光纖微小電流感測器是利用將金蒸鍍至光纖上，來感應電流流過鍍金部分所形成的電阻熱效應，藉由光纖溫度的改變，使得光纖的折射率與長度變化，造成光纖干涉儀中兩臂導光路徑不同而產生相位差，最後以觀察相位訊號的強弱，即可得知待測電流的大小。本實驗以全光纖麥克遜式干涉儀搭配法拉地旋轉鏡，可組成一個消除環境對偏振面擾動，而產生訊號褪變效應的架構，再利用相位載波解調技術PGC，可穩定且靈敏的解調出相位變化訊號。本架構可量測的最小相位訊號為1.611×10-5rad/Hz；最小可測直流電流為3.416×10-7A，動態範圍為89.33dB；最小可測交流電流為4.193×10-7A，動態範圍為87.55dB。利用光纖微小電流感測器的微小電流量測能力，及其穩定靈敏的解調特性，將來可作為量測如腐蝕電流範圍的微小電流，並作成多工分布感測的實用階段。

The fiber-optic microampere current sensor used two metal-coated single mode optical fibers to detect the current when it pass through the coated part which existing a thermal resistance effect.When the optical fiber experience temperature change,variation of the phase shift would be incurred by the change of refractive index and geometric structure of the fiber.Then we can observe the phase amplitude to know the input current.Besides we combine the all-fiber
Michelson interferometer with the Faraday rotator mirror to build up a polarization-insensitive structure.Final using the phase-generated carrier technique(PGC) to stabilize demodulate the phase signal.

目 錄 頁次
摘要 i
致謝 ii
目錄 iii
表目錄 vi
圖目錄 vii
符號表 ix
第一章 序論 1
1.1 研究背景 1
1.2 研究動機 3
1.3 論文架構 5
第二章 微小電流感測器之理論分析 6
2.1 電流感測原理 6
2.2 鍍金光纖的電流熱傳導效應 8
2.3 電流與相位的關係 10
2.3.1 直流電流 10
2.3.2 交流電流 14
第三章 光纖微小電流感測器之設計 16
3.1麥克遜式光纖干涉儀 16
3.2 感測系統的架構與組成元件 18
3.2.1 光源調制單元 18
3.2.1.1 雷射驅動器 19
3.2.1.2 光隔離器 20
3.2.2 光纖感測單元 21
3.2.2.1 2x2耦合器 21
3.2.2.2 感測光纖 23
3.2.2.3 法拉第旋轉鏡 25
3.2.3 訊號解調單元 27
3.2.3.1 PZT相位調制器 27
3.2.3.2 PIN檢光器 29
3.2.3.3 PGC解調電路 30
第四章 實驗步驟與結果討論 33
4.1 鍍金光纖與儀器之製作 33
4.1.1 材料與儀器的準備 33
4.1.2 蒸鍍儀器 34
4.1.3 蒸鍍過程 35
4.2 微小電流感測器之安裝 36
4.3 PGC解調電路的調整 37
4.4 微小電流感測器系統模擬 49
4.4.1 PZT相位調制器特性量測 40
4.4.2 感測系統模擬 41
4.5 電流量測 42
4.5.1 直流電流量測 42
4.5.2 交流電流量測 43
4.6 實驗結果與討論 44
4.6.1 交流偏壓電流之影響 44
4.6.2 交流偏壓頻率之影響 45
4.6.3 以微分器增加交流電流量測頻寬 46
4.6.4 不同電阻值之影響 47
4.6.5 頻率與電阻誤差的討論 48
第五章 結論與未來發展 49
5.1 結論 49
5.2 未來發展與建議 51
參考文獻 52
附表 54
附圖 57
中英對照表 82
作者簡歷 85

參考文獻

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