在傳統的光纖耦合技術上，光纖耦合器有著體積龐大、組裝不易等問題，而部分的光纖透鏡製造技術，雖然可以有效地降低光學系統的複雜性，並提高光纖與光源間的耦合效率，但也面臨無法量產、設備昂貴、製作耗時等缺點。有鑑於此，本研究提出一套低成本、可大量生產的光纖透鏡製程，其利用SU-8光阻為透鏡材料，藉由表面張力在漸變折射率的塑膠光纖(外徑=500 μm)及單模玻璃光纖上(外徑=125 μm)，形成一個半球狀的微透鏡結構。再將此半球狀微透鏡的溫度維持在SU-8的玻璃轉換溫度(Tg)以上，在均勻電場的作用下，透過靜電力的拉伸而形成非球面狀的微透鏡。微透鏡的曲率半徑可在靜電力拉伸的過程中，透過施加不同電場強度予以控制。本研究並量測SU-8光阻的光譜特性，以驗證SU-8材料適合光學透鏡製作。量測結果顯示，SU-8在可見光至近紅外光波段(380 nm至1600 nm)的光穿透特性極佳。此外，SEM顯示成型後之微透鏡具有良好的表面平滑度，其有利於光纖光學性能的提升。本研究亦透過光學軟體ZEMAX®，來模擬光纖透鏡之光束傳播路徑，模擬結果顯示與利用雷射光在螢光染劑中所激發之實驗光束路徑一致。
為評估所製作之光纖透鏡效能，本研究以波長為1310 nm 的Fabry-Perot雷射晶片，與光纖透鏡進行耦光。量測結果顯示，塑膠光纖透鏡的耦合效率，在工作距離為90 μm時，有效地提高至78% (R=48 μm)，相較於平端光纖高出近2倍。玻璃光纖透鏡的耦合效率在工作距離為24 μm時，提高至72% (R=23 μm)，相較於平端光纖高出2.3倍。本研究提出以靜電力拉伸製作光纖透鏡的技術，不僅改善了部分光纖耦合技術的製程複雜、無法量產等缺點，並能有效地降低成本，且達到提升光纖耦合效率的目的，相當具商業化的潛力。

This paper proposed a low-cost and high-throughput method to fabricate lensed optical fibers. SU-8 Photoresist is used as the material for fabricating the proposed lens structure and is directly applied on two kinds of optical fiber tip, single mode glass fibers (O.D.=125 μm) and plastic graded-index plastic fiber (O.D.=500 μm), utilizing surface tension force to form a hemi-circular shape lens structure. The hemi-circular shape SU-8 lens is then electrostatically pulled to form non-spherical shape in an uniform electric field at a temperature higher than the glass temperature (Tg) of SU-8. Microlens with various radius of curvature can be easily produced by tuning the applied electric fields during the electrostatic pulling process. In addition, this study also measures the UV-Vis-NIR spectrum SU-8 photoresist to confirm the optical property of SU-8. Results indicate the SU-8 has high optical transmittance from the wavelength range of 380-1600 nm. SEM observation also indicates the fabricated SU-8 microlens has excellent surface smoothness which is essential for optical applications. A commercial optical simulation software of ZEMAX® is used to predict the light path of the fabricated lensed fiber. The numerical results show good agreement with the experimental test obtained by projecting laser light into a diluted fluorescence solution.
Furthermore, a Fabry-Perot laser chip with the wavelength of 1310 nm is used for light coupling test for the fabricated lensed fibers. Results show the coupling efficiency is up to 78% at working distance of 90 μm while using the plastic lensed fiber (R =48 μm), which is around 2 fold higher than that of a flat-end fiber. The coupling efficiency of glass lensed fiber (R =23 μm) is up to 72% at working distance of 24 μm, which is around 2.3 fold higher than that of a flat-end fiber. The proposed method is feasible of producing high-quality lensed optical fiber in a high throughput and low-cost way. The method proposed in the current study may give substantial impacts on fabricating lensed fiber in the future.

目錄 I
圖目錄 IV
表目錄 VII
簡寫表 VIII
符號表 X
摘要 XI
Abstract XIII
第一章 緒論 1
1.1 前言 1
1.2 光纖的分類 4
1.2.1 依材料區分 4
1.2.2 依模態區分 5
1.3 光纖透鏡結構 8
1.4 文獻回顧 9
1.4.1 透鏡組裝式之光纖耦合技術 10
1.4.2 光纖透鏡式之光纖耦合技術 11
1.5 研究動機與目的 19
1.6 論文架構 20
第二章 理論分析 22
2.1 光纖通信用光源簡介 22
2.2 模態匹配與耦合理論 23
2.2.1高斯光束(Gaussian beam) 23
2.2.2 模態匹配(Mode matching) 24
2.2.3 耦合效率分析 26
2.3 庫侖定律與靜電力 29
2.3.1 庫侖定律與電場強度 29
2.3.2 靜電力拉伸理論 31
2.3.3 實驗操作概念 33
第三章 光纖微透鏡之製作及其特性量測 35
3.1 SU-8光阻簡介 35
3.2光纖透鏡製程 37
3.4 光學性質之量測 44
3.4.1 光纖聚焦之量測架構 44
3.4.2 光束路徑傳播之量測架構 45
3.4.3 光束路徑傳播之模擬方法 46
3.4.4 耦合效率之量測架構 47
第四章 結果與討論 49
4.1 SEM探討 49
4.2 透鏡曲率與電場關係 50
4.3 光纖聚焦之量測結果 53
4.4 光束路徑傳播之量測與模擬結果 55
4.5 耦合效率之量測結果 56
第五章 結論與未來展望 61
5.1 結論 61
5.2 未來展望 62
參考文獻 63
自述 67

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