臺灣博碩士論文加值系統

我們分別使用1.3mm對稱型結構、1.55mm非對稱型結構之InGaAsP多重量子井來製作半導體光放大器。磊晶結構方面，因非對稱型多重量子井具有寬頻帶的特性，使得可以被放大的光信號波長範圍變寬。於元件結構方面，我們使用傾斜端面結構來降低鏡面殘餘的反射率，以減少因FP共振模態造成的增益波動。
由於傾斜端面結構的反射率和脊狀波導的寬度、偏斜的角度有關，我們使用Marcuse 模型和高斯近似法，模擬TE基模於不同角度下之反射率，模擬的結果表示，在脊狀波導寬度為3mm、 長度為700mm且角度分別為3o、 5o、 7o、 9o時，有低於10-4以下之反射率。在製程方面，我們所採用的是複雜性低的單溝槽製程，用於製作雷射而有著良好的特性，所以應用此方式來製作傾斜波導結構。
量測結果方面，經由I-V量測得知，1.55mm非對稱型結構的雷射因空乏區內的漏電流過大，於室溫下並沒有連續電流的操作特性。而1.3mm對稱型結構於傾斜脊狀波導方面，當角度為0o時，具有臨界電流22.5mA，當傾斜角度為7o時，臨界電流約為0o時的2倍。量測偏壓於臨界電流以下的輸出光譜，當傾斜角度越大時，其Fabry-Perot模態的峰谷差值有變小的趨勢，5o時的反射率估計約減少為0.2，由這些量測結果，皆表示著反射率的降低。

Traveling-wave semiconductor optical amplifiers（TWSOAs）of symmetric and asymmetric multiple quantum wells（MQWs）have been implemented by using angled-facet structures. The asymmetric MQWs structures are designed to increase the wavelength range of the gain spectrum.
The angled-facet structures, which can suppress gain ripple from FP resonance, are of 3mm-wide and 700mm-long ridge waveguides, and of different angles（q）at 3o, 5o, 7o, and 9o. From Marcuse’s model, the calculation shows that the angled-facet structures have reflectivities lower than 10-4. We have also developed a single-trench process to fabricate the angled-facet TWSOAs.
The l=1.55mm asymmetric structure, which shows a low epitaxial quality of large leakage current, is not suitable for SOA application. For the l=1.3mm asymmetric structure, the threshold current（Ith）at q=0o was 22.5mA, while at q=7o the Ith increased to 45mA. We have also measured the spectrum below threshold current. The differences between FP resonance peak and valley become smaller at larger q. We estimated that the reflectivity is about 0.2 at 5o. The results show that the reflectivity was decreased by angled-facet structure.

第一章 簡介……………………………………………………………..1
1-1 前言…………………………………………………………….1
1-2 半導體光放大器……………………………………………….2
1-3 降低端面反射率的元件結構………………………………….4
1-4 論文架構……………………………………………………….5
第二章 理論背景………………………………………………………..7
2-1 半導體光放大器的基本特性………………………………….7
2-2 磊晶結構……………………………………………………...10
2-3 端面反射率之模擬結果……………………………………...11
第三章 製程步驟………………………………………………………18
3-1 傾斜脊狀波導之製程………………………………………...18
第四章 結果分析與討論………………………………………………28
4-1 前言…………………………………………………………...28
4-2 半導體雷射量測結果………………………………………...28
4-2-1 輸出功率對電流曲線…………….………………………28
4-2-2 電流對電壓曲線………………………………………….30
4-2-3 雷射輸出光譜…………………………………………….31
4-2-4 遠場發散角……………………………………………….32
4-3傾斜波導量測結果……………………………………………33
4-3-1輸出功率對電流曲線……………………………………..33
4-3-2電流對電壓曲線…………….…………………………….35
4-3-3 輸出光譜………………………………………………… 36
第五章 結論……………………………………………………………41
參考文獻………………………………………………………………..42

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