基于FPGA及Nios II嵌入式系统实现PMD动态补偿
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摘要
随着光纤传输速率的提高,由偏振模色散(PMD)导致的脉冲展宽的问题将越来越严重。为了补偿传输线路中的PMD效应,本实验室已做了几年的理论研究。在前人理论研究的基础上,本课题采用了前向反馈的动态补偿方案,在实验室实现了PMD的动态补偿。其中本人主要负责电路控制补偿部分的研究、设计及实现,具体工作如下:
1.提出以FPGA为控制核心的硬件电路设计方案,并进行芯片选型、电路原理图设计,六层PCB布局和布线,芯片和元器件的焊接。为整个电路控制系统提供了一个硬件平台;
2.在FPGA中,通过Verilog语言,采用流水线设计技术,快速实现了PMD理论中相关物理量的计算;同时构建了Nios II嵌入式软核,提出了有效的动态补偿算法,并通过C语言实现;
3.提出了三维坐标系旋转变换理论并进行相关公式的推导,实现了对偏振控制器的有效控制;
4.进行了两个关键性实验的研究:偏振稳定实验和PMD动态补偿实验。偏振稳定实验的成功为PMD动态补偿实验提供了强有力的保障,其偏振稳定精度最高达可到0.5度,偏振稳定响应时间最快可达5ms。
本系统的优点是:实现了PMD的动态补偿,补偿速率较快。并且提出的动态补偿方案是光速率透明的,即无论光的速率是多少都能通过本方案进行PMD的动态补偿。
本系统的不足是:对于判别传输线路中快慢轴的问题,从理论上我们还没有找到合适的方法。
针对本系统的不足,我们提出了一种将前向反馈系统和后向反馈系统相结合的改进方案,即在本系统方案的基础上增加了一套后向反馈机制,以解决传输线路快慢轴的判别问题。
As the increase of the optical transmission speed, the problem of pulse broadening caused by Polarization Mode Dispersion (PMD) will be more and more serious. In order to compensate the PMD influence, several years theory research had been taken in our laboratory. On the bases of the research, the forward feedback dynamic compensation scheme was adopted in our project, implementing the dynamic PMD compensation. My job is mainly concerned with the research, the design and the implement of circuit for compensation control. Specifically speaking:
1. The proposal of the hardware design with FPGA as the control centre, the selection of IC, the circuit schematic design, the layout and fitting on PCB, the jointing of IC and components. All of these provided a hardware build-up for the whole circuit control.
2. In FPGA, some PMD theory values were fast computed by Verilog HDL programing with the pipelining technology. The Nios II Embedded soft CPU was constructed in FPGA and efficient dynamic compensation algorithm was put forward by C language.
3. Three dimension coordinate system turning transforming theory was proposed and the related formula was deduced, which promoted the effective control for Polarization controller (PC)
The advantages of our project: PMD dynamic compensation was implemented with high speed. The project was independent of transmission speed. That is, the project can work successfully at whatever transmission speed.
The disadvantage of our project: We haven’t found an effective way from theory for the judgement between fast-axis and slow-axis of transmission line.
Concerning the disadvantage, we put forward another scheme which was the integration of the forward feedback system and backward feedback system. That is, a backward feedback mechanism was considered on the basis of our current project.
1.提出以FPGA为控制核心的硬件电路设计方案,并进行芯片选型、电路原理图设计,六层PCB布局和布线,芯片和元器件的焊接。为整个电路控制系统提供了一个硬件平台;
2.在FPGA中,通过Verilog语言,采用流水线设计技术,快速实现了PMD理论中相关物理量的计算;同时构建了Nios II嵌入式软核,提出了有效的动态补偿算法,并通过C语言实现;
3.提出了三维坐标系旋转变换理论并进行相关公式的推导,实现了对偏振控制器的有效控制;
4.进行了两个关键性实验的研究:偏振稳定实验和PMD动态补偿实验。偏振稳定实验的成功为PMD动态补偿实验提供了强有力的保障,其偏振稳定精度最高达可到0.5度,偏振稳定响应时间最快可达5ms。
本系统的优点是:实现了PMD的动态补偿,补偿速率较快。并且提出的动态补偿方案是光速率透明的,即无论光的速率是多少都能通过本方案进行PMD的动态补偿。
本系统的不足是:对于判别传输线路中快慢轴的问题,从理论上我们还没有找到合适的方法。
针对本系统的不足,我们提出了一种将前向反馈系统和后向反馈系统相结合的改进方案,即在本系统方案的基础上增加了一套后向反馈机制,以解决传输线路快慢轴的判别问题。
As the increase of the optical transmission speed, the problem of pulse broadening caused by Polarization Mode Dispersion (PMD) will be more and more serious. In order to compensate the PMD influence, several years theory research had been taken in our laboratory. On the bases of the research, the forward feedback dynamic compensation scheme was adopted in our project, implementing the dynamic PMD compensation. My job is mainly concerned with the research, the design and the implement of circuit for compensation control. Specifically speaking:
1. The proposal of the hardware design with FPGA as the control centre, the selection of IC, the circuit schematic design, the layout and fitting on PCB, the jointing of IC and components. All of these provided a hardware build-up for the whole circuit control.
