fiber-opticcommunicationsystems-在線瀏覽
2024-08-25 18:38本頁面
【正文】 e media: large loss ? 1960, Maiman Ruby laser: stable, reliable optical source atmosphere: large scattering loss 2022/8/12 OE of HUST 23 Milestone in Evolution ? Fiber: low loss media! 1966, 1000 dB/km to 20 dB/km (by reducing concentration of impurities) 1970, Corning →20 dB/km 1972, Corning → 7dB/km 1973, Bell lab → 1976, Japan → 181。 intrinsic absorption) 2022/8/12 OE of HUST 24 ? LD: stable, reliable optical source! 1970, DFB (distributed feedback) theory 1975, Long wavelength laser diode InGaAsP/InP, λ1181。m=106m, nm=109m, pm=1012m 1975, Multiquantum well → MQW DFB LD low threshold →10mA narrow band with → 20dB high output power →1mw 10()( ) 1 0 l o g1P o w e r m wP o w e r d B mmw???????2022/8/12 OE of HUST 25 ? Systems: 1976, Atlanta, lightwave system 1977, Chicago, field test: audio, data, video 2022/8/12 OE of HUST 26 Several Generations ? The first generation LD →multi longitudinal mode Fiber →multimode fiber λ→ 181。DWDM DWDM pointtomultipoint Static OADMs dynamic OADMs eg STM1 on demand Coloured section rings OXC and DXC coexistence wavelength conversion Wavelength routing Optical packet switching 2022/8/12 OE of HUST 30 Chapter 1. Introduction ? System Components amp。 Digital Signals Representation of (a) an analog signal and (b) a digital signal ? Analog signals: audio, video (continuous) ? Digital signals: data (discrete, binary representation) 2022/8/12 OE of HUST 32 . Three steps of required for converting an analog signal into a binary digital signal (a) sampling, (b) quantization, and (c) coding. 2022/8/12 OE of HUST 33 ? Analog → Digital ? Sampling: fs 2⊿ f ( Nyquist C
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