基於扇形晶格設計具任意角度之光子晶體波導轉折

Abstract

光子晶體的研究中, 光在光子晶體波導中經過轉折後的能量散失一直是個很大的問題. 許多研究都在想辦法改善這個問題. 目前為止已經提出許多的方法來改善波導轉折的能量散失, 但是都是在60度或120度這些特別角上面做改善. 在任意角度下波導轉折能量散失的研究卻不多見.

在這篇論文中, 我們結合了圓形光子晶體跟環型布拉格反射鏡的概念做出了可以彎曲任意角度的光子晶體波導, 並且我們調整波導的寬度使波導在通訊的波段上有低損耗且寬頻的特性. 也用二維有限時域差分法模擬的方式證明了我們的結構在60度到120度都可以有相同的高傳輸率頻帶. 元件也可以成功的被製造出來. 我們也用間接與直接的方法去量測我們的元件.

In the research of photonic crystal, photonic crystal waveguide bending loss is always a big problem. There are many studies to improve it. Lots of methods are proposed to improve the bending loss, but usually in special angle like 60° or 120°. The research of arbitrary waveguide bending loss is rarity.

In the thesis, we combine the concepts of circular photonic crystal and annular bragg reflector to design a arbitrary waveguide bend, and optimizing the waveguide width achieve low loss and with broad bandwidth at communication wavelength. We also using 2D FDTD simulate our structure in possession of the same high transmission band at 60°~120°. The device has fabricated, and measures it by direct and indirect method.