本論文透過雷射近場波前重建來探討雷射與光纖透鏡的耦合機制。雷射與光纖的耦合在雷射近場範圍，為了探討雷射與光纖的耦合機制，需先量測雷射近場光場(包括能量與相位)。雷射近場能量分佈可藉由顯微物鏡與CCD攝影機測得，而雷射近場相位分佈，由於雷射光點尺寸太小(~μm)，相位不易直接測量，本文利用相位補償演算法，取兩組雷射近場能量平面的分佈，計算出雷射近場的相位分佈，結合雷射近場能量分佈與相位分佈，即可重建雷射近場光場。光纖透鏡係由研磨與融燒方式製作而成，將光纖透鏡與波長980nm的二極體雷射進行耦合，透過量測建立光纖透鏡表面形狀模型，並計算雷射近場光場經過光纖透鏡之後的光場，配合光纖透鏡與980nm二極體雷射的耦合結果，說明耦合機制。
透過光束傳播法，我們發現光纖透鏡在雷射與光纖的耦合機制中，主要作用在於改變雷射近場相位分佈，將雷射近場相位從較彎曲的曲面轉變為近似平面波相位的平緩曲面，提高雷射與光纖的耦合效率。其中以縱軸曲率半徑為2.7μm的橢圓錐形光纖透鏡最能將雷射光場相位轉變為類似平面波相位的平緩曲面，其經過光纖透鏡之後的雷射近場相位與平面波相位的差異為0.283 radian，耦合效率是76%，為實驗中耦合效率最高、使雷射相位最接近平面波相位的光纖透鏡。

Applying laser near-field wavefront reconstruction, we have discussed the coupling mechanism of the laser and optical lensed fiber. The coupling of the laser and optical lensed fiber is in the near-field range. In order to discuss the coupling mechanism of the laser and optical lensed fiber, we had to measure laser beam in near-field(including intensity and phase).The laser near-field intensity could be measured directly with an objective and a CCD camera. Because the laser spot size was too small, it was difficult to measure the laser near-field phase directly. Therefore, we used the phase retrieval algorithms, intercepting two groups of laser near-field intensity distribution plane to calculate laser near-field phase distribution. Combining laser near-field intensity distribution and phase distribution, we could rebuild laser beam in near-field. Lensed fiber is fabricated by means of grinding and fusing. We measured the coupling efficiency of the lensed fiber and laser diode(the wavelength of laser beam is 980nm), and simulated the surface of the lensed fiber with software. Applying beam propagation method, we could calculate the laser near-field distribution which propagated through lensed fiber, and cooperate the coupling efficiency of the lensed fiber and laser diode to explain the coupling mechanism.
In summary, we discovered that the lensed fiber in the course of the coupling mechanism of the laser and optical lensed fiber changed the laser near-field phase from a bending curved surface into a flat curved surface just like the phase of plane wave, and it also improved the coupling efficiency.

中文摘要.....................................................................................................I
Abstract......................................................................................................II
致謝..........................................................................................................III
內容目錄..................................................................................................IV
圖表目錄..................................................................................................VI
第一章 緒論..............................................................................................1
1.1 研究背景.....................................................................................1
1.2 研究動機.....................................................................................3
1.3 文獻回顧.....................................................................................4
1.3.1 高斯光束..........................................................................4
1.3.2 繞射理論..........................................................................7
1.4 論文架構.....................................................................................9
第二章 理論基礎....................................................................................10
2.1 雷射特性...................................................................................10
2.2 模態耦合理論...........................................................................13
2.3 相位補償演算法.......................................................................15
2.4 光束傳播法...............................................................................18
第三章 光纖透鏡製作與量測................................................................22
3.1 光纖透鏡製作...........................................................................22
3.1.1 光纖研磨機台................................................................22
3.1.2 光纖透鏡製程................................................................24
3.2 光纖透鏡量測...........................................................................31
3.2.1 光纖透鏡外型量測........................................................31
3.2.2 耦光效率量測................................................................32
第四章 雷射近場重建與數值模擬........................................................43
4.1 雷射近場重建...........................................................................43
4.1.1 雷射近場能量分佈........................................................43
4.1.2 雷射近場相位分佈........................................................51
4.2 數值模擬...................................................................................56
4.2.1 光束傳播法....................................................................56
4.2.2 模態耦合與光纖透鏡....................................................60
第五章 結論與未來工作........................................................................76
5.1 結論...........................................................................................76
5.2 未來工作...................................................................................77
參考文獻..................................................................................................78

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