On-ChipSystemCutsPowerConsumption,DrivesDataCenterEfficiency.CORVALLIS,Ore.,May25,2023—AccordingtotheU.S.DepartmentofEnergy(DOE),adatacentercanconsumeupto50×moreenergypersquarefootoffloorspacethanatypicalofficebuilding.Datacentersaccountforroughly2%ofallelectricityuseintheU.S.,accordingtotheDOE.Asaresult,interconnectscharacterizedbyhighenergy-efficiencysystemsareneededtoreducepowerconsumption.Inresponse,researchersatOregonStateUniversity(OSU)andBaylorUniversityhavedevelopedasiliconphotonicsmethodthatreducestheamountofenergyconsumedbyphotonicchipsusedindatacentersandsupercomputers.Specifically,theenergy-efficientmethodcompensatesfortemperaturevariationsthatdegradethechips.Theresearcherstargetedsiliconmicro-ringresonators(Si-MRRs)inthework;accordingtotheresearchers,Si-MRRsplayessentialrolesinon-chipwavelengthdivisionmultiplexing(WDM)systems.Thisisduetotheirultracompactsizeandlowenergyconsumption.However,theresonantwavelengthofSi-MRRsisverysensitivetotemperaturefluctuationsandfabricationprocessvariation.“Typically,eachSi-MRRintheWDMsystemrequiresprecisewavelengthcontrolbyfreecarrierinjectionusingPINdiodesorthermalheatersthatconsumehighpower,”theresearcherssaid.Asaresult,significantenergyhasbeenrequiredtokeeptheperformanceofthesechipshighandtheirtemperaturestable.Ph.D.studentJessicaPetersonandprofessorJohnConleydiscussingtheoperationofoneofhisgroup’satomiclayerdepositionsystems.CourtesyofOregonStateUniversity.Theresearchersexperimentallydemonstratedgate-tuning,on-chipWDMfilterswithlargewavelengthcoveragefortheentirechannelspacingusinganSi-MRRarray,drivenbyhigh-mobilitytitanium-dopedindiumoxidegates.AccordingtotheOSUCollegeofEngineering’sJohnConley,controloftheprototypesviagatevoltagemeantthatvirtuallynoelectriccurrentwasusedtoobtaincontrol.Usingtheapproach,theresearchersshowedthatitispossibletoreducetheenergyneededfortemperaturecontrolofphotonicchipsbyafactorofmorethan1million.Theon-chipWDMfilterswerecomposedoffourcascadedtunableSi-MRRswithmetal-oxidesemiconductorgatesformedbyahigh-mobilitytransparentconductiveoxide,whichshowmuchlargerelectro-opticefficienciesthanreversedp-njunctions.ResearcherAlanWang,nowatBaylor,saidthatthephotonicsindustryexclusivelyreliesonthermalheaterstofinetunetheworkingwavelengthsofhigh-speed,electro-opticdevicesandoptimizetheirperformance.Thesethermalheatersconsumeseveralmilliwattsofelectricityperdevice,hesaid.“ThatmightnotsoundlikemuchconsideringthatatypicalLEDlightbulbuses6to10watts,”Wangsaid.“However,multiplythoseseveralmilliwattsbymillionsofdevicesandtheyaddupquickly,sothatapproachfaceschallengesassystemsscaleupandbecomebiggerandmorepowerful.”"Ourmethodismuchmoreacceptablefortheplanet,”Conleyadded.“Itwillonedayallowdatacenterstokeepgettingfasterandmorepowerfulwhileusinglessenergysothatwecanaccessevermorepowerfulapplicationsdrivenbymachinelearning,suchasChatGPT,withoutfeelingguilty.”TheresearchwassupportedbyIntel,NASA,andtheNationalScienceFoundation,andwaspublishedinScientificReports(www.doi.org/10.1038/s41598-023-32313-0).Photonics.comMay2023explorerelatedcontent.

【光电信息技术】 2023-05-29