Chidule:Tapanga chiwongolero cha mafunde cha lithiamu tantalate cha 1550 nm chopangidwa ndi insulator chomwe chili ndi kutayika kwa 0.28 dB/cm ndi ring resonator quality factor ya 1.1 miliyoni. Kugwiritsa ntchito kwa χ(3) nonlinearity mu nonlinear photonics kwaphunziridwa. Ubwino wa lithiamu niobate pa insulator (LNoI), yomwe imasonyeza bwino kwambiri χ(2) ndi χ(3) nonlinear properties pamodzi ndi kutsekeka kwamphamvu kwa kuwala chifukwa cha kapangidwe kake ka "insulator-on", kwapangitsa kuti pakhale kupita patsogolo kwakukulu muukadaulo wa mafunde a ma modulators a ultrafast ndi ma photonics osakanikirana osagwirizana [1-3]. Kuwonjezera pa LN, lithium tantalate (LT) yafufuzidwanso ngati chinthu chosagwirizana ndi kuwala. Poyerekeza ndi LN, LT ili ndi malire apamwamba a kuwonongeka kwa kuwala komanso zenera lalikulu la kuwala [4, 5], ngakhale kuti magawo ake a kuwala, monga refractive index ndi nonlinear coefficients, ndi ofanana ndi a LN [6, 7]. Motero, LToI imadziwika ngati chinthu china champhamvu kwambiri chogwiritsira ntchito ma photonic amphamvu kwambiri. Komanso, LToI ikukhala chinthu chachikulu chogwiritsira ntchito zida zosefera za pamwamba pa acoustic wave (SAW), zomwe zimagwiritsidwa ntchito muukadaulo wa mafoni ndi opanda zingwe. Pachifukwa ichi, ma wafer a LToI akhoza kukhala zinthu zodziwika kwambiri pakugwiritsa ntchito ma photonic. Komabe, mpaka pano, zida zochepa zokha za photonic zochokera ku LToI zanenedwa, monga ma microdisk resonators [8] ndi ma electro-optic phase shifters [9]. Mu pepalali, tikuwonetsa ma waveguide a LToI otsika mtengo komanso momwe amagwiritsidwira ntchito mu ring resonator. Kuphatikiza apo, timapereka mawonekedwe a χ(3) osakhala a linear a LToI waveguide.
Mfundo Zofunika:
• Amapereka ma wafer a LToI a mainchesi 4 mpaka 6, ma wafer a lithiamu tantalate opyapyala, okhala ndi makulidwe apamwamba kuyambira 100 nm mpaka 1500 nm, pogwiritsa ntchito ukadaulo wapakhomo komanso njira zokhwima.
• SINOI: Ma wafer a silicon nitride ocheperako kwambiri omwe amataya mphamvu.
• SICOI: Ma substrates a silicon carbide opyapyala kwambiri okhala ndi filimu yopyapyala ya silicon carbide yolumikizidwa.
• LTOI: Mpikisano wamphamvu wa lithiamu niobate, ma wafers a lithiamu tantalate opyapyala.
• LNOI: LNOI ya mainchesi 8 yothandizira kupanga zinthu zambiri za lithiamu niobate zopyapyala kwambiri.
Kupanga pa Ma Waveguides a Insulator:Mu phunziroli, tagwiritsa ntchito ma wafer a LToI a mainchesi 4. Gawo lapamwamba la LT ndi gawo la LT lozungulira la 42° lozungulira la Y-cut la zipangizo za SAW, lomwe limalumikizidwa mwachindunji ku gawo la Si lokhala ndi gawo la thermal oxide wandiweyani wa 3 µm, pogwiritsa ntchito njira yodulira mwanzeru. Chithunzi 1(a) chikuwonetsa mawonekedwe apamwamba a wafer wa LToI, wokhala ndi makulidwe apamwamba a gawo la LT la 200 nm. Tinayesa kukhwima kwa pamwamba pa gawo lapamwamba la LT pogwiritsa ntchito atomic force microscopy (AFM).
Chithunzi 1.(a) Mawonekedwe apamwamba a LToI wafer, (b) Chithunzi cha AFM cha pamwamba pa LT layer yapamwamba, (c) Chithunzi cha PFM cha pamwamba pa LT layer yapamwamba, (d) Schematic cross-section ya LToI waveguide, (e) Mawerengedwe oyambira a TE mode profile, ndi (f) Chithunzi cha SEM cha LToI waveguide core isanafike SiO2 overlayer deposition. Monga momwe zasonyezedwera mu Chithunzi 1 (b), roughness pamwamba ndi yochepera 1 nm, ndipo palibe mizere yokanda yomwe idawonedwa. Kuphatikiza apo, tidayang'ana momwe polarization imakhalira ya LT layer yapamwamba pogwiritsa ntchito piezoelectric response force microscopy (PFM), monga momwe zasonyezedwera mu Chithunzi 1 (c). Tatsimikiza kuti polarization yofanana idasungidwa ngakhale pambuyo pa njira yolumikizira.
