical amplifier in fiber optical communication systems

This paper deals with the placement of semiconductor optical amplifier for 10 Gb/s non-return to zero format in single mode and dispersion-compensated fiber link. We investigated post-, pre- and symmetrical power compensation methods for different positions of the SOA in fiber link. The effect of increase in signal input power for the three power compensation methods is compared in terms of eye diagram, bit error rate, eye closure penalty and output received power. It is found that the post-power compensation method is superior to pre- and symmetrical power compensation methods. Further, the effect of variation in length of the standard single mode fiber and dispersion-compensated fiber for three power compensation configurations has also been observed. The impact of eye closure penalty is observed for large transmission distances for different signal input powers.