光相位调制格式解调与相干探测研究
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摘要
激增的网络业务需求促使光纤通信迅猛发展，随着光信号传输速率和传输距离要求的不断提高，先进相位调制格式研究受到越来越多学术圈和工业界的关注。相位调制格式具有巨大的优势：不仅接收灵敏度比传统强度调制信号提高3dB，而且在光纤传输中有更大的非线性容忍度，此外，其高阶调制形式四相相移键控（QPSK）降低了信号波特率，减轻对高速电子器件的要求。因此相位调制信号的产生、解调、以及探测技术是关键的研究课题。近些年由于引入光相干探测技术，相位调制格式接收方式更加灵活，利用强大的数字信号处理技术还可以实现光纤传输损伤的补偿。
在此背景下，本论文针对光相位调制格式的产生、信号解调和相干探测展开理论和实验研究，概括全文可以总结为以下几个方面：
（1）分析了光调制的理论基础，研究了差分相移键控（DPSK）、QPSK、高阶正交幅度调制（QAM）先进调制格式的产生、解调和探测机理。
（2）基于马赫-曾德尔延时干涉仪（MZDI）解调DPSK信号原理，提出了联合差分相移键控到双二进制码（DPSK-DB）调制方式应用于40Gb/s长距离接入WDM-PON下行链路传输的方案，利用了DPSK信号长距离传输的优势结合DB信号大色散容忍度和直接探测接收的特点，实现无源光网络中80公里干道传输和5公里接入传输的实验，并演示了基于一个MZDI进行4信道DPSK信号到DB信号的并行转换，节约了系统成本。
（3）基于微环谐振腔（MRR）解调DPSK信号原理，提出了一种新型硅基偏振复用差分相移键控（DP-DPSK）解调器件，利用信号模式变换和多模干涉（MMI）结构实现偏振态分离，以及利用一个微环谐振腔实现双偏振态DPSK信号同时解调。首次实验展示了片上80Gb/s DP-DPSK信号的偏振解复用和相位解调。
（4）基于相位调制到强度调制的鉴频原理，提出了基于硅基微环谐振腔耦合马赫-曾德尔干涉仪（MRR-MZI）器件产生超宽带（UWB）信号的新方案，该器件具有鉴频响应度高、线性度好的优点。实验演示了由高斯相位调制脉冲通过MRR-MZI器件产生正负极性UWB信号。
（5）分析了光相干探测的基本原理和光相干接收机的工作机制，详细论述了不同调制格式信号恢复算法的原理及过程。通过系统仿真评估了QPSK信号恢复算法的性能和受限因素，通过传输实验数据的信号恢复，展示了算法的工作流程和均衡效果。提出了一种新型的级联盲均衡算法，在误差函数中引入相位项使得均衡器具有载波相位恢复的功能，利用最后判决信息来做误差反馈使得该算法与调制格式无关。通过QPSK和16-QAM实验数据的信号恢复证实了该算法的有效性，实验结果表明其恢复性能与经典算法相当。
（6）为了提高频谱效率，提出了一种光域超强滤波的Nyquist QPSK方案，并对中间采样点形成的9-QAM信号进行处理，利用提出的一套9-QAM信号恢复算法成功抑制了码间干扰（ISI）效应。11×112Gb/s DP-QPSK25GHz间隔Nyquist-WDM背靠背实验证明该方案在接收光信噪比方面比国际领先方案改善0.5dB。另外进行了3×112Gb/s DP-QPSK信号1120公里光纤传输实验，每信道被压缩至18GHz超窄带宽，信号传输后最小误码率达到1×10~(-4)
The high development of optical fiber communications is excited by the rapidincreasing demand of network services. Advanced phase modulation formats have beenattracting more and more attentions both from academic and industry as the higher bit rateand transmission length are required. The advantages of phase modulation format are: thesensitivity to receive phase modulated signal is superior to traditional intensity modulationby3dB. Phase modulation format can tolerate higher fiber nonlinearity effect in the fibertransmission. The deployment of Quadrature Phase Shift Keying (QPSK) decreases thesignal baud rate and releases the requirement of high speed electronic devices. Therefore,phase modulated signal generation, demodulation, and conversion become very importantresearch issues. Optical coherent detection has made revolutionary progress in recent years.Phase modulation formats are used more widely because the phase signal can be receivedby the coherent detection. Besides the transmission impairments can be compensatedthanks to the powerful digital signal processing techniques.
The optical signal generation, conversion and optical coherent detection with respectto the phase modulation formats are theoretical investigated and experimentally studied inthis thesis. The major research achievements and contributions of this dissertation aresummarized as follows:
(1) The optics modulation principle is investigated. The generation, demodulation, anddetection of Differential Phase Shift Keying (DPSK), QPSK and high level QuadratureAmplitude Modulation (QAM) are studied.
