在最近幾年中，DQPSK是其中一個最吸引人且先進的調便技術，因為它在光譜效率當中，有非常好的效率，DQPSK可以一次傳輸兩個位元，它和DPSK比較起來，它有兩倍的光譜效率，這個也是DQPSK的優點之一，這篇的碩士論文專注於利用分波復用的系統（WDM）來探討DQPSK在長距離傳輸下的現象，WDM是利用把不同波長的雷射載入到訊號中，而訊號在光纖裡面傳輸。

以實驗來說，DQPSK的實驗架構需要一些特別的技巧來架設，當延遲解調器被利用於DQPSK的訊號中，編碼或者是解碼是需要去讓接收一連串的訊號會和傳輸一連串的訊號相同，這樣我們才能解調和傳輸訊號。但是電訊號的編碼或解碼是很困難去了解的，所以我們利用一些軟體來計算編碼或解碼的位元，因此我們在實驗開始之前先準備好這些參數，然後，把計算好的位元輸入到錯誤偵測（ED）儀器當中，我們就可以利用這樣來量測誤碼率（BER）。

最後，我們利用DQPSK的WDM系統來量測不同波長或通道的傳輸現象，最後的傳輸距離是連續傳輸495km的實驗架構。

Differential quadrature phase-shift keying (DQPSK) is one of the most attractive advanced modulation format in these years, because it has a good spectral efficiency. The DQPSK can transmit two bits per symbol, and it has twice the spectral efficiency of the differential phase-shift keying (DPSK). This master thesis focuses on to study the DQPSK performance in the long-haul transmission with the wavelength-division multiplexing system (WDM). The WDM multiplexes multiple optical carriers in the single optical fiber using the different wavelength lasers to carry the signal.

For the experiment, the DQPSK needs a little special technique to conduct. When a delay demodulator is used for the DQPSK signal, an encoder or decoder is required to make the received serial data to be the same as the transmitted serial sequence. As an electrical encoder or decoder is difficult to realize, a software to calculate encoded pattern or decoded sequence is prepared for the experiment. Then, calculated pattern is installed into the error detector, and it is used to measure the bit error rate.

Finally, the performance of the different channels of the WDM DQPSK transmission is measured experimentally. The transmission distance is 495km for the straight line experimental setup.

Master Thesis
Experimental Study of DQPSK WDM Transmission Performance

◎ Acknowledgments …………………………………………….I
◎中文摘要…..………………..…. …………………………..Ⅲ
◎ Abstract…………………………………………………......Ⅳ

Chapter 1 Introduction
1.1 Background of the long-haul optical fiber transmission…………..1
1.2 Motivation of this study…………………………………………...2
1.3 Structure of this thesis……………………………………………..2

Chapter 2 Theoretical study of 960 Gb/s (96 x 10G) long-haul RZ-DPSK transmission performance using dispersion managed fiber
2.1 Introduction………………………………………………………..4
2.2 Simulation method and model…………………………………….4
2.3 Results and discussions……………………………………………6
2.4 Conclusion…………………………………………………………8

Chapter 3 Theoretical study of the DQPSK system
3.1 Introduction………………………………………………………10
3.2 Theory of the DPSK format……………………………………...10
3.3 theoretical of DQPSK format…………………………………….13
3.4 DQPSK pattern calculation………………………………………14

Chapter 4 Experimental study focusing on the transmission performance of the DQPSK format
4.1 Introduction………………………………………………………18
4.2 Experimental setup……………………………………………….18
4.2.1 Transmitter…………………………………………………..19
4.2.2 Transmission line……………………………………………20
4.2.3 Receiver……………………………………………………...22
4.3 Results and discussions…………………………………………..24
4.3.1 Back-to-back eye diagram for DI and DQ…………………..24
4.3.2 DI and DQ eye diagrams after 495 km transmission………..34
4.3.3 BER measurement of before and after 495 km transmission..43
4.4 Conclusion………………………………………………………..45

