Mfundo yofunikira ya ma laser a fiber a single-mode

Mfundo yofunikira yama laser a fiber a single-mode

Kupanga laser kumafuna kukwaniritsa zinthu zitatu zofunika: kusintha kwa anthu, malo oyenera ozungulira, ndi kufikiralasermalire (kuchuluka kwa kuwala mu resonant cavity kuyenera kukhala kwakukulu kuposa kutayika). Kagwiridwe ka ntchito ka ma single-mode fiber lasers kamadalira mfundo zazikulu izi zakuthupi ndipo kamakwaniritsa magwiridwe antchito kudzera mu kapangidwe kapadera ka ma fiber waveguides.

Ma radiation oyambitsidwa ndi kusintha kwa anthu ndi maziko enieni opangira ma laser. Pamene mphamvu ya kuwala yotulutsidwa ndi gwero la pampu (nthawi zambiri semiconductor laser diode) ilowetsedwa mu ulusi wopeza womwe uli ndi ma ayoni a rare earth (monga Ytterbium Yb³⁺, erbium Er³⁺), ma ayoni a rare earth amayamwa mphamvu ndikusintha kuchoka ku ground state kupita ku excited state. Pamene chiwerengero cha ma ayoni mu excited state chaposa cha ground state, population inversion state chimapangidwa. Pa nthawiyi, incident photon idzayambitsa stimulated radiation ya excited-state ion, ndikupanga ma photon atsopano a frequency, phase ndi direction yomweyo monga incident photon, potero kukwaniritsa optical amplification.

Mbali yaikulu ya single-modema laser a ulusiIli m'mimba mwake mwa ma core awo ochepa kwambiri (nthawi zambiri 8-14μm). Malinga ndi chiphunzitso cha ma wave optics, ma core oterewa amatha kulola kuti ma electromagnetic field mode amodzi okha (monga, fundamental mode LP₀₁ kapena HE₁₁ mode) azitha kutumizidwa mokhazikika, ndiko kuti, single mode. Izi zimachotsa vuto la kufalikira kwa ma electromagnetic field lomwe lilipo mu multimode fibers, ndiko kuti, pulse broadening phenomenon yomwe imachitika chifukwa cha kufalikira kwa ma mode osiyanasiyana pa liwiro losiyana. Kuchokera pamalingaliro a ma transmission, kusiyana kwa njira ya kuwala komwe kumafalikira motsatira axial direction mu single-mode optical fibers ndi kochepa kwambiri, zomwe zimapangitsa kuti output beam ikhale ndi mgwirizano wangwiro wa malo ndi kugawa mphamvu kwa Gaussian, ndipo beam quality factor M² imatha kufika pa 1 (M²=1 ya Gaussian beam yoyenera).

Ma laser a fiber ndi oimira abwino kwambiri a m'badwo wachitatuukadaulo wa laser, zomwe zimagwiritsa ntchito ulusi wagalasi wopangidwa ndi zinthu zachilendo ngati njira yopezera phindu. M'zaka khumi zapitazi, ma laser a single-mode fiber akhala ndi gawo lofunika kwambiri pamsika wa laser wapadziko lonse lapansi, chifukwa cha zabwino zawo zapadera. Poyerekeza ndi ma laser a multimode fiber kapena laser yachikhalidwe ya solid-state, ma laser a single-mode fiber amatha kupanga beam yabwino kwambiri ya Gaussian yokhala ndi beam quality yofanana ndi 1, zomwe zikutanthauza kuti beam imatha kufika pafupifupi pa theoretical minimum divergence Angle ndi minimum focused spot. Mbali imeneyi imapangitsa kuti isasinthidwe m'magawo opangira ndi kuyeza omwe amafunikira kulondola kwambiri komanso kutentha kochepa.