光纖通信：第一章 概要

第一章概要VocabularyChapter12SOEI,HUSTNearinfrared近紅外DWDM:densewavelengthdivisionmultiplexing密集波分復(fù)用Modulationformat調(diào)制格式Regenerator再生器Repeaterspacing中繼距離Bitrate-distanceproduct比特率距離的乘積Dispersionshiftedfiber色散位移光纖Submarinetransmissionsystem海底傳輸系統(tǒng)Dryfiber無水光纖Opticalsoliton光孤子Binaryrepresentation二進(jìn)制表示方法Samplingtheorem抽樣定理Nyquistcriterion奈奎斯特準(zhǔn)則Quantizationnoise量化噪聲PPM脈沖位置調(diào)制PDM脈沖寬度調(diào)制PCM脈沖編碼調(diào)制TDM時(shí)分復(fù)用FDM頻分復(fù)用Digitalhierarchy數(shù)字體系SONET同步光網(wǎng)絡(luò)SDH同步數(shù)字體系STM同步轉(zhuǎn)移模塊RZ歸零碼NRZ非歸零碼CSRZ載波抑制歸零碼AM/FM/PM幅度/頻率/相位調(diào)制ASK/FSK/PSK幅/頻/相移鍵控OOK：通斷鍵控Free-spaceopticalcommunication自由空間光通信系統(tǒng)Opticaltransmitter光發(fā)射機(jī)Launchedpower發(fā)射功率IM/DD強(qiáng)度調(diào)制/直接探測BER誤碼率Receiversensitivity接收機(jī)靈敏度Quantumnoise量子噪聲Shotnoise散粒噪聲Thermalnoise熱噪聲1.1 系統(tǒng)結(jié)構(gòu)&系統(tǒng)元件1.2歷史進(jìn)程回顧1.3基本概念第一章概要Chapter13SOEI,HUST1.1.1基本摘要Chapter14SOEI,HUST通信光通信光纖通信載體:微波光波媒介:自由空間光纖

電報(bào)

無線電廣播

有線電視

無線電….1.什么是光纖通信系統(tǒng)Chapter15SOEI,HUST

載波頻率→比特率微波→300MHz~3GHz→B~100Mb/s

光波→200THzat→B~10Tb/s倍!2.為什么使用光波載體?Chapter16SOEI,HUST優(yōu)點(diǎn)在可見光和近紅外區(qū)域低損耗保密性好&抗電磁干擾低成本(silica)體積小:125mm包層直徑;重量輕抗腐蝕缺點(diǎn)難以耦合和分離難以熔接不能過度彎曲已折斷損耗→傳輸距離(L)通信容量積

定義為(比特率與傳輸距離乘積)3.為什么使用光纖?Chapter17SOEI,HUST波長:μm=10-6m,nm=10-9m,pm=10-12m帶寬(MHz/GHz/THz):M=106,G=109,T=1012,100GHz~0.8nm(1550nm通信窗口)

光功率換算關(guān)系:1mW對應(yīng)0dBm1μW對應(yīng)-30dBm1W對應(yīng)30dBm4.重要單位功率功率1.1.2系統(tǒng)結(jié)構(gòu)&系統(tǒng)元件Chapter18SOEI,HUSTReamplifyRetimeReshape中繼器光接收機(jī)電接收機(jī)數(shù)據(jù)/圖像/音頻O/E光發(fā)射機(jī)電端機(jī)數(shù)據(jù)/圖像/音頻E/OO/E/OorO/O光纖光纖1.系統(tǒng)結(jié)構(gòu)96x40/100Gbit/sT-bit級光傳輸系統(tǒng)Chapter19SOEI,HUST單個(gè)二進(jìn)制編碼/線路編碼調(diào)制器光源(LDorLED)驅(qū)動電路PCM信道耦合光信號輸出LD/LED

發(fā)射功率

光譜線寬窄線寬

光發(fā)射機(jī)2.系統(tǒng)元件Chapter110SOEI,HUST光纖損耗光纖色散非線性&高階模色散光纖卷盤

光纖Chapter111SOEI,HUST中繼器3R:Reamplification（再放大）Retiming（重新定時(shí)）Reshaping（重整波形）O/E/O3R:數(shù)據(jù)格式不透明,傳輸速度受限.O/O3R:光放大，色散補(bǔ)償

光中繼器Chapter112SOEI,HUST

EDFASOAChirped

Bragggrating??