2. In FPGA, some PMD theory values were fast computed by Verilog HDL programing with the pipelining technology. The Nios II Embedded soft CPU was constructed in FPGA and efficient dynamic compensation algorithm was put forward by C language.
3. Three dimension coordinate system turning transforming theory was proposed and the related formula was deduced, which promoted the effective control for Polarization controller (PC)
The advantages of our project: PMD dynamic compensation was implemented with high speed. The project was independent of transmission speed. That is, the project can work successfully at whatever transmission speed.
The disadvantage of our project: We haven’t found an effective way from theory for the judgement between fast-axis and slow-axis of transmission line.
Concerning the disadvantage, we put forward another scheme which was the integration of the forward feedback system and backward feedback system. That is, a backward feedback mechanism was considered on the basis of our current project.
引文
[1] R.Noe, D.Sandel, v.Mirvoda, et al., Polarization Mode Dispersion Detected by Arrival Time Measurement of Polarization Scrambled Light, Journal of Lightwave technol., 2002, 20(2): 229-235
[2] H.Bülow, W.Baumert, H.Schmuck, Measurement of the Maximum Speed of PMD Fluctuation in Installed Field Fiber, WE4-1, 83~85
[3] C. D. Poole, J. Nagel, Polarization effects in lightwave systems, Optical Fiber Telecommunications IIIA, I. P. Kaminow and T. L. Koch, Eds. San Diego, CA: Academic Press, 1997, 114~161.
[4] Matera, F.; Settembre, M et al., Impact of polarisation mode dispersion in field demonstration of 40 Gbit/s soliton transmission over 500 km, Electronics Letters, 1999, 35(5): 407-408.
[5] Wai, P.K.A.; Menyuk, C.R. et al., Effect of axial inhomogeneity on solitons near the zero dispersion point, Quantum Electronics, 1988, 24(2): 373-381.
[6] F. Curti et al., Statistical Treatment of the Evolution of the Principal States of Polarization in Single-Mode Fibers, J. of Lightwave Technol., 1990, 8(8): 1162~1166
[7] C. D. Poole, D. L. Favin, Polarization-Mode Dispersion Measurements Based on Transmission Spectra Through a Polarizer, J. of Lightwave Technol., 1994, 12(6): 917~929
[8] P. K. A. Wai, C. R. Menyuk, Polarization Mode Dispersion, Decorrelation and Diffusion in Optical Fibers with Random Varying Birefringence, J. of Lightwave Technol., 1996, 14(2): 148~157
[9] P. A. Williams, C. M. Wang, Corrections to Fixed Analyzer Measurements of Polarization Mode Dispersion, J. of Lightwave Technol., 1998, 16(4): 534~541
[10] C.D.Poole, Neal S.Bergano, R.E.Wagner, et al., Polarization Dispersion and Principal States in a 147-kmUndersea Lighwave Cable [J], Journal of Lightwave Technology, Vol.6, No.7, July, 1988:1185~1190
[11]吴重庆,光波导理论[M],北京,清华大学出版社,2000:127
[12] R.M.A.阿查姆,N.M.巴夏拉,椭圆偏振测量术和偏振光[M],北京,科学出版社,1986:31
[13] R.M.Jopson, L.E.Nelson, Kogelnik et al., Probability Densities of Depolarization 61Associated with Second-Order PMD in Optical fibers [C], OFC, 2000:ThA4-1
[14] H, Poincaré, Théorie Mathématique de la lumière, Gauthiers-Villars, Paris, 1892, 2, Ch. 12
