絕緣層上覆矽(Silicon-on-Insulator, SOI)是近年來廣泛應用在高速且低功耗電子元件，因為具有高折射率係數可大幅縮小元件體積,同時製作方式與互補式金屬氧化物半導體(Complementary Metal Oxide Semiconductor, CMOS)製程相容，有利於光電積體電路的發展。本文研究設計的馬克-詹德方向耦合器(Mach-Zehnder Directional Coupler, MZDC)，它是由一段短的延遲長度，在前端與後端加上方向耦合器所組成;馬克-詹德方向耦合器比多模干涉器(Multimode Interference, MMI)有著任意分光率的優點，也可以克服方向耦合器(Directional Coupler, DC)製程容忍度低及波長敏感的缺點。文中將設計不同分光率的馬克-詹德方向耦合器，探討其分光率在C-band (1530~1565nm)的輸出比例是否對波長有不敏感的現象。
數位時代的來臨，視訊廣播由數位式取代傳統類比傳輸方式，我們將數位電視傳輸系統結合現有的被動光網路系統，運用分光比95/5馬克-詹德方向耦合器取代50/50光耦合器以利光電積體電路的整合，其中分光比5%給下行用戶端做觀看；且將分光比95%做為注入鎖模的上行傳輸，並成功將SOI元件應用與光通訊系統中，且並不影響訊號品質與強度。
差動相位偏移調變系統(Differential Phase Shift Keying, DPSK)對雷射的頻譜要求相對低，進而對於色散及偏振模色散(Polarization Mode Dispersion, PMD)的容忍度高，增加傳輸距離。差動相位偏移調變系統接收端與振幅調變系統不同是在為了恢復未編碼前的二進位制數據，需加入一個延遲干涉儀做解調變功能。此延遲干涉儀由多模干涉器和馬克-詹德方向耦合器與延遲100 ps的路徑組成，其中100 ps延遲對應於兩路徑長度差為8689.6 m，也等同於10 Gb/s的調變速率。影響傳輸品質與延遲干涉儀輸出的隔離度(Isolation)特性有關，其主要參數為延遲路徑的光損耗及馬克-詹德方向耦合器的分光率，我們在延遲干涉儀前端使用分光率為50/50的多模干涉器，而後端使用可任意分光的馬克-詹德方向耦合器來優化DPSK的隔離度，實驗數據顯示在1550 nm與1552 nm，其隔離度最大為9 dB。

Silicon-on-insulator (SOI) has been widely utilized in high-speed and low-power electronics these few years due to its high refractive index to significantly reduce the component size and processing compatibility with complementary metal oxide semiconductor (CMOS), which advantages the developing of optoelectronic integrated circuits. Mach-Zehnder directional coupler (MZDC) is composed by two directional couplers connected with a short phase delay length. Compared with the multimode interferometer (MMI), MZDC owns the advantage of any splitting ratio and wavelength independence. In this thesis, different ratios from MZDC will be designed and demonstrated in the wavelength range from 1530 nm to 1565 nm.
In the digital communication applications, the Digital Video Broadcasting replaces traditional analog transmission. We digitized the television transmission system with the existing passive optical network system. Then a SOI based 95/5 splitting ratio MZDC was used to replace the fiber coupler for facilitating the integration of optoelectronic integrated circuits. For downstream signal, a 5% MZDC ratio was routed to the user and 95% was reserved for the upstream transmission, which was illustrated using direct modulated injection locking scheme in thesis. We successfully demonstrated the SOI based MZDC practically applied onto optical communication systems.
Differential Phase Shift Keying (DPSK) modulation system requires relatively low laser spectral quality, and then owns more tolerance for chromatic dispersion and polarization mode dispersion besides the extended transmission distance. Different from the amplitude demodulation, DPSK receiving is constructed by the delayed interferometer.
Using the 100-ps optical phase difference, corresponding to a path difference of 8689.6 μm, and two couplers through the MMI and MZDC, a delayed interferometer demodulator was demonstrated for 10 Gb/s DPSK demodulation. Meanwhile, the characteristic optical isolation from the delayed interferometer output is strongly dependent on the optical propagation loss and MZDC ratios. Because of the tunable laser source tunability, 50/50 ratios from MMI and MZDC were utilized to demonstrate the DPSK isolation as 9 dB only between 1550 to 1552 nm wavelengths.

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