介電質微碟共振腔及其波導耦合之研究

Abstract

在本篇論文中，我們設計三種被動介電質波導微碟耦合結構以及 主動奈米矽晶微碟結構。首先，在二氧化矽/矽結構中，波導場型透 過基板強烈損耗而無法傳輸。 其次，在苯環丁烯/二氧化矽/矽結構中，我們可驗證光在波導傳 導的可行性。然而於穿透頻譜中卻未見模態訊號，此外蝕刻出柱子 又遇到波導倒塌與苯環丁烯/二氧化矽附著力不足的瓶頸。 其三，在氮化矽/二氧化矽/矽結構中。10 微米微碟品質因子值 約為2500，12 微米微碟品質因子值約3100，14 微米微碟品質因子 值約3600。另外在調變波導寬度對耦合之影響量測中，發現波導寬 度小於1 微米的耦合結構方可達成與共振腔模態耦合。另外在調變 波導微碟間距對耦合之影響量測中，發現品質因子隨間距增加而增 加，並發現穿透頻譜的凹陷在間距150 奈米有最深值，對應到耦合 理論中的臨界耦合值。 其四，我們亦探討奈米矽晶微碟其共振腔之特性，利用漸細光纖 量測系統來進行耦合，發現15 微米微碟品質因子值約為6000。

In this thesis we designed three passive dielectric microdisk waveguide coupling structures and active silicon nanocrystal microdisks. Firstly, in silicon dioxide / silicon structure, waveguides cannot properly guide because of the substrate radiation loss. Secondly, in benzocyclobutene (BCB) / silicon dioxide / silicon structure, we verified light is guided in the waveguide. However, the WGMs (whispery gallery modes) hadn’t be observed in the spectrum. In addition, etching process encountered two bottlenecks waveguide instability and insufficient adhesion between BCB and silicon dioxide. Thirdly, in the silicon nitride / silicon dioxide / silicon structure, quality factor of a 10 micron microdisk in diameter is about 2500, while those of 12 and 14 micron microdisks are 3100 and 3600, respectively. In the waveguide width tuning measurement, we observed the mode signal in transmission spectra with waveguide width less than 1 micron. In the gap tuning measurement, we found the quality factor increases with gap widened, and the deepest transmission dip at 150nm that it corresponds critical coupling. Finally, we used tapered-fiber measurement system to investigate the characteristics of silicon nanocrystal microdisks. The quality factor of a silicon nanocrystal microdisk with 15 micron in diameter is about 6000.