現在網際網路已成為人們的生活必需品，各式各樣的網路不論是電話網路，電腦網路，甚至到行動電話的GSM、CDMA網路，最終還是要靠光纖網路來連接，而且光纖不受干擾又適合長距離通訊等許多的優點又符合節省能源的未來趨勢，因此有人說二十世紀是電的世紀，二十一世紀則是光的世紀。由於光放大器和光調變器技術在近年來不斷增進，光纖通訊系統也因此帶動起來，為了增加傳送速度並且得到最佳的結果，在傳送端與接收端的訊號處理開始變得重要。新的通訊系統上使用光的正交分頻多工架構，這種架構只需設計晶片來執行傅立葉轉換就可將原本訊號載到多個正交載波上，因此可以減化系統複雜度和整合難度。而且正交分頻多工技術除了有高頻譜效率的優點，還因為正交載波特性而能抵抗符號間干擾，即使運用在遠距離傳輸也幾乎不需要另外對色散做補償，可以降低傳輸時的成本。
　　本篇論文使用加上光放大器的自我同調偵測，結合直接偵測以及同調偵測的優點，使用自身攜帶的載波取代雷射光，並使用平衡接收機來減少雜訊項，減少成本並增加系統表現。另外，本篇論文討論了可使得多重訊號段正交分頻多工在直接偵測下可實行的訊號編排方式，利用交錯法在攜帶有訊號的子載波中插入空的（不攜帶訊號的）子載波，在直接偵測下使得經過光偵測器後產生的訊號段與訊號段拍頻雜訊所坐落的位置會與訊號存在的位置錯開，消除訊號段與訊號段拍頻雜訊對於訊號的影響，並使用正交訊號段多工技術來縮小訊號段與訊號段之間的間距頻寬，以提高頻譜效率。

[1] H. Schulze and C.Luders, Theory and Applications of OFDM and CDMA, (John Wiley & Sons, Ltd, 2005)
[2] R. W. Chang. Synthesis of band-limited orthogonal signals for multi-channel data　transmission【J】.Bell syst.Tech. J.，Dec. 1966，45：1775 - 1796.
[3] R. W. Chang. A Theoretical Study of Performance of an Orthogonal Multiplexing　Data Transmission Scheme【J】.IEEE Trans. Commun.，1968，C-16：529-540.
[4] S. B. Weinstein and P. M. Ebert. Data transmission by frequency division　multiplexing using the discrete Fourier transform【J】.IEEE Trans. Commun.　Technol.，Oct. 1971，vol. COM- 19：628 – 634.
[5] Richard van Nee and Ramhee Prasad, OFDM Wireless Multimedia Communication, (Artech House, Boston/London, 1999)
[6] Arthur Lowery and Jean Armstrong, "Orthogonal-frequency-division multiplexing for dispersion compensation of long-haul optical systems," Opt. Express 14, 2079-2084 (2006)
[7] A. J. Lowery and J. Armstrong, “Adapation of Orthogonal Frequency Division Multiplexing to Compensate Impairments in Optical Transmission Systems”, ECOC Tutorial: Berlin 2007
[8] A. J. Lowery, L. B. Du, and J. Armstrong, “Performance of Optical OFDM in Ultralong-Haul WDM Lightwave Systems”, Journal of Lightwave Technology, vol 25, NO. 1, January 2007
[9] W. Shieh, H. Bao, and Y. Tang, "Coherent optical OFDM: theory and design," Opt. Express 16, 841-859 (2008)
[10] W. Shieh and C.Athaudage,“Coherent Optical Orthogonal Frequency Division Multiplexing,”IEE Electron. Lett., vol. 42, No. 10, May, 2006
[11] I. B. Djordjevic and B. Vasic,“Orthogonal Frequency Division Multiplexing for high-speed optical transmission,” Opt. Express, 14, pp. 3767-3775, 2006.
[12] J. W. Cooley and J. W. Tuke, “An Algorithm for Machine Computation of Complex Fourier Series,” Math. Computation, Vol. 19, pp. 297-301, April 1965.
[13] D. Chanda, A. B. Sesay and B. Davids,“Performance of clipped OFDM signals in fiber”Proc. IEEE Candian Conference on Electrical and Computer Engineering 4, pp. 2401-2404, 2004
[14] M. Sieben, J. Conradi, and D. E. Dodds,”Optical Single Sideband Transmission at 10Gb/s Using Only Electrical Dispersion Compensation”, Journal of Lightwave Technology, vol 17, NO.10, October 1999
[15] R. I. Killey, P. M. Watts, V. Mikhailov, M. Glich, and P. Bayvel,”Electronic Dispersion Compensation by Signal Predistortion Using Digital Processing and a Dual-Drive Mach-Zehnder Modulator”, IEEE Photonic technology Letters, vol 17, NO. 3, March 2005
[16] M. Sieben, J. Conradi, and D. E. Dodds,”Optical Single Sideband Transmission at 10Gb/s Using Only Electrical Dispersion Compensation”, Journal of Lightwave Technology, vol 17, NO.10, October 1999
[17] R. I. Killey, P. M. Watts, V. Mikhailov, M. Glich, and P. Bayvel,”Electronic Dispersion Compensation by Signal Predistortion Using Digital Processing and a Dual-Drive Mach-Zehnder Modulator”, IEEE Photonic technology Letters, vol 17, NO. 3, March 2005
[18] S.L. Jansen, I. Morita, T.C.W. Schenk and H. Tanaka, "121.9-Gb/s PDM-OFDM Transmission with 2 b/s/Hz Spectral Efficiency over 1,000 km of SSMF," IEEE/OSA Journal of Lightwave Technology (JLT), Vol. 27, No. 3, pp. 177-188, 2009.
[19] A. J. Lowery, “Improving Sensitivity and Spectral Efficiency in Direct-Detection Optical OFDM Systems,” in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2008), paper OMM4.
[20] K-Po Ho,”Phase-Modulated Optical Communication Systems”,(Springer Science and Business Media, 2005)
[21] L. Xu, J. Hu, D. Qain,and T. Wang,”Coherent Optical OFDM Systems Using Self Optical Carrier Extraction”, OMU4, OFC/NFOEC 2008
[22] X. Yi, W. Shieh, and Y. Tang,”Phase Estimation for Coherent Optical OFDM Transmission”,COIN-ACOFT,24-27, July 2007
[23] W. Shieh, Q. Yang, and Y. Ma, "107 Gb/s coherent optical OFDM transmission over 1000-km SSMF fiber using orthogonal band multiplexing," Opt. Express 16, 6378-6386 (2008)
[24] X. Zheng, J. L. Wei, and J. M. TANG, "Transmission performance of adaptively modulated optical OFDM modems using subcarrier modulation over SMF IMDD links for access and metropolitan area networks," Opt. Express 16, 20427-20440 (2008)
[25] W. Peng, X. Wu, V. Arbab, B. Shamee, L. Christen, J. Yang, K. Feng, A. Willner, and S. Chi, "Experimental Demonstration of a Coherently Modulated and Directly Detected Optical OFDM System Using an RF-Tone Insertion," in Optical Fiber Communication Conference and Exposition and The National Fiber Optic Engineers Conference, OSA Technical Digest (CD) (Optical Society of America, 2008), paper OMU2.
[26] Arthur James Lowery, "Amplified-spontaneous noise limit of optical OFDM lightwave systems," Opt. Express 16, 860-865 (2008)