1、激光器驅動電路中英文翻譯激光器驅動電路中英文翻譯激光器驅動電路中英文翻譯中文2540字LaserdrivercircuitSmallchangeswilldirectlysemiconductorlaserdrivecurrenttotheoutputintensityfluctuation.Tostabilizetheoutputpowersemiconductorlaser,Voltagenegativefeedbackprincipletodesignaconstantcurrentdrivingcircuitcomprisesasoftstartingandcurrentlimitin

2、gprotectioncircuitbasedon;Atthesametime,accordingtotheneedofthelightsourceismodulatedtoeliminatetheinfluenceofbackgroundlightand,integratedlasermodulationcircuitcomprisesacrystaloscillationcircuitanddividercircuitdesign.Makingthespecificcircuitandcompletetherelevantexperimental.Theexperimentalresult

3、sshowthatthecircuitcanprovideadrivingcurrentofhighstability,Currentstabilityupto0.05%;Softstartandcurrent-limitingprotectioncircuitcanprotectthesemiconductorlaserandenhancetheimpactcapability.Modulationcircuitgeneratesacarriersignalneededforlaserdiodemodulationanddirecttocompletetheoutputlightmodula

4、tion,Theswitchcanbeconvenientlyrealizedfrom256Hzto512kHzrangeof12kindsofcommonlyusedmodulationfrequencyselection.Semiconductorlaserwithitsexcellentcharacteristics,highefficiency,simplestructure,smalliswidelyusedinscientificresearch,nationaldefense,medical,andotherareasofprocessing,itsdrivetechnology

5、becomesmoreandmoreimportant.Semiconductorlaseristheidealelectron-photondirectconversiondevices,quantumefficiencyisveryhigh,thecurrentsmallchangeswillleadtoagreatchange,theoutputlightintensityofthetherefore,semiconductorlaserdrivecurrentrequirementsisveryhigh.Drivingtechnologyofsemiconductorlaserusua

6、llyadoptsconstantcurrentdrivemode,thiswork,throughtheprincipleofnegativefeedbackcontrolloop,directlyprovidetheeffectivecontrolofthedrivecurrent.Inaddition,thetransientcurrentorvoltagespikes,andovercurrent,overvoltagewilldamagethesemiconductorlaserdrivecircuit,thereforeshouldbeconsideredintheprotecti

7、oncircuitagainstelectricshockmeasuresandspecial.Insomeapplications,DCsemiconductorlasersproduceDCdrivelightinthemeasurementprocessisvulnerabletointerferencefromambientlightslowchange,whichcouldnotbeseparatedfromtheenvironmentlightrequiredDCopticalsignal,thesignal-to-noiseratioistoosmall,sotocarryont

8、hemodulation.Whenthehigh-speedmodulatedsemiconductorlasers,therewillbedynamiccharacteristicsis1complex,suchastherelaxationoscillation,sincethepulseandmulti-pulsephenomena.Inthispaper,experimentswereconductedtostudythecharacteristicsoflowfrequencymodulation.Semiconductorlaseroutputisstable,andcanbedi

9、rectlymodulated,ithasbeenwidelyappliedinopticalsystem,isthepreferredsourcesensorsystem.Thispaperdescribesthedesignofahighstabilitydrivingcurrent,modulation,simpleoperationandlowcostdrivingcircuitforthelightsourceofopticalfibersystems.Inthispaper,thedesignofdrivingthesemiconductorlasermodulationcircu

10、itcomposedoffourparts,includingconstantcurrentcircuit,asoftstart,currentlimitprotectionandmodulationsignalgeneratingcircuit.Theconstantcurrentcircuittogenerateahighstabledrivecurrent.Softstartistheroleofeliminatingsurgemaybepresentinthecircuit,topreventtheharmofsurgeforlaser.Toavoiddamageduetoovercu