Pogwiritsa ntchito gawo la LToI ili, tinapanga waveguide motere. Choyamba, wosanjikiza wa chigoba chachitsulo unayikidwa kuti uume pambuyo pake wa LT. Kenako, electron beam (EB) lithography idachitidwa kuti ifotokoze mawonekedwe a waveguide core pamwamba pa wosanjikiza wa chigoba chachitsulo. Kenako, tinasamutsa mawonekedwe a EB resist kupita ku wosanjikiza wa chigoba chachitsulo kudzera mu dry etching. Pambuyo pake, LToI waveguide core idapangidwa pogwiritsa ntchito electron cyclotron resonance (ECR) plasma etching. Pomaliza, wosanjikiza wa chigoba chachitsulo unachotsedwa kudzera mu wet process, ndipo SiO2 overlayer idayikidwa pogwiritsa ntchito plasma-enhanced chemical vapor deposition. Chithunzi 1 (d) chikuwonetsa schematic cross-section ya LToI waveguide. Kutalika konse kwa core, kutalika kwa mbale, ndi m'lifupi mwa core ndi 200 nm, 100 nm, ndi 1000 nm, motsatana. Dziwani kuti m'lifupi mwa core imakula kufika pa 3 µm pamphepete mwa waveguide kuti pakhale optical fiber coupling.
Chithunzi 1 (e) chikuwonetsa kugawa kwa mphamvu ya kuwala koyezedwa kwa fundamental transverse electric (TE) mode pa 1550 nm. Chithunzi 1 (f) chikuwonetsa chithunzi cha scanning electron microscope (SEM) cha LToI waveguide core isanayambe kuyika SiO2 overlayer.
Makhalidwe a Waveguide:Choyamba tinayesa makhalidwe a kutayika kwa mzere poika kuwala kwa TE-polarized kuchokera ku mafunde a 1550 nm omwe amawonjezera kutulutsa kwadzidzidzi mu mafunde a LToI okhala ndi kutalika kosiyanasiyana. Kutayika kwa kufalikira kunapezeka kuchokera ku mtunda wa ubale pakati pa kutalika kwa mafunde ndi kufalikira pa mafunde onse. Kutayika kwa kufalikira komwe kunayesedwa kunali 0.32, 0.28, ndi 0.26 dB/cm pa 1530, 1550, ndi 1570 nm, motsatana, monga momwe zasonyezedwera pa Chithunzi 2 (a). Mafunde a LToI opangidwa adawonetsa magwiridwe antchito otsika ofanana ndi mafunde a LNoI apamwamba kwambiri [10].
Kenako, tinayesa kusalingana kwa χ(3) kudzera mu kusintha kwa mafunde komwe kumapangidwa ndi njira yosakanikirana ndi mafunde anayi. Tinayika kuwala kwa pampu ya mafunde kopitilira pa 1550.0 nm ndi kuwala kwa chizindikiro pa 1550.6 nm mu waveguide yayitali ya 12 mm. Monga momwe zasonyezedwera mu Chithunzi 2 (b), mphamvu ya chizindikiro cha mafunde a kuwala kwa phase-conjugate (idler) inawonjezeka ndi mphamvu yowonjezera yowonjezera. Chithunzi chomwe chili mu Chithunzi 2 (b) chikuwonetsa mtundu wamba wa kusakanikirana kwa mafunde anayi. Kuchokera pa ubale pakati pa mphamvu yolowera ndi mphamvu yosinthira, tinayerekeza kuti parameter ya nonlinear (γ) ndi pafupifupi 11 W^-1m.
Chithunzi 3.(a) Chithunzi cha maikulosikopu cha resonator ya mphete yopangidwa. (b) Ma spectra otumizira a resonator ya mphete yokhala ndi magawo osiyanasiyana a mipata. (c) Sipekitiramu yotumizira yoyesedwa ndi Lorentzian ya resonator ya mphete yokhala ndi mipata ya 1000 nm.
Kenako, tinapanga resonator ya LToI ring ndikuwunika mawonekedwe ake. Chithunzi 3 (a) chikuwonetsa chithunzi cha maikulosikopu cha resonator ya ring yopangidwa. Ring resonator ili ndi mawonekedwe a "racetrack", okhala ndi dera lopindika lokhala ndi radius ya 100 µm ndi dera lolunjika la 100 µm m'litali. M'lifupi mwa gap pakati pa ring ndi bus waveguide core zimasiyana mu kuwonjezeka kwa 200 nm, makamaka pa 800, 1000, ndi 1200 nm. Chithunzi 3 (b) chikuwonetsa ma transmission spectra pa gap iliyonse, kusonyeza kuti extinction ratio imasintha ndi kukula kwa gap. Kuchokera ku ma spectra awa, tinapeza kuti 1000 nm gap imapereka mikhalidwe yofunika kwambiri yolumikizirana, chifukwa ikuwonetsa extinction ratio yapamwamba kwambiri ya -26 dB.
Pogwiritsa ntchito resonator yolumikizidwa mozama, tinayesa chinthu chapamwamba (Q factor) poyika chizindikiro cha transmission spectrum ndi Lorentzian curve, ndikupeza Q factor yamkati ya 1.1 miliyoni, monga momwe zasonyezedwera pa Chithunzi 3 (c). Monga momwe tikudziwira, ichi ndi chiwonetsero choyamba cha resonator ya LToI ring yolumikizidwa ndi waveguide. Chodziwika bwino n'chakuti, mtengo wa Q factor womwe tidapeza ndi wapamwamba kwambiri kuposa wa ma resonator a LToI microdisk olumikizidwa ndi fiber [9].
Mapeto:Tinapanga LToI waveguide yokhala ndi kutayika kwa 0.28 dB/cm pa 1550 nm ndi ring resonator Q factor ya 1.1 miliyoni. Kugwira ntchito komwe kwapezeka kukufanana ndi kwa ma LNoI waveguide apamwamba kwambiri omwe amataya pang'ono. Kuphatikiza apo, tinafufuza χ(3) nonlinearity ya LToI waveguide yopangidwa pa ntchito zopanda mzere pa chip.
Nthawi yotumizira: Novembala-20-2024