高效率之光模轉換器在光連接或光纖通訊中是很重要的光電元件，因為使用光模轉換器可以在不同的光模組、光波導之間做有效率光模態轉換；為了達成體積小的操作，光模轉換器使用直接耦合共振模式與漸變式波導結構以獲得高效率光模轉換在不同模組之間，但是因為直接耦合的共振模式對波長得靈敏度會非常高，這使得利用分波多工(wavelength division multiplexer,WDM)的方式來增加通訊容量技術大大受到限制。
本工作中主要提出分段式的漸變直接耦合共振光波導而達到較寬波段之光模轉換器，並選擇電致吸收光調變器作為例子與其整合，藉由上波導折射率漸近變大光模態會由下波導耦合至上波導當折射率最大時模態會限制在上波導中藉此達成高效率耦合，但固定材料系統下波長的不同所對應的共振點不同，所以利用此種方式在不同區段中之有效折射率不同達到寬波段中的高耦合率。本工作利用光速傳播法模擬，其結果波長1530nm~1550nm的耦合效率大於70%以上，並由光模態圖之轉換確定不同波長不同耦合區域；而本工作中又利用模擬所得設計波導與半導體製程，製作元件利用不同方向光輸入方式，所得到之光電流來比較波長1570nm~1585nm的耦合效率可以被觀察到。

High efficient optical spot size converter (SSC) is one of the most important building blocks for dense optical interconnection network and high-speed optical fiber communications due to efficient optical power transfer between different optical modules. Using tapered optical direction coupler (TODC) as SSC can reduce the dimension with high efficiency because of resonant condition and tapered structure. However, the strong dependence of operation on wavelength leads to narrow band operation, reducing the usage of wavelength division multiplexer (WDM) technique for upgrading optical data capacity through optical spectrum.
In this work, based on multi- resonant points of TODC, a broadband SSC integrated with optical electroabsorption modulator (EAM) is proposed, designed, and fabricated. By tapering quantum well of the top active waveguide (AW), the integration with bottom passive waveguide (PW) can form a TODC. With the tapered structure, the gradually varied effective index forms a resonant point along wave propagation, inducing strong coupling, collecting optical power after resonant point, and thus leading to high efficient coupling. With multi-section of resonant conditions and also tapered structure, broadband operation can be realized. Through 3 section of tapered AW of TODC, the calculated coupling efficiency from bottom PW with larger than 70% is found for the regime of 1530nm~1550nm wavelength. The EAM-integrated SSC is also fabricated. With counter direction of optical coupling, the measured photocurrent in EAM shows a broadband of flap coupling from 1570nm~1585nm is observed, suggesting the multi-section TODC can bring out broadband operation.

論文授權書..………………………………………………..…….….…i
中文審定書..……………………………………………….………..…ii
英文審定書..……………………………………………….….……...iii
誌謝…………..……………………………………………….….…….v
中文摘要…………………………………..…………………..………vi
英文摘要..…………………………………...……….………..…..… vii
目錄……………………………...……………………………...…...viii
圖次……………………………………………………………..……xiv
表次………………………………………………………………….xvi
第一章 緒論……………………………………………………………1
1-1 前言…………………………………………………………………1
1-2 研究動機…………………………………………………………4
1-3 研究步驟……………………………………………………………8
1-4 論文架………………………………………………………………9
第二章 理論介紹…..……………………………………………...10
2-1光點轉換器種類及工作原理……………………………………10
2-1-1光模轉換器種類………………………………………………10
2-1-2光模轉換器工作原理………………………………………13
2-2 電致吸收光調變器工作原理……………………………………16
2-2-1 載子躍遷 ……………………………………………………16
2-2-2 量子侷限史塔克效應（QCSE）……………………………17
2-2-3 電致吸收光調變器之高速特性……………………………19
2-3結論…………………………………………………………………20
第三章 光波導模擬分析……..………………………..……….……21
3-1 磊晶層折射率理論模型…………………………………………21
3-2 光模轉換器之光波導模擬分析…………………………………23
3-2-1光波導之主動波導模擬…………………………………… 23
3-2-2光波導之直接耦合…………………………………………27
3-2-3 光波導之被動波導模擬……………………………………32
3-2-4 分段式主動波導模擬………………………………………33
3-5 結論………………………………………………………………36
第四章 元件製………………………..……………………….……….37
4-1元件製程步驟…………………………………………………… 39
4-12結論………………………………………………………………51
第五章 量測結果與討論………………..…………………………… 52
5-1元件電壓電流曲線…………………………………………………52
5-2 元件與光波導耦合特性…………………………………………53
5-2-1傳輸損耗分析(耦合損耗) …………………………………55
5-2-2傳輸損耗分析(轉換損耗) …………………………………57
5-2-3傳輸損耗分析(轉換損耗) …………………………………59
5-3結果與討論…………………………………………………………61
5-4未來工作……………………………………………………………62
參考文獻……..……………………………………………….……….. 63

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