【正文】 指數(shù)，較大的輸出光功率。把EDFA置于光接收機(jī)PIN光檢側(cè)器的前面，來自光纖的信號經(jīng)EDFA放大后再由PIN檢測。 EDFA的增益特性增益G是指輸出信號光功率Pout與輸入信號光功率Pin之比，一般以分貝(dB)來表示。EDFA的放大特性的放大特性。用泵浦光功率Pp做參變量，給出了增益G (dB)與光纖長度1之間的關(guān)系曲線。還可得知，Lopt與輸入泵浦光功率有關(guān)，泵浦光功率越大，Lopt也越長以光纖長度1做參變量給出了增益G與泵浦功率凡之間的關(guān)系。（2）根據(jù)相近參數(shù)的摻餌光纖（根據(jù)速率方程），長度分別為：(a) 15m；(b)10m；(C)5m。W。W。W；(c) 100181。EDFA的閾值功率(Ppth)幾乎和信號光入射功率無關(guān)。采用前向泵浦光激勵功率。EDFA的泵浦方式對增益的影響：取摻餌光纖長度為20m， 1024/m3，用1480nm的泵浦光進(jìn)行激勵，對1536nm的信號光進(jìn)行放大：(a)前向泵浦光激勵方式，前向泵浦光功率為8mW； (b)反向泵浦光激勵方式，反向泵浦光功率為8mW。（1)前向（同向）泵浦在摻餌光纖的輸入端，泵浦光較強(qiáng)，故粒子反轉(zhuǎn)激勵也強(qiáng)，其增益系數(shù)大，信號一進(jìn)入光纖即得到較強(qiáng)的放大。（3)雙向泵浦為使EDFA中摻雜粒子得到充分的激勵，必須提高泵浦功率，所以可以用多個(gè)泵浦源激勵光纖。以摻鉺光纖為主要核心的摻鉺光纖放大器和摻鉺光纖光源自1987年以來一直是光纖通信領(lǐng)域的研究熱點(diǎn)。在本論文中，主要完成了以下工作：（1）概要介紹了光纖放大技術(shù)，包括光纖放大器的分類、發(fā)展前景以及發(fā)展的方向。（4）介紹了摻餌光纖放大器的工作原理及性能參數(shù)。本論文設(shè)計(jì)在老師的悉心指導(dǎo)和嚴(yán)格要求下業(yè)已完成，從課題選擇到具體的寫作過程，論文初稿與定稿無不凝聚著孟憲江老師的心血和汗水，在我的畢業(yè)設(shè)計(jì)期間，孟憲江老師為我提供了種種專業(yè)知識上的指導(dǎo)和一些富于創(chuàng)造性的建議，孟老師一絲不茍的作風(fēng)，嚴(yán)謹(jǐn)求實(shí)的態(tài)度使我深受感動，沒有這樣的幫助和關(guān)懷和熏陶，我不會這么順利的完成畢業(yè)設(shè)計(jì)。我還要感謝同組的各位同學(xué)以及我的各位室友，在畢業(yè)設(shè)計(jì)的這段時(shí)間里，你們給了我很多的啟發(fā)，提出了很多寶貴的意見，對于你們幫助和支持，在此我表示深深地感謝！參考文獻(xiàn)[1] 毛謙．我國光纖通信技術(shù)發(fā)展現(xiàn)狀和前景．人民郵電出版社．2006 ：2527[2] 吳重慶．光通信導(dǎo)論．清華大學(xué)出版社．2008 ：7881[3] 包建新．光纖通信技術(shù)基礎(chǔ)．哈爾濱工程大學(xué)出版社．2008 ：5455[4] 王景國，朱少林．微波信號光纖傳輸技術(shù)．2009年10期[5] 邱昆．光纖通信．電子科技大學(xué)出版社，2011 ：6566[6] 馬麗．華光纖通信系統(tǒng)．北京郵電大學(xué)出版社．2011 ：123125[7] Agrawal GP，賈東方等譯．非線性光纖光學(xué)原理及應(yīng)用．電子工業(yè)出版社．2002 ：8182[8] 郭玉彬．光纖激光器及其應(yīng)用．科學(xué)出版社．2008 ：7879[9] 黃德修，張新亮黃，黎蓉．半導(dǎo)體光放大器及其應(yīng)用．科學(xué)出版社．2012 ：5457[10] 程成．光纖放大原理及器件優(yōu)化設(shè)計(jì)．科學(xué)出版社．2011 ：108110[11] 劉德明．光纖光學(xué)與光纖通信基礎(chǔ)實(shí)驗(yàn)．華中科技大學(xué)出版社．2009 ：4144附 錄附錄 A 英文原文Optical fiber access network technologyThe entire telemunication network according to network function is divided into three sections: switching, transmission,and access. Access to telemunications business transparent to users, transmit specific, access to local switch and the user that the connection between the parts, usually include subscriber line transmission system, reuse equipment, crossing connection device or user/network terminal equipment. And actually pick for business entity is business nodes.1. Access network development process Network (AN: Access by business) refers to a node interface (SNI) and related users Network interface (UNI) between a series of transmit entity (such as line facilities and transmission facilities) for transmission consisting of telemunication business provide the required transmit load capacity, implementation system configurations percentile management interface via and management. Access can be seen as with business and application irrelevant transmission network, mainly finish crossing connection, reuse and transmission function, it is transparent to users of signaling.Based on modern of telemunication network access network is integrated service access, simple local voice access will be increasingly cannot meet the requirements, the voice, data and image prehensive access is being access network development