1、激光器驅(qū)動電路中英文翻譯激光器驅(qū)動電路中英文翻譯激光器驅(qū)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(qū)動電路半導(dǎo)體激光器驅(qū)動電流的微小變化將直接致使其輸出光強的顛簸。為實現(xiàn)半導(dǎo)體激光器的堅固功率輸出,鑒于電壓負反應(yīng)原理設(shè)計

30、了包含軟啟動和限流保護電路的恒流驅(qū)動電路;同時針對為除去背景光的影響而對光源進行調(diào)制的需要,設(shè)計了包含晶體振蕩電路和分頻電路的集成激光器調(diào)制電路。制作詳細電路并完成了有關(guān)實驗。實驗結(jié)果表示該電路能夠供給高堅固度的驅(qū)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(dǎo)體激光器并提升其抗沖擊能力。調(diào)制電路產(chǎn)生半導(dǎo)體激光器調(diào)制所需的載波信號并直接達成輸出光調(diào)制,經(jīng)過開關(guān)可方便地實現(xiàn)從256Hz到512kHz范圍內(nèi)12種常用調(diào)制頻次的選擇。半導(dǎo)體激光器以其超小型、高效率、構(gòu)造簡單等優(yōu)秀特色被廣泛應(yīng)用于科研、國防、醫(yī)療、加工等領(lǐng)域,其相應(yīng)的驅(qū)動技術(shù)也顯得愈來愈重要。半導(dǎo)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(dǎo)體激光器的驅(qū)動電流要求特別高。半導(dǎo)體激光器的驅(qū)動技術(shù)平常采納恒流驅(qū)動方式,在此工作方式下,經(jīng)過負反應(yīng)原理控制回路,直接供給驅(qū)動電流的有效控制。其余,瞬態(tài)的電流或電壓尖峰脈沖,以及過流、過壓都會破壞半導(dǎo)體激光器,所以驅(qū)動電路中還應(yīng)試慮特其余抗電沖擊舉措和保護電路。在一些丈量應(yīng)用中,直流驅(qū)動的半導(dǎo)體激光器產(chǎn)生的直流光在丈量過程中簡單遇到遲緩變化的環(huán)境光的攪亂,致使沒法從環(huán)境光中分別出所需直流光信號,本文系統(tǒng)信噪比過小,所以要對其進行調(diào)制。當(dāng)半導(dǎo)體激光器進行高速調(diào)制時,會出現(xiàn)很復(fù)雜的動向特色,如馳豫振蕩、自脈動以

32、及多脈沖等現(xiàn)象。本文對其低頻調(diào)制特色進行了實驗研究。半導(dǎo)體激光器輸出有足夠的堅固性,且可直接調(diào)制,它已在光纖系統(tǒng)中獲取廣泛應(yīng)用,是傳感器系統(tǒng)的首選光源。本文為光纖系統(tǒng)的光源設(shè)計了一種高堅固度驅(qū)動電流、可調(diào)制、操作簡單且成本低價的驅(qū)動電路。本文設(shè)計的半導(dǎo)體激光器驅(qū)動調(diào)制電路由四大多數(shù)構(gòu)成,包含恒流電路、軟啟動、限流保護和調(diào)制信號產(chǎn)生電路。恒流電路產(chǎn)生高堅固度驅(qū)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(dǎo)體激光器不能夠恢復(fù)的破壞,則在驅(qū)動電路中加入限流保護。調(diào)制信號產(chǎn)生電路實現(xiàn)調(diào)制和頻次可調(diào)。實質(zhì)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(dǎo)通程度,并由此獲取相應(yīng)的輸出電流。該輸出電流經(jīng)過取樣電阻Rs產(chǎn)生取樣6電壓,該取樣電壓經(jīng)放大后作為反應(yīng)電壓反應(yīng)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(jīng)過三極管Q2對輸出電壓進行調(diào)整,從而對半導(dǎo)體激光器的輸出電流進行調(diào)整,使整個閉環(huán)反應(yīng)系統(tǒng)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(guān)開啟的瞬時會產(chǎn)生電壓、電漂泊涌沖擊,以及外界攪亂產(chǎn)生的浪涌影響都有可能造成半導(dǎo)體激光器的擊穿和破壞,所以必然在激光器驅(qū)動電路中設(shè)計

34、軟啟動電路,即利用RC電路的充放電,實現(xiàn)時間上的延緩,詳細電路如圖2所示。開關(guān)S1閉合后,電流經(jīng)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(dǎo)通,輸出電壓Vo實現(xiàn)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(dāng)電源斷開時,上述過程反向,從而實現(xiàn)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(yīng)電阻有關(guān),當(dāng)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(shè)電源電壓為Vi,電容電壓為Vo,電容充電公式為:71V0Vi(1eRC)依據(jù)此公式能夠計算電路充放電的時間。半導(dǎo)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(shè)定范圍內(nèi)。三極管Q2的發(fā)射極電壓作為反應(yīng)電壓加在運放A3的同相端,