- 學位論文
以介電薄膜理論探討分佈型布拉格反射器的高反射特性
Study on High Reflective Property of Distributed Bragg Reflector(DBR) with Theory of Dielectric Films
摘要
中文摘要 最近這幾年因網路的蓬勃發展使光通訊變得相當熱門，而半導體雷射的重要性是在這當中扮演著訊號光的主要來源。 形成雷射輸出的基本條件；除了使增益介質達到居量反轉；還有一個重要的影響因素就在於雷射共振腔。由於光波如果只在活性物質中通過一次所產生的光增益率通常很低，因此必須讓光波在共振腔中反覆來回才能獲得足夠的增益率。 另外; 就是這些一開始向四方散射的受激產生的光束會因為受到共振腔的侷限, 使得只有沿某一可以在共振腔內來回振盪的行進方向受到增益；而其他方向的光束將受到抑制,而且在這過程當中,垂直反射壁行進的光束之間會發生干涉效應，這樣一來只有特定的波長或頻率的光束能夠滿足共振條件；也就是形成駐波而進行光增益過程。 新一代的面射型半導體雷射採用分佈型布拉格反射器(DBR)當作共振腔的反射壁；這是由於極高反射率的需要。一開始我們將先簡單介紹雷射的諸項基本工作原理及共振腔結構--Fabry-Perot干涉原理(這是共振腔結構的基本原理)；接者針對介電質薄膜穿透及反射理論作一介紹，然後根據這些已知的理論配合實驗的結果，我們將以理論模擬的方式來驗證我們對於DBR形成高反射器機制的了解。
並列摘要
Abstract Recently, owing to the importance of semiconductor laser is rapidly increasing along with the progress of optoelectronics fields such as optical fiber communication and optical disk memories. Here, the importance of semiconductor laser is to play a main role as a light source1. There are two important factors about the basic condition to form the laser output, except make the gain media achieve the population inversion, another, laser resonant cavity. The gain generated by light is always low when the light passes through the active material only once. Therefore, it is necessary to set the light traveling back and forth in the resonant cavity and one then can get the sufficient gain rate1,2. Additionally, these radiative photons which come from stimulate emission will be confined by resonant cavity. It means that lights propagate only along certain direction in the cavity get gain, and photons radiate to other direction will be restrained. Then, there are occurrence of the interference effect between light beams that perpendicular to reflector in process. It makes some lights which have certain wavelength or frequency can satisfied the resonant condition and then they can be existed in the cavity. New generational semiconductor laser includes a DBR structure employed as resonant cavity for the need of extra high reflectivity. At first we introduce the basic structure and related theory of laser cavity. After that, introduce a theory about the property of transmittance and reflectance of a dielectric thin film. Finally, proposing a marvelous model according to the well-known theory to simulate the operating mechanism of DBR. And make comparison of the results obtained from both simulation and experiment.