Chapter 5 Conclusion………………………………………………………….47

[1] X. Zhou, J. Yu, M. Du, and G. Zhang, “2 Tb/s (20×107 Gb/s) RZ-DQPSK straight-line transmission over 1005 km of standard single mode fiber (SSMF) without Raman amplification,” Proc. of OFC 2008, paper OMQ3, 2008.
[2] P. J. Winzer, G. Raybon, C. R. Doerr, L. L. Buhl, T. Kawanishi, T. Sakamoto, M. Izutsu, and K. Higuma, “2000-km WDM Transmission of 10x107-Gb/s RZ-DQPSK”, Proc. of ECOC 2006, paper Th4.1.3, 2006.
[3] T. Tokle, C. R. Davidson, M. Nissov, J.-X. Cai, D. Foursa and A. Pilipetskii, “6500km transmission of RZ-DQPSK WDM signals,” Electron. Lett., vol. 40, no. 7, pp. 444-445, April 2004.
[4] C. Fürst, J.-P. Elbers, H. Wernz, H. Grieser, S. Herbst, A. Erhardt, D. Breuer, D. Fritzsche, S. Vorbeck, M. Schneiders, W. Weiershausen, R. Leppla, J. Wendler, M. Schrödel, T. Wuth, C. Fludger, T. Duthel, B. Milivojevic, and C. Schulien, “Analysis of Crosstalk in Mixed 43 Gb/s RZ-DQPSK and 10.7 Gb/sDWDM Systems at 50 GHz Channel Spacing”, Proc. of OFC 2007, paper OThS2, 2007
[5] P. Bofi, L. Marazzi, L. Paradiso, P. Parolari, A. Righetti, R. Siano, “Experimental comparison of RZ-IMDD and RZ-DQPSK performance in a standard 2000-km DWDM system” Proc. of CLEO 2004, paper CThBB5 , 2004.
[6] K. Ishida, K. Shimizu, T. Mizuochi, K. Motoshima, D. Gagnon, and K.Kikuchi, “Transmission of 20x20-Gb/s RZ-DQPSK signals over 5090km with 0.53 b/s/Hz spectral efficiency,” Proc. of OFC 2004, Paper FM2, 2004.
[7] M. Serbay, C. Wree, and W. Rosenkranz, ”Comparison of six different RZ-DQPSK transmitter set-upsregarding their tolerance toward fibre impairments in 8x40 Gb/s WDM-systems”, IEEE/LEOS Workshop on Advanced Modulation Formats, pp. 9-10, 2004.
[8] P. S. Cho, V. S. Grigoryan, Y. A. Godin, A. Salamon, and Y. Achiam, “Transmission of 25-Gb/s RZ-DQPSK signals with25-GHz channel spacing over 1000 km of SMF-28 fiber,” IEEE Photon. Technol. Lett., vol. 15, no. 3, pp. 473–475, March 2003.
[9] C. Wree, N. Hecker-Denschlag, E. Gottwald, P. Krummrich, J. Leibrich, E. Schmidt, B. Lankl, and W. Rosenkranz, “High spectral efficiency 1.6-b/s/Hz transmission (8×40-Gb/s with a 25-GHz Grid) over 200-km SSMF using RZ-DQPSK and polarization multiplexing,” IEEE Photon. Technol. Lett., vol. 15, no. 9, pp. 1303–1305, September 2003.
[10] S. Hayase, N. Kikuchi, K. Sekine, and S. Sasaki, “Chromatic dispersion and SPM tolerance of 8-state/symbol (binary ASK and QPSK) modulated signal,” Proc. of OFC 2004, Paper ThM3, 2004.
[11] B. Zhu, B. Zhu, L. Leng, A. H. Gnauck, M. O. Pedersen, D. Peckham, L. ENelson, S. Stulz, S. Kado, L. Grüner-Nielsen, R. L. Lingle, S. Knudsen,J. Leuthold, C. Doerr, S. Chandrasekhar, G. Baynham, P. Gaarde, Y.Emori, and S. Namiki, “Transmission of 3.2 Tb/s (80 x 42.7 Gb/s) over 5200 km of UltraWave fiber with 100-km dispersion-managed spans using RZ-DPSK format,” Proc. of ECOC 2002, vol. 5, pp. 1- 2, 2002.
[12] H. Taga, S.-S. Shu, J.-Y. Wu, and W.-T. Shih “A theoretical study of the effect of zero-crossing point within the dispersion map upon a long-haul RZ-DPSK system,” Optics Express, vol. 16, no. 9, pp. 6163-6169, April 2008
[13] T. Inoue, K. Ishida, T. Tokura, E. Shibano, H. Taga, K. Shimizu, K. Goto,and K. Motoshima, “150km repeater span transmission experiment over 9,000km,” Proc. of ECOC 2004, Paper Th4.1.3, 2004.
[14] S. N. Knudsen, MO Pedersen, L Gruner-Nielsen, ”Optimisation of dispersion compensating fibres for cabled long-haul applications,” Electron. Lett., vol. 36, no.25, pp. 2067-2068, December 2000.
[15] G. P. Agrawal, Nonlinear Fiber Optics (Fourth Ed), Academic Press, San Diego, CA, 2006
[16] X. Wei, X. Liu, and C. Xu, “Numerical simulation of the SPM penalty in a 10-Gb/s RZ-DPSK system,” IEEE Photon. Technol. Lett., vol 15, no. 11, pp. 1636-1638, November 2003.
chapter
[17] G. P. Agrawal, Fiber-Optic Communication System (Third Ed), Willy Inter-Science, Rochester, NY, 2002.
[18] J. M. Senior, Optical Fiber Communication Principles and Practice (Second Ed), Prentice-Hall, Englewood Cliffs, NJ, 1992.
[19] K. Ishida, K. Shimizu, T. Mizuochi, and K. Motoshima "Transmission of 20 x 20 Gb/s RZ-DQPSK signals over 5090 km with 0.53 b/s/Hz spectral efficiency," Proc. of OFC2004, paper FM2, 2004.
[20] http://en.wikipedia.org/wiki/File:QPSK_timing_diagram.png
[21] R. A. Griffin and A. C. Carter, “Optical differential quadrature phase-shift-key (oDQPSK) for high capacity optical transmission,” Proc. of OFC 2002, paper WX6, 2002.
[22] M. Serbay, C. Wree and W. Rosenkranz, “Implementation of differential precoder for high-speed optical DQPSK transmission,” Electron. Lett., vol. 40, no. 20, pp. 1288-1289, 2004.
[23] Y. Konishi, Kazuyuki Ishida, Kazuo Kubo and Takashi Mizuochi, “True PRBS transmission of DQPSK by differential precoder employing parallel prefix network,” Proc. of OFC 2006, paper OThR3, 2006.
[24] S. Benedetto, and E. Biglieri, Principles of digital transmission, Plenum, New York, NY, 1999.
[25]. L. Thylén, “Integrated optics in LiNbO3: Recent developments in devices for telecommunications,” J. of Lightwave Technol., vol. 6, no. 6, pp. 847–861, 1988.
[26]. H. Taga, S.-S. Shu, J.-Y. Wu, and W.-T. Shih, "A theoretical study of the effect of the dispersion map upon a long-haul RZ-DPSK transmission system," IEEE Photon. Technol. Lett., vol. 19, no. 24, pp. 2060–2062, December 2007.