電致吸收光調變器（Electroabsorption Modulator）在長距離光纖通訊中扮演著重要的角色，且其具整合光電積體電路之潛力，但是由於半導體光電元件的模態通常是1×2 μm∼1×3 μm的橢圓模態，而單模光纖則是8 μm的圓形模態，所以此元件直接和單模光纖耦合會有非常大的耦合損耗，通常大約在7-10dB左右[21]，而傳統的方法是利用micro lens 或 tapered fiber去降低耦合損耗，本論文中主要提出了一新穎結構，即利用濕蝕刻方式來整合光點轉換器及電致吸收調變器上以提高耦合損耗。
我們利用底切蝕刻的方法可以調整波導寬度，利用此點可製作熱絕緣之光點轉換器及電致吸收調變器之元件。由於底切蝕刻可降低元件之電容，且光的損耗可由選擇性蝕刻來降低。利用文獻中的折射率模型[1]去找出我們材料的折射率，接著用BPM(Beam Propagation Method)軟體去模擬這結構三維的光模態轉換及耦合效率，又利用等效電路模型來分析微波傳輸，以決定元件結構。
在本論文中利用濕蝕刻及底切蝕刻之方法已成功製作了光點轉換器與行波式電致吸收調變器之整合。本工作已製作出此類的調變器。在光傳輸損耗方面，利用比較沒有光轉換器之調變器下，在1550nm到1570nm的測試下，光之損耗在每端面可平均減少約4dB左右，最高的消光比可達21dB調變效率約為21dB/1V，在高頻調變下其電對光傳輸頻寬約12GHz。

Electro–Absorption Modulator has become a very important element in optical fiber communication due to its capability of integrating with other semiconductor devices. In order to get high-speed performance, the small size of waveguides is necessary. But it also brings to high coupling loss, resulting in low optical fiber link. In general, the waveguide mode is elliptical shape with sizes of 1×2μm to 1×3μm, which will definitely lead to high mode mismatch as adapted to conventional single–mode optical fibers of 8μm circular mode and cause 7~10 dB insertion loss[21]. Typically, micro lens, tapered fibers or taper optical waveguides are used to confine optical fiber mode to waveguide in order to reduce the insertion loss. In the thesis, we have developed a novel structure of tapered optical spot-size mode converter monolithically integrated with traveling-wave electro-absorption modulator (TWEAM) by using whole wet-etching processing.
The optical waveguides are fabricated by wet-etching and subsequent selective undercut etching. By adjusting the wet-etching time, the waveguide core for TWEAM and the tapered spot-size mode converter can thus be engineered. The selective undercut wet etching not only can reduce the optical scattering loss, but also decrease the parasitic capacitance, leading to high optical and microwave transmission of TWEAM. Based on the model described in literature [4-8] and also Beam Propagation Method (BPM), the optical index of epi-layers is used to calculate the three–dimension modal of optical mode and coupling efficiency. The microwave equivalent circuit is used to calculate and design device structure.
In this thesis, the Spot–Size Converter monolithically with Traveling–Wave Electro–Absorption Modulator device is successfully fabricated and demonstrated. TWEAM integrated spot-size optical mode converter is measured and compared with single TWEAM (without converter) with optical wavelength of from 1550nm to 1570nm. The average optical insertion loss of about 4dB is found. The maximum extinction-ratio is about 21dB with modulation efficiency of 21dB/V, E-O response about 12GHz of –3dB bandwidth at 50Ω termination is demonstrated.

目錄..................................................ii
誌謝..................................................iv
中文摘要..............................................vi
英文摘要.............................................vii
第一章 緒論............................................1
1.1 前言 1
1.2 研究動機 2
1.3 研究步驟 3
1.4 論文架構 4
第二章 理論背景........................................5
2.1電致吸收光調變器工作原理 5
2.1.1載子躍遷 5
2.1.2量子侷限史塔克效應（QCSE） 6
2.2光點轉換器種類及工作原理 8
2.2.1光點轉換器種類 9
2.2.2光點轉換器的工作原理 11
2.3結論 13
第三章 光波導設計和行波式電極模擬分析.................14
3.1折射率理論模型與量測比較 14
3.1.1折射率理論模擬與分析 14
3.1.2量測架設及結果比較 15
3.2光波導的模擬分析 18
3.2.1光波導的模擬結果 18
3.2.2材料結構和特性 25
3.3行波式電極模擬分析 27
3.3.1行波式電極 VS.集總式電極 27
3.4 結論 29
第四章 元件製作.......................................30
4.1元件製作步驟 31
4.2結論 45
第五章 量測結果.......................................46
5.1 金半接觸電阻特性 46
5.2 光波導傳輸係數及元件耦合特性 50
5.3電對電傳輸特性 52
5.4 電對光傳輸特性 54
5.5結果討論 56
第六章 結論...........................................59
參考文獻..............................................60

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