王維新臺灣大學：光電工程學研究所林佳蔚Lin, Chia-WeiChia-WeiLin2007-11-252018-07-052007-11-252018-07-052004http://ntur.lib.ntu.edu.tw//handle/246246/50691本實驗結合了模態轉換器與極化分離器，成左漪蒚s出可調式大角度光極化分離器。極化分離器的波導結構主要由非對稱式Y分岔波導所構成。為了有效縮短元件尺寸，Y分岔中的彎曲分支以簡式同調耦合結構設計。此外，鋅鎳共同擴散的波導結構亦有助於改善僅用鎳為擴散源時，波導光場侷限性不佳的缺點。經由實驗的方式，將同調耦合長度設計為350μm，並根據簡式同調耦合理論，將彎曲波導之總彎曲角度設計為4°，各段的彎曲角度分別為1°、3°、4°、3°、1°，在此結構下可使兩輸出端之波導分開達195μm以上，十分方便與後段光纖之耦合封裝。在極化分離器的訊熄比方面，TE分支與TM分支分別高達27.6dB與24.8dB，這是目前大角度光極化分離器最好的結果。另一方面為了使鈮酸鋰優異的電光效應得以發揮，此極化分離器亦設計在Z切X傳播的鈮酸鋰基板上，並於分岔波導前端加上指狀電極形成模態轉換器來調變TE及TM的光必v比，當外加電壓為100V時，有43%的TM/TE轉換效率，這是目前所知可調式大角度光極化分離器的最佳結果。A tunable wide-angle optical polarization splitter, consisting of a mode converter and a polarization splitter, is demonstrated. The splitter is essentially an asymmetric Y- junction waveguide. To reduce the device length, the bending branch of the Y-junction is replaced by simplified coherently-coupled waveguide segments. To improve the poor confinement of waveguide made by Ni diffusion, a small amount of Zn is added to Ni as the diffusion source. By trial and error, the coupling length of waveguide segments is found to be 350μm. In particular, when the total bending angle is 4°, the bending angles of the segments are designed as 1°, 3°, 4°, 3°, and 1° according to the simplified coherent coupling (SCC) theory. That results in a separation distance of about 195μm for the two output branches, which is advantageous for fiber connection. The measured extinction ratios of the optical polarization splitter are 27.6dB and 24.8dB for the TE- and TM-branch, respectively. So far, those are the best results reported for wide-angle optical polarization splitter. To use the strong electro-optic (EO) effect of LiNbO3, the polarization splitter is implemented on a Z-cut X-propagation LiNbO3 substrate. With an applied voltage of 100V, the measured tunability of TE/TM modal power conversion is 43%, which is the first result reported for tunable wide-angle optical polarization splitter.第一章 緒論…………………………………………………………1 1-1 內容概述……………………………………………………1 1-2 鈮酸鋰的特性………………………………………………1 1-3 研究動機與目的……………………………………………5 第二章設計原理…………………………………………………………8 2.1 極化分離器………………………………………………………8 2.2 鋅鎳金屬擴散式光波導之極化方向……………………………10 2.3 模態檢選效應……………………………………………………12 2.4 簡式同調耦合效應….…………………………………………16 2.5 模態轉換器………………………………………………………19 2.6 可調式大角度光極化分離器及其設計…………………………24 第三章 可調式大角度光極化分離器的製作過程…………………25 3.1 校準作業……………………………………………………25 3.2 積體光學元件製程…………………………………………26 3.2.1晶片切割…………………………………………………………26 3.2.2晶片清洗…………………………………………………………27 3.2.3光製版術與圖案轉移……………………………………………27 3.2.4鍍金屬薄膜…….………………………………………………29 3.2.5高溫擴散…………………………………………………………31 3.2.6晶片研磨…………………………………………………………32 3.2.7電極製作…………………………………………………………32 3.2.8特性量測…………………………………………………………33 3.3可調式大角度光極化分離器之製程………………………………35 第四章 實驗結果與討論……………………………………………40 4.1 鋅鎳擴散式波導……………………………………………40 4.2 大角度光極化分離器………………………………………43 4.3 可調式大角度光極化分離器………………………………46 第五章 結論與未來展望……………………………………………50 參考文獻………………………………………………………………51979946 bytesapplication/pdfen-US簡式同調耦合結構模態轉換器鋅鎳金屬擴散式光波導模態檢選效應simplified coherently-coupled waveguidemode converterextinction ratiosthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/50691/1/ntu-93-R91941013-1.pdf