11、rrentcausedbysemiconductorlasercannotberestored,thenaddingcurrent-limitingprotectioninadrivercircuit.Circuittorealizethemodulationandfrequencycanbeadjustedtogenerateamodulatedsignal.Theconstantcurrentcircuitisshowninfigure1,Thein-phaseendvoltagereferenceVrintoA1opamp,theoperationalcontrolamplifierco

12、nductinglevel,andthustoobtainthecorrespondingoutputcurrent.TheoutputcurrentgeneratedbysamplingvoltagesamplingresistorRs,thesamplingvoltageisamplifiedastheinvertinginputvoltagefeedbackvoltagefeedbackamplifierA1,andvoltageandthein-phaseinputendofcomparison,Q2toadjusttheoutputvoltagethroughthetriode,ad

13、justmentandoutputcurrentofsemiconductorlasers,sothatthewholeclosed-loopfeedbacksysteminthedynamicbalance.+12VR7A11KQ2Vr2N2222AOPAMPU71-12V2laserAR?61OPAMPR81A1R5A161R6A161M5.1KFigure1ConstantcurrentmapBecausetheswitchinstantaneousinpowersupplygeneratesavoltage,currentsurge,aswellasthesurgeinterferen

14、ceeffectsarelikelytocausethebreakdownand2thedamageofthesemiconductorlaser,andthereforemustbeinthedesignofsoftstartcircuitdrivelaser,namelytheuseofthechargeanddischargeofRCcircuit,delaytime,thespecificcircuitasshowninFigure2asshownin.SwitchS1isclosed,thecurrentthroughtheresistorR1andcapacitorC3tochar

15、ge,thebaseelectrodeofthetriodeQvoltagegraduallyrises.Asthecapacitorchargingandtheconductionofthetriode,outputvoltageVoisachievedfrom0tothemaximumriseslowly,untilthecapacitorchargesaturation,thevoltageandcurrentstabilizing.Whenthepowersupplyisdisconnected,theprocessofreverse,soastorealizethecurrentan

16、dvoltagedecreasesslowly.S1U1R1Q78L052N2222A1Vout31MVinDNGC3C6C21051052104V0Figure2SoftstartcircuitdiagramLasersoftstarttimeandthechargingcapacitorandthecorrespondingresistance,whenthecapacitorchargingtendstosaturation,theoutputvoltagesoftstartcircuitcanachievemaximum.PowersupplyvoltageisVI,thecapaci

17、torvoltageisVo,thecapacitorchargingformula:1V0Vi(1eRC)Accordingtothisformulacancalculatetheelectricchargeanddischargetime.Semiconductorlaserwithotherdevices,havenormalworkingcurrent,ifthecurrentexceedsthisrange,thelaserwillbedamaged,thereforemustrestrictcurrentlaserinthesetrange.Emittervoltagetransi

18、storQ2asthefeedbackvoltageterminalphaseinA3opamp,whenthefeedbackvoltageislessthanthelimitvoltage,VA3opampoutputlowlevel,thetransistorQ1isturnedon,thistimebyatriodeQ2outputvoltagefeedbackvoltageisgreaterthanthelimit;whenthevoltageofV,A3opampoutputhigh,triodeQ1cutoff,thislimitsthetriodeQ2emissionincre

19、asesverycurrent,andislimitedtoaspecificvalue.SoevenifthecurrentcausedbyVrcontrolvoltageexceedstheset3value,thetriodeQ1andQ2areconnectedinseries,sothetotalcurrentwillbeclampedinthesettingcurrentvalue.Modulationsignalgeneratingcircuitiscomposedofacrystaloscillatingcircuitanddividercircuitiscomposedoft

20、woparts,usedtogeneratethehighstabilityoffrequency,dutycyclesquarewavesignalisstable.Crystaloscillatingcircuitdirectlygeneratedbytheactiveoscillator,oscillationfrequencyis1MHz.FrequencydividercircuitcomposedofaCMOSintegratedcircuit4040.1MHzpulsesignalafterthefrequencyby4040,pinoutputfrequencyfromthes

