Thaum koj xav tau ib qho teeb me ntsis ntawm koj cov teeb meem ntawm qhov muag fiber,
Tig mus rau OTDR.
Optical sij hawm sau reflometers (OTDRs) yog cov khoom ntiag tug muaj nqis. Lawv xa pulses ntawm lub teeb rau hauv optical fibers ntawm ntau hom pulse widths, txheeb xyuas cov minuscule nyiaj ntawm lub teeb reflected rov qab rau lawv los ntawm faults nyob rau hauv lub fibers, thiab siv complex computations los txiav txim siab qhov loj thiab deb mus rau cov txheej xwm ntsib nyob rau hauv lub fiber khiav. Cov txheej xwm yog txhais tias yog poob lossis hloov hauv lub fais fab ntawm lub teeb ntes.
Ib qho OTDR siv lub teeb nraub qaum thim rov qab los txhawm rau txhawm rau cov fibers. Hauv qhov essence, nws yuav siv cov snapshot ntawm cov khoom siv fais fab ntawm fiber ntau los ntawm kev xa ib lub siab siv hluav taws xob mus rau ib qho kawg ntawm cov fiber ntau thiab ntsuas lub teeb ntais rov qab mus rau qhov ntsuas. Yog li ntawd, koj tuaj yeem siv OTDR los mus rau kev siv tus lej hauv kab, txuas, thiab sib txuas, nrog rau kev ntsuas teeb pom kev hauv lub cev. Txawm li cas los xij, zoo li OTDRs, lawv muaj cov kev txwv nram no:
Raug poob soj ntsuam. Yog tias koj tsuas yog ntsuas ib kawg ntawm lub cable nrog ib tug OTDR, koj yuav poob qhov tseeb. Koj tuaj yeem kuaj ob qho tagnrho ntawm cov fiber ntau thiab qhov nruab nrab ntawm kev nyeem ntawv koj tau txais kev ntsuas kom ncaj.
Nqi. Cov chav tsev saum toj-nqi yuav kim tshaj kaum txhiab daus las, yog li koj npaj siab siv OTDR nquag, nws ua rau kev txiav txim siab yuav ib qho. Yog tias tsis yog, koj yuav xav xauj ib qho thaum koj xav tau, tab sis nco ntsoov tias koj xauj ib chav tsev uas nyuam qhuav tuaj yeem kho.
"Tuag aav." OTDRs muaj ib tug "tuag tsam" (Fig. 1, txoj cai) uas tej zaum yuav ntev ib puas meters los ntawm lub tsev nyob rau hauv uas muaj tseeb readings yog luv. Koj muaj peev xwm kov yeej no muaj kev txwv tias yog koj siv ib tug community launch cable, tab sis koj yuav tsum ua tib zoo txhais lub teeb liab txoj lw (Fig. 2, hauv qab no).
Tejzaum ntawm kev siv. OTDR kev nyeem ntawv yuav tsum raug tshuaj xyuas thiab raug txhais los ntawm cov neeg tau txais kev kawm thiab kev paub. Nws tsis yooj yim rau ib tus neeg tsim nyog dua los ua tus OTDR thiab ua kev nkag siab tawm ntawm nws. Yog li ntawd, siv cov cuab yeej no yuav tsum muaj sij hawm ntau thiab dag zog.
Thaum twg koj xav tau ib daim OTDR? Koj tuaj yeem siv lub OTDR los nrhiav kev so lossis qhov teeb meem zoo li hauv kab khiav, lossis siv lub snapshot ntawm cov fibers ua ntej yuav xa ib qho qhauj mus rau tus neeg qhua. Cov snapshot, uas yog daim ntawv luam ntawm ODTR kab, muab koj cov ntaub ntawv ruaj khov ntawm lub xeev ntawm qhov fiber ntau ntawm txhua lub sijhawm. Qhov no tuaj yeem pab cov neeg nruab nrab thaum cov fibers tau raug puas los yog kho tom qab kev teeb tsa, ua pov thawj qhov chaw lub luag hauj lwm rau kev puas tsuaj. Qhov tseeb, qee tus neeg tuaj yeem yuav thov kom OTDR kuaj xyuas raws li qhov kev lees paub rau kev lees paub.
Txawm hais tias OTDRs tsis yog tshwj xeeb tshaj yog qhov kev xeem poob, lawv tuaj yeem siv los kuaj kev qeeb ntev, sab nraum zoov ntawm singlemode fiber uas nkag mus rau ob hnub ntawm lub cable tsis yog cov tswv yim. Nws kuj tseem yuav pab tau rau cov txheej txheem tiv thaiv kev tiv thaiv, xws li kev soj ntsuam txhua zaus hauv lub chaw ua haujlwm.
OTDR Cov Lus Qhia. Los sau cov txiaj ntsig ntawm OTDR, koj yuav tsum to taub cov lus qhia nram qab no:
Dynamic khwv. Qhov no yog ua ke ntawm tag nrho cov nyiaj siv zog ntawm qhov chaw laser thiab lub cuab yeej ntawm lub sensor.
