Laser qhov thev naus laus zis rau optical fiber sensing Part 2

Laser qhov thev naus laus zis rau optical fiber sensing Part 2

2.2 Ib qho wavelength cheblaser qhov chaw

Lub realization ntawm laser ib wavelength cheb yog qhov tseem ceeb los tswj lub cev lub zog ntawm cov cuab yeej nyob rau hauv lublaserkab noj hniav (feem ntau yog qhov nruab nrab wavelength ntawm kev khiav hauj lwm bandwidth), thiaj li ua tiav kev tswj thiab xaiv ntawm oscillating longitudinal hom nyob rau hauv kab noj hniav, thiaj li mus cuag lub hom phiaj ntawm tuning cov zis wavelength. Raws li lub hauv paus ntsiab lus no, thaum ntxov li xyoo 1980s, qhov kev paub ntawm tunable fiber ntau lasers tau ua tiav los ntawm kev hloov lub ntsej muag ntawm lub ntsej muag ntawm lub laser nrog lub ntsej muag diffraction grating, thiab xaiv lub laser kab noj hniav hom los ntawm manually rotating thiab tuning lub diffraction grating. Nyob rau hauv 2011, Zhu et al. siv cov ntxaij lim dej tunable kom ua tiav ib lub wavelength tunable laser tso zis nrog nqaim linewidth. Nyob rau hauv 2016, Rayleigh linewidth compression mechanism tau siv rau dual-wavelength compression, uas yog, kev ntxhov siab tau siv rau FBG kom ua tiav dual-wavelength laser tuning, thiab cov zis laser linewidth tau soj ntsuam tib lub sijhawm, tau txais lub wavelength tuning ntau ntawm 3. nm. Dual-wavelength ruaj khov tso zis nrog ib kab dav ntawm kwv yees li 700 Hz. Nyob rau hauv 2017, Zhu et al. siv graphene thiab micro-nano fiber Bragg grating los ua ib qho tag nrho-optical tunable lim, thiab ua ke nrog Brillouin laser nqaim thev naus laus zis, siv cov nyhuv photothermal ntawm graphene ze 1550 nm kom ua tiav lub laser linewidth tsawg li 750 Hz thiab photocontrolled ceev thiab Kev ntsuas qhov tseeb ntawm 700 MHz / ms hauv wavelength ntau ntawm 3.67 nm. Raws li pom nyob rau hauv daim duab 5. Cov saum toj no wavelength tswj txoj kev yeej paub qhov laser hom xaiv los ntawm ncaj qha los yog indirectly hloov lub passband center wavelength ntawm lub ntaus ntawv nyob rau hauv lub laser kab noj hniav.

Fig. 5 (a) Kev sim teeb tsa ntawm qhov muag-tswj wavelength-tunable fiber ntau laserthiab ntsuas qhov system;

(b) Tso zis spectra ntawm cov zis 2 nrog kev txhim kho ntawm cov twj tso kua mis tswj

2.3 Dawb laser qhov chaw

Txoj kev loj hlob ntawm lub teeb dawb tau ntsib ntau theem xws li halogen tungsten teeb, deuterium teeb,semiconductor laserthiab supercontinuum lub teeb ci. Tshwj xeeb, lub teeb pom kev zoo ntawm supercontinuum, nyob rau hauv qhov excitation ntawm femtosecond los yog picosecond pulses nrog super transient power, ua rau cov teebmeem nonlinear ntawm ntau yam kev txiav txim nyob rau hauv lub waveguide, thiab lub spectrum yog heev nthuav, uas yuav npog lub band los ntawm pom lub teeb mus rau ze infrared, thiab muaj kev sib raug zoo. Tsis tas li ntawd, los ntawm kev kho cov dispersion thiab nonlinearity ntawm cov fiber tshwj xeeb, nws cov spectrum tuaj yeem txuas mus rau nruab nrab-infrared band. Qhov zoo ntawm laser qhov no tau zoo heev siv nyob rau hauv ntau lub teb, xws li kho qhov muag coherence tomography, gas detection, biological imaging thiab thiaj li nyob. Vim qhov kev txwv ntawm lub teeb ci thiab qhov nruab nrab uas tsis yog-linear, lub supercontinuum spectrum thaum ntxov tau tsim los ntawm cov khoom siv lub xeev laser siv cov iav kho qhov muag los tsim cov supercontinuum spectrum hauv qhov pom ntau yam. Txij thaum ntawd los, kho qhov muag fiber ntau tau maj mam dhau los ua qhov nruab nrab zoo tshaj plaws rau kev tsim cov dav dav supercontinuum vim nws cov coefficient loj uas tsis yog-linear thiab me me kis hom teb. Cov teebmeem tseem ceeb uas tsis yog-linear suav nrog plaub-yoj sib xyaw, kev hloov pauv tsis ruaj khov, hloov kho tus kheej-theem, hloov pauv hloov pauv, soliton splitting, Raman tawg, soliton tus kheej zaus hloov pauv, thiab lwm yam. pulse dav ntawm excitation mem tes thiab dispersion ntawm fiber. Nyob rau hauv dav dav, tam sim no lub supercontinuum lub teeb qhov chaw yog tsuas yog rau kev txhim kho lub laser lub zog thiab nthuav cov spectral ntau yam, thiab xyuam xim rau nws coherence tswj.

3 Cov ntsiab lus

Daim ntawv no qhia txog thiab tshuaj xyuas cov khoom siv laser siv los txhawb fiber ntau sensing technology, nrog rau nqaim linewidth laser, ib zaus tunable laser thiab broadband dawb laser. Daim ntawv thov yuav tsum tau thiab txoj kev loj hlob ntawm cov lasers nyob rau hauv lub teb ntawm fiber sensing yog qhia nyob rau hauv kom meej. Los ntawm kev txheeb xyuas lawv cov kev xav tau thiab kev txhim kho, nws tau txiav txim siab tias qhov zoo tshaj plaws laser qhov chaw rau fiber ntau sensing tuaj yeem ua tiav ultra-qis thiab ultra-ruaj khov laser tso tawm ntawm txhua lub sijhawm thiab txhua lub sijhawm. Yog li ntawd, peb pib nrog txoj kab nqaim dav laser, tunable nqaim kab dav laser thiab dawb lub teeb laser nrog dav nce bandwidth, thiab nrhiav tau txoj hauv kev zoo kom paub qhov zoo tshaj plaws laser qhov chaw rau fiber ntau los ntawm kev txheeb xyuas lawv txoj kev loj hlob.