高效率光波導一直是發展積體光學最重要的元件，然而隨著元件積體化尺寸縮小，光波導損耗變成積體光學發展最重大的阻礙。這篇文章中我們利用簡單的蝕刻及氫鍛燒製程在SOI (Silicon-on-insulator)晶圓上製作出一種新型的矽次微米線波導，經過測量後此線波導傳播損耗及耦合損耗分別為1.26dB/cm、2.5dB/side[33]。在此實驗中我們證明矽次微米線波導在小於500mW的輸入光功率時非線性損耗並不明顯，推估其相對應的等效自由載子生命週期小於10 ns。另外我們在矽線波導中觀測到的四波混頻效應在Pump wave功率為17.8dBm時可產生約-32.84dB的轉換效率，其重要性是可在全矽晶片上製作波長轉換器並應用在分波多工系統(WDM system)上。最後我們也證實了透過施加正確的電場方向我們能控制波導內自由載子密度分布，藉由此特性我們可以進一步製作全矽晶片的光調變器。

High-performance waveguide is always the most important device in integrated silicon photonics. However, as the device size reduces, waveguide loss became significant due to surface roughness. In this paper, we demonstrated a novel silicon wire waveguide on SOI wafers by a simple etching and hydrogen annealing process. According to the measurement, the propagation loss and coupler loss of silicon wire waveguide are 1.26dB/cm and 2.5dB/side[33], respectively we also demonstrated that the nonlinear loss in this silicon wire waveguide was not obvious when the input power was lower than 500mW. We calculated the effective free carrier lifetime shorter than 10ns. Additionally, we observed the four-wave mixing in the silicon wire waveguide, and the maximum conversion efficiency was -32.84dB when the pump power was as high as 17.8dBm. The importance of four-wave mixing could be used for wavelength conversion in DWDM system. Finally, we demonstrated that we could control the free carrier density distribution in the si-wire waveguide by applying electric field at the two sides. Via this mechanism, we can implement a silicon-based optical modulator.

[1] Bahram Jalali, Mario Paniccia, and Graham Reed (2006). “Silicon photonics.” IEEE microwave magazine 7(3):58-68.
[2] Jalali, B. and S. Fathpour (2006). "Silicon photonics." Journal of Lightwave Technology 24(12): 4600-4615.
[3] Lipson, M. (2005). "Guiding, modulating, and emitting light on silicon - Challenges and opportunities." Journal of Lightwave Technology 23(12): 4222-4238.
[4] Lee, K. K., D. R. Lim, et al. (2001). "Fabrication of ultralow-loss Si/SiO2 waveguides by roughness reduction." Optics Letters 26(23): 1888-1890.
[5] Neamen, D. A. (2003). Semiconductor physics and devices : basic principles McGraw-Hill.
[6] Haus, C. M. a. H. A. (2001). Compact mode-size converters for efficient coupling between fibers and integrated optical waveguides. LEOS.
[7] Almeida, V. R., R. R. Panepucci, et al. (2003). "Nanotaper for compact mode conversion." Optics Letters 28(15): 1302-1304.
[8] Vivien, L., S. Laval, et al. (2003). "2-D taper for low-loss coupling between polarization-insensitive microwaveguides and single-mode optical fibers." Journal of Lightwave Technology 21(10): 2429-2433.
[9] Tien, P. K. (1971). "Light Waves in Thin Films and Integrated Optics." APPLIED OPTICS Vol. 10, No. 11: p2395-p2413.
[10] Fischer, U., T. Zinke, et al. (1996). "0.1 dB/cm waveguide losses in single-mode SOI rib waveguides." Ieee Photonics Technology Letters 8(5): 647-648.
[11] Jalali, B., P. D. Trinh, et al. (1996). "Guided-wave optics in silicon-on-insulator technology." Iee Proceedings-Optoelectronics 143(5): 307-311.
[12] Lin, S. Y., J. G. Fleming, et al. (1998). "A three-dimensional photonic crystal operating at infrared wavelengths." Nature 394(6690): 251-253.
[13] McNab, S. J., N. Moll, et al. (2003). "Ultra-low loss photonic integrated circuit with membrane-type photonic crystal waveguides." Optics Express 11(22): 2927-2939.
[14] Almeida, V. R., Q. F. Xu, et al. (2004). "Guiding and confining light in void nanostructure." Optics Letters 29(11): 1209-1211.
[15] Desmond R. Lima, B. E. L., Kevin K. Leea, and H. H. F. Michael Morseb, H. A. Haiisa and Lionel C. Kimerling (1999). Micron-sized channel dropping filters using silicon waveguide devices. Part of the SPIE Conference on Optical Devices for Fiber Communication.
[16] Hammond, R. B. and R. N. Silver (1980). "Temperature-Dependence of the Exciton Lifetime in High-Purity Silicon." Applied Physics Letters 36(1): 68-71.
[17] Lipson, M. (2006). "Compact electro-optic modulator's on a silicon chip." Ieee Journal of Selected Topics in Quantum Electronics 12(6): 1520-1526.
[18] Soref, R. A. and B. R. Bennett (1987). "Electrooptical Effects in Silicon." Ieee Journal of Quantum Electronics 23(1): 123-129.
[19] Tamor, M. A. and J. P. Wolfe (1980). "Drift and Diffusion of Free-Excitons in Si." Physical Review Letters 44(25): 1703-1706.
[20] Barwicz, T., H. Byun, et al. (2007). "Silicon photonics for compact, energy-efficient interconnects [Invited]." Journal of Optical Networking 6(1): 63-73.
