臺灣博碩士論文加值系統

電致吸收調變器易於與其他半導體元件整合，且具有高速與低操作偏壓特性，所以已逐漸成為光纖網路中重要的一環。為了使元件更適合操作於高頻環境，往往造成元件與光纖之插入損耗過大、耦合誤差容忍度不佳。利用整合光模轉換耦合器與電致吸收調變器以提升元件與光纖之插入損耗，並提高耦合誤差容忍度。本文接續先前工作，利用濕蝕刻與選擇性底切蝕刻主動波導來製作光模轉換耦合器與電致吸收調變器之整合元件。同時用高能量離子轟擊波導漸變區以提高波導漸變區之電阻、降低電容，並且可確保光模轉換效率與高速特性。
主動區與漸變式主動波導為p-InP、量子井與n-InP之三明治結構所構成，而光模轉換耦合器之被動波導為InGaAsP與InP交替磊晶而成。使用HBr溶液蝕刻漸變寬度為6um至8um之主動波導，並利用H2O2溶液來選擇底切蝕刻主動波導，接著藉由蝕刻方式在主動式波導下方蝕刻被動式波導。利用E-Beam蒸鍍機蒸鍍p金屬:Ti/Pt/Au與n金屬:Ni/AuGe/Ni/Au。使用PMGI製作元件平坦化與金屬攀爬之橋樑，最後蒸鍍微波餽入區與負載區之共平面式電極Ti/Au。最終，漸變式波導長度為350um。
本文已成功引入濕蝕刻技術來製作光模轉換耦合器與電致吸收調變器之整合元件。光纖與元件耦合插入損耗約為12.5dB，1V調變消光比為10dB(1570nm, TE)、10dB(1570nm, TM)。藉由Fabry-Perot方式估計光模轉換損耗約為2dB。由於使用離子佈植製程技術降低元件波導漸變區之電容、且提升該區電阻，其最終電-光頻寬約為45GHz。

Semiconductor Electroabosortion Modualtor (EAM) has become an important element in optical fiber communications because of its capability to integrate with other semiconductor devices, high-speed and low driving voltage. However, high optical insertion loss and low tolerance in optical power coupling are main general problems to be solved in order to get high electro-optical (EO) efficiency. Monolithically integrating EAM with optical spot-size converter (SSC) can lead to high-efficiency single-mode fiber coupling, but the price is on the complex fabrication methods. In this paper, based on previous work, the selective undercut etching active region (UEAR) and the whole wet-etching techniques are employed to fabricate the integration of laterally tapered SSC and EAM. Also, by applying the ion-implantation in SSC region, the reliable transfer efficiency and also high-speed performance are obtained based on the high resistance and low parasitic capacitance in SSC.
The active region containing 10 strain compensated multiple-quantum-wells (MQWs) sandwiched by n-InP (bottom) and p-InP (top) for the electroabsorption region of EAM and also the top region of lateral tapered SSC. The converted waveguide in SSC consists of alternating InGaAsP and InP layers. An HBr-base etching solution is first used to define the top p-cladding with the widths of from 6um to 8um. An H2O2-base solution is then utilized to selectively undercut-etch the MQWs from InP material. The active waveguide p-cladding in EAM is set as 8um. After defining EAM and SSC, the converted waveguide is fabricated by aligning the top SSC and then wet-etched. By using an e-beam evaporator, Ti/Pt/Au and Ni/AuGe/Ni/Au are deposited as p- and n-type metallization, respectively. PMGI is spun serving as the passivation, planarization and bridging. The microwave coplanar waveguide (CPW) line is finally defined by depositing Ti/Au for microwave load- and feed- lines and connecting EAM. The length of SSC is 350um.
The Spot-Size Converter monolithically integrated with Electroabsortion Modulator using whole wet-etching technique is demonstrated. –12.5dB of fiber-to-fiber insertion loss and 10dB (TE) 10dB(TM) extinction ration in 1V(1570nm excitation) is obtained in this device. Using Fabry-Perot method, the average optical transfer loss in SSC is extracted to be 2dB, quite consistent with simulation results. By applying ion-implantation on SSC, the broadband EO performance 45GHz of –3dB bandwidth is achieved for 100um long device due to the low capacitance and the high resistivity in SSC.

目錄.....................................................................................2
致謝.....................................................................................4
中文摘要.............................................................................6
英文摘要.............................................................................8
第一章 緒論......................................................................10
1.1 前言............................................................................10
1.2研究動機.....................................................................10
1.3 研究步驟....................................................................11
1.4 論文架構....................................................................11
第二章 理論基礎與基本模擬..........................................13
2.1 電致吸收調變器....................................................... 13
2.2 光模轉換耦合器........................................................16
2.3 小結.............................................................................20
第三章 理論計算與元件特性提升...................................21
3.1主動區波導寬度之計算............................................. 21
3.2離子佈植之運用..........................................................24
3.3 小結............................................................................ 26
第四章 元件製作...............................................................28
4.1製作P型脊狀光波導....................................................29
4.2 N型電極與被動式導之製作.......................................33
4.3 Mesa與平坦化製程....................................................35
4.4 蒸鍍共平面式電極與切割線蝕刻..............................37
4.5 元件截面圖..................................................................38
第五章 結果與討論............................................................39
5.1 TLM接觸電阻量測.......................................................39
5.2 光輸出與偏壓關係.......................................................41
5.3 微波S參數....................................................................46
5.4 電-光頻率響應.............................................................47
5.5 討論..............................................................................48
第六章 結論.......................................................................54
參考文獻............................................................................55

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