简介:AnovelInGaAs/InAlAscoupledquantumwellstructureisproposedforlargefield-inducedrefractiveindexchangewithlowabsorptionloss.Inthecaseoflowappliedelectricfieldof15kV/cmandlowabsorptionloss(±≤100cm-1),alargefield-inducedrefractiveindexchange(fortransverseelectric(TE)mode,△n=0.012;fortransversemagnetic(TM)mode,△n=0.0126)isobtainedinthestructureattheoperationwavelengthof1.55μm.Thevalueislargerbyoveroneorderofmagnitudethanthatinarectangularquantumwell.Theresultisveryattractiveforsemiconductoropticalswitchingdevices.
简介:Anovelnonlinearopticalloopmirror(NOLM)withanonreciprocalphaseshiftbias(NPSB),calledpowerequalizationNOLM(PE-NOLM),isproposedforreducingthepowerfluctuationofpulsetrains.NPSBprovidespartofthenonreciprocalphasedifferencesothattherequiredinputpowerisreduced,andnonsymmetricalcouplingratioofcouplercanadjustthetransmissioncurvetoimprovetheequalizationrange.IthasbeenshowntheoreticallythatcomparedwithearlierPE-NOLM,about1.6dBofequalizationpowerreductionandabout2.2dBofequalizationrangeenhancementcouldbeachieved.Experimentshavedemonstratedthattheoutputpowerfluctuationisreducedtolessthan0.4dB,whiletherequiredinputpeakpowerrangeis4.5dBm(15.6-20.1dBm).