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研究生(外文):Chi-Kai Chaung
論文名稱(外文):Study of Liquid Crystal Waveguides and Its Applications
外文關鍵詞:liquid crystaloptical waveguideindium tin oxidefused quartz
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石英基板上之液晶光波導為一TM和TE雙極化可調光波導,在未施加電壓時,TE與TM模態都能導光但傳輸損失較大。對於TM 極化,在電壓4.5V前為單模傳輸,直到電壓超過5V時轉變為多模傳輸。兩極化的輸出光當外加電壓達4.5V時光強度開始增強,隨著電壓持續增加,傳輸損耗會逐漸變小,直到電壓達到10V時趨近於飽和。TM模態傳輸損耗最低為0.94 dB/cm,TE模態傳輸損耗最低為7.9dB/cm。

We present two new structure of liquid crystal waveguide, its advantage is simple fabrication, low cost and without restrict lattice structure of substrate. Waveguide can be fabricated in any direction. In etching process, we provide ultrasonic etch method and a novel metal-photoresister etching mask, which can efficiency improvements in the quality of etched structure and reduce the surface roughness after the etching.
In our result, we observe refractive index distribution be changed with applied voltage, It can be applied to modulate transition modes and output intensity in waveguide. In B270 substrate liquid crystal waveguide (LCWG), that is TE mode tunable optical waveguide. At 4.5V will turn waveguide on in single-mode and over 7V will be turn to multi-mode. The output intensity and transition mode increases with more electric field. Output intensity is saturation in voltage over 10V. The propagation loss can decreases with higher voltage, and it achieved 1.31dB/cm at 10 V. A maximum extinction ratio is 27.3 dB when the applied voltage was reversed.
In quartz substrate LCWG is TM and TE mode tunable optical waveguide, without applied voltage it can propagate two modes light but the propagation loss is higher. For TM mode is single mode at 4.5V and voltage over 5V will be turn to multi mode. The TM and TE mode output intensity and transition mode increases with more electric field. Output intensity is saturation in voltage over 10V. The TM mode propagation loss is 0.94dB/cm and TE mode propagation loss is 7.9dB/cm when voltage is 10V. In future, it can be an important component in integrated optical circuits.

中文摘要 i
英文摘要 ii
誌謝 iii
目錄 iv
表目錄 vi
圖目錄 vii
第一章 緒論 1
1.1光波導簡介 1
1.2液晶核心光波導簡介 2
1.3 內容簡介 6
第二章 液晶核心光波導特性與原理 7
2.1液晶簡介 7
2.1.1液晶分子的基本構造與分類 7
2.1.2液晶之種類 8
2.1.3液晶之雙折射性 12
2.1.4介電常數異向性 14
2.1.5液晶連續體彈性理論 14
2.1.6溫度對向列型液晶影響 15
2.1.7液晶分子排列秩序參數 16
2.1.8液晶的配向技術 17
2.2基板材料光學特性 18
2.2.1 B270光學玻璃 18
2.2.2熔融石英 19
2.3液晶核心光波導工作原理 20
2.3.1光的偏振態 20
2.3.2液晶光波導傳輸原理 22
第三章 液晶核心光波導製程與量測 25
3.1 B270基板上製作液晶光波導 25
3.1.1製作流程 25
3.1.2降低蝕刻表面粗糙度 29
3.2石英基板上製作液晶光波導 32
3.2.1製作流程 32
3.2.2蝕刻遮罩製作 35
3.3元件特性量測 39
第四章 實驗結果與討論 44
4.1各種液晶、配向層、與摩擦配向組合的特性量測 44
4.2 B270基板之液晶光波導量測 60
4.2.1光場隨電壓變化之量測 60
4.2.2光強隨電壓變化之量測 62
4.3石英基板之液晶光波導量測 63
4.3.1光場隨電壓變化之量測 63
4.3.2光強隨電壓變化之量測 65
第五章 結論 68
參考文獻 69
中英文名詞對照表 72
附錄:發表於2011年台灣真空學會研討會之論文 75

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