微光纖布拉格光柵的製作

Fabrication of Fiber Bragg Gratings in Microfibers

林祐群(Yu-Chun Lin)

指導教授 ： 王倫

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.00245

摘要

光纖布拉格光柵(fiber Bragg grating)在感測以及光通訊中為一個重要的元件。而自從微光纖被提出後也逐漸受到矚目。由於微光纖的小體積、高比例的漸逝波，微光纖十分適合做為感測上的應用。在應用上，微光纖布拉格光柵結合了光纖布拉格光柵和微光纖的特性。由於微光纖有高比例的漸逝波，所以微光纖布拉格光柵相對於一般的光纖布拉格光柵有更好的感測能力。
在這個論文中，我們主要研究兩個關於微光纖的題目: 可調式微光纖布拉格光柵以及鋸齒狀微光纖布拉格光柵(corrugated microfiber Bragg grating)。可調式微光纖布拉格光柵的結構為將微光纖接觸一外加的光柵。在可調式光纖布拉格光柵的結構中，我們可以藉由改變微光纖和光柵的角度、拉長光柵的長度來改變光纖布拉格訊號的波長。而最終的目的是想要以此結構來達成可調式分佈回饋式微光纖雷射(distributed feedback microfiber laser)。
鋸齒狀微光纖布拉格光柵的研究主要是想要發展以低成本、高產量製作高折射率調變(high-index modulation)、較長長度的玻璃基質鋸齒狀微光纖布拉格光柵，我們首先以壓印(imprinting)和干涉微影(two-beam interference lithography)在微光纖上做出光阻週期性光柵，接著將有光柵圖案的微光纖以反應式離子蝕刻(reactive ion etch)將微光纖蝕刻成鋸齒狀微光纖布拉格光柵，或者以沉積的製程在微光纖上長出不同於玻璃材料的光柵。最後將光阻除去後，玻璃基質的鋸齒狀微光纖布拉格光柵就製作完成。

關鍵字

微光纖 ； 光纖布拉格光柵 ； 干涉微影

並列摘要

Fiber Bragg grating (FBG) is one of the key elements in functional photonic circuits and devices for a variety of applications such as optical sensing and communication. Recently microfibers have attracted attention since they were first reported. Because of small size, high fraction of evanescent wave, a microfiber is an appropriate medium for sensing. In some applications, a microfiber FBG (MFBG) combines properties of the FBG and microfiber together. With higher evanescent fields of microfiber, a microfiber FBG has better sensing ability than a common FBG.
In this thesis, we focus on two topics relevant to a microfiber: tunable microfiber Bragg grating and corrugated microfiber Bragg grating (CMFBG). The structure of tunable microfiber Bragg grating is an external grating in contact with a microfiber. In this structure, the FBG wavelength can be changed by changing the effective period of external grating such as tilting or stretching the grating under the microfiber. The ultimate goal of the experiment is to fabricate a tunable microfiber distributed feedback laser by using such structure.
The study of a corrugated microfiber Bragg grating is to aim at fabricating a SiO2 based CMFBG with lower cost, longer length, high-index modulation, which may offer potential advantages of mass production. We first propose a method that patterning the resist grating on a microfiber by imprinting or two beam interference lithography. Then the microfiber with resist pattern can either become a CMFBG by applying reactive ion etch (RIE) or create a grating with different material by deposition process. Finally, after removing the resist on the microfiber, a targeted SiO2 based MFBG can be obtained.

並列關鍵字

microfiber ； fiber Bragg grating ； two-beam interference lithography

參考文獻

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