矽基片抗諧振反射(ARROW)結構光子晶體波導之設計、研製與特性量測

Abstract

本論文主要是探討抗諧振反射光波導(ARROW)結構結合三角晶格光子晶體波導元件之設計、研製與特性量測。此波導元件結構在水平方向上，利用二維光子晶體能隙導波機制；而在垂直方向上，利用抗諧振條件形成反射光波導結構，因導光核心層較大，可以和單模光纖做有效率的耦合。我們利用RSoft套裝軟體模擬並獲得ARROW結構之光子晶體波導之各項參數以及觀察導光狀況：首先以平面波展開法來計算二維三角晶格光子晶體體能帶，再使用有限差分時域法來模擬光子晶體波導在波長λ為1.55 um下傳輸行為單模傳輸。 為了能達到更大的蝕刻深寬比，選取a-Si為核心材料。先利用國家奈米元件實驗室的製程機台製作出ARROW結構結合三角光子晶體波導元件，再由儀科中心進行深蝕刻，最後以本實驗室架設的光學量測儀器，觀察並量測ARROW結構之光子晶體波導元件，藉由紅外光攝影系統觀察到亮點，證實元件具有導光能力；利用回切法量得數據計算出ARROW以及ARROW-based PCW的傳輸損耗。此初步實驗製作之元件，可確認ARROW元件具有導光能力，而整個ARROW結構光子晶體波導之傳輸損耗非常大。最後，討論元件高傳輸損耗的原因和提出製程上可能改善方法。

In this thesis, the Si-based ARROW photonic crystal waveguides are investigated, including device design, fabrication, and characterization. The structure confines light with the 2D triangular PC waveguide in the horizontal direction and the ARROW structure in the vertical direction because a thick guiding core layer provides efficient coupling with a single-mode fiber. We simulated the ARROW-based photonic crystal waveguide (PCW) to achieve the parameters and propagation condition by the software “RSoft”: we utilized the plane wave expansion method (PWE) to simulate the band diagram of the 2D triangular PC waveguide and then used the finite difference time domain method (FDTD) to simulate the transmission behavior of the wave in the PC waveguide is single mode propagation at a wavelength of 1.55 um in the ARROW-based PCW. In order to achieve high aspect ratio, a-Si was chosen as the core material. We fabricated the ARROW-based PCWs with the equipments in the National Nano Device Laboratories. Then, we sent our devices to Instrument Technology Research Center (ITRC) to etch core layer. Finally, we observed the light spots with IR system and measured the transmission power with the instruments in our laboratory. By using the cut-back method, the propagation losses of the devices can be calculated. The preliminary results demonstrate the guide functions of ARROW devices. However, the propagation losses of ARROW-based PCWs are very high, which need to be further improved.