矽基片B型抗諧振反射光波導結構光子晶體波導元件之研製與特性量測

Abstract

本論文研究矽基片上結合 B 型抗諧振反射光波導結構之 60 度彎折光子晶體波導、120 度彎折光子晶體波導、以及光子晶體 Y 型分光元件之製作與特性量測。這些波導結構具有相對大尺寸的導光核心層，可有效與單模光纖耦合。藉由在光子晶體波導彎折處及 Y 型接面處增加一個簡單膠囊形狀之拓樸缺陷 (capsule-shaped defect) 來增進光的彎折傳輸效率及分光能力。此膠囊形缺陷是一種簡單的幾何形狀設計，其平滑的孔洞形狀有利於微影蝕刻製程，使得製程較為容易，並且仍可維持與原先設計之孔洞形狀。三維有限時域差分法之頻譜分析結果顯示所設計之結合 B 型抗諧振反射光波導結構之彎折型光子晶體波導與 Y 型光子晶體分光元件能提供涵蓋 C-band 與 L-band 寬頻之光的傳輸。設計之光波導元件經由實際製作，並以光學量測系統量測波導元件傳輸效率。比較我們設計之膠囊形狀彎折光子晶體波導與傳統彎折光子晶體波導的量測數據，結果顯示所製作的光子晶體波導具有較低的彎折損耗之特性，並展現其寬頻之光傳輸能力。

The fabrication and characterization of silicon-based (Si-based) photonic crystal waveguides (PCWs) based on type-B antiresonant reflecting optical waveguide (ARROW-B) structures with 60° bends, 120° bends, and Y-branch power splitters were investigated. These waveguide structures has relatively large core sizes, which is suitable for efficient coupling with single-mode fibers. By adding simple capsule-shaped defects at the PC bend corners and Y-junctions, the light bending ability and power-splitting ability will be enhanced. This capsule-shaped defect was a simple geometric design, which has a smooth hole shape to fabricate easier and can still maintain its shapes as the original design. The 3D finite-difference time-domain (FDTD) spectrum analysis results show that all our designed ARROW-B PC bends and Y-branch power splitters could provide broadband transmissions in the whole C band and L band. We fabricated the ARROW-B PCWs with the equipments in the National Nano Device Laboratories and Nano Facility Center at National Chiao Tung University. The propagation losses of designed capsule-shaped bend PCWs and conventional bend PCWs were evaluated. Finally, the characteristics of waveguides were demonstrated. Broad-band light transmission was shown also.