Linewidth
Cov npe ntawm cov kab dav thiab bandwidth ntawm lub laser yog qhov zoo sib xws, tab sis lub ntsiab lus txawv heev. Ua ntej, cia peb saib ntawm kab dav. Cov kab dav yog yooj yim to taub, uas yog ib nrab-ncej tag nrho dav ntawm lub laser spectrum.
Bandwidth
Lub laser bandwidth tsis yog ib chav tsev ntawm qhov ntev ntawm ib spectrum. Nws lub npe tag nrho yuav tsum hu ua laser modulation bandwidth.
Lub modulation bandwidth ntawm ib tug semiconductor laser hais txog lub siab tshaj plaws teeb liab tus nqi uas yuav tsum tau tso zis los yog loaded (rau cov teeb liab), los yog lub siab tshaj plaws bandwidth ntawm cov zis (los yog loaded) analog teeb liab.
Yog li ntawd, yog tias koj xav nkag siab txog qhov bandwidth, koj yuav tsum xub nkag siab qhov kev hloov kho ntawm lub laser, hom kev hloov kho, thiab lub ntsiab lus. Bandwidth yog qhov txwv uas tshwm sim hauv qhov kev hloov kho.
Lub hauv paus ntsiab lus ntawm kev sib txuas lus laser yog ib hom binary, coded modulation ntawm 1 thiab 0.
Piv txwv li, lub teeb laser siv nyob rau hauv high-theem tsav yog loj, sawv cev rau 1, thiab lub laser lub teeb lub zog nyob rau hauv qis-theem tsav yog tsis muaj zog, sawv cev rau 0.
Cov ntaub ntawv tuaj yeem kis tau los ntawm kev hloov pauv sai ntawm lub zog sib txawv.
Qhov kev hloov pauv ceev no tuaj yeem ua rau ntxiv cov teeb liab ua ntej thiab tso tawm rau lub zog laser nkhaus, uas yuav ua rau "qhov muag daim duab".
Qhov muag daim duab tsim
Rau cov cim digital, qhov kev hloov pauv ntawm qib siab thiab qis tuaj yeem muaj ntau qhov sib txuas ua ke. Noj 3 khoom ua piv txwv, tuaj yeem muaj 8 kev sib txuas ntawm 000-111. Nyob rau hauv lub sij hawm sau, txaus ntawm cov saum toj no ib theem zuj zus raws li ib tug tej yam kev taw qhia, thiab ces cov waveforms yog superimposed los ua ib lub qhov muag daim duab. Raws li pom nyob rau hauv daim duab 1. Rau qhov ntsuas ntsuas, lub moos teeb liab ntawm lub teeb liab yog thawj zaug rov qab los ntawm lub teeb liab yuav tsum tau kuaj, thiab tom qab ntawd daim duab qhov muag yog superimposed raws li lub moos siv, thiab thaum kawg tso tawm.
Rau daim duab qhia qhov muag tiag tiag, raws li pom hauv daim duab 2, peb tuaj yeem pom thawj theem pib hloov pauv tsis tau ntawm digital waveform, xws li lub sijhawm nce nruab nrab (Rise Time), lub caij nplooj zeeg (Lub Caij Nplooj Ntoos Hlav), overshoot (Overshoot), undershoot. (Undershoot), theem pib (Threshold/CrossingPercent).
Nws yog tsis yooj yim sua rau qhov voltage qhov tseem ceeb ntawm cov theem siab thiab qis ntawm cov teeb liab kom nyob twj ywm zoo ib yam txhua txhua lub sij hawm, thiab nws tseem tsis yooj yim sua kom paub meej tias qhov nce thiab poob ntug ntawm txhua theem siab thiab qis yog tib lub sijhawm. . Raws li pom nyob rau hauv daim duab 3, vim lub superposition ntawm ntau lub teeb liab, lub teeb liab kab ntawm lub qhov muag daim duab ua thicker thiab qhov muag plooj (Plur) tshwm sim. Yog li ntawd, lub qhov muag daim duab kuj qhia txog lub suab nrov thiab jitter ntawm lub teeb liab: nyob rau hauv ntsug voltage axis, nws yog reflected raws li voltage suab nrov (VoltageNoise); ntawm kab rov tav lub sij hawm axis, nws yog reflected li lub sij hawm sau jitter (Jitter).
Qhov no yog me ntsis deb-fetched. Daim duab qhov muag tsis yog patent ntawm laser kis tau tus mob. Nws yog siv rau hauv lwm yam kev sib txuas lus.
Cia peb rov qab mus rau lub bandwidth ntawm lub laser.
Nyob rau hauv lub laser nti, bandwidth yuav tsum raug txwv los ntawm lub sij hawm recombination tas li ntawm electron qhov.
