隨著科技的進步，一些TV或是Video等等的影音產品所需要的頻寬需求也越來越高，所以為了面對未來客戶對頻寬需求的快速成長，具成本效益被動光網路(passive optical network ,PON)被視為是一個很適合的解決方案。

而近來，正交分頻多工(orthogonal frequency division multiplexing, OFDM)不論在有線或是無線通訊上都受到大量的矚目因為其具備較高的頻譜使用效益，而正交分頻多址(orthogonal frequency division multiple access, OFDMA)則為OFDM技術的演進並且為下時代的被動光網路提供更佳的動態頻寬分配。
除此之外，便宜簡單的強度調變與直接偵測 (intensity modulation/direct detection, IMDD) 系統更為高速的OFDM長距離被動式光網路大大增加其可行性。然而，IMDD-OFDM訊號會受到色散造成的功率衰減和非線性失真的問題，傳輸性能也會隨著傳輸距離不同而改變，因此調變格式與載子間的能量分配也需要隨著傳輸距離作動態的配置，而造成較複雜的網絡管理。

在本篇論文中，我們提出了結合電致吸收光調變器和半導體光放大器(EAM-SOA)來實現負啁啾調變的OFDM訊號，並藉由其在傳輸後提供的能量增益來達到提升可使用的頻寬，但不幸的在負啁啾調變的區域往往會落在調變的非線性區而造成訊躁比變差，於是我們使用新的非線性失真補償於子載波間干擾消除技術來針對由電吸收調變器造成的非線性失真進行補償。最後，我們成功地實現簡單的網絡管理並滿足FEC限制上傳輸距離為60~100km之間的正交分頻多址傳輸。

With the advancement of technology, the bandwidth requirements of video products are ever increasing. In order to solve the fast-growing demand for bandwidth in the future, the cost-effective passive optical network is considered to be a very suitable solution.
Recently, OFDM has attracted a lot of attention both in wired and wireless communications because it has high spectral efficiency, and OFDMA is a multi-user version of OFDM which can enable superior scalability to guarantee dynamic bandwidth allocation for next-generation optical access network.
Besides, the cost-effective intensity modulation and direct detection system increase the feasibility of high speed OFDM long-reach passive optical network. However, IMDD-OFDM signals still suffer power fading and nonlinear distortion from optical chromatic fiber dispersion. Furthermore, the transmission performance will vary with the transmission distance, and both modulation format and power allocation of subcarrier need to be adaptive controlled according to the distance.
In this thesis, an integration of EAM and SOA is proposed to realize an optical OFDM signal with negative chirp for enhancing the transmission bandwidth. But the operating point of negative chirp always located at nonlinear region, thus leading to more modulation nonlinearity. Hence, we use the nonlinear compensation based on SSII cancellation scheme to compensate the nonlinearity of modulator. Finally we successfully demonstrate the simple network management and achieve FEC limit at 60~100 km transmission in OFDMA LR-PON.

Acknowledgements............ii
中文摘要..............iii
Abstract.......... iv
Contents .......... vi
List of Figure......... viii
Chapter 1 Introduction ...................1
1.1 Development of PON network..............1
1.2 Long Reach PON..........................3
1.3 Thesis Motivation..........................5
Chapter 2 Optical IMDD OFDM (A) LR-PON.................6
2.1 Introduction of OFDM........................................6
2.1.1 What is OFDM................................................7
2.1.2 Benefit of OFDM system..................................10
2.1.3 Disadvantage of OFDM system.........................12
2.2 Optical IMDD OFDM(A) Transmission System.................13
2.2.1 Optical IMDD OFDM................................................13
2.3 Challenges of IMDD-OFDM system..............................15
2.3.1 RF Power Fading.......................................................15
2.3.2 Subcarrier to subcarrier intermixing Interference......................17
2.4 SSII cancellation technique.................................................18
2.5 OFDMA...................................................21
Chapter 3 Negative-Chirp Modulator...............................23
3.1 Network Management............................................23
3.1.1 Negative-Chirp for EAM..................................................24
3.1.2 Integrated EAM-SOA.....................................................25
3.2 Nonlinear compensation......................................................26
Chapter 4 Experiment Demonstration of Distance-insensitive long-reach OFDMA PONs.................28
4.1 Experimental Setup........................................................28
4.2 Measurement Results and Discussions.....................................30
4.3 Pattern analysis...........................................................42
Chapter 5 Conclusion...................................................................46
5.1 summary of works...................................................................46
Reference..................................................................................48

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