[21] Gan, F. W. and F. X. Kartner (2005). "High-speed silicon electrooptic modulator design." Ieee Photonics Technology Letters 17(5): 1007-1009.
[22] Liu, A. S., R. Jones, et al. (2004). "A high-speed silicon optical modulator based on a metal-oxide-semiconductor capacitor." Nature 427(6975): 615-618.
[23] Almeida, V. R., C. A. Barrios, et al. (2004). "All-optical control of light on a silicon chip." Nature 431(7012): 1081-1084.
[24] Xu, Q. F., B. Schmidt, et al. (2005). "Micrometre-scale silicon electro-optic modulator." Nature 435(7040): 325-327.
[25] Murphy, T. E., J. T. Hastings, et al. (2001). "Fabrication and characterization of narrow-band Bragg-reflection filters in silicon-on-insulator ridge waveguides." Journal of Lightwave Technology 19(12): 1938-1942.
[26] Foresi, J. S., P. R. Villeneuve, et al. (1997). "Photonic-bandgap microcavities in optical waveguides." Nature 390(6656): 143-145.
[27] Yoshie, T., J. Vuckovic, et al. (2001). "High quality two-dimensional photonic crystal slab cavities." Applied Physics Letters 79(26): 4289-4291.
[28] Pavesi, L., L. Dal Negro, et al. (2000). "Optical gain in silicon nanocrystals." Nature 408(6811): 440-444.
[29] Dimitropoulos, D., R. Jhaveri, et al. (2005). "Lifetime of photogenerated carriers in silicon-on-insulator rib waveguides." Applied Physics Letters 86(7).
[30] Vlasov, Y. A. and S. J. McNab (2004). "Losses in single-mode silicon-on-insulator strip waveguides and bends." Optics Express 12(8): 1622-1631.
[31] Lee, M. C. M. and M. C. Wu (2006). "Thermal annealing in hydrogen for 3-D profile transformation on silicon-on-insulator and sidewall roughness reduction." Journal of Microelectromechanical Systems 15(2): 338-343.
[32] Hunsperger, R. G. (1995). Integrated optics :/theory and technology Springer.
[33] Ming-Chang M. Lee, W.-C. C., Tse-Ming Yang, Chin-Hung Chen, and Ming C. Wu (2006). Low-Loss Silicon Wire Waveguides with 3-D Tapered Couplers Fabricated by Self Profile Transformation. The Conference on Lasers and Electro-Optics (CLEO).
[34] 劉育松、林建宏、許佳振 (2003). "有機高分子薄膜非線性光電性質-基礎與應用." 物理雙月刊 25卷2期: P.286.
[35] Cheng., D. K. (1989). Field and wave electromagnetics, Addison-Wesley Pub. Co.
[36] Dadap, J. I., R. L. Espinola, et al. (2004). "Spontaneous Raman scattering in ultrasmall silicon waveguides." Optics Letters 29(23): 2755-2757.
[37] Espinola, R. L., J. I. Dadap, et al. (2004). "Raman amplification in ultrasmall silicon-on-insulator wire waveguides." Optics Express 12(16): 3713-3718.
[38] Liang, T. K. and H. K. Tsang (2004). "Role of free carriers from two-photon absorption in Raman amplification in silicon-on-insulator waveguides." Applied Physics Letters 84(15): 2745-2747.
[39] Liang, T. K., H. K. Tsang, et al. (2002). "Silicon waveguide two-photon absorption detector at 1.5 um wavelength for autocorrelation measurements." Applied Physics Letters 81(7): 1323-1325.
[40] Claps, R., V. Raghunathan, et al. (2004). "Influence of nonlinear absorption on Raman amplification in Silicon waveguides." Optics Express 12(12): 2774-2780.
[41] Espinola, R. L., J. I. Dadap, et al. (2005). "C-band wavelength conversion in silicon photonic wire waveguides." Optics Express 13(11): 4341-4349.
[42] Rong, H. S., Y. H. Kuo, et al. (2006). "High efficiency wavelength conversion of 10Gb/s data in silicon waveguides." Optics Express 14(3): 1182-1188.
[43] Fukuda, H., K. Yamada, et al. (2005). "Four-wave mixing in silicon wire waveguides." Optics Express 13(12): 4629-4637.
[44] Bahaa E.A. Saleh, M. C. T. (1991). Fundamentals of photonics New York Wiley.
[45] Liu, A. S., H. S. Rong, et al. (2004). "Net optical gain in a low loss silicon-on-insulator waveguide by stimulated Raman scattering." Optics Express 12(18): 4261-4268.
[46] Xiao., H. (2001). Introduction to semiconductor manufacturing technology, Prentice Hall.
[47] Yamada, H., M. Shirane, et al. (2005). "Nonlinear-optic silicon-nanowire waveguides." Japanese Journal of Applied Physics Part 1-Regular Papers Brief Communications & Review Papers 44(9A): 6541-6545.
[48] Png, C. E., S. P. Chan, et al. (2004). "Optical phase modulators for MHz and GHz modulation in silicon-on-insulator (SOI)." Journal of Lightwave Technology 22(6): 1573-1582.
[49] Liao, L., D. Samara-Rubio, et al. (2005). "High speed silicon Mach-Zehnder modulator." Optics Express 13(8): 3129-3135.
[50] Xu, Q. F., V. R. Almeida, et al. (2005). "Demonstration of high Raman gain in a submicrometer-size silicon-on-insulator waveguide." Optics Letters 30(1): 35-37.