trend. After years of development, access network define though does not change, but its connotation and forms has changed significantly. Superior traditional access network integrated optical fiber access network will be users access the future developing trend.Optical fiber access from SNI to UNI refers to all or part of the access network by using optical fiber as medium. ITU T about access network remendations indicate that fiber, user access system is posed of three parts: optical line terminal(OLT), optical distribution network (ODN) and optical network unit (ONU). to the requirement of system access framework and the important characteristics, access network can be summarized as the following. to access business provides bearing capacity, achieve business transparent transfer. access is transparent to users signaling, except for some users signaling format conversion outside, signaling and business processing function is still in business node. introduction of should not be restricted access all kinds of existing access types and business, access network should through the limited standardization interface and business node connected. network have independent from the business node in the network management system, this system through the standardized interfaces connected TMN, access network operation for implementation TMN, maintenance and management.2 .Fiber structure linear structure. Refer to the public bus, fiber as each user terminals through direct connect with bus coupler network structure. Its characteristic is sharing backbone fiber, save lines to remove node investment, the demand is higher, dynamic range, interfere with each other effect is small. Defect is loss of accumulation, the backbone fiber user acceptance dependence is strong. structure. Refers to all share a fiber optic link node, fiber optic link its end to end the closed loop network structure. Characteristic is selfhealing, namely can be realized without intervention, the network can be in a relatively short period of time to recover from failure have preached business, high reliability. Defect is hanged by the number of users of monocylic limited, polycyclic interchange is relatively plex, not suitable for CATV, etc FenPeiXing business. structure. This structure is actually pointtopoint way, each user terminals in the central node through with control and switch functions of the astral couplers exchange information. Characteristics of simple structure, maintenance is convenient and easy to upgrade and expansion between, each user relatively independent, good secrecy, business adaptability. Defect is higher, networking required fiber cost of poor flexibility, high reliability requirements of central node. structure. Similar to the branches, a hierarchical structure, shape in transfer boxes and FenXianHe place adopts multiple optical distributor, will signal filtering down top end innings allocation, have strong control coordination. Characteristic is suitable for broadcasting business. Defect is power loss is bigger, twoway munication difficulty bigger.3．The status of optical access network in the modern municationOpt