综合参考作业4 pan assignments 4ee274.pdfVIP

EE274Assignment4

PanXin

FiberBandwidth

Inputandoutputpowersoffiberscanberelatedbyageneralrelationifregardingthe

systemtobelinear.



P(t)h(tt)P(t)dt

outin



Foranimpulseinput,h(t)istheoutputandiscalledimpulseresponseofthelinear

system,andifwedoFouriertransformwecanget



H(f)h(t)exp(2ift)dt





Theopticalfiberactsasabandpassfilter.Thefiberbandwidthfcorrespondsto

3dB

thefrequencyf=f3dBatwhich|H(f)|isreducedbyafactorof2orby3dB.

However,opticalfiberscannotgenerallybetreatedaslinearconsideringthepower.

ButwecanstillmakeapproximationwhenVw»1.

if1/2(f/f)2

1



H(f)(1)exp

f2(if/f)

22

Forlightwavesystemsoperatingfarawayfromthezero-dispersionwavelength(f1

≪f2),

1/21

f(2ln2)f0.188(|D|L)0.188

3dB1D

B1.33f3dB

Forlightwavesystemsoperatingatthezero-dispersionwavel