光子晶體為週期排列的人工結構，可以使得某些頻段的光無法在結構中傳
遞，而可進行一些光學元件上的設計與應用。光子晶體共振腔為一項重要的發
展領域，能應用在雷射與單光子光源發射器元件，其目標為製作出高Q質，及
小體積的結構。本研究使用一維光子晶體，模擬其中光學特性，再將其彎曲形
成環型光子晶體的共振腔。應用某些頻段的光不可傳遞的特性，可使得光可以
被侷限在共振腔中。本論文分別進行垂直方向與水平方向光侷限的結構探討，
並進行優化模擬，而達到高Q質的要求，使光不易散失出共振腔。
我們使用Comsol模擬軟體，其模擬結果在水平方向可達極佳的光侷限結
果，水平方向Q值最高可以達到5*10^8，在垂直方向幾乎沒有光漏出去，此共
振腔的直徑只有16.6μm，光波長為1.2μm。

Photonic crystals (PCs) are periodic dielectric or metal-dielectric structures exhibiting photonic band gaps (PBG). An electromagnetic wave cannot propagate in a PC if its frequency is located in a PBG of the PC. Based on this effect, many useful photonic elements can be designed, such as photonic crystal waveguides (PCWs) and photonic crystal cavities (PCCs).
Research concerning PCCs makes important progresses recently. These new achievements can be utilized to design photonic crystal semiconductor lasers and
single-photon source components. The goal is to design cavities having high-quality factor (Q factor) and small structure sizes. In this study, we design high Q cavities of
one-dimensional PCs (1D PCs). We calculated the band structures of these 1D PCs and simulated their optical properties such as transmission rates, and then bent them
to form the annular photonic crystal cavities (APCCs), which are the candidates of the desired high-Q cavities for confining light. We discuss and analyze how to achieve the high-Q requirements through reducing the vertical and horizontal leakage of energy. By examining a lot of candidates having different refractive index/layer-thickness distributions, we found systematic ways to select the desired
high-Q structures. All the simulations of field patterns in this thesis are implemented by using
Comsol simulation software. The maximum Q value in the horizontal plane is found to be 8*10^5, and the vertical leakage of this cavity is very small. The diameter of this
cavity is 16.6 μm, and the working wavelength is 1.2 μm.

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