絕緣體上鍍矽波導在近幾年來被高度地關注並應用於光積體電路中，這是由於其高折射率差的結構特性能夠產生較強的光場侷限效果，進而實現光積體電路微型化的目的。然而，絕緣體上鍍矽波導結構本身具有強烈的極化相依現象，因此限制了和其他光學元件的相容性。過去提出了許多極化轉換器的相關研究，而大部分的設計為了達到高極化消光比和低鑲嵌損耗的特性，通常會忽略元件長度的考量，因而無法得到微型化的極化轉換元件。
在本研究中我們引入表面電漿效應來縮短極化轉換所需的長度，進而達到元件尺寸微型化的目的。首先，我們利用三維有限元素法(3D-FEM)來分析我們所設計的雙向漸變金屬結構極化轉換器，由模擬結果顯示，極化消光比會隨著金屬覆蓋面積的比例增加而上升，並隨著間隔層的厚度增加而減少。因此我們透過最佳化的程序，可以達到垂直極化光轉水平極化光在元件長度為5.2 μm時有20.76 dB的極化消光比和2.89 dB的鑲嵌損耗，水平極化光轉垂直極化光則是在元件長度為5 μm時有17.36 dB的極化消光比和2.7 dB的鑲嵌損耗結果。
除此之外，我們也提出傾斜金屬光柵和矩形波導所組成的極化轉換器，當固定金屬光柵的傾斜角時，極化消光比會隨著金屬結構的比例上升而增加，並隨著間隔層厚度的增加而減少。因此我們透過結構參數的優化，得到水平極化光轉垂直極化光時，元件長度為2.2 μm、極化消光比為17.36 dB和鑲嵌損耗為2.7 dB的結果，成功地利用表面電漿效應縮短極化轉換器的長度。

Silicon-On-Insulator (SOI) waveguides have attracted great attention for their ability to confine light in a small region. However, one of the main drawbacks of SOI waveguides is their strong polarization dependence. To overcome this issue, variety types of silicon-based polarization rotators have been proposed with long device lengths to achieve sufficient extinction ratios and low insertion losses.
We first utilize the surface plasmon polariton (SPP) effect to design an ultra-compact polarization rotator consisting of a SOI waveguide covered by a linearly tapered aluminum with a silica gap. The numerical results from a three-dimensional finite element method (3-D FEM) show that the extinction ratio can be enhanced by increasing the device length and reducing the gap. We can obtain a 5.2-μm long polarization rotator with 20.76-dB extinction ration and 2.9-dB loss for TM–TE conversion, and 5-μm long device length with 17.36-dB extinction ration and 2.7-dB insertion loss for TE–TM conversion.
We have also proposed a tilt-metal-grating polarization rotator to achieve TE–TM conversion with high extinction ratio. The polarization conversion efficiency is in proportional to the increased metal thickness and decreased silica gap. Finally, we can obtain a 2.2-μm long polarization rotator with 20.84-dB extinction ration and 3.3-dB insertion loss by optimizing the performance of the rotator.

誌謝......................................................................................................................i
中文摘要…………………………………………………………………..…...ii
Abstract………………………………..……………………..………………..iii
目錄………………………………………………………………….…… ......iv
表目錄…………………………………………………………..……………..vi
圖目錄………………………………………………………….……………..vii
第一章 緒論……….…………………………………………………...…...........…1
1-1 絕緣體上鍍矽光波導……………………………...……………….1
1-2 極化分集系統……………………………………………………....2
1-3 極化轉換器……………………………………………………...….3
1-4 混和式表面電漿波元件…………………………………………….7
1-5 研究動機…………………………………………………………..11
第二章 表面電漿波………………………………………...……..........…...........13
2-1 表面電漿波簡介…………………………………..………….........13
2-2 表面電漿波之共振模態………………………………..…….....…14
2-3 表面電漿波之激發架構………………………………..………….22
第三章 漸變金屬極化轉換器之數值分析……………………..……..……....26
3-1 漸變金屬結構之極化轉換器……………………………….....…26
3-2 雙向漸變金屬極化轉換器……………………………...…………29
3-3 雙向漸變金屬極化轉換器之特性分析………………………..….33
第四章 傾斜金屬光柵極化轉換器之數值分析………………….……….......46
4-1 金屬週期性結構之極化相關元件…………………….…………..46
4-2 傾斜金屬光柵極化轉換器………………….…………….……….48
4-3 傾斜金屬光柵極化轉換器之特性分析………………….………..52
第五章 結論…………………………………………………………………........62
第六章 參考文獻…………………………………………………………….......63

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