利用光纖干涉儀所製作的感測器因為具有體積小、成本低以及不受電磁波干擾等優點，因此近年來被廣泛提出及應用。然而，由於光纖干涉儀之干涉頻譜較寬且消光比較小，因此會限制量測的精準度。在本論文中，我們成功地利用錯位熔接光子晶體光纖與單模光纖的方式製作出光子晶體光纖Mach-Zehnder干涉儀(PCF-based MZI)，並進一步將此PCF-based MZI置入摻鉺光纖雷射的環型共振腔中，以形成光纖雷射感測器。利用錯位熔接的方式，我們可以在光子晶體光纖中同時激發出core mode和cladding mode，由於兩個模態之間的有效折射率不同，因此會產生相位差，當這兩個模態被耦合回單模光纖時便能得到干涉頻譜。我們將PCF-based MZI置入摻鉺光纖雷射的環形共振腔中形成光纖雷射感測器，相較於MZI之干涉頻譜，PCF-based MZI光纖雷射感測器的輸出有很大的訊雜比(40dB)以及很窄的線寬(<1nm)，因此能夠提高量測的精準度。
我們利用製作出的PCF-based MZI光纖雷射感測器進行外在溫度、曲率以及外在環境折射率的感測。由量測結果可知，當外在環境溫度變化從30oC至150oC
時，雷射頻譜之變化量很小，經計算後可得其溫度敏感度約為5pm/oC。而將MZI彎曲使其曲率變化由0.6925m-1至3.096m-1時，PCF-based MZI雷射感測器的雷射波長會呈現指數增加的趨勢。此外，隨著外在環境折射率由1.3388增加至1.3638時，雷射頻譜會呈現往長波長位移的現象，其折射率敏感度約為52.35nm/RIU。由結果得知，我們所提出的PCF-based MZI光纖雷射感測器可以進行不同參數的感測，且由於其具有很大的訊雜比及很窄的線寬，因此能夠提高量測精準度。

Optical sensors based on fiber interferometers have been investigated extensively due to their significant advantages of compact size, low cost and immunity to electromagnetic interference. However, their accuracy is poor due to the broad 3-dB bandwidth and low extinction ratio of the interference spectrum. In this dissertation, we fabricate a fiber Mach-Zehnder interferometer (MZI) by splicing a photonic crystal fiber (PCF) with SMFs with an offset. Due to the misalignment of the two fibers, the input light from the SMF will induce the core mode and cladding mode of the PCF with different propagation velocities. These two modes are coupled back to the other SMF to form the interference spectrum due to the accumulated phase difference. We then place the PCF-based MZI into an erbium-doped fiber ring laser to form the fiber laser sensor. Compared with the spectrum of the PCF-based MZI, the lasing peak of the fiber laser sensor has high signal to noise ratio (40dB) and narrow 3-dB bandwidth (<1nm), which can enhance the sensing accuracy.
We have demonstrated the sensing properties of our PCF-based MZI fiber laser sensor for temperature, bending curvature and surrounding refractive index. The temperature sensitivity of the PCF-based MZI fiber laser sensor is about 5pm/oC between 30oC to 150oC. As we increase the bending curvature from 0.6925m-1 to 3.096m-1, it is observed that the lasing wavelength is exponentially increased. In addition, the measured refractive-index sensitivity is about 52.35nm/RIU as the surrounding refractive index is varied from 1.3388 to 1.3638. As a result, our proposed PCF-based MZI fiber laser sensors can be utilized as useful sensors which have high signal to noise ratio and narrow 3-dB bandwidth to enhance the sensing accuracy.

致謝 i
中文摘要 ii
Abstract iii
目錄 v
表目錄 vii
圖目錄 viii
第一章 緒論 1
1-1 光纖感測器 1
1-2 光子晶體光纖干涉儀 6
1-3 研究動機 14
第二章 錯位熔接Mach-Zehnder光纖干涉儀 15
2-1 Mach-Zehnder光纖干涉儀的原理 15
2-2 元件製作方法 20
2-2.1 光纖介紹 20
2-2.2 元件製作 21
2-3 元件特性量測與分析 26
第三章 PCF-based MZI摻鉺光纖雷射感測器 34
3-1 摻鉺光纖 34
3-2 光纖雷射感測器 37
3-2.1 摻鉺光纖雷射 37
3-2.2 摻鉺光纖雷射感測器 39
3-3 PCF-based MZI雷射感測器之雷射特性曲線量測 41
3-3.1 摻鉺光纖雷射架構及量測 41
3-3.2 PCF-based MZI光纖雷射之雷射特性量測 44
3-3.3 PCF-based MZI光纖雷射之穩定度 49
第四章 感測特性及量測 50
4-1 溫度感測特性 50
4-2 曲率感測特性 56
4-3 折射率感測特性 61
第五章 結論 69
參考文獻 70

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