此篇論文使用全光纖雷射系統，使用cladding pump技術，激發摻鐿光纖產生976-nm的CW雷射。摻鐿光纖在模態競爭下，使用較長的長度將會率先產生1030-nm四階雷射，且使用cladding pump系統使摻雜粒子吸收效率降低，因此本篇論文主要目的使用氫氟酸蝕刻縮減摻鐿光纖的直徑，提升摻雜粒子對泵浦光源的吸收，並且改善摻鐿光纖的蝕刻製程，最佳化蝕刻後泵浦吸收效率，使雷射效率提升。我們更換雷射架構，使用步進馬達蝕刻摻鐿光纖，蝕刻後雷射的量測證實換了架構後雷射效率得到提升，由8.2%提升到10.26%；步進馬達製作的taper region過長，造成摻鐿光纖部分的吸收效率較低，因此更換馬達為Z825B，將馬達轉速度調整更緩慢，縮短taper region長度後，雷射效率由步進馬達10.26%提升至15.09%；泵浦光源的能量在蝕刻後光纖傳遞，傳遞到taper region內60微米以下時能量損耗開始增加，因此使用變速度兩段式的蝕刻，將60微米以下的taper region斜率製作更緩和，並將後段的光纖蝕刻至更細提升泵浦吸收效率，使用變速度兩段式蝕刻後，雷射效率由15.09%提升到18.66%；在改善了蝕刻製程後，雷射效率由去年的8.2%提升到18.66%，證實能夠提升雷射的表現。

This thesis uses all fiber laser system with cladding pump technique. We use 915-nm multimode laser diode as a pumping source to pump Ytterbium doped fibers. Our goal is to generate 976-nm CW laser. Considering mode competition, we can’t use longer Ytterbium doped fiber. Besides, using cladding pump system leads to lower pump efficiency of doped fibers. Therefore, our main purpose is to increase pump intensity by etching fibers with 24.5% HF. Improving laser performance by optimizing etching process. We get familiar with etching process and fiber characteristic after etching by transmission experiment. We found that PIA25 motor was not suitable for our etching system. We can keep transmission about 70% etching by step motor when cladding diameter is less than 40 micron. We improved slope efficiency from 8.2% to 10.26% after we changed laser scheme. Tapered region made by step motor was too long that some particles’ absorption strength was too low. Therefore, we changed to Z825B motor for slower motor speeds. After adjusting tapered region length, we improved laser efficiency from 10.26% to 15.09%. Laser power improved from 450mW to 622mW. After that, we found that the pump power loss will increase when going through the region less than 60 micron. Therefore, we use various speeds etching to get smoother tapered region and less tapered angle. Besides, we etched the fiber thinner to promote pump intensity. We improved laser efficiency from 15.09% to 18.66%. After improving etching process, we improved laser efficiency from 8.2% to 18.66% and laser power from 320mW to 789mW.

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