光纤通信课件Solutions (8-9)

《光纤通信课件Solutions (8-9)》由会员上传分享，免费在线阅读，更多相关内容在应用文档-天天文库。

1、SolutionsofChapter8-91.Acouplerhasoneinputportand16outputports,alloutputportsareequal.Iftheinputsignalpoweris-10dBm，computerthepowerofoneoutputport.Solution:Whenlightistransmittingfromafiberofcoreradiustoonehavingcoreradiusb,supposeandthebothfibersarestep-indexandmultimode.Computerthelos

2、s.Solution:2.Sketchathree-wavelengthfiber-gratingdemultiplexer,showinghowthetotalthreewavelengths,,canbedetectedindividually.(Hint,Fig.9.48inthetextbook)Solution:Thedeviceconsistsof4couplersand4gratings.Theleft2gratingsaredesignedtoreflectatwavelength,andtransmittheothertwowavelengths,wh

3、iletheright2gratingsaredesignedtoreflectatwavelength,andtransmitthewavelength.Thus,thetotalthreewavelengthscanbedetectedindividually1.Afour-portdirectionalcoupler(DC)showsbelow,assume,writetheexpressionsofThroughputLoss,TapLoss,Directionality,ExcessLossandSplittingRatio.Solution:1)Throug

4、hputLossLTHP=-10log(P1/P0)2)TapLossLTAP=-10log(P2/P0)3)DirectionalityLD=-10log(P3/P0)4)ExcessLossLE=-10log[(P1+P2)/P0]5)SplittingRatioSR=(P1/P2)2.ABragggratingisresonantat1550nm.Thegratingwillbetunedthermally.Theincreaseingratingperiodfromanincreaseintemperatureis0.1%per℃.1)Calculatetheg

5、ratingperiod.2)Whatisthechangeinresonantwavelengthper℃?Givetheanswerinnm/℃.Solution:assumetherefractiveindexoffibercoreis1.51)accordingto(9.19)inpage304,wecanget:,hereismeasuredinthefibercore,so2)