近年來隨著科技的進步，網際網路快速的成長，人們對網路的需求也越來越高。隨著媒體的進步，傳輸所需要的資料量也越來越多，而如何快速的傳輸如此大量的資料成為技術發展重要的挑戰。目前，光通訊可以在傳輸速率上符合其需求，且較同軸電纜相比有較低的能量耗損與傳輸距離上的優勢。

為了達到高容量以及長距離的傳輸，我們使用具較高的頻譜使用效率的調變格式 正交分頻多工 (Orthogonal Frequency Division Multiplexing, OFDM)。並且在成本效益的考量底下，我們使用較簡單且便宜的強度調變與直接偵測 (Intensity Modulation /Direct Detection, IM/DD) 系統。然而在長距離傳輸下IM/DD-OFDM訊號會受到色散所影響。對於直接調變DFB雷射 (Directly Modulated DFB Lasers, DML)在長距離傳輸後有大量的非線性失真。而對於電致吸收調變器 (Electro-Absorption Modulated, EAM) 以及直接調變雷射在長距離傳輸後皆會有功率衰落的問題。故我們使用單邊帶訊號來從根本上解決這兩個問題。

本篇論文中，我們也提出了一個新穎的單邊帶 OFDM訊號調變方法，使用串聯直接調變雷射以及電致吸收調變器產生單邊帶訊號。在不需補償的狀態下，頻寬 5GHz的 IM/DD-OFDM訊號在傳輸 250公里可以達到12.8 Gbps。在補償二階非線性失真傳輸250公里可達到13.8 Gbps。

In recent years, with technology advances, many different multimedia applications have been developed. The demand for network is increasing. How to quickly transfer a large of data has become an important challenge. Higher bit rates, lower power consumption and reaching longer distance with the deploy standard are main feature of all optical networks.
In order to meet these requirements, we need high capacity modulation technique and cost-effect transmission systems. We use a high spectral efficiency modulation format, orthogonal frequency division multiplexing (OFDM). And under cost -effect considerations, we use a simple system, Intensity modulation and direct detection (IM/DD). However, after long distance transmission, traditional IM/DD OFDM transmission suffers dispersion-induced power fading and nonlinear distortion. Frequency modulation (FM) in a DML-based system leads to considerable distortion to degrade transmission performance On the other hand, severe fading turns to be a major issue in EAM-based OFDM transmission. We use single sideband signal to solve these two problems fundamentally.
In this thesis, based on a cascaded DML/EAM, we proposed a novel IM/DD scheme to generate SSB OFDM signals, featuring tolerance to dispersion-related fading and distortion. Without compensation for dispersion and nonlinear distortion, 5-GHz SSB-OFDM signal can achieve 12.8 Gbps after 250 km. With compensation for dispersion and nonlinear distortion, signal can achieve 13.8 Gbps after 250 km.

論文審定書 i
致謝 ii
中文摘要 iii
Abstract iv
目錄 v
圖次 vii
第一章 緒論 1
1.1前言 1
1.2研究動機 2
第二章 直接調變強度偵測正交分頻多工系統 4
2-1正交分頻多工 4
2-1-1正交分頻多工簡介 4
2-1-2 正交分頻多工之原理 4
2-1-3 正交分頻多工的優缺點 6
2-1-4 光學正交分頻多工的架構 10
2-2強度調變直接偵測 12
2-2-1 強度調變直接偵測簡介 12
2-2-2 電致吸收調變器 13
2-2-3 直接調變DFB雷射 14
2-2-4光二極體 15
第三章 長距離傳輸之挑戰 16
3-1 光纖傳輸系統 16
3-2-1 光纖傳輸簡介 16
3-2-2 色散 16
3-2-3 啁啾 17
3-2 非線性失真 18
3-2-1 元件產生之非線性失真 18
3-2-2 子載波間混頻干擾 19
3-2-3 沃爾泰拉濾波器 22
3-3 功率衰減 24
第四章 單邊帶訊號 27
4-1 單邊帶訊號原理 27
4-2 M.E. Chaibi之單邊帶訊號調變 28
4-3 新穎單邊帶訊號調變 31
第五章 實驗架構與結果 34
5-1 實驗架構 34
5-1-1 實驗設備 34
5-1-2 M.E. Chaibi調變單邊帶訊號 36
5-1-3 新穎單邊帶調變 37
5-2實驗結果與討論 38
5-2-1 M.E. Chaibi調變單邊帶與新穎調變單邊帶比較 38
5-2-2 單邊帶調變與雙變帶調變比較 40
第六章 結論 46
參考文獻 47

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