隨著時間的演進與科技的日新月異，從過去簡單的電子郵件傳輸，到現在的3D視頻撥放，消費者的需求越來越大，頻寬所需也將越來越大，而為了面對頻寬的快速成長，我們需要具成本效益的傳輸架構，而被動式光網路的網路架構是使用光纖被動元件，不用電源來做驅動，降低了成本，並可同時達到高頻寬、高品質傳輸，適合光纖接取網路。傳統的被動式光網路傳輸距離為20公里，但為了面對不斷增加的網路需求，下一世代的被動式光網路將與部分的都會光網路結合以降低成本與延遲，並將距離提升到60公里以上。

在本篇論文中，我們提出了簡易同調偵測應用於無色光源波長分波與正交分頻多工存取長距離被動式光網路的架構。無色光源技術之應用使整體架構更具有成本效益，而同調偵測能夠彌補一般長距離傳輸使用直接偵測所造成的敏感度不足問題，還能夠將訊號做色散補償，以及減經無色光源技術中所造成的下行訊號殘留文提，並且降低拉長傳輸距離所造成的色散影響，進而提升訊號品質。而一般同調偵測會著重於複雜相位雜訊的補償，我們提出較簡易的架構，將其訊號調變在強度上面，最後只需要將訊號絕對值平方，去除相位雜訊的影響，並希望能增加雷射線寬之容忍度。

In recent years, science and technology have developed and progressed rapidly. Demands for bandwidth grow dramatically. The technology based on copper cannot provide enough bandwidth.
For a cost-effective system, passive optical network based on fibers is commonly used to achieve high bandwidth and transmission without additional power support. The transmission distance can be improved to 60 kilometers by a new long-reach passive optical network compared with a traditional one. However, we design a simple coherent detection for reducing the increasing dispersion influence from longer transmission distance.
In this thesis, we propose an efficient detection which can improve the transmission distance and the performance in colorless WDM-OFDMA LR-PON.

致 謝 ii
摘 要 iii
Abstract iv
目 錄 v
圖列表 vii
第一章 緒論 1
1-1 前言 1
1-2 研究動機 2
第二章 光學調變與接收技術 4
2-1 光學調變器 4
2-1-1 Mach-Zehnder調變器 (MZM) 4
2-1-2 電致吸收調變器 (EAM) 7
2-2 光的接收端 8
2-2-1 直接偵測 (Direct Detection) 8
2-2-2 同調偵測 (Coherent Detection) 10
2-2-3 比較直接偵測與同調偵測差異 14
第三章 正交分頻調變與傳輸技術 15
3-1 正交分頻多工系統原理 15
3-1-1 正交分頻多工系統簡介 15
3-1-2 正交分頻多工系統調變 19
3-1-3 正交分頻多工系統解調 21
3-1-4 使用數位方式實現正交分頻多工系統 23
3-1-5 正交振幅訊號製作(QAM mapping) 25
3-1-6 循環字首 (CP) 26
3-1-7 估算通道響應 30
3-1-8 正交分頻多工存取 (OFDMA) 32
3-2 正交分頻多工之被動式光網路(OFDM-PON) 33
3-2-1 波長分波多工技術 (WDM) 33
3-2-2 被動式光網路 (PON) 35
3-2-3 長距離被動式光網路 (LR-PON) 37
3-2-4 正交分頻多工存取之長距離被動式光網路(OFDMA LR-PON) 38
3-2-5 無色光源技術(Colorless) 39
第四章 簡易同調技術之模擬與結果 41
4-1 引論 41
4-2 目標架構 44
4-3 模擬架構與結果分析 51
4-4 實驗結果 72
第五章 結論 75
5-1 總結與討論 75
參考文獻 76

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