在本論文，描述一個新型的塑膠透鏡光纖架構，其優點是光源距離塑膠透鏡光纖的工作距離很長時，還能保有很高的耦光效率，並利用實驗來證明之。此塑膠透鏡光纖架構是利用雷射焊接技術，將非球面凹凸塑膠透鏡焊接在平頭光纖上，形成非球形端面的透鏡光纖。藉由塑膠透鏡的設計，不但可以增加工作距離，並保持著高耦合效率；根據本論文的設計結果，可以將工作距離延長至300μm，並耦合效率保持在80％。此外，根據實驗的結果顯示，雷射焊接技術具有較小的熱影響區、較高的焊接強度…等；但由於雷射焊接技術的一些限制條件，而導致無法廣泛的應用，所以在本篇論文研究中，將改善雷射焊接技術，使雷射焊接技術不再侷限在限制條件，使其擴展雷射焊接的應用。

A novel lensed plastic optical fiber (LPOF) scheme to achieve the high coupling efficiency with a long working distance between the light source and LPOF is proposed. The advantages of the proposed LPOF are demonstrated by proofs of the experiment. In this study, an aspheric convex-concave plastic lens (CCPLs) is bonded with a flattened end of the plastic fiber by using the laser transmission welding (LTW) to form an aspheric-endface fiber. The working distance between the light source and LPOF can be increased with high coupling efficiency by the design of the CCPLs. According to the proposed design in this study, the working distance and the coupling efficiency can reach to 300μm and 80%, separately. Furthermore, the analysis shows that the LTW can achieve a high welding strength and a small heat affected zone that meets the commercial utilization. But the LTW technology has some restrictions, the disadvantages of the LTW technology are improved in this study to spread the application of the laser welding.

謝 誌..............................................................................................................................1
Content ...........................................................................................................................2
List of figures.................................................................................................................4
List of tables...................................................................................................................6
摘要................................................................................................................................7
Abstract ..........................................................................................................................8
Chapter 1 Introduction...................................................................................................9
1-1 Introduction of the plastic optical fiber (POF) ................................................9
1-2 The lensed fiber structures .............................................................................10
1-3 Introduction of the plastic lens ......................................................................12
1-4 Motivation and purpose .................................................................................13
Chapter 2 Reference Review........................................................................................15
2-1 Introduction of the joining methods of the plastic.........................................15
2-2 The principle of the laser welding method ....................................................16
2-3 Problem..........................................................................................................18
Chapter 3 Analysis and Proposed method ...................................................................20
3-1 Scheme of the lensed plastic optical fiber (LPOF) ........................................20
3-2 Analysis of the laser welding for PMMA material........................................21
3-2-1 Design of the absorbed layer..............................................................21
3-2-2 Analysis of laser energy absorbed for PMMA ...................................23
3-2-3 Experimental results with the PMMA sheet.......................................28
3-2-4 The applied method for an absorbed layer .........................................32
3-3 The hot molding process of the POF .............................................................33
3-3-1 The hot molding amount ....................................................................33
3-3-2 Scheme of the automation molding system........................................33
3-4 Design and analysis of the aspheric plastic lens ............................................36
3-4-1 The entire scheme of the LPOF..........................................................36
3-4-2 Determine to the curvature of a spherical plastic lens ........................36
3-4-3 Optimize performance of an aspheric pla stic lens by ZEMAX .........39
3-4-4 The simulation of the coupling efficiency..........................................44
Chapter 4 Experiments and result ................................................................................46
4-1 The experimental setup ..................................................................................46
4-2 The experimental procedure ..........................................................................46
4-3 The experimental result .................................................................................50
Chapter 5 Conclusion and Further work ......................................................................54
5-1 Conclusion.....................................................................................................54
5-2 Further work ..................................................................................................55
Reference .....................................................................................................................56

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