光波導調變器一直是發展積體光學最重要的元件之一，在本篇論文中，主要研究在通訊波段1.55微米下的矽電光調變器製作在Silicon-On-Insulator(SOI)基板上。我們成功的利用Spin-on-dopant (SOD)技術取代了離子佈植的方式，其優點包含低成本、製作簡單、不具離子佈值時所造成的表面缺陷、可大量生產等優點且此技術也能和現今的CMOS製程相容。
元件方面是由被動式的波導干涉器，加上相位偏移器組合而成的電光調變器，其中的被動式波導干涉器分為三種：Y型(Y-junction MZI)、傳統式多模干涉型(Original MMI MZI )、串接式多模干涉型(Cascaded MMI MZI)，而相位偏移器則是利用垂直於波導的PN二極體，藉由載子注入的方式達到調變即為自由載子消散效應，上述元件已被成功的製作在SOI基板上，而實驗結果顯示在不同調變長度下的靜態調變深度接近100%調變且調變時達到第一個π相位的輸入功率皆只需約0.2W且上升時間為約為74ns與下降時間約為64 ns，最後為了使二極體切換時間暫態縮短以三端量測方式測得上升時間為約為52ns與下降時間約為48 ns、截止頻率(f3dB)為6.5MHz。

The optical waveguide modulator is one of the most important devices being used in integrated optics. In this thesis, an attention is focused on the development of electro-optic Si-based modulator working at 1.55 μm communication wavelengths. Instead of using the ion implantation, the Spin-on-dopant (SOD) technology is successfully adapted into the fabrication of pn-junction based devices. The advantages associated with use of the SOD include low cost, simplicity, and mass productivity. Furthermore, the SOD method is compatible with standard CMOS process.
The devices under study are the electro-optic modulators combing the passive silicon waveguide interferometer with the phase shifters. Three different configurations of waveguide interferometer are fabricated, namely, the Y-junction MZI, the conventional two 1×2 MMI and the cascaded MMI. The phase shifter is fabricated based on alternating interleaved PN junctions on one section of each MZI arm that are responsible for injecting free carriers into the active region to modulate the optical signal. According to the experimental results shown, a nearly 100% modulation depth is achieved for modulators with different modulation lengths, and only 0.2 W of input power is needed for devices to reach first πphase shift. The devices fabricated on SOI substrates would operate with the rise and fall time of 74ns and 64ns, respectively. Finally, in order to facilitate the optical switching, the device is biased with a three-terminal fashion as a transistor and the result shows that the respective rise and fall time are brought down to 52 ns and 48 ns, while the 3dB cutoff frequency(f3dB) is reached up to 6.5 MHz.

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