21、witchisselected,thedutycycleis50%,amplitudeis5Vsquarewavesignal.Themodulationfrequencydividingfrequencywere256Hz,512Hz,1kHz,2kHz,4kHz,8kHz,16kHz,32kHz,64kHz128kHz,256kHz,512kHz.Drivinganimportanttechnicalparametersofcircuitforcurrentstability.Currentstabilityisinacertainperiodoftime,severalmeasureme

22、ntsthroughthecurrentsizeofthesemiconductorlaser,namelytheratioofoutputcurrentstabilityfortherelativechangeamountandinputcurrent,stabilitycalculation,therewillbecurrentrelativechangeisdefinedasthemeasurementofthemaximumandminimumvalues,willmeasuretheaveragevalueastheinputcurrentvalue.Drivecircuitbase

23、donvoltagenegativefeedbackprinciple,byconstantcurrentdrivemodetorealizethecontroloftheinjectioncurrentandoutputpowerofsemiconductorlaser,anditcanprovidehighstableoutputcurrent,currentstability0.05%.Drivecircuitwithsoftstart,currentlimitcircuitprotection,reducethedamageofsemiconductorlasertosurgebrea

24、kdownandcurrent,themodulationcircuitandthedrivecircuiteffectivelycombined,realizethefrequencyis,thedevelopmentofnewtechnologyofopticalfibercommunicationisessential.Thecausesofdispersion:Oneisthelightemittedbythelightsourceisnotmonochromaticlight;twoisthemodulationsignalhasacertainbandwidth.Thedisper

25、sionoftheclassification:Bydifferentmodesordifferentfrequency(orwavelength)lightsignalcomponents,transmissioninopticalfibers,duetothephysicalphenomenonofdifferentgroupvelocitiescausesignaldistortioniscalledfiberdispersion.Thefiberdispersionisdividedintomodedispersion(orintermodaldistortion),materiald

26、ispersionandwaveguidedispersion.Aftertwokindsofdispersionisthedispersionapattern,alsoknownasintra-modaldispersion.Dispersionharm:Fiberdispersioninopticalsignalwaveformdistortion,performanceforthepulsewidth,itisthetimedomaincharacteristicsofopticalfiber.4Indigitalcommunicationsystem,pulsebroadeningof

27、opticalsignalisanimportantindex.Pulsebroadeningistoolargecancauseadjacentpulsegapdecreases,theadjacentpulsewilloverlapandregenerativerepeaterdecisionerrorsoccur,whichincreasestheBER,transmissionbandwidthnarrowing,limitthetransmissioncapacityofopticalfiber.Saidmethodofdispersion:Commonlyuseddispersio

28、nrepresentationhasmaximumtimedelayfor$S,pulsewidthRandopticalbandwidthof3dBBthree.Themaximumtimedelaydifferencedelaydescriptionfiberinthefastestandmostslowwavecomponent.Usedtodescribetheeffectoffiberdispersiononthetransmissionsignalpulsebroadeningandopticalfiberbandwidth.Asectionofopticalfiberasanet

29、workanalysisofthedispersioncharacteristics,theavailabletimedomainmethodandfrequencydomainmethod.Wheninthetimedomainanalysis,dispersioneffectisrepresentedbythepulsebroadening,andanalyzedinthefrequencydomain,thetransmissionbandwidthsaid.5激光器驅動電路半導體激光器驅動電流的微小變化將直接致使其輸出光強的顛簸。為實現半導體激光器的堅固功率輸出,鑒于電壓負反應原理設計

30、了包含軟啟動和限流保護電路的恒流驅動電路;同時針對為除去背景光的影響而對光源進行調制的需要,設計了包含晶體振蕩電路和分頻電路的集成激光器調制電路。制作詳細電路并完成了有關實驗。實驗結果表示該電路能夠供給高堅固度的驅動電流,電流堅固度達0.05%;軟啟動和限流保護電路可保護半導體激光器并提升其抗沖擊能力。調制電路產生半導體激光器調制所需的載波信號并直接達成輸出光調制,經過開關可方便地實現從256Hz到512kHz范圍內12種常用調制頻次的選擇。半導體激光器以其超小型、高效率、構造簡單等優秀特色被廣泛應用于科研、國防、醫療、加工等領域,其相應的驅動技術也顯得愈來愈重要。半導體激光器是理想的電子-光

