雙抗諧振反射光波導馬赫任德干涉式元件之設計與分析

Abstract

本論文提出一種運用雙抗諧振反射光波導（ARROW）結構之新型馬赫任德干涉（Mach-Zehnder interferometer）元件。論文中討論元件設計、分析所運用的方法，並詳盡探討抗諧振反射光波導之模態特性，以及雙抗諧振反射光波導之耦合行為。由於雙抗諧振反射光波導之最大耦合效率可利用調整結構對稱性來控制，應用此一概念與模態分析之結果，可設計出馬赫任德干涉元件所需之分光／合光器，再進一步組合成無須使用冗長彎折波導結構之雙抗諧振反射光波導馬赫任德干涉元件，此一小巧的元件架構可依不同應用需求設計不同的輸出波導間距，能在不犧牲元件性能的情況下，有效縮小元件尺寸。本論文並以感測器與調制器／交換元件作為設計實例，探討設計上的種種考量，所設計出之雙抗諧振反射光波導馬赫任德干涉式感測器，能在不到一英吋的元件長度下，於水中環境偵測出小至10-5的折射率變化。

Novel configurations of Mach-Zehnder interferometer (MZI) devices based on dual antiresonant reflecting optical waveguide (ARROW) structures are proposed. Designs and analyses of these devices have been investigated. Numerical methods for the analysis of ARROW waveguides are briefly reviewed. Modal characteristics of a single ARROW and coupling behavior of dual ARROW structures are analyzed and discussed in detail. Design considerations of a dual-ARROW 3-dB coupler are provided. Based on dual ARROW structures, Mach-Zehnder interferometer devices without any bending structure can be realized by adjusting the degree of structural symmetry to control the coupling behavior. In additional to slab-type Mach-Zehnder interferometers, three-dimensional Mach-Zehnder configurations based on dual strip ARROW structures are also analyzed. Operating principles and simulation characteristics of the devices are presented. Examples of the configuration applying to chemical sensing and modulation/switching are designed. Simulation results of the MZI sensors show that a refractive-index detection limit of 10^{-5} can be achieved with a device length less than one inch.