宽带宽与新波段光纤放大器进展

宽带、调整、长距离和智能化是目前光纤通信系统发展的趋势所在，迅速膨胀的信息服务量使宽带成为最迫切的需求，新波段与长增益带宽光纤放大器的研究炙手可热，本文阐述了近期各波段光纤放大器以及拉曼放大器的进展，并揭示了光纤放大器向短波段和混合型发展的趋势。     

正在崛起的新型光纤放大器——拉曼光纤放大器

拉曼(Raman)光纤放大器(RFA)是被誉为光纤通信发展里程碑的掺饵光纤放大器(EDFA)之后又一个引人注目的光放大器。RFA的出现,将会对光纤放大器和光纤通信产生重大的影响。人们对RFA的兴趣来源于这种放大器可以提供整个光纤波长波段的放大,通过适当改变泵浦激光光波波长可达到在任意波段进行光放大的宽带放大器,甚至可以在1270nm～1670nm整个光纤波段内提供光放大。     

宽波段光放大器技术

光纤通信系统宽带化和大容量的实现，离不开光放大器。目前光纤通信的发展明显趋向于挖掘光纤的低损耗波长资源，相应的宽带放大技术就成为关键技术之一，文中简介可望而且正在实现的各种光放大器，这些技术有机会实现石英玻璃光纤在1300－1700nm波段的宽波段通信。     

掺铒碲基光纤放大器最新研究进展

掺铒碲基光纤放大器(EDTFA)由于能同时在C L波段(1530-1610nm)或L波段(1580-1620nm)对光信号进行有效的放大，目前已成为通信领域内竞相开发的一种新型宽带光纤放大器，为此简单介绍了该放大器的研究历程，综述了其最新研究进展和应用情况。     

L-波段光纤放大器及其研究进展

介绍了实现Ｌ－波段放大的三种光纤放大器:增益移位掺饵光纤放大器、掺饵碲化物光纤放大器和光纤拉曼放大器,就每一种光纤放大器的原理、结构、特点和发展现状进行了综述．     

宽带、超宽带光纤放大器研究进展

目前,实现宽带、超宽带光纤放大器的技术主要有四种:宽带掺铒光纤放大(EDFA)技术、宽带拉曼放大技术、宽带混合放大技术和光纤参量放大技术.综述了宽带和超宽带光纤放大器的研究现状,并分别分析了其特点及发展趋势.     

宽带平坦增益光纤喇曼放大器最新进展

在整个工作波段内具有较好的增益平坦度是对应用在波分复用光纤通信系统中的光纤喇曼放大器的一个基本要求.在光纤喇曼放大器的数学模型的基础上分析了实现其平坦增益的几种方法,然后对宽带平坦增益光纤喇曼放大器的最新进展进行了综合评述,最后对其发展进行了展望.     

光纤放大器技术发展前景可期

本文主要从光纤放大器的技术发展趋势:高输出化、宽带化、平坦化及低噪声化等研究焦点出发,介绍光纤放大器的最新技术动向及其主要元器件的技术特点,重点介绍了1.5μm及其长/短侧波段,1.3μm波段及喇曼放大的最新研究现状。     

掺铥光纤放大器及其研究进展

介绍了S-波段光纤放大器——掺铥光纤放大器和增益位移掺铥光纤放大器的原理、结构、发展现状。     

喇曼光纤放大器的几项关键技术

喇曼光纤放大器具有优越的宽带性能 ,是现代宽带通信的较理想放大器。它的实用化得益于一些关键性技术的发展。对喇曼光纤放大器的最新发展进行了研究 ,对其中的关键性技术进行了分析、对比 ,以期有利于今后的实用化研制工作     

Recent Advances in New Band Rare-earth Doped Fiber Amplifiers

Broadband, high bit rate, long hauls and system intelligence are current trends in developing fiber optic communication systems. The ever-increasing traffic demands have made it urgent to develop new band optical fiber amplifier. Laser characteristics of various rare-earth ion including Er^3 , Tm^3 , Pr^3 , Dy^3 ,Ho^3 ,and Nd^3 doped fiber are reviewed. Recent advances of rare-earth doped fiber amplifiers with wideband and flat gain are also introduced.     