[15] R.M.Jopson,L.E.Nelson, Kogelnik et al., Probability Densities of Depolarization Associated with Second-Order PMD in Optical fibers, OFC,2000:ThA4-1
[16] E. L. O’Nell, Introdution to Statistical Optics, Addison-Wesley, Reading, Massachusetts, 1963, Ch. 9
[17] M. Born, E. Wolf, Principles of Optics, Pergamon, New York, 1970, Ch. 10
[18] S.C.Rashleigh, R.Ulrich, Polarization Mode Dispersion in Single-mode Fibers, Opt. Lett., 1978, 3: 60~62
[19] C.D. Poole, R.E.Wagner, Penomenological approach to polarization Disperion in long single-mode fibers, Electron. Lett., 1986, 22: 1029~1030
[20] C.D.Poole, C,R,Giles, Polarization-dependent Pulse Compression and broadening due to polarization dispersion in dispersion-shifted fiber, Opt.Lett., 1988, 13:155~158
[21] B.L.Heffner, Automated measurement of polarization mode dispersion using Jones Matrix Eigenanalysis [J], IEEE Photonics, Technology Lett., Vol.4, Sept. 1992:1066~1069
[22] D.Andresciani, F.Curti, F.Matera, at el., Measurement of group-delay difference between the principal states of polarization in a low birefringence terrestrial fiber cable [J], Opt. Lett., vo.12,Oct.1987:844~846
[23] R.M.Jopson, L.E.Nelson, and H.Kogelnik, Measurement of Second-order Polarization mode dispersion vectors of optical fibers [J], IEEE Photonics Technol. Lett.,vol.11 No.9, Sept, 1999:1153~1155
[24] R.M.Jopson, L.E.Nelson, and H.Kogelnik, Influence of Measurements parameters on Polarization Mode Dispersion Measurements using the Signal Delay Method [C], Proc. OFC’99, 1999:WE3 (80~82)
[25] Djupsjobacka, On Differential Group Delay Statistics for Polarization Mode Dispersion Emulators [J], Journal of Lightwave Technol., 19(2) 2001:285~290
[26] W.Zhao, L.Wang, H.Wang, Crystal–Optical Higher Order PMD Emulator for 40 Gbit/s Systems [C], OECC/IOOC’01, ME, 2001
[27] L.S.Yan, M.C.Hauer, C.Yeh, et al., High-Speed Stable and Repeatable PMD Emulator with Tunable Statistics [C], OFC, 2003: MF
[28] Takashi ono, Shuntaro Yamazaki, Haruhito Shimizu, and Katsumi Emura,Polarization Control Method for Suppressing Polarization Mode Dispersion Influence in Optical Transmission Systems [J], Journal of Lightwave Technology, Vol. 12, No. 5, May 1994
[29] Yan, L.-S., Yu, Q., Luo, T., Willner, A.E., Yao, X.S., Compensation of higher order polarization-mode dispersion using phase modulation and polarization control in the transmitter [J], Photonics Technology Letters, IEEE, Volume: 14, Issue: 6, June 2002 Pages: 858– 860
[30] F. Heismann, A. F. Ambrose, T. O. Murphy, and M. S. Whalen, Polarization-Independent Photonic Switching System Using Fast Automatic Polarization Controllers [J], IEEE Photonics Technology Letters, Vol. 5, No. 11, November 1993
[31] R.Noe, H.Heidrich, D.Hoffmann, Endless Polarization Control Systems for Coherent Optics [J], IEEE JLT 6, 1988, 7:1199~1208
[32] F.Heismann and M.S.Whalen, Fast Automatic Polarization Control System [J], IEEE PTL 4(1992): 503~505
[33] Q.Yu and A.E.Willner, Comparison of Optical PMD Compensation Using a Variable and Fixed Differential Group Delays [C], Proc. OFC, Anaheim, California Mo2, 2001:17~21
[34] X.Yi, X.Yang, Optical Device for PMD Compensation by Using High-birefringence Linear Chirped Grating [C], vol.1, OFC, 2003:315~316
