臺灣大學: 光電工程學研究所孫啟光呂任棠Lu, Jen-TangJen-TangLu2013-03-272018-07-052013-03-272018-07-052011http://ntur.lib.ntu.edu.tw//handle/246246/253567兆赫波科技已經被證實在高速通訊、生醫造影、分子偵測、材料性質分析、反恐技術、以及天文遙測方面都有極高的應用潛力。為了使兆赫波能更廣泛地被應用，各類型的兆赫波光纖以及波導在過去十年之間被廣泛地研究。而我們也在兩年前提出一種低損耗的圓管型波導作為傳遞兆赫波之用。利用市售的鐵弗龍管，我們成功地使損耗係數低於0.001 cm-1。 為了建造輕巧簡便的兆赫波系統，我們在此論文中提出了數種管型波導化的兆赫波元件。首先，我們研究圓管型波導的彎曲損耗特性，發現圓管型波導擁有極佳的彈性、以及出乎預期地低的彎曲損耗。而為了建構兆赫波偏振控制器以及方向耦合器，我們進一步地提出正方形以及長方形的管型波導。我們發現長方管型波導除了擁有極低的損耗係數外 (約0.002 cm-1)，也具備了區分兆赫波偏振的能力。 除此之外，我們利用兩個正方管型波導建立出漏模特性(leaky mode)的兆赫波方向耦合器。此方向耦合器對於兆赫波的偏振極為敏感，我們利用管型波導的抗共振反射式的傳導機制，使得此方向耦合器在最低損耗的波長區段能最有效率地耦合兆赫波。最後，我們提出了一個簡單的波導耦合器作為結合圓管型以及正方或是長方管型波導之用。利用開口對開口的耦合方式 ，我們能高效率地(趨近100%)耦合正方、長方以及圓管型波導。 我們相信這些低損耗、對偏振敏感、以及波導化的兆赫波元件對於未來兆赫波的發展都極具幫助。THz technology has been proved to have high potential in a variety of fields such as high-speed telecommunications, bio imaging, molecular detection, material property study, anti-terrorism applications, and astronomical remote sensing. To facilitate THz technology, various kinds of THz fibers and waveguides have been extensively investigated in the past decade. Two years ago, we previously proposed a circular pipe waveguide for low-loss THz waveguiding. With commercial Teflon pipes, an attenuation constant lower than 0.001 cm-1 had been achieved. In this thesis, we proposed several kinds of THz pipe-waveguide-based components for the purpose of constructing compact and flexible THz systems. We first investigated the bending loss characteristics of the pipe waveguides. It is found that the circular pipe waveguides possess magnificent flexibility and unexpected low bending loss. In order to construct THz polarization controllers and directional couplers, we modified the circular pipe waveguides into square and rectangular ones. The proposed rectangular waveguides not only suffer low attenuation (~0.002 cm-1), but also possess polarization-sensitivity to guided THz waves. Moreover, we established a THz leaky mode directional coupler with two square pipe waveguides. The proposed directional coupler is polarization-sensitive. Because of the　anti-resonant reflecting guiding principle of the pipe waveguides, the directional coupler works most efficiently in the minimal-attenuation wavelength regime. We further devised a simple butt coupler setup to combine circular pipe waveguides and rectangular ones. With butt coupling method, square and rectangular pipe waveguides can be high-efficiently (almost 100%) coupled with circular ones. It is expected that these low loss, polarization-sensitive waveguide-based components have high potential in future THz applications.2864706 bytesapplication/pdfen-US兆赫波波導波導化元件管型抗共振反射TerahertzTHzWaveguideWaveguide-Based ComponentsPipeAnti-ResonantARROW[SDGs]SDG16thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/253567/1/ntu-100-R97941042-1.pdf