简介:Inthispaper,awavelengthdivisionmultiplexing(WDM)transmissionsystemderivedfromthecoherentopticalorthogonalfrequencydivisionmultiplexing(CO-OFDM)withpolarizationdivisionmultiplexing(PDM)and16-orderquadratureamplitudemodulation(QAM)isstudied.Asimulationof80-channelWDMtransmissionsystemwithdatarateof200Gbit/sisbuilt,andthetransmissionperformanceofthesystemisanalyzed.ThesimulationresultsshowthatthesystemQvalueoftheWDMchannelsat16Tbit/swithaspectralefficiencyof7.14bit/s/Hzispotentiallyover10.0dBforalonghaultransmissionupto1800kminastandardsingle-modefiber.
简介:WereportthedepositionofNb2O5filmsonunheatedBK-7glasssubstratesusingremoteplasmasputteringsystem.Theremoteplasmageometryallowspseudoseparationofplasmaandtargetbiasparameters,whichofferscompletedepositionratecontrol.Usingappropriateoxygenflowrates,high-densityandlow-lossNb2O5filmsaredepositedwithratesupto0.49nm/s.Lowerdepositionrates(~0.026nm/s)canalsobeobtainedbyworkingatlowtargetcurrentandvoltageandatlowpressure.Nb2O5filmsdepositedatdifferentrateshavetherefractiveindexofabout2.3andtheextinctioncoefficientaslowas6.9×10-5.
简介:WefabricatepolycrystallineCu(In,Ga)Se2(CIGS)filmsolarcellsonpolyimide(PI)substrateattemperatureof450°Cwithsingle-stageprocess,andobtainapoorcrystallizationofCIGSfilmswithseveralsecondaryphasesinit.Forimprovingitfurther,thetwo-stageprocessisadoptedinsteadofthesingle-stageone.AnextraCu-richCIGSlayerwiththethicknessfrom100nmto200nmisgrownonthesubstrate,andthenanotherCu-poorCIGSfilmwiththicknessof1.5-2.0μmisdepositedonit.Withthemodificationoftheevaporationprocess,thegrainsizeofabsorberlayerisincreased,andtheadditionalsecondaryphasesalmostdisappear.Accordingly,theoveralldeviceperformanceisimproved,andtheconversionefficiencyisenhancedbyabout20%.