?

llonglshortG.652:PositiveDispersion@1550nmDCM

光放大器

色散補(bǔ)償調(diào)制器(DCM)Chapter113SOEI,HUST信道耦合光探(PINorAPD)前置放大線性通道判決單個(gè)二進(jìn)制二進(jìn)制碼元譯碼PCM（脈沖編碼調(diào)制）信號光信號輸入噪聲&靈敏度!2.5Gb/sAPD

10Gb/sPIN

光接收機(jī)第一章概要Chapter114SOEI,HUST1.1 系統(tǒng)結(jié)構(gòu)&系統(tǒng)元件1.2歷史進(jìn)程回顧1.3基本概念1.2.1歷史解讀Chapter115SOEI,HUST早期烽火信號光電話(Bell,1880)光源:不穩(wěn)定&不可靠媒介:高損耗Laserdiode(transmitter)光纖(medium)1960Maimanrubylaser1962LD（GaAs870nm)1970sLDatroomtemperature(GaAsAl850nm)1310

,1550nm多模LD單縱模LD1951醫(yī)用光纖(1000dB/km)1965E.Miller透鏡波導(dǎo)1966

Loss<20dB/km(高錕)1970Corning光纖(20dB/km)0.5dB/km@1310nm,0.2dB/km@1550nm單模光纖(SMF)短波到長波多模到單模K.C.Kao高錕2.里程碑Chapter117SOEI,HUST1st:LD:多縱模(MLM)光纖

:多模(MMF)波長:0.85μm(3.5dB/km)2nd:LD:MLM光纖:MMF→單模(SMF)波長:1.31μm3rd:LD:MLM→SLM（單縱模）光纖:SMF→DSF波長:1.55μm4th:多波長

→WDM

（耦合器）DSF:色散位移光纖5th:多級調(diào)試格式,S+L波段,拉曼放大器,

相干探測，色散&非線性效應(yīng)利用3.幾代光纖Chapter118SOEI,HUST單個(gè)波長:40Gb/s多根光纖傳輸單根光纖多個(gè)再生器單個(gè)光放大器已實(shí)現(xiàn)傳輸速率:1~10Tbit/s多波長波分復(fù)用:40Gb/s1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM光放大器1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERM1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTR1310RPTRTERMTERMOC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48OC-48

波分復(fù)用技術(shù)：Chapter119SOEI,HUST196619701980199520012015理論LD壓縮強(qiáng)度，連續(xù)波操作

單模，長波長LDWDM先進(jìn)調(diào)制格式超高速度超大容量超長距離色散量子效率非線性量子效率量子效率非線性色散

三個(gè)關(guān)鍵問題推進(jìn)傳輸系統(tǒng)改革Chapter120SOEI,HUSTFunctionality年份199420002006opticalamplifierspoint-to-pointWDM&DWDMDWDMpoint-to-multipointStaticOADMsdynamicOADMs

e-g-STM1ondemandColouredsectionringsOXCandDXCco-existencewavelengthconversionWavelengthroutingOpticalpacketswitching連接性容量復(fù)雜性4.點(diǎn)對點(diǎn)到光學(xué)網(wǎng)絡(luò)第一章概要Chapter121SOEI,HUST1.1 系統(tǒng)結(jié)構(gòu)&系統(tǒng)元件1.2歷史進(jìn)程回顧1.3基本概念1.3.1模擬與數(shù)字信號

