- 學位論文
基於 D 型矽核光纖之凹槽式波導光纖感測器的設計與漸細化波導式蕭基特光偵檢器的開發
The Design of Slot Waveguide Optical Fiber Sensor and Development of Tapered Waveguide Schottky Photodetector Based on D-shaped Silicon Core Fibers
摘要
在本論文中，我們將矽核光纖以火焰抽絲的方式成功縮小到330奈米等級，且能夠利用光學顯微鏡配合Matlab，觀測在加熱漸細化過程中的矽所發出黑體輻射的特徵來判斷成功下拉抽絲的時機。我們也成功利用矽核光纖套入空芯光纖製作出奈米矽核探針，由於是利用熱拉伸的方式製作，比利用蝕刻方式製作在矽晶片上來的奈米矽探針還平滑且長度較長。此論文也接續先前我們實驗室研磨拋光Ｄ型矽核光纖的工作，首先取代手持式研磨架構，架設了滾輪式研磨平台以改善研磨的準確性和重複性，且配合雷射位移量測系統和即時測量研磨時造成的光損失來判斷研磨深度。我們在第三章中提出了凹槽式波導結合在D型矽核光纖的設計，利用Rsoft和COMSOL分別模擬3D和2D結構，其中討論了光學傳輸特性和尺寸上的設計，以及凹槽數量對於外界折射率變化靈敏度的影響，其結果顯示凹槽式D型矽核光纖的表現不輸於傳統矽波導的結構，不僅有凹槽式波導高靈敏度的優點，也保留直接與其他光纖元件耦合的優點。於第四章中，延續之前兩位學長製作於蝕刻纖衣的矽核光纖和D型矽核光纖的蕭基特光偵檢器，我們使用滾輪式研磨平台製作漸細化的結構來提升光場的強度，藉此提升光和蕭基特金屬的接觸，進而縮小所需元件面積和提升靈敏度，其結果也驗證了不輸於先前製作較大面積的D型矽核光纖蕭基特光偵檢器。
並列摘要
In this work, we have successfully reduced the silicon core fiber to 330 nm in diameter by flame drawing. We can use an optical microscope with Matlab to observe the characteristics of the black body radiation emitted by the silicon during the tapering process to determine the successful pulldown timing. We have also successfully fabricated nano-silicon core probes by sheathing silicon core fibers into hollow-core fibers. Because they are made by thermal tapering, they are smoother and longer than nano-silicon probes made on silicon wafers by the etching process. This thesis work also continues study on work of polishing D-shaped silicon core fibers. Firstly, the handheld polishing structure was replaced with a lapping wheel polishing platform to improve the accuracy and repeatability of the process. The system is cooperated with the laser displacement instrument and real-time measurements of light loss caused by the grinding depth and polished region was carried out. In Chapter 3, we proposed the design of slot waveguide combined with D-shaped silicon core fiber, and use Rsoft and COMSOL to simulate 3D and 2D structures, respectively. We discussed the design of optical transmission characteristics and dimensions, as well as the number of grooves. Regarding the influence of the sensitivity of the external refractive index change, the results show that the performance of the slot waveguide on a D-shape silicon core fiber is comparable to the structure of the traditional silicon waveguide. It not only has the advantage of high sensitivity of the slot waveguide but also retains the convenience of direct coupling with other optical components. In Chapter 4, we continue to improve the performance of a Schottky photodetector based on a silicon core optical fiber and a D-shaped silicon core optical detector made by the previous two seniors. In this work, the intensity of the light field was enhanced by a tapering structure, which increased the interaction between light and the Schottky contact, thereby reducing the required element area and increasing the sensitivity. The result also proved that it is comparable to the larger-area D-type silicon core fiber Schottky optical detection or even better.