在現今的世界裡，長距離光纖通訊系統是一個非常重要的建設來支持最新的寬頻通訊。歸零碼差分相移鍵調變(RZ-DPSK)，在現在吸引了更多的注意歸因於其改善了長距離傳輸的增益表現，而去了解這種技術來改善系統的傳輸增益也是非常重要的。
在目前的長距離光纖傳輸系統當中，色散圖是一項非常重要的技術，並且也廣泛的使用在世界各地的海底光纖傳輸系統當中。就現今而言，一種全新地，而且完全不同於以往已使用在海底光纖通訊系統當中的色散圖已經被發表出來，並展現出了對於長距離RZ-DPSK傳輸增益的提升。儘管如此，改善增益的原因尚未完全的証實；而這也是我們必須非常重要的探討並釐清增益改善在整個物理實驗上的機制，因為這將提供在不久之後，改進整個長距離光纖通訊系統的系統設計的可能性。
在這篇論文當中，我們可以學習到在長距離RZ-DPDK傳輸系統當中的增益表現。包括了電腦上的模擬以及實作上的實驗，並且以這兩種所得出的結果來驗證在長距離RZ-DSPK傳輸系統當中不同因素對於傳輸增益的影響。從理論上，我們得知了自我相位調變(SPM)在傳統色散圖中，扮演了明顯的角色衰減整體的傳輸增益；但在新的色散圖中，這並沒有造成明顯的增益衰減。此觀察到的現象將會用實際上的實驗來驗證得知。

Long-haul optical fiber communication system is an important infrastructure to support the latest broadband communication in the world. It is important to study a technology to improve the performance of such system, and the Return-to-Zero Differential Phase Shift Keying (RZ-DPSK) modulation attracts much attention because of its improved long distance transmission performance.
One important technology of the current long-haul optical fiber communication system is the dispersion map, and it is widely deployed for already installed undersea optical fiber communication system in the world. Recently, a new dispersion map that was totally different from the map used for already deployed system was proposed, and it demonstrated advantageous performance of the long-haul RZ-DPSK transmission. Even though, the reason of the performance improvement is not investigated, and it is important to clarify the physical mechanism of the performance improvement, because it will contribute to improve the system design of the long-haul optical fiber communication systems in near future.
In this master thesis, the performance of the RZ-DPSK format in the long-haul transmission system is studied. Both computer simulations and experiments are conducted to confirm the effects of various factors in the long-haul RZ-DPSK transmission system. From the theoretical study, it is pointed out that the Self-Phase Modulation (SPM) played a significant role to degrade the transmission performance of the conventional map, while it does not cause so significant degradation in the new map. The effects of the SPM and the Cross-Phase Modulation (XPM) with the conventional map are investigated through the experimental study.

◎ Acknowledgments ……………………………………………II
◎ 中文摘要…..………………..…. ………………………..III
◎ Abstract…………………………………………………...IV
◎ List of Contents……………………………………………V

Chapter 1 Introduction
1.1 Background of long-haul optical fiber communication
system……………………………………………………………1
1.2 Motivation of this Thesis………………………………………...1
1.3 Structure of this Thesis…………………………………………..2

Chapter 2 Theoretical study of the dispersion map upon the transmission performance of the long-haul RZ-DPSK system……
2.1 Explanation of the simulation model……………………………4
2.1.1 Simulation model………………………………………....4
2.1.2 Simulation scheme………………………………………...6
2.1.3 Dispersion map…………………………………………..14
2.2 Comparison of the dispersion maps……………………………
2.2.1 Effects of the SPM and the XPM………………………..17
2.2.2 Effects of the repeater output power…………………….19
2.2.3 Discussions………………………………………………22

Chapter 3 Experimental study of the transmission performance of the long-haul RZ-DPSK system
3.1 Introduction…………………………………………………...25
3.2 Experimental setup……………………………………………25
3.2.1 Transmitter………………………………………………26
3.2.2 Transmission Line……………………………………….27
3.2.3 Operation of recirlating fiber loop…. …………………..29
3.2.4 Receiver…………………………………………………31
3.3 Measurement of the transmission performance……………….32
3.3.1 Performance dependence upon the repeater output power.33
3.3.2 Performance for different wavelength after 5000km transmission……………………………………….......36
3.3.3 Experimental investigation of the effect of the XPM….36
3.3.4 Experimental investigation of the effect of the SPM…..39
3.4 Discussions…………………………………………………….42.

Chapter 4 Conclusion………………………………………………………...43

List of Abbreviation..........................................................................................45

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