光纖雷射在應用上經常使用到環形的共振腔迴路，在這裡我們使用到共振腔外加布拉格光柵(Fiber Bragg Grating，FBG)或薄膜濾波器(add/drop filter)來做為主要選取波長的依據，藉由兩種不同的實驗設計方法，來控制所輸出的訊號波長與調變。
　　一開始我們所使用兩種不同波長的布拉格光柵搭配上共振腔的應用在C-band波長的範圍下輸出我們要的光纖雷射，會選用C-band波長範圍主要原因為在傳統C-band的範圍內不容易產生lasing。第一種的控制方式為使用雙幫浦雷射，由各別控制其供給的能量，達到控制輸出的波長、功率，藉此達到波長選擇的效果。
　　再來我們將使用另外一種方式來做為波長選取的方法，用薄膜濾波器達到波長選擇的效果，然後將長週期光纖光柵(Long-Period Fiber Grating，LPFG)彎曲，在不同曲度下各波長的損耗也不同，通過此特性來調變輸出的雷射訊號。
　　兩種方式各有其優點和缺陷，第一種所能調整的範圍較廣，而且可輕易調整輸出的光功率；第二個實驗設計上調變方式較為方便，且只需要一台幫浦雷射即可，兩種實驗成本不高的關係，調變方式皆利於各種學術或工程等應用。

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