本論文中，我們提出一個能有效耦合光纖與矽通道波導的光耦合器。透過rib waveguide幾何結構與模態場分布、tapered coupler與graded-index layer的基本原理，設計一製程簡單、誤差容忍度大且在尺寸差異極大的狀況下耦合效率亦高的元件。
利用調變氫氣含量使折射率漸變的非晶矽（Amorphous Silicon）薄膜製作與光纖模態場吻合的大尺寸波導，使光在入射端面能量損失低的情況下，產生向下方單晶矽波導結構傳遞的趨勢，在配合分層式、分段式的taper結構，使光場產生在垂直方向與水平方向的模態大小的變化，使模態能在較低的損耗下縮小到與輸出端波導模態分佈類似。由於導光層的矽（Silicon）與包覆層的二氧化矽（Silicon Oxide）產生的高折射率差，這樣的結構變化中對光仍擁有很好的侷限能力，最後使光纖的入射光有效率的耦合進末端的單模脊狀矽波導之中。

〔1〕Y. Cai, T. Mizumoto, E. Ikegami, and Y. Naito, “An effective method for coupling single-mode fiber to thin-film waveguide,” IEEE Journal of Lightwave Technology, Vol. 9, pp. 577-853(1991)
〔2〕U. Jain, A. Sharma, K. Thyagarajan, and A. K. Ghatak ,“Coupling characteristics of a diffused channel-waveguide directional coupler,” Journal of Optcal Society, Vol. 72, No. 11, pp. 1545-1549(1982)
〔3〕P. E. Barclay, K. Srinivasan, M. Borselli, and O. Painter , “Efficient input and output fiber coupling to a photonic crystal waveguide,” Optical Letters, Vol. 29, No. 7, pp. 697-699(2004)
〔4〕K. O. Hill, and G. Meltz, “Fiber Bragg Grating Technology Fundamentals and Overview,” Journal of Lightwave Technology, Vol. 15, No. 8, pp. 1263-1276 (1997)
〔5〕G. Roelkens,* D. V. Thourhout, and R. Baets, “High efficiency grating coupler between silicon-on-insulator waveguides and perfectly vertical optical fibers,” Optical Letters, Vol. 32, No. 11, pp. 1495-1497(2007)
〔6〕R. G. Wilson, “Ball-lens coupling efficiency for laser-diode to single-mode fiber: comparison of independent studies by distinct methods,” Applied Optics, Vol. 37, No. 15, pp. 3201-3205(1998)
〔7〕R.G. Hunsperger, Intergratrd Optics,Fifth Edition,pp. 114-127(2002)
〔8〕R. Ulrich, and R. Torge, “Measurement of Thin Film Parameters with a Prism Coupler,” Applied Optics, Vol. 12, No. 12, pp. 2901-2908(1973)
〔9〕P. P. Ingrid Moerman, and P. M. Van Daele, “A review on fabrication technologies for the monolithic integration of taper with III-V semiconductor devices,”IEEE Journal of selected topics in Quantum Electonics, Vol. 3, No. 6, pp. 1380-1320(1997)
〔10〕A. R. Nelson,“Coupling optical waveguides by tapers,” Applied Optics Vol. 14, No. 12, pp. 3012-3015 (1975)
〔11〕T. Shoji, T. Tsuchizawa, T. Watanabe, K. Yamada, and H. Morita,“Low loss mode size converter from 0.3μm square Si wire waveguides to singlemode fibres,” Electronics Letters, Vol. 38 No. 25, pp. 1669-1670(2002)
〔12〕M. B. Frish, J. Fijol, E. E. Fike, S. A. Jacobson, P. B. Keating, W. J. Kessler, and J. LeBlanc,“Coupling of single mode fibers to planar Si waveguides using vertically tapered mode converters,” Confluent Photonics Corp., 2002, http://www.confluentphotonics.com/
〔13〕P. Sewell, T. M. Benson, and P. C. Kendall,“Rib Waveguide Spot-Size Transformers:Modal Properties,” Journal of Lightwave Technology, Vol. 17, No. 5, pp. 848-855(1999)