Qhov tseeb, nws yog tus nqi ntawm kev hloov hluav taws xob rau hauv lub teeb. Txawm hais tias nws yog ceev los yog tsis, vim hais tias cov tshuaj txhaj tam sim no yuav tsum ceev ceev hloov qhov voltage loj raws li lub teeb liab. Thaum lub sijhawm hloov pauv no, nws yuav tsum tau hloov hluav taws xob mus rau hauv lub teeb kom sai li sai tau thiab tso tawm, thiaj li tsis cuam tshuam rau lub teeb liab tom ntej ntawm hluav taws xob. Txawm li cas los xij, cov hluav taws xob thiab qhov tsis sib txuas tam sim tom qab nkag mus. Nyob rau hauv ib tug tej yam voltage, lawv yuav xaiv khiav maj mam. Qee lub sij hawm, muaj ib qho shortcut thiab lawv tseem xav mus ncaj qha los ntawm cheeb tsam recombination. Tsis zoo, tsis kam, capacitance, thiab lwm yam hauv cov khoom yuav muaj kev cuam tshuam. Yog li ntawd, muaj kev txwv bandwidth.
Hauv kev xyaum, muaj ntau yam kev txwv rau bandwidth.
Yog tias qhov kev hloov pauv bandwidth ntawm lub laser yuav tsum tau txhim kho, qhov tseem ceeb yog txo qis kev cuam tshuam ntawm cov hluav taws xob parasitic yam ntawm lub laser, tshwj xeeb tshaj yog cov kab mob parasitic capacitance thiab kev thauj mus los ntawm cov neeg nqa khoom hauv quantum zoo qauv.
Thaum tsim high-speed lasers, cov kev ntsuas hauv qab no tuaj yeem raug coj los txhim kho 3dB bandwidth ntawm lub cuab yeej:
① Qhov chaw ua haujlwm tau txais kev lim dej (them nyiaj them) ntau-quantum zoo qauv-quantum zoo laser zoo cov khoom raug rau biaxial compressive strain nyob rau hauv cov kev taw qhia thaum uas tig mus rau qhov zoo nto thiab tensile strain nyob rau hauv cov kev taw qhia perpendicular mus rau lub qhov dej nto, thiab cov hnyav qhov zog theem nyob rau sab saum toj ntawm lub valence band nce, thiab qhov valence band yog degenerate, ua qhov tshwm sim ntawm electron hloov los ntawm spin-orbit splitting band mus rau lub qhov hnyav band kwv yees li sib npaug zos rau xoom, txo lub Auger recombination probability ntawm chav tsev. Qhov kub thiab txias, ua rau txo qis ntawm qhov pib tam sim no ntawm qhov quantum zoo laser, qhov txo qis ntawm txoj kab dav txhim kho qhov zoo, thiab qhov tseem ceeb nce hauv kev so oscillation zaus, kev hloov pauv bandwidth, thiab qhov sib txawv nce coefficient.
② P-hom doping nyob rau hauv cheeb tsam nquag - p-hom doping tuaj yeem txo qhov kev thauj mus los thaum hla thaj tsam SCH, uas yog qhov tseem ceeb txwv rau kev kub ceev quantum zoo li; p-hom doping tuaj yeem tau txais qhov sib txawv siab heev thiab ua rau kev faib cov neeg nqa khoom hauv quantum zoo dua qub.
Yog hais tias Zn doping concentration nyob rau hauv lub active cheeb tsam yog ze rau 1018 cm-3, nws 3dB bandwidth yuav ncav cuag 25GHz, thiab doping kuj yuav ua rau kom lub oscillation zaus ntawm lub ntaus ntawv mus rau 30GHz (kab noj hniav ntev yog 300μm). Tsis tas li ntawd, hnyav doping kuj tau txais txiaj ntsig los txo cov kab dav txhim kho qhov zoo thiab ntxiv txhim kho qhov sib txawv nce, uas yog txhua yam muaj txiaj ntsig los txhim kho cov yam ntxwv ntawm cov khoom siv.
③ Txo cov kab hluav taws xob tsis zoo - txhawm rau txo cov kab hluav taws xob tsis zoo ntawm cov tshuab hluav taws xob siab ceev, tshwj xeeb tshaj yog cov kab mob parasitic capacitance, semi-insulating Fe-InP regrowth faus thev naus laus zis tuaj yeem siv, thiab thaj chaw electrode yuav tsum tau txo tib lub sijhawm; self-aligned nqaim mesa qauv (SA-CM) yog siv los txo cov kab mob parasitic capacitance ntawm lub cuab yeej. Cov tib neeg kuj feem ntau siv txoj kev sau cov polyimide kom txo tau cov kab mob parasitic capacitance.
④ Ua kom cov photon concentration thiab sib txawv nce hauv lub laser - Ua kom cov photon concentration nyob rau hauv lub laser kab noj hniav yuav ua rau kom intrinsic resonant zaus. Siv cov qauv DFB los ua kom lub lasing wavelength thiab qhov nce siab tshaj wavelength tsis zoo detuned (-10nm) tuaj yeem ua kom qhov sib txawv nce, uas tuaj yeem nce qhov -3dB modulation bandwidth.
Cov kev soj ntsuam saum toj no ntawm cov yam ntxwv uas txwv cov yam ntxwv ntawm kev hloov pauv siab ceev ntawm semiconductor lasers thiab txoj hauv kev los ua kom cov kev hloov pauv bandwidth ntawm lasers, cov yam ntxwv no thiab lawv cov yam ntxwv zoo li qub yog qhov muaj txiaj ntsig zoo, yog li thaum tsim cov lasers siab ceev, lwm yam ntxwv, xws li raws li qhov pib, kub yam ntxwv, thiab lwm yam, yuav tsum tau xav txog.
Peb qhov chaw nyob
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