摘要
在光學的領域裡，光子晶體因為其擁有在一狹小的空間中限制光子呈直角的傳播以及極低的傳輸損耗的能力，而廣泛的被應用於光通訊領域上。而"可調變式"的光子晶體在未來的光積體電路應用上將有著更多的潛能。近來，二維光子晶體結構因為在製程上較三維容易實現，且無論是透過點缺陷或者線缺陷皆可提供一個在平面中操控光子的傳播行為，因此被廣泛而深入的研究著。透過有著線缺陷的光子晶體設計以及整合於其中的波導(waveguide)，我們將可控制光子的數種傳播模態。
近幾年來在光通訊領域上，光子晶體禁帶結構結合了微機電技術而有了更多元的發展。但大多數常見的光子晶體的設計皆屬於固定式結構，無法隨著應用端任意調變。在本研究中，基於光子晶體以及微機電技術，我們提出了一個新穎的、極窄頻的光波段開關調變器。藉由加熱沈積於多晶矽(polysilicon)底層之二氧化矽(SiO2)材料，我們可以改變建立於多晶矽上的光子晶體的孔洞大小，進而調變入射於其中的光波波段(1.55μm)；亦即藉由我們的熱致動式光子晶體開關來操控光子的傳播。
本研究目前已經完成大部分在機械結構上(孔洞的熱膨脹收縮)以及在光子禁帶結構中光子傳播情形的模擬。亦成功的在微機電製程中實現了我們的設計。而在現階段的實驗當中，則是更加確定了本研究的可行性。

Abstract
The photonic crystals (PCs) have been attractive for wide range tele- communication applications because of its capability on confining light propagation in a sharp bend within small spaces and its extreme low transmission loss. The tunable PCs might have even more potential for optical integral circuit in the future. Recently, 2-D PCs have been studied extensively since they are relatively easy to fabricate and could be used to provide in-plane confinement of light through either point or line defects. Through PCs with a single line defect and integrated waveguide design, the modes of light propagation could be controlled.
MEMS technology has been combined with photonic band gap (PBG) structures for optical-communication field in recent years. Most of conventional PC devices are fixed structure and could not be tuned for different applications. In this research, we present a novel narrow band optical tunable switch based on photonic crystal and MEMS technology. Through the change of the perforated holes dimensions (PC structure) on polysilicon by heating underneath the silicon dioxide (SiO2) slab, we could tune the incident light wave (1.55μm), which means manipulate the "on/off" mechanism of a narrow band pass light source by our thermal actuated PC switch.
In this research, we have done most of the simulation analyses including mechanical models for the thermal expanding of the perforated holes, and the optical models for the light propagation in PBG structures. Also, we have fabricated the devices successfully in mechanical portion. In the present experiments, we have confirmed the feasibility of our research.

References
[1] K. Busch, "Photonic band structure theory: assessment and perspectives", Received and accepted 23 November 2001 Note presented by Guy Laval.
[2] A. Sharkawy, S. Shi and DennisW. Prather, "Electro-optical switching using coupled photonic crystal waveguides", 7 October 2002 / Vol. 10, No. 20 / OPTICS EXPRESS 1048.
[3] M. C. Mark Lee, D. Hah, Erwin K. Lau, Hiroshi Toshiyoshi, M. Wu, "Nano-Electro-Mechanical Photonic Crystal Switch", 1999 Optical Society of America.
[4] S. P. Timoshenko and J. N. Goodier, "Theory of Elasticity", McGraw-Hill, New York, 2nd edition, 1970.
[5] J. S. Foresi et. al. , Nature 390, pp.143-145, 1997.
[6] S. G. Johnson et. al., Phys. Rev. E65, 066611, 2002
[7] Chee Wei Wong, Yong Bae Jeon, George Barbastathis and Sang-Gook Kim. "Strain-Tuning of Periodic Optical Devices: Tunable Gratings and Photonic Crystals", Transducers '03, Boston, 2B1.3.
[8] Tetsuya Tada, Vladimir V. Poborchii and Toshihiko Kanayama, "Channel Waveguides Fabricated in 2D Photonic Crystals of Si Nanopillars", Microelectronic Engineering 63 (2002) 259-265.
[9] J. D. Joannopoulos, Pierre R. Villeneuve and Shanhui Fan, "Photonic Crystals", Solid State Communications, Vol. 102, No.2-3, pp. 165-173,1997.
[10] J. D. Joannopoulos, R. D. Meade, J. N. Winn, Photonic Crystals: Molding the Flow of Light, Princeton University Press, New Jersey, 1995.
[11] Susumu Noda, "Three-dimensional photonic crystals operating at optical wavelength region", Physica B 279(2000) 142-149.
[12] Bae-Ian Wu, "Analysis of Photonic Crystal Filters by the Finite-Difference Time-Domain Technique", M.S. thesis, Massachusetts Institute of Technology, 1999.
[13] Marko Lon?ar, Theodor Doll, Jelena Vu?kovi?, and Axel Scherer, "Design and Fabrication of Silicon Photonic Crystal Optical Waveguides", Journal of Lightwave Technology, Vol. 18, No. 10, October 2000.
[14] P. R. Villeneuve, S. Fan, S. G. Johnson, and J. D. Joannopoulos, "Three-dimensional photon confinement in photonic crystals of low-dimensional periodicity", IEE Proceedings - Optoelectronics, vol. 145, pp. 384 (1998)
[15] Susumu Noda, Takashi Asano, and Masahiro Imada, "Semiconductor Photonic Crystals and Devices", IEEE 2002.
[16] Attila Mekis, J. C. Chen, I. Kurland, Shanhui Fan, Pierre R. Villeneuve, and J. D. Joannopoulos, "High Transmission through Sharp Bends in Photonic Crystal Waveguides", Physical Review Letters, pp.3787-3790, 1996.
[17] Naoyuki Fukaya, Daisuke Ohsaki and Toshihiko Baba, "Two-dimensional Photonic Crystal Waveguides with 60° Bends in a Thin Slab Structure", Jan. J. Appl. Phys. Vol. 39 (2000) pp.2619-2623