以光功率量測之溫度無感的布拉格光纖光柵應力感測器

Temperature-Insensitive Fiber Bragg Grating Force Sensor Based on Power Detection

沈康馨(Kang-Xin. Shen)

指導教授 ： 王立康

國立清華大學/電機資訊學院/光電工程研究所/碩士(2019年)

摘要

這篇論文利用簡易的三角形彈簧鋼片粘合光纖布拉格光柵（FBG），在表面各處產生不同的應變，讓彈簧鋼片受力變形而產生FBG的週期變化，即形成週期漸變的FBG。在此論文實驗中，我們將980nm的pump光打入EDF得到一個寬頻光源，再打入FBG之中，觀察反射光的頻譜。通過實驗說明待測應力（force）與FBG反射回來的光的頻寬以及FBG反射的光功率是線性關係。我們在實驗中不但增加應力，也減小應力，觀察到所繪製的關係曲線幾乎重合在一起，證明系統的可逆性。之後，又再次利用加熱器改變環境溫度，測量不同溫度下的FBG反射情況，依舊發現光頻寬曲線與FBG反射的光功率只隨重量變化，幾乎不受溫度影響。

關鍵字

光纖光柵 ； 感測器 ； 光纖耦合器 ； 摻鉺光纖 ； 週期漸變光柵

並列摘要

In this thesis, we measure the force applied on a flexible triangular steel sheet with fiber bragg grating(FBG) bonded upon. When the force is applied at the pointed end of the triangular steel sheet, the bending curvatures at different parts of the steel sheet are different, leading to different longitudinal strain on the FBG. Thus, the original uniform distribution grating period becomes that of a chirped type, widening the reflection spectrum of the FBG. Such widening of bandwidth is insusceplible to the ambient temperature. We measure the bandwidth of the reflection spectrum of the FBG, and the reflected optical power from the FBG for changing forces. It is obtained experimentally that such force measurement is temperature insensitive.

並列關鍵字

FBG ； Sensors ； fiber couple ； Erbium Doped Fiber ； Chirp Grating

參考文獻

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