TheelectricalnonlinearityofsiliconmodulatorsbasedonreversedPNjunctionswasfoundtoseverelylimitthelinearityofthemodulators.Thiseffect,however,wasinadvertentlyneglectedinpreviousstudies.Consideringtheelectricalnonlinearityinsimulation,a32.2dBdegradationintheCDR3(i.e.,thesuppressionratiobetweenthefundamentalsignalandintermodulationdistortion)ofthemodulatorwasobservedatamodulationspeedof12GHz,andthespuriousfreedynamicrangewassimultaneouslydegradedby17.4dB.ItwasalsofoundthatthelinearityofthesiliconmodulatorcouldbeimprovedbyreducingtheseriesresistanceofthePNjunction.Thefrequencydependenceofthelinearityduetotheelectricalnonlinearitywasalsoinvestigated.
