光波導元件之同調耦合

Abstract

這篇論文主要是探討彎曲光波導結構的同調耦合效應. 是發生在連續彎曲 的光波導結構.由於此效應的影響,連接 間的連接長度可以被最佳化,而可 以得到較高的傳輸效率.我們利用以有限差值法為基礎的光束傳播分析法( Finite Difference Beam Propagation.這個方法是以矩陣的相乘來模擬 光波導的傳播.在 s波導結構時,為了降低矩陣的大小,使用了可移動的取 點來作模擬. 可以計算出能量在連接區域的導波層裡的變化情形.由此能 量的變化情形,可以找出最佳的連接長度,以得到較高的傳輸效率. □如果 我們將一個轉彎結構分成兩個或三個連續的轉彎,而將其每一段的長度都 予以最佳化,便可以得到較高的傳輸效率. In this thesis, we investigate the coherent coupling effect in bended waveguide structure. Coherent coupling effect can occure in a succesive bends Because of this effect the intercennection length between these corner bends can be optimized to obtain a higher transmission Finite difference beam propagation method is used to sinulate the effect. In this method the matrix multiplication is used to beam propagation. We propose a moving grids method to reduce the dimension in simulation of a small angle bend. With the simulation results, we can find the power in the guiding layer in the interconnection region between two waveguide bends. observing this power the optimum interconnection length can be to achieve a higher transmission efficiency. With the coherent coupling effect, a one bend structure can be into two or three waveguide bends, with intercenncetion segments optimized lengths to obtain a higher transmission efficiency.