本篇論文首次提出並製作出，在-x切z傳播方向的鈮酸鋰(LiNbO3)基板，以鋅金屬擴散波導的模態轉換器，並且驗證可操作在633nm的波長。此模態轉換器最大轉換效益的相位匹配電壓與模態切換電壓，分別為12V與5V，其轉換效益可達99.5%；另外在連續六十分鐘長時間量測下，仍可穩定的達到模態間的轉換，並且維持最大轉換效益。
在長時間量測發現，模態轉換電壓在+6V時，操作初期可達到最大轉換效益，但是因光折效應的影響，轉換效益隨著操作時間增長而有逐漸減弱的現象；在本次研究也利用模態轉換器的結構做為相位調制器使用，並且製作一組鈦擴散波導的相位調制器，藉此來觀察鋅金屬與鈦金屬擴散波導對光折效應的影響，從實驗結果顯示鋅擴散波導長時間穩定度優於鈦擴散波導。
此外，本實驗利用偏壓-雷射修正的方法，將鋅擴散波導的光折效應影響減少許多，並且在連續六十分鐘長時間量測下，仍然能穩定的達到最高轉換效益，甚至將輸出光提高至80μW仍可維持穩定的轉換，雖然模態轉換器的切換電壓從原先的5V上升至8V，但是經過偏壓-雷射修正，使得波導內可激發載子大量減少，因此提升在短波長模態轉換器穩定轉換之特性。

In this study, we proposed a Zn-indiffused mode converter fabricated in an -x-cut z-propagation lithium niobate substrate for the first time. The proposed converter was verified that it can operate at a wavelength of 633 nm. It has a stable conversion efficiency of about 99.5% from the input TM polarization to the converted TE one, when it works at the phase-matching voltage of 12V, and mode-conversion switching voltages of 5 V. On the other hand, this converter can still keep the maximum conversion efficiency in a period of 60 min measurement.
During the long-term measurements, although this converter has maximum conversion efficiency at the mode-conversion voltage of 6 V, the maximum conversion efficiency only keeps in the beginning of the measurement. Because of the photorefractive effect, the efficiency will reduce when it works for a long time. In this study, we used the structure of the converter to treat it as a phase modulator, and also fabricated a phase modulator with Ti-indiffused waveguides in the same geometry substrates. Then we compared their operation stabilities under the impacts of the photorefractive effect. The results show that the power-handing stabilities of Zn-indiffused waveguides are better than that of the conventional Ti-indiffused waveguides.
In addition, we used a method of biased-voltage and laser-trimming to suppress effectively the photorefractive effects in the Zn-indiffused mode converter. After treatments, the maximum conversion efficiency is stable even using a higher irradiating power of 80w in a measurement period of 60 min. The improvements are achievable resulting from the stable phase-matching conditions of mode converter after treatments. This effect is attributed to a permanent lowering of the amount of photo-excitable electrons in the channel waveguide. Although the applied voltages of complete conversion are increased from 5V to 8V after treatments, the carrier-depletion effects to suppress the phase-bias drift are still worthwhile evaluations for improving stability of mode converter operating in short wavelengths.

摘 要 i
Abstract ii
誌 謝 iii
目 錄 iv
表 目 錄 vi
圖 目 錄 vii
第一章 緒論 1
1.1 研究背景 1
1.2 研究動機 2
第二章 基礎理論 3
2.1 鈮酸鋰晶體特性 3
2.2 電光效應 3
2.3 模態轉換器 6
2.3.1 指狀電極模態轉換器 6
2.3.2 雙平行電極模態轉換器 7
2.3.3 相位可調模態轉換器 8
2.4 相位調制器 10
2.5 光折效應 12
2.6 偏壓-雷射修正 13
第三章 鋅擴散模態轉換器製程 14
3.1 晶片切割 14
3.2 波導層製作 15
3.2.1 晶片清洗 15
3.2.2 光阻塗佈 15
3.2.3 曝光 16
3.2.4 顯影 17
3.2.5 薄膜沉積 18
3.2.6 光阻掀離 19
3.2.7 熱擴散 19
3.3 晶片研磨與導光量測 20
3.3.1 晶片研磨 20
3.3.2 導光量測 20
3.4 緩衝層製作 22
3.5 電極製作 23
第四章 鋅擴散模態轉換器特性量測與結果分析 26
4.1 切換電壓與模態切換光場量測 26
4.1.1 切換電壓量測與結果 26
4.1.2 模態切換光場量測與結果 28
4.2 長時間穩定度量測與結果 30
4.3 鋅波導穩定度與相位調制器切換電壓量測 32
4.3.1 波導穩定度量測與結果 32
4.3.2 相位調制器切換電壓量測與結果 34
4.3.3 鋅波導相位調制器長時間量測與結果 36
4.4 偏壓-雷射修正方法對操作穩定度之影響 39
4.4.1 相位調制器切換電壓量測與結果 40
4.4.2 模態轉換器切換電壓與重疊積分量測 43
第五章 結論 47
參考文獻 48

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