〔14〕T. Wu, Z. X. Wang, and D. X. Huang, “Theoretical analysis of a tapered-rib semiconductor optical amplifier,” Optics Communications- Elsevier（2002）
〔15〕S. S. Saini, V. Vusirikala, R. Whaley, F. G. Johnson, D. Stone, and M. Dagenais, “Compact Mode Expanded Lasers Using Resonant Coupling Between a 1.55-μm InGaAsP Tapered Active Region and an Underlying Coupling Waveguide,” IEEE Photonics Technology Letters, Vol. 10, No. 9, pp. 1232-1234(1998)
〔16〕 D. X. Dai, S. L. He, and H. K. Tsang, “Bilevel Mode Converter Between a Silicon Nanowire Waveguide and a Larger Waveguide,” Journal of Lightwave Technology, Vol. 24, No. 6, pp. 2428-2433(2006)
〔17〕A. Delage, S. Janz, D. X. Xu, D. Dalacu, B. Lamontagne, and A. Bogdanov,“Theoretical analysis of a tapered-rib semiconductor optical amplifier,” Optical Components and Devices, edited by J. C. Armitage, S. Fafard, R. A. Lessard, G. A. Lampropoulos, Proceedings of SPIE vol. 5577,pp. 204-212(2004)
〔18〕S. Janz, A. Delbge, A. Bogdanov, D. Dalacu, B. Lamontagne, and D. X. Xu,“Graded index waveguide couplers for silicon-based microphotonics,” 1st IEEE International Conference on Group IV Photonics, pp. 148-150(2004)
〔19〕V. Nguyen, T. Montalbo, C. Manolatou, A. Agarwal, C. Y. Hong, J. Yasaitis, L. C. Kimerling, and J. Michel, “Silicon-based highly-efficient fiber-to-waveguide coupler for high index contrast systems,” Applied Physics Letters 88, (2006)
〔20〕蔡惠茹, “矽通道波導與光纖耦合之nanotaper 設計,”清華大學電
機工程學系,碩士論文(2006)
〔21〕BeamPROPTM(BPM) and FullWAVETM(FDTD) from Rsoft Design Group, Inc.
〔22〕劉鎧銘, “利用時域有限差分法針對一維光子晶體超稜鏡效應在多工分波元件模擬量測方法之建立與分析,”清華大學電機工程學系,碩士論文(2004)
〔23〕M. Quirk, J. Serda 著, 劉文超, 許渭州 校閱, 劉文雄, 蔡榮輝 譯 “Semiconductor Manufacturing Technology,”,滄海書局出版
〔24〕P. V. Zant 著, 姜庭隆議譯, 李佩雯校閱, “半導體製程－第四版,”滄海書局出版
〔25〕宋憬智﹐“利用Expanded-Core 結構耦合光纖與矽通道波導，”清華大學電機工程學系﹐碩士論文（2008）
〔26〕S. P. Pogossian, L. Vescan, and A. Vonsovici, “The Single-Mode Condition for Semiconductor Rib Waveguides with Large Cross Section,” Journal of Lightwave Technology, Vol. 22, No. 8, pp. 1923-1929(1998)
〔27〕A. G. Rickman, G. T. Reed, and F. Namavar, “Silicon-on-Insulator Optical Rib Waveguide Loss and Mode Characteristics,” Journal of Lightwave Technology, Vol. 12, No. 10, pp. 1771-1776(1994)
〔28〕M. Maguchi, and K. Origaki, “Effect of hydrogen dilution on the optical properties of hydrogenated amorphous silicon prepared by plasma deposition,” Philosophmicaagla Zinbe, 1999, Vol. 79, No. 3, pp. 387-405(1999)
〔29〕D. Marcuse, “Radiation losses of step-tapered channel waveguides,” Applied Optics Vol. 19, No. 21, pp. 3676-3681(1980)
〔30〕M. Krause, H. Renner, and E. Brinkmeyer,“Polarization-Dependent Curvature Loss in Silicon Rib Waveguides,” IEEE Journal of Selected Topics in Quantum Electronics, Vol. 12, No. 6, pp. 1359-1362(2006)