[35] S.Lee, R.Khosravani, J.Pen, et al., High birefringence Nonlinearly-chirped Fiber Bragg Grating for Tunable Compensation of Polarization Mode Dispersion [C], OFC, 1999: 272~274
[36] L.S.Yan, C.Yeh,G.Yang et al., Fast Digitally Variable Differential Group Delay Module Using Polarization Switching [C], Postdeadling Paper, OFC,2002: FA5-1
[37] L.S.Yan, M.C. Hauer, C.Yeh, et al., High Speed Stable and Repeatable PMD Emulator with Tunable Statistics [C], OFC, 2003: MF6
[38] T.Ono and Y.Yano, 10Gb/sPMD Compensation Field Experiments over 452km Using Principal State Transmission Method [J], Optica & Photonics News, May 2000: 61
[39]王剑,于晋龙,刘剑飞等,10Gbit/s光纤通信系统的偏振模色散动态补偿技术[J],光电子激光,2003年第6期
[40]王剑,偏振模色散动态补偿技术研究[D],[博士学位论文],天津,天津大学电信学院
[41] Patrick C. Chou, John M. Fini, and Hermann A. Haus, Real-Time Principal State Characterization for Use in PMD Compensators [J], IEEE Photonics. Technol. Lett., vol. 13, No 6, JUNE 2001: 568~570
[42]王剑,于晋龙,刘剑飞等,10Gbit/s光纤通信系统的偏振模色散动态补偿技术[J],光电子激光,2003年第6期
[43] E.Corbel, S.Lanne and J-P.Thiery, Improvement of first-order optical PMD compensator by relevant control of input state of polarization [C], Technical Digest, Anaheim, CA, USA, OFC, 2002:301~302
[44] Nobuhiko Kikuchi, Analysis of Signal Degree of Polarization Degradation Used as Control Signal for Optical Polarization Mode Dispersion Compensation [J], Lightwave Technol. Vol.19, No.4, April 2001:480~486
[45] C.Franchia, F.Bruyere, J.P.Thiery, and D.Penninckx, Simple dynamic polarization mode dispersion compensator [J], Electron. Lett., vol.35, no.5, Mar. 1999: 414~415
[46] F.Roy, C.Francia, F.Bruyere, A Simple Dynamic Polarization mode Dispersion Compensator, Proc, OFC’99,1999:TuS4 (275~278)
[47] Hok Yong Pua,Kumar Peddanarappagari,et al., An Adaptive First-Order Polarization-Mode Dispersion Compensation System Aided by Polarization Scrambling: Theory and Demonstration, Journal of Lightwave Technology,2000,18(6):832～841
[48] G. Ishikawa and H.Ooi, Polarization-mode dispersion sensitivity and monitoring in 40-Gbit/sOTDM and 10-Gbit/s NRZ transmission experiments, OFC’98, Technical Digest, WC5, 1998:117~119
[49] H.Bulow, W.Baumert,H.Schmuck, et al., Measurement of the maximum speed of PMD Fluctuation in installed field fiber, ECOC’99,1999:83~85
[50] H.Bulow, F.Buchali, G.Thielecke, Electronically enhanced optical PMD Compensation, Proc. ECOC, Munich, Germany, Vo..II, 2000: 4.2.4 (39~40)
[51]丁玉美,数字信号处理(第二版) [M],西安,西安电子科技大学出版社,2001:195
[52] EDA先锋工作实验室,Altera FPGA/CPLD设计(高级篇) [M],北京,人民邮电出版社,2005:264~269
[2] H.Bülow, W.Baumert, H.Schmuck, Measurement of the Maximum Speed of PMD Fluctuation in Installed Field Fiber, WE4-1, 83~85
[3] C. D. Poole, J. Nagel, Polarization effects in lightwave systems, Optical Fiber Telecommunications IIIA, I. P. Kaminow and T. L. Koch, Eds. San Diego, CA: Academic Press, 1997, 114~161.
[4] Matera, F.; Settembre, M et al., Impact of polarisation mode dispersion in field demonstration of 40 Gbit/s soliton transmission over 500 km, Electronics Letters, 1999, 35(5): 407-408.
[5] Wai, P.K.A.; Menyuk, C.R. et al., Effect of axial inhomogeneity on solitons near the zero dispersion point, Quantum Electronics, 1988, 24(2): 373-381.
