Investigation of Optical Characteristics of Silica- and Polymer-based Photonic Crystal Fibers

我們研究在製作塑膠光子晶體光纖時相關的重要參數，並利用相同的製程製造出各種不同結構的塑膠光子晶體光纖，只要在光纖的微結構上做些釭瘍雂ぇK可以得到截然不同的光纖特性。接著，我們對各種不同結構的塑膠光子晶體光纖研究其光學特性，包含具有實心核心及環形結構的光纖。我們證明所製作出具有實心結構的光纖可以在非常寬的頻段內保持單模狀態，其頻段至少由600至1600奈米。我們亦證明具有較大空孔率的實心結構光纖能具有多模模態，而該光纖能傳輸的模態可以利用有限差分法精確地加以預測。經由實驗跟模擬，我們亦確認出釵h在環形結構中存在的模態，而光纖中的環形模態扮演著如同在步階型光纖中纖殼模態的角色。利用具有環型結構光纖之核心模態以及環型模態的互相耦合，可在光纖通訊系統中作為濾波器及交換器之用。最後，我們利用鎖模式鈦藍寶石雷射成它a在商用玻璃材質光子晶體光纖上產生超寬頻，其輸出頻譜在波長上達530至1450奈米。利用稜鏡組對輸出頻譜中的綠光成份做色散補償，其脈衝寬度成它a由155.9皮秒壓縮為112皮秒。We report the investigations of the parameters that are critical in fabricating microstructured polymer optical fibers (MPOFs). MPOFs of different structures are manufactured with a fabrication framework. A slight change in microstructure can provide MPOFs of distinct functionalities. Then, we study the optical characteristics of various MPOFs, including solid-core and ring-shaped fibers. We show that the solid-core fiber can provide single-mode waveguiding in a very large spectral range, at least covering from 600 through 1600 nm in wavelength. We also show that the solid-core fiber with a larger air-filling ratio can provide multi-mode operation. The number of the guided modes can be precisely predicted with the finite-difference method. In the ring-shaped fiber, we identify various ring modes from experiments and simulations. The ring modes can play the roles of cladding modes, like in a conventional step-index fiber. Coupling between the core mode and the ring modes in a ring-shaped fiber can be used for filtering and switching in fiber communications. Finally, we successfully implement supercontinuum generation in a commercial silica-based photonic crystal fiber pumped with a mode-locked Ti:Sapphire laser. The output spectrum extends from 530 to 1450 nm in wavelength. The pulse duration of the green-light component of the fiber output spectrum is compressed from 155.9 to 112 ps by using a prism pair for dispersion compensation.Contents Chapter 1 Introduction 1 1.1 General Reviews of Photonic Crystal Fiber 1 1.2 Properties of Microstructured Fibers 3 1.3 Properties of Photonic Band Gap Fibers 10 1.3.1 Photonic Band Gap Effect 10 1.3.2 Frustrated Tunneling and Bragg Photonic Band Gap Fibers 12 1.4 Modeling of Photonic Crystal Fibers 14 1.4.1 Finite-Difference Method 15 1.4.2 Transparent Boundary Condition and Symmetry Condition 18 1.5 Research Motivations 20 Chapter 2 Fabrication and Handling of Microstructured Polymer Optical Fibers 30 2.1 Advantages of Microstructured Polymer Optical Fibers 30 2.2 Fabrication of Microstructured Polymer Optical Fibers 31 2.3 Handling of Microstructured Polymer Optical Fibers 34 Chapter 3 Optical Characteristics of Solid-core and Ring-shaped Microstructured Polymer Optical Fibers 42 3.1 Single-mode Microstructured Polymer Optical Fibers 42 3.1.1 Single-mode Operation in Microstructured Polymer Optical Fibers 42 3.1.2 Loss Properties of Single-mode Microstructured Polymer Optical Fibers 45 3.2 Multi-mode Microstructured Polymer Optical Fiber 46 3.3 Ring-shaped Microstructured Polymer Optical Fiber 47 3.4 Air-Core Photonic Band Gap Polymer Fiber 49 Chapter 4 Supercontinuum Generation in Silica-based Microstructured Fibers 65 4.1 Supercontinuum Generation 65 4.1.1 Self-phase Modulation 65 4.1.2 Stimulated Raman Scattering 66 4.1.3 Four-wave mixing 67 4.1.4 Soliton Propagation 68 4.2 Highly Nonlinear Microstructured Fiber 68 4.3 Experiments of Supercontinuum Generation 69 4.4 Dispersion Compensation Using a Prism Pair 71 4.4.1 Principle of Dispersion Compensation Using a Prism Pair 71 4.4.2 Experimental Results of Pulse Compression Using a Prism Pair 73 Chapter 5 Conclusions 81 References 8