波導模態共振之元件應用

Abstract

本論文探討波導模態共振(Guide-mode resonance, GMR)為機制的兩個元件應用。第一個應用是遠紅外線寬頻高反射率之反射鏡，結構是在GaAs基板上面成長低折射率的SiOx，其上再製作高折射率Ge的三角晶格二維光柵。依此結構製作出中心8 μm，反射率達95% 以上之反射鏡，可應用於紅外波段的光電元件，如量子點紅外線偵測器。第二個元件是適用於0.95 μm波段之波長選擇光偵測器，其結構是以布拉格反射鏡(distributed Bragg reflector, DBR)和波導模態共振光柵所形成的共振腔，在特定波長增強光的偵測效率，藉由改變波導模態共振光柵洞的大小，可調變等效共振腔的等效長度，以調變吸收光的波長。在文中完整討論以光柵繞射理論、波導理論以及等效介質理論為基礎的設計原理，還有針對兩個元件的設計、製作與實驗結果進行分析比較，並驗證波導模態共振理論應用於光電元件整合的可行性。

In this thesis, we introduce two device applications of Guide-mode resonance (GMR). First one is broad-band reflector for far infrared on GaAs substrate, we deposit low refractive index material SiOx, and then fabricate a two-dimensional triangular lattice grating made by high refractive index Ge. With this structure, we have obtained a reflector with 95% high reflectivity at 8μm. The reflector can be integrated with far infrared photonic device such as quantum dot infrared photodetector (QDIP). Second device is wavelength sensitive PIN photodetector using guided-mode resonance for 0.95 μm. The cavity is formed by bottom distributed Bragg reflector (DBR) and top GMR grating to enhance detection efficiency. By changing the filling factor of the grating, effective cavity length can be tuned. Therefore, we can fabricate an array of resonant cavity enhanced (RCE) photodiodes on a single chip, on which every photodiode aims for a specific wavelength by means of GMR grating design. In this thesis, we discuss the design principle based on grating diffraction theory, wave guide theory and equivalent medium theory. We aim at the analysis of the design, fabrication and experimental results of the two device applications to verify that GMR is feasible to be integrated into photonic devices.