Chapter122SOEI,HUST模擬信號:音頻、圖像(連續(xù))數(shù)字信號:數(shù)據(jù)(離散、通常用二進(jìn)制表示)

模擬信號數(shù)字信號光通信系統(tǒng)通常用數(shù)字信號1.模擬與數(shù)字信號定義

Chapter123SOEI,HUST在噪聲和色散失真下仍能恢復(fù)信號2.數(shù)字信號優(yōu)勢

Chapter124SOEI,HUST

三步:

采樣

量化

編碼3.模數(shù)轉(zhuǎn)換(ADC)

Chapter125SOEI,HUST(奈奎斯特準(zhǔn)則)減少附加噪聲:M>Amax/AN(量化信號電平)SNR=20log10(Amax/AN)(信噪比)ConsiderBinarycoding:(mbits/采樣值)比特率

傳輸比特率要求：

采樣:

量化:

編碼:Amax:給定信號最大振幅

AN:模擬信號噪聲均方Chapter126SOEI,HUST數(shù)字音頻信號?f=3.1kHz(300Hz~3.4kHz),SNR=30dBB>31kbit/s實(shí)際,fs=8kHz,m=8bits/sampleB=64kbit/s數(shù)字視頻信號?f=4MHz,SNR=50dB(HDTV)B>66Mbit/s實(shí)際,fs=10MHz,m=10bits/sampleB=100Mbit/s

舉例Chapter127SOEI,HUSTRZ(歸零)有利于重新定時(shí)頻域?qū)扤RZ(非歸零)頻域窄碼間串?dāng)_效應(yīng)數(shù)字比特流010110…分別用(a)RZand(b)NRZ格式.4.數(shù)字信號數(shù)據(jù)形式:RZandNRZ1.3.2調(diào)制與多路復(fù)用Chapter128SOEI,HUST1.光信號電場表達(dá)式偏振態(tài)空間分布振幅復(fù)頻率相位時(shí)間Chapter129SOEI,HUSTAMFMPM,,是模擬信號,對應(yīng)于AM,FMandPM調(diào)制(carrier)×AMsignal=2.調(diào)制格式模擬調(diào)制Chapter130SOEI,HUST,,為數(shù)字信號,對應(yīng)于ASK,FSKandPSK調(diào)制ASKPSKFSKASKFSKPSK電場二進(jìn)制比特流光信號數(shù)字調(diào)制Chapter131SOEI,HUSTPolSKQAM:正交調(diào)幅其他調(diào)制技術(shù)tx-pol.y-pol.OOK(ASK)BPSKDPSKQPSKDQPSKMulti-levelQPSK16QAMChapter132SOEI,HUST調(diào)制的總符號數(shù)碼元傳輸速率比特率比特:信息容量度量OOK:BPSK/DPSK:QPSK/DQPSK:16QAM:(等概率下)比特率(bit/s)和波特率(Baud/s)頻（波）分服用(FDMorWDM)Chapter133OEI,HUSTTDMFDMorWDM10101信道1信道210101101011010112t12信道210101信道1

110011001110101t1時(shí)分復(fù)用(TDM)3.信道復(fù)用Chapter134SOEI,HUSTETDM:電時(shí)分多路復(fù)用OTDM:光時(shí)分多路復(fù)用(詳見第6章)對于多路復(fù)用，24路數(shù)字音頻信道為1幀,每路音頻信道為64Kbit/s(8KHz*8bits/sample),總比特率：24*64KHz=1.536Mbit/s1242幀(8000幀/s~8kHz)信道ETDM與其數(shù)字分級體系Chapter135SOEI,HUST64Kb/s1544Kb/s2048Kb/s6312Kb/s32064Kb/s97728Kb/s397200Kb/s44736Kb/s274176Kb/s8448Kb/s34368Kb/s139264Kb/s564992Kb/s24304753464444JapanUSAEurope,China附加比特率：1.536Mbit/s

PDH:準(zhǔn)同步數(shù)字體系Chapter136SOEI,HUSTSONET(US)Linerate(