利用無色散間隔器探討雙向光纖傳輸系統

Abstract

在一個光纖鏈結中執行雙向傳輸為一吸引人的架構。雙向傳輸不僅可減少一半的基礎設施—例如傳輸光纖，光學分光器和光纖放大器—, 還可增加頻寬的使用率。然而，要實現雙向放大和阻絕雷利後散射是雙向傳輸系統中所需要克服的困難。因此我們提出了利用間隔器組成一個單向放大路徑的結構用以達成雙向傳輸的效果。

在本論文中，先研究間隔器的相關原理和數學模型的建立，並且附上實際元件量測與間隔器在單向放大路徑的結構之操作。我們架設了兩個雙向傳輸系統(直接雙向傳輸架構與雙向迴路架構)，實驗測試以間隔器為基礎的雙向放大器的可行性。且由這兩個實驗的結果所啟發，我們利用VPI這一模擬軟體模擬比較直接雙向傳輸架構與雙向迴路架構。總的說來，由實驗結果和模擬結果展露出一項訊息: 若使用雙向迴路架構評估長距離雙向傳輸系統，將會獲得一過於樂觀的系統效能評估。

Bidirectional transmission over a single fiber link is an appealing architecture. Not only could it reduce the infrastructure -- such as fibers, optical splitters and optical amplifiers -- by a factor two, but it also increases the potential of bandwidth utilization. However, realization of bidirectional amplification and Rayleigh backscattering are the difficulties among bidirectional transmission. Therefore, we proposed a unidirectional amplification scheme which facilitates bidirectional transmission by using an interleaver. In this thesis, the principle and mathematical model of the interleaver are studied first, where the experimental measurement and operations of an interleaver are included as well. In a bidirectional transmission system, we installed two bidirectional transmission systems (i.e., straight line and re-circulating loop configurations) to demonstrate the feasibility of such interleaver-based bidirectional amplifier. Afterward, inspired by the experimental results, we simulated both the loop and the straight line bidirectional transmission systems. All in all, both experimental and simulation results reveal that it is over-optimistic to estimate long distance bi-directional transmission performance using a re-circulating loop.