31、子直接變換器件,有很高的量子效率,微小的電流變化都將致使其輸出光強的很大變化,所以,半導體激光器的驅動電流要求特別高。半導體激光器的驅動技術平常采納恒流驅動方式,在此工作方式下,經過負反應原理控制回路,直接供給驅動電流的有效控制。其余,瞬態的電流或電壓尖峰脈沖,以及過流、過壓都會破壞半導體激光器,所以驅動電路中還應試慮特其余抗電沖擊舉措和保護電路。在一些丈量應用中,直流驅動的半導體激光器產生的直流光在丈量過程中簡單遇到遲緩變化的環境光的攪亂,致使沒法從環境光中分別出所需直流光信號,本文系統信噪比過小,所以要對其進行調制。當半導體激光器進行高速調制時,會出現很復雜的動向特色,如馳豫振蕩、自脈動以

32、及多脈沖等現象。本文對其低頻調制特色進行了實驗研究。半導體激光器輸出有足夠的堅固性,且可直接調制,它已在光纖系統中獲取廣泛應用,是傳感器系統的首選光源。本文為光纖系統的光源設計了一種高堅固度驅動電流、可調制、操作簡單且成本低價的驅動電路。本文設計的半導體激光器驅動調制電路由四大多數構成,包含恒流電路、軟啟動、限流保護和調制信號產生電路。恒流電路產生高堅固度驅動電流。軟啟動的作用是除去電路中可能存在的浪涌,防備浪涌對激光器的危害。為防備因為過流等要素惹起半導體激光器不能夠恢復的破壞,則在驅動電路中加入限流保護。調制信號產生電路實現調制和頻次可調。實質的恒流電路見圖1,基準電壓Vr送入運放A1的同

33、相端,該運放控制放大器的導通程度,并由此獲取相應的輸出電流。該輸出電流經過取樣電阻Rs產生取樣6電壓,該取樣電壓經放大后作為反應電壓反應回電壓放大器A1的反相輸入端,并與同相輸入端的電壓比較,經過三極管Q2對輸出電壓進行調整,從而對半導體激光器的輸出電流進行調整,使整個閉環反應系統處于動向的均衡中。+12VR7A11KQ2Vr2N2222AOPAMPU71-12V2laserAR?61OPAMPR81AR5AR6A1161161M5.1K圖1恒定電流圖因為在電源開關開啟的瞬時會產生電壓、電漂泊涌沖擊,以及外界攪亂產生的浪涌影響都有可能造成半導體激光器的擊穿和破壞,所以必然在激光器驅動電路中設計

34、軟啟動電路,即利用RC電路的充放電,實現時間上的延緩,詳細電路如圖2所示。開關S1閉合后,電流經電阻R1向電容C3充電,三極管Q基極電壓漸漸高升。跟著電容的充電以及三極管的導通,輸出電壓Vo實現了從0到最大的遲緩上漲,直到電容充電飽和后,此時電壓和電流趨于堅固。當電源斷開時,上述過程反向,從而實現電流和電壓的遲緩降落。S1U1R1Q78L052N2222A1Vout31MVinDNGC3C62C2105105104V0圖2軟啟動電路圖激光器的軟啟動時間與充電電容和相應電阻有關,當電容充電趨于飽和時,軟啟動電路的輸出電壓能夠達到最大。設電源電壓為Vi,電容電壓為Vo,電容充電公式為:71V0Vi(1eRC)依據此公式能夠計算電路充放電的時間。半導體激光器同其余器件同樣,都有正常工作電流,假如電流超出這個范圍,激光器將會被破壞,所以必然把激光器的工作電流限制在設定范圍內。三極管Q2的發射極電壓作為反應電壓加在運放A3的同相端,