Tuag tsam. Raws li tau hais los saum toj no, qhov chaw tuag yog qhov chaw ntawm qhov chaw muaj fiber ntau tom qab kev txheeb xyuas kev txhoj puab, uas siab siab qib ntawm qhov kev xav rov npog sab qis dua ntawm rov qab. Qhov chaw no ncaj nraim ntsig txog qhov mem tes ntawm qhov chaw laser; Ib qho luv mem thev dhau los ua ib qho chaw me me, thiab ua rau lub plawv ntev qis dua ib thaj chaw loj.
Resolution. Qhov no yog qhov peev xwm ntawm OTDR kom paub qhov txawv ntawm cov theem ntawm lub hwj chim nws tau txais. Nws kuj tuaj yeem hais txog kev daws teebmeem, uas yog qhov kev sib ze ntawm cov ntaub ntawv ntawm cov ntaub ntawv.
Theem raug thiab linearity. Cov no yog ntsuas ntawm qhov hluav taws xob tam sim no sib npaum li cas rau cov tswv yim optical zog. Qhov no yog hais txog qhov ntaus nqi ntxiv-lossis-rho tawm (+/-) dB lossis qhov feem pua ntawm lub zog.
Ze raug. Kev ua ncaj ncees yog nyob ntawm kev ruaj ntseg ntawm kev lag luam, cov ntaub ntawv taw tes nrawm, thiab theem ntawm kev tsis meej ntawm qhov Performance index ntawm refraction.
Kev khiav haujlwm OTDR. Kev khiav haujlwm ntawm OTDR tsis yog tshwj xeeb tshaj yog nyuaj, tab sis nws tsis tas yuav paub cov lus tshaj tawm ntawm qhov ua thiab qauv koj siv. Yuav kom khiav lag luam OTDR, feem ntau koj yuav tau ua cov nram qab no:
Fiber hom. Singlemode los yog multimode.
Wavelength. Singlemode yog teem rau 1310 nm los yog 1550 nm, thiab multimode yog teem rau 850 nm los yog 1300 nm.
Ntsuas tsis. Qhov tsis raug teeb tsa yog qhov kev nrug deb, kev daws teeb meem, thiab qhov dav hlau.
Cov kev tshwm sim pib. Qhov no pom tau hais tias ntau npaum li cas los yog pauv hloov yuav raug cim raws li qhov kev tshwm sim.
Index of refraction. Qhov no yog qhov ceev ntawm lub teeb nyob rau hauv uas fiber. Koj tuaj yeem tau daim duab no los ntawm cov chaw tsim hluav taws xob. Feem ntau koj tuaj yeem coj nws ncaj qha los ntawm cov txheej txheem tus qauv.
Zaub units. Cov no feem ntau yog muaj npe hauv taw lossis ntsuas.
Cia nco. Qhov no yuav tsum tau cleared thiaj li tau txais ib daim duab tshiab tau txais kev cawmdim thiab / los yog khaws cia.
Tuag tsam jumper. Koj yuav tsum txuas lub tshuab fais fab no, uas yuav tsum ntev txaus, ntawm OTDR thiab cov fiber ntau hauv kev sim. Qee lub sij hawm koj yuav tau txuas nws ntawm qhov kawg ntawm lub cable, thiab.
Cov teeb meem ntsuas. Lub sijhawm koj yuav ntsib ib co teeb meem uas koj tsis tuaj yeem kov yeej. Cov xwm txheej hauv qab no yuav ua rau koj qhov kev txhawj xeeb teeb meem rau qhov kev xeem.
Nonreflective so. Qhov no tshwm sim thaum muaj fiber ntau tau tawg los yog raus hauv kua. Nyob rau hauv ob qho tib si, tsawg heev teeb qhia rov qab rau OTDR, thiab nws nyuaj rau txheeb xyuas qhov so.
Gainer. Ib tus neeg tau txais txiaj ntsig yog ib txoj kab rau hauv ib lub tshuab fiber ntau uas pom tau tias nws nce qib hauv kev lag luam. Lub cuab yeej ua ke zoo li ib txoj kab tsis tuaj yeem tsim teeb pom kev thiab tsis tuaj yeem ua rau lub qhov muag pom kev. Tab sis yog hais tias muaj ib qho kev tsis haum ntawm cov fibers uas tau spliced, nws yuav tshwm tau rau OTDR li qhov nce. Piv txwv li, yog qhov khub ntawm 50-micron fiber ntau rau 62.5 micron fiber, qhov txawv ntawm thim rov qab (qhov 62.5-micron tub ntxhais loj dua) tshwm rau OTDR ua qhov nce siab.
Ghosts. Ghosts yog repetitions ntawm ib txoj lw los sis ib feem ntawm ib txoj kab. Lawv tshwm sim los ntawm ib tug loj reflection nyob rau hauv ib tug luv luv fiber, ua lub teeb rau thaws rov los thiab tawm.
Xaus. OTDRs yog cov khoom lag luam uas muaj nuj nqis uas muaj peev xwm ua kom pom teeb meem ntawm koj cov iav fiber ntau ua ntej lawv coj koj lub hauv caug. Thaum koj paub txog nws cov kev txwv thiab yuav ua li cas kov yeej lawv, koj yuav tsum npaj mus ntes thiab tshem tawm koj cov khoom siv fiber ntau ntawm fiber ntau.
