Cov kab hluav taws xob fiber ntau muaj cov lus sib dhos tab sis nws' s tseem ceeb kom nkag siab. Ib qho ntawm cov lus tsis meej pem ntau rau ntau yog" wavelength." Nws suab heev science, tab sis nws tsuas yog siv lo lus siv los txhais tau qhov peb xav tias xim xim ntawm lub teeb.
Teeb yog ib feem ntawm" electromagnetic spectrum" uas tseem suav nrog xoo hluav taws xob, hluav taws xob ultraviolet, microwaves, xov tooj cua, TV, xov tooj ntawm tes, thiab tag nrho lwm cov cim tsis ua haujlwm. Lawv tsuas yog hluav taws xob hluav taws xob sib txawv ntawm cov yoj hluav taws xob sib txawv. Peb hais txog qhov ntau ntawm wavelengths ntawm hluav taws xob hluav taws xob raws li lub teeb hluav taws xob.
Wavelength thiab zaus muaj feem xyuam, yog li qee qhov hluav taws xob tau txheeb xyuas los ntawm nws lub yoj yoj thaum lwm tus raug xa mus los ntawm lawv cov zaus. Rau cov hluav taws xob ntawm luv nthwv yees, lub teeb, UV thiab xoo hluav taws xob, piv txwv li, peb feem ntau xa mus rau lawv lub nthwv dej txhawm rau txheeb xyuas lawv, thaum lub sijhawm ntev ntev xws li xov tooj cua, TV thiab microwaves, peb hais txog los ntawm lawv cov zaus.
Lub teeb uas peb paub tshaj yog, yog, qhov tseeb peb pom tau. Peb qhov muag pom tau yooj yim rau lub teeb uas nws qhov ntev yoj nyob hauv thaj tsam ntawm 400 nanometers (billions ntawm ib mais) txog 700 nanometers, los ntawm xiav / violet rau xim liab. Yog tias koj xav paub tias vim li cas qhov no yog qhov ntau ntawm cov xim peb tuaj yeem pom, nws' s vim tias nws yog cheeb tsam tib yam li cov hnub ci ci tshaj plaws ntawm lub hnub. Hauv lwm lo lus, peb tau tsim kev pom nyob rau hauv qhov kev pom ntawm cov txiaj ntsig ntawm peb lub hnub qub hauv zej zog, muaj lub tswv yim zoo tiag tiag.
Txog rau cov iav siv hluav taws xob nrog iav fiber ntau, peb siv lub teeb pom kev hauv cheeb tsam infrared uas muaj lub teeb ntev dua li pom kev, feem ntau ntawm 850, 1300 thiab 1550 nm. Vim li cas peb ho siv infrared? Vim hais tias lub attenuation ntawm fiber ntau ntau tsawg dua ntawm cov wavelengths. Lub attenuation ntawm iav optical fiber yog tshwm sim los ntawm ob yam, nqus thiab tawg. Kev nqus tau tshwm sim nyob rau hauv ob peb lub yoj qhov ntev hu ua cov kab qhwv dej vim qhov nqus ntawm feeb los ntawm cov dej nyob hauv lub khob.
Tawg pob yog tshwm sim los ntawm lub teeb bouncing tawm atoms lossis cov lwg me me hauv lub khob. Nws yog muaj zog ua haujlwm ntawm wavelength, nrog ntev dua wavelengths muaj ntau dua qhov tawg. Koj puas tau xav tias vim li cas lub ntuj xiav xiav? Nws' s vim hais tias lub teeb los ntawm lub hnub yog xav paub ntau tawg nyob rau hauv xiav.
Fiber optic kis wavelengths txiav txim siab los ntawm ob yam: ntev ntev dua nyob rau hauv infrared rau kev poob qis hauv cov iav fiber ntau thiab ntawm wavelengths uas nyob nruab nrab ntawm cov kis ua kom haum. Yog li ib txwm wavelengths yog 850, 1300 thiab 1550 nm. Qhov zoo, peb tseem tuaj yeem ua cov hloov khoom siv (lasers lossis LEDs) thiab cov txais khoom (cov tshuab thaij duab) ntawm cov nthwv dej tshwj xeeb no.
Yog hais tias lub attenuation ntawm fiber ntau tsawg nyob ntev wavelengths, vim li cas tsis txhob' t peb siv ntev dua wavelengths? Qhov duab infrared wavelengths kev hloov pauv ntawm lub teeb thiab cua sov, zoo li koj tuaj yeem pom lub npub liab lub ntsej muag ntawm lub tshuab hluav taws xob cua sov thiab hnov cov cua sov. Ntawm ntev dua wavelengths, qhov kub thiab txias tom qab ua suab nrov tom qab, cuam tshuam kev taw qhia. Thiab nws muaj cov cim dej nyob hauv infrared.
Yas optical fiber (POF) yog tsim los ntawm cov ntaub ntawv uas muaj qis dua ntawm qhov ntev wavelengths, yog li lub teeb liab ntawm 650 nm feem ntau siv nrog POF, tab sis ntawm 850 nm attenuation tseem siv tau yog li luv luv wavelength iav fiber transmitters yuav siv tau.
Peb feem ntau xa mus rau wavelengths hauv fiber ntau. Lub wavelengths peb siv rau kev xa khoom yuav tsum yog lub wavelengths peb kuaj rau qhov poob hauv peb cov nroj tsuag cable. Peb lub zog ntsuas tau ntsuas ntawm cov kab hluav taws xob kom peb thiaj li kuaj cov khoom siv sib txuas hauv peb nruab.
Peb qhov prime wavelengths rau fiber ntau qhov muag, 850, 1300 thiab 1550 nm tsav txhua yam peb tsim lossis sim. NIST (US National Institute of Standards and Technology) muab lub zog ntsuas hluav taws xob ntsuas ntawm peb txoj kab hluav taws xob no rau cov hlua hluav taws xob. Multimode fiber yog tsim los ua haujlwm ntawm 850 thiab 1300 nm, thaum ib leeg fiber ntau yog qhov zoo rau 1310 thiab 1550 nm. Qhov sib txawv ntawm 1300 nm thiab 1310 nm tsuas yog qhov teeb meem ntawm kev sib cog lus, muaj teeb meem rov qab rau hnub thaum AT& T dictated cov fiber ntau cov lus sib dhos. Lasers ntawm 1310 nm thiab LEDs ntawm 1300 nm tau siv rau hauv tib leeg thiab multimode fiber feem.