光纤放大器的研究动态

介绍了国内外光放大器的最新研究动态,主要包括掺铒光纤放大器、掺铥光纤放大器、光纤喇曼放大器及半导体光放大器,并指出相关放大器的发展趋势,最后对光纤放大器的特性进行了比较分析.     

Distributed fiber Raman amplifiers with localized loss

Backward pumped C- and L-band distributed fiber Raman amplifiers are described, where discrete losses from 0-8 dB were added at various positions to examine the effect of localized loss. Below 3-dB additional loss, the overall optical performance degraded similarly, regardless of loss position in a hybrid Raman and erbium-doped fiber amplifier. Above 3 dB, the performance degradation worsened as the loss position became closer to the signal output. The spectral shape change of the fiber output against loss variation was made tolerable within /spl plusmn/0.4 dB simply by balancing the output power of L band with that of C band, unless the loss was close to pump input. The tolerance provides design flexibility for hybrid optical amplifiers and allows the use of fixed gain-flattening filters.     

半导体行波光放大器

光通信的发展促进了光放大器的研究,半导体行波光放大器目前看来是最有前途的光放大器,因为它结构简便,需要外加的功率小,频带十分宽。本文首先讨论在半导体光放大器两端的防反射膜问题;其次讨论放大器的性能,如增益性能饱和、噪声、增益受偏振的影响;接着讨论放大器在使用中的问题:作为光接收机的前置放大器、级联使用问题和作为光纤通信系统中的中继器问题;最后,文中提出光放大器目前的改进方向及远景研究问题。     

Gain and output-saturation limit evaluation in Pr/sup 3+/-doped fluoride fiber amplifier operating in the 1.3 mu m band

The optical amplification characteristics in a Pr/sup 3+/-doped fluoride fiber have been demonstrated. The amplification band in a Pr/sup 3+/-doped fluoride fiber fully covers the 1.3 mu m telecommunication window, and a practical optical gain value of over 13 dB was obtained. Moreover, a saturation power of +9 dBm was attained. If the problems of pumping efficiency and wavelength are solved, Pr/sup 3+/-doped fluoride fiber will become available for 1.3 mu m booster amplifiers.<>     

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.     

Design of Hybrid Optical Amplifiers for High Capacity Optical Transmission

This paper describes our design of a hybrid amplifier composed of a distributed Raman amplifier and erbium‐doped fiber amplifiers for C‐ and L‐bands. We characterize the distributed Raman amplifier by numerical simulation based on the experimentally measured Raman gain coefficient of an ordinary single mode fiber transmission line. In single channel amplification, the crosstalk caused by double Rayleigh scattering was independent of signal input power and simply given as a function of the Raman gain. The double Rayleigh scattering induced power penalty was less than 0.1 dB after 1000 km if the on‐off Raman gain was below 21 dB. For multiple channel amplification, using commercially available pump laser diodes and fiber components, we determined and optimized the conditions of three‐wavelength Raman pumping for an amplification bandwidth of 32 nm for C‐band and 34 nm for L‐band. After analyzing the conventional erbium‐doped fiber amplifier analysis in C‐band, we estimated the performance of the hybrid amplifier for long haul optical transmission. Compared with erbium‐doped fiber amplifiers, the optical signal‐to‐noise ratio was calculated to be higher by more than 3 dB in the optical link using the designed hybrid amplifier.     

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     

S—波段光纤放大器及其研究进展

介绍了实现S-波段放大的3种光纤放大器；掺铥光纤放大器（TDFA）、增益位移TDFA（GSTD-FA）和光纤喇曼放大器，就其原理、结构、特点和发展现状进行了综述。