Anovelnonlinearopticalloopmirror(NOLM)withanonreciprocalphaseshiftbias(NPSB),calledpowerequalizationNOLM(PE-NOLM),isproposedforreducingthepowerfluctuationofpulsetrains.NPSBprovidespartofthenonreciprocalphasedifferencesothattherequiredinputpowerisreduced,andnonsymmetricalcouplingratioofcouplercanadjustthetransmissioncurvetoimprovetheequalizationrange.IthasbeenshowntheoreticallythatcomparedwithearlierPE-NOLM,about1.6dBofequalizationpowerreductionandabout2.2dBofequalizationrangeenhancementcouldbeachieved.Experimentshavedemonstratedthattheoutputpowerfluctuationisreducedtolessthan0.4dB,whiletherequiredinputpeakpowerrangeis4.5dBm(15.6-20.1dBm).
