由於光子晶體具有相當優異的光子禁帶，能夠限制在某一特定的頻率範圍的光通過光子晶體時停止傳播。這些由兩種不同介電常數材料做週期性排列形成的結構，依週期排列的維度又可分為一維、二維及三維的光子晶體，布拉格反射鏡就是一種最常見的一維光子晶體。光子晶體除了能禁止特定頻率的電磁波進行傳播外，當在結構中加入點缺陷便可以形成共振腔，而加入了線缺陷則可以做為波導使用。目前有許多光子晶體的應用，比方低耗損的介電材反射鏡、光子晶體微諧振腔、極窄頻濾波器及與光子晶體整合的高效率雷射等。一旦這些元件的開發技術成熟，將有助於實現由光子晶體與其他主動、被動元件構成的高效率積體光路系統。
傳統光子晶體的元件因為著重在排列的設計，多半為靜態結構且因本身缺少調控機制，應用面相當有限，而微機電技術的進步與奈米技術的整合，將有助於延伸光子晶體的應用，尤其在動態需求方面，目前利用微機電開發製作的微小光學元件已經行之有年，與電子電路╱半導體製程最大不同之處就在可動元件的製作。在本文中，我們提出一個以微機電技術為基礎、整合光子晶體的可調變的致動裝置，它不僅解決光子晶體靜態結構的限制，更因加入調變功能，當被應用時，波長的選擇更有彈性。

Periodic photonic crystal composed of two dielectric materials forms a photonic band-gap, and photons within this band-gap cannot propagate through the structure. This excellent property has made photonic crystals useful for communication applications such like narrow-band filters, frequency-selective mirrors, and high-Q cavities. Nowadays several theoretical researches and fabrication methods have been proposed. There are more and more evidences that the integration of these photonic crystals, passive and active components will be helpful to realize complex optical circuits.
Conventional photonic crystals are usually designed as stationary structures. Therefore, the applications to various fields are limited. It is thanks to the aid of MEMS technology and nano fabrication techniques that we are able to extend the applications of photonic crystals. So far, many tunable photonic crystal devices have been proposed. We here present a novel MEMS-based tunable photonic crystal device. It not only overcomes limits that exist in conventional photonic crystals, but provides more flexible and extensive applications.

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