1、12Section 5.1 阶跃折射率光纤阶跃折射率光纤Step-Index Fiber n1n2 sin12nnc n1n23Section 5.1 Step-Index Fiber121nnn 4STEP-INDEX FIBER5STEP-INDEX FIBER6STEP-INDEX FIBERFibern1n2NA oAll-glass1.481.460.2413.9 Plastic-CladSilica1.461.40.4124.2 All-plastic1.491.390.5332 7STEP-INDEX FIBER2221sinnnnNAoo 24.0sin o 8STEP-IND
2、EX FIBER 282o 2 o 14o 是接收角的一半 o9STEP-INDEX FIBERn2n110Section 5.2 渐变折射率光纤渐变折射率光纤Graded-Index FiberCladding Corez2an1n2a0Ray PathsIndex11Section 5.2 Graded-Index Fiberararnrn ,21)(1 arnnrn ,21)(2112GRADED-INDEX FIBER 212222212121nnnn 2122212122212nnnnn 13GRADED-INDEX FIBER121nnn 2112121212122)(2)(nnn
3、nnnnnn 14GRADED-INDEX FIBERaa00rrSnells Lawn(r)1 2 c1212sinsin nn n2n12211sinsin nn 15GRADED-INDEX FIBER16NUMERICAL APERTUREn2n2n1 0 0 212221nnnNA17NUMERICAL APERTURE 0 1 1 c but 2 cRadiation39Geometric Effects 403.02.5210.5ATTENUATION(dB/km)800 900 1000 1100 1200 1300 1400 1500 1600 1700 1.50WAVELE
4、NGTH(nm)Total LossRayleigh ScatteringOH Absorption Peak 5.3.6 Total Attenuation总损耗总损耗 410.50.40.20.10.30.01280 1320 1360 1400 1440 1480 1520 1560 1600 1640 ATTENUATION(dB/km)WAVELENGTH(nm)42434530201510ATTENUATION(dB/km)WAVELENGTH(nm)400 600 800 1000 1200 40352550 445000500300200ATTENUATION(dB/km)WAVELENGTH(nm)400 500 600 700 800 200010001005045464748495051
