在光纖通訊傳輸這塊領域大部分所使用的解調方式為強度調變/直接解調(IM/DD)已持續一段時間了，此種技術也以被商業化。但使用此種技術會使光訊號中相位的資訊被忽略掉。由於通訊技術日益增進，傳輸量越做越大，使用IM/DD 這種傳輸系統只能單單增測到光訊號強度的變化，它無法運用到光裡面所含的相位及頻率所提供的資訊，因此這種技術很難改進來符合未來發展高速傳輸的需求，如果我們能利用光訊號的相位資訊來當作傳送訊號的媒介，將會使傳輸量大大增進。因此一種新的解調方式稱作：同步解調技術慢慢被人們研究，次技術對近來光纖通訊研究專注於高傳輸量有相當大的幫助，但是此種技術由於主要是靠光的相位來當作傳輸的媒介，對光相位的敏感程度相對要求較為嚴格。在1980 年代
此種技術剛開始發展，但也因為碰到上述相位敏感度的嚴格限制，此種技術沒落了一陣子，但近幾年由於電腦的普及化，所能處理得資料量越來越大，可以藉由數位訊號處理的方式去克服原先類比訊號及硬體上的不便，此種技術近幾年來又開始被人們所探討。結合數位訊號處理技術和光同步解調技術可以改善同步解調所面臨到電路複雜的問題，此篇論文在探討如何結合此兩種技術進而使同步解調有機會實現高速光纖傳輸系統。

In the field of optical fiber communication, the IM/DD system had been used to commercial usage for many years. The merits of this scheme are its simple idea and easiness to realize. However, such a system can not afford the requirement of the capacity people demand anymore. Recently, the research of the optical fiber communication is focused on how to increase the spectral efficiency to attend the high speed transmission. Coherent system had been
investigated widespreadly a few tens years ago. This technique could improve the spectral efficiency. Nevertheless, the difficulty of coherent system was its
receiver circuit was quite complicated and could not be realized at that time. Accompanying with the improvement of the technique, a developed technique
called digital signal processing (DSP) could overcome such difficulties. This master thesis is focused on how to cooperate these two techniques that may be required for the next generation high speed transmission system.

感謝 I

中文摘要 II

Abstract III
1. Introduction 1
1.1 The background of coherent detection scheme 1
1.2 Motivation of this thesis 2
1.3 The structure of this thesis 3
1.4 References 3
2. Study of transmission performance comparison of 100Gbit/s
OFDM signal using QPSK and 16QAM forma 5
2.1 Introduction 5
2.2 Simulation setup 5
2.2.1 Transmitter 6
2.2.2 Transmission line 7
2.2.3 Receiver 8
2.3 Result and discussion 9
2.4 Conclusion 11
2.5 References 12
3. The application of digital signal processing 13
3.1 Basic concept of digital signal processing 13
3.2 Limitation of digital signal processing analysis 15
3.2.1 Maximum sampling points 15
3.2.2 Sampling point location 16
3.2.3 Sampling distance mismatch 18
3.3 Source program 19
3.4 Example of result 22
3.5 Conclusion 23
3.6 References 24
Attachment of chapter 3 26
4. Experimental investigation of digital coherent receiver 29
4.1 Basic concepts of coherent detection scheme 29
4.2 Limitation factors of coherent detection 30
4.2.1 Phase mismatch 30
4.2.2 Wavelength mismatch 31
4.3 Experimental setup 31
4.3.1 Transmitter 31
4.3.2 Transmission line 33
4.3.3 Receiver 34
4.4 Result and discussion 35
4.5 References 37
5. Summary 39

chapter 1
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chapter 2
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chapter 3
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25
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chapter 4
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[8] G. P. Agrawal, Nonlinear Fiber Optics (Fourth Ed.), (Academic Press, San
38
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