[6] F. Curti et al., Statistical Treatment of the Evolution of the Principal States of Polarization in Single-Mode Fibers, J. of Lightwave Technol., 1990, 8(8): 1162~1166
[7] C. D. Poole, D. L. Favin, Polarization-Mode Dispersion Measurements Based on Transmission Spectra Through a Polarizer, J. of Lightwave Technol., 1994, 12(6): 917~929
[8] P. K. A. Wai, C. R. Menyuk, Polarization Mode Dispersion, Decorrelation and Diffusion in Optical Fibers with Random Varying Birefringence, J. of Lightwave Technol., 1996, 14(2): 148~157
[9] P. A. Williams, C. M. Wang, Corrections to Fixed Analyzer Measurements of Polarization Mode Dispersion, J. of Lightwave Technol., 1998, 16(4): 534~541
[10] C.D.Poole, Neal S.Bergano, R.E.Wagner, et al., Polarization Dispersion and Principal States in a 147-kmUndersea Lighwave Cable [J], Journal of Lightwave Technology, Vol.6, No.7, July, 1988:1185~1190
[11]吴重庆,光波导理论[M],北京,清华大学出版社,2000:127
[12] R.M.A.阿查姆,N.M.巴夏拉,椭圆偏振测量术和偏振光[M],北京,科学出版社,1986:31
[13] R.M.Jopson, L.E.Nelson, Kogelnik et al., Probability Densities of Depolarization 61Associated with Second-Order PMD in Optical fibers [C], OFC, 2000:ThA4-1
[14] H, Poincaré, Théorie Mathématique de la lumière, Gauthiers-Villars, Paris, 1892, 2, Ch. 12
[15] R.M.Jopson,L.E.Nelson, Kogelnik et al., Probability Densities of Depolarization Associated with Second-Order PMD in Optical fibers, OFC,2000:ThA4-1
[16] E. L. O’Nell, Introdution to Statistical Optics, Addison-Wesley, Reading, Massachusetts, 1963, Ch. 9
[17] M. Born, E. Wolf, Principles of Optics, Pergamon, New York, 1970, Ch. 10
[18] S.C.Rashleigh, R.Ulrich, Polarization Mode Dispersion in Single-mode Fibers, Opt. Lett., 1978, 3: 60~62
[19] C.D. Poole, R.E.Wagner, Penomenological approach to polarization Disperion in long single-mode fibers, Electron. Lett., 1986, 22: 1029~1030
[20] C.D.Poole, C,R,Giles, Polarization-dependent Pulse Compression and broadening due to polarization dispersion in dispersion-shifted fiber, Opt.Lett., 1988, 13:155~158
[21] B.L.Heffner, Automated measurement of polarization mode dispersion using Jones Matrix Eigenanalysis [J], IEEE Photonics, Technology Lett., Vol.4, Sept. 1992:1066~1069
[22] D.Andresciani, F.Curti, F.Matera, at el., Measurement of group-delay difference between the principal states of polarization in a low birefringence terrestrial fiber cable [J], Opt. Lett., vo.12,Oct.1987:844~846
[23] R.M.Jopson, L.E.Nelson, and H.Kogelnik, Measurement of Second-order Polarization mode dispersion vectors of optical fibers [J], IEEE Photonics Technol. Lett.,vol.11 No.9, Sept, 1999:1153~1155
[24] R.M.Jopson, L.E.Nelson, and H.Kogelnik, Influence of Measurements parameters on Polarization Mode Dispersion Measurements using the Signal Delay Method [C], Proc. OFC’99, 1999:WE3 (80~82)
[25] Djupsjobacka, On Differential Group Delay Statistics for Polarization Mode Dispersion Emulators [J], Journal of Lightwave Technol., 19(2) 2001:285~290
[26] W.Zhao, L.Wang, H.Wang, Crystal–Optical Higher Order PMD Emulator for 40 Gbit/s Systems [C], OECC/IOOC’01, ME, 2001
[27] L.S.Yan, M.C.Hauer, C.Yeh, et al., High-Speed Stable and Repeatable PMD Emulator with Tunable Statistics [C], OFC, 2003: MF
[28] Takashi ono, Shuntaro Yamazaki, Haruhito Shimizu, and Katsumi Emura,Polarization Control Method for Suppressing Polarization Mode Dispersion Influence in Optical Transmission Systems [J], Journal of Lightwave Technology, Vol. 12, No. 5, May 1994
[29] Yan, L.-S., Yu, Q., Luo, T., Willner, A.E., Yao, X.S., Compensation of higher order polarization-mode dispersion using phase modulation and polarization control in the transmitter [J], Photonics Technology Letters, IEEE, Volume: 14, Issue: 6, June 2002 Pages: 858– 860
[30] F. Heismann, A. F. Ambrose, T. O. Murphy, and M. S. Whalen, Polarization-Independent Photonic Switching System Using Fast Automatic Polarization Controllers [J], IEEE Photonics Technology Letters, Vol. 5, No. 11, November 1993
[31] R.Noe, H.Heidrich, D.Hoffmann, Endless Polarization Control Systems for Coherent Optics [J], IEEE JLT 6, 1988, 7:1199~1208
[32] F.Heismann and M.S.Whalen, Fast Automatic Polarization Control System [J], IEEE PTL 4(1992): 503~505
[33] Q.Yu and A.E.Willner, Comparison of Optical PMD Compensation Using a Variable and Fixed Differential Group Delays [C], Proc. OFC, Anaheim, California Mo2, 2001:17~21
[34] X.Yi, X.Yang, Optical Device for PMD Compensation by Using High-birefringence Linear Chirped Grating [C], vol.1, OFC, 2003:315~316
[35] S.Lee, R.Khosravani, J.Pen, et al., High birefringence Nonlinearly-chirped Fiber Bragg Grating for Tunable Compensation of Polarization Mode Dispersion [C], OFC, 1999: 272~274
[36] L.S.Yan, C.Yeh,G.Yang et al., Fast Digitally Variable Differential Group Delay Module Using Polarization Switching [C], Postdeadling Paper, OFC,2002: FA5-1
[37] L.S.Yan, M.C. Hauer, C.Yeh, et al., High Speed Stable and Repeatable PMD Emulator with Tunable Statistics [C], OFC, 2003: MF6
[38] T.Ono and Y.Yano, 10Gb/sPMD Compensation Field Experiments over 452km Using Principal State Transmission Method [J], Optica & Photonics News, May 2000: 61
[39]王剑,于晋龙,刘剑飞等,10Gbit/s光纤通信系统的偏振模色散动态补偿技术[J],光电子激光,2003年第6期
[40]王剑,偏振模色散动态补偿技术研究[D],[博士学位论文],天津,天津大学电信学院
[41] Patrick C. Chou, John M. Fini, and Hermann A. Haus, Real-Time Principal State Characterization for Use in PMD Compensators [J], IEEE Photonics. Technol. Lett., vol. 13, No 6, JUNE 2001: 568~570
[42]王剑,于晋龙,刘剑飞等,10Gbit/s光纤通信系统的偏振模色散动态补偿技术[J],光电子激光,2003年第6期
[43] E.Corbel, S.Lanne and J-P.Thiery, Improvement of first-order optical PMD compensator by relevant control of input state of polarization [C], Technical Digest, Anaheim, CA, USA, OFC, 2002:301~302
[44] Nobuhiko Kikuchi, Analysis of Signal Degree of Polarization Degradation Used as Control Signal for Optical Polarization Mode Dispersion Compensation [J], Lightwave Technol. Vol.19, No.4, April 2001:480~486
[45] C.Franchia, F.Bruyere, J.P.Thiery, and D.Penninckx, Simple dynamic polarization mode dispersion compensator [J], Electron. Lett., vol.35, no.5, Mar. 1999: 414~415
[46] F.Roy, C.Francia, F.Bruyere, A Simple Dynamic Polarization mode Dispersion Compensator, Proc, OFC’99,1999:TuS4 (275~278)
[47] Hok Yong Pua,Kumar Peddanarappagari,et al., An Adaptive First-Order Polarization-Mode Dispersion Compensation System Aided by Polarization Scrambling: Theory and Demonstration, Journal of Lightwave Technology,2000,18(6):832～841
[48] G. Ishikawa and H.Ooi, Polarization-mode dispersion sensitivity and monitoring in 40-Gbit/sOTDM and 10-Gbit/s NRZ transmission experiments, OFC’98, Technical Digest, WC5, 1998:117~119
[49] H.Bulow, W.Baumert,H.Schmuck, et al., Measurement of the maximum speed of PMD Fluctuation in installed field fiber, ECOC’99,1999:83~85
[50] H.Bulow, F.Buchali, G.Thielecke, Electronically enhanced optical PMD Compensation, Proc. ECOC, Munich, Germany, Vo..II, 2000: 4.2.4 (39~40)
[51]丁玉美,数字信号处理(第二版) [M],西安,西安电子科技大学出版社,2001:195
[52] EDA先锋工作实验室,Altera FPGA/CPLD设计(高级篇) [M],北京,人民邮电出版社,2005:264~269