(2) We propose and demonstrate combining DPSK and duobinary (DB) transmissionfor the downstream in40Gb/s long-reach wavelength division multiplexed-passive opticalnetworks (WDM-PONs) in order to provide robust transmission performance in thebackhaul section and simple detection at the Optical Network Units (ONUs). DPSK isdeployed in the trunk span as it provides stronger robustness to fiber nonlinearity. DB isused in the access span where its higher chromatic dispersion tolerance relieves the need fordispersion compensation.4channel all-optical modulation format conversion from DPSKto duobinary is realized in a single Mach-Zehnder delay interferometer (MZDI) in the Remote Node (RN) to decrease system cost.
(3) A novel silicon based dual polarization DPSK (DP-DPSK) demodulation device isproposed. The polarization separation is realized based on the mode conversion and themulti-mode interference (MMI) structure. The orthogonal polarization DPSK signals aredemodulated based on only one microring resonator. We first time demonstrate the80Gb/sDP-DPSK polarization de-multiplexing and demodulation on chip.
(4) Ultra-wideband (UWB) generation based on the microring-coupled Mach-ZehnderInterferometer (MZI) is proposed. Microring-coupled MZI plays the role of high sensitivelinear discriminator. Two polarity Monocycle pulses are generated from Gaussianmodulated phase signal using silicon microring-coupled MZI device.
(5) Optical coherent detection principle and coherent receiver are investigated. Digitalsignal processing (DSP) algorithms for different modulation formats are studied in principleand simulation analysis. The performances of algorithms are presented for the experimentaldata recovery. We propose a novel cascaded adaptive blind equalizers based ondecision-directed modified least mean square (DD-MLMS) algorithm for polarizationseparation and carrier phase recovery. The algorithm is compatible with varioussquare-QAM formats. The experimental results of DP-QPSK and DP-16QAM back-to-backtransmission show that the performance is very close to the general algorithm but with abenefit of the reduced operation complexity.
(6) We propose9-QAM data recovery for DP-QPSK signal in presence of strongfiltering to approach Nyquist bandwidth in order to increase spectrum efficiency. Thedecision-directed least radius distance (DD-LRD) algorithm for blind equalization is usedfor9-QAM recovery and inter-symbol interference (ISI) compression.11×112Gb/sDP-QPSK25-GHz spaced Nyquist-WDM experiment result shows optical signal-to-noiseratio (OSNR) tolerance is improved by0.5dB at a bit error rate (BER) of1x10-3comparedto constant modulus algorithm (CMA) plus post-filter algorithm.3×112Gb/s DP-QPSKover1120km transmission is demonstrated. The BER can achieve1×10-4when thebandwidth per channel is strongly compressed to18GHz.
在此背景下，本论文针对光相位调制格式的产生、信号解调和相干探测展开理论和实验研究，概括全文可以总结为以下几个方面：
（1）分析了光调制的理论基础，研究了差分相移键控（DPSK）、QPSK、高阶正交幅度调制（QAM）先进调制格式的产生、解调和探测机理。
（2）基于马赫-曾德尔延时干涉仪（MZDI）解调DPSK信号原理，提出了联合差分相移键控到双二进制码（DPSK-DB）调制方式应用于40Gb/s长距离接入WDM-PON下行链路传输的方案，利用了DPSK信号长距离传输的优势结合DB信号大色散容忍度和直接探测接收的特点，实现无源光网络中80公里干道传输和5公里接入传输的实验，并演示了基于一个MZDI进行4信道DPSK信号到DB信号的并行转换，节约了系统成本。
（3）基于微环谐振腔（MRR）解调DPSK信号原理，提出了一种新型硅基偏振复用差分相移键控（DP-DPSK）解调器件，利用信号模式变换和多模干涉（MMI）结构实现偏振态分离，以及利用一个微环谐振腔实现双偏振态DPSK信号同时解调。首次实验展示了片上80Gb/s DP-DPSK信号的偏振解复用和相位解调。
（4）基于相位调制到强度调制的鉴频原理，提出了基于硅基微环谐振腔耦合马赫-曾德尔干涉仪（MRR-MZI）器件产生超宽带（UWB）信号的新方案，该器件具有鉴频响应度高、线性度好的优点。实验演示了由高斯相位调制脉冲通过MRR-MZI器件产生正负极性UWB信号。
（5）分析了光相干探测的基本原理和光相干接收机的工作机制，详细论述了不同调制格式信号恢复算法的原理及过程。通过系统仿真评估了QPSK信号恢复算法的性能和受限因素，通过传输实验数据的信号恢复，展示了算法的工作流程和均衡效果。提出了一种新型的级联盲均衡算法，在误差函数中引入相位项使得均衡器具有载波相位恢复的功能，利用最后判决信息来做误差反馈使得该算法与调制格式无关。通过QPSK和16-QAM实验数据的信号恢复证实了该算法的有效性，实验结果表明其恢复性能与经典算法相当。
（6）为了提高频谱效率，提出了一种光域超强滤波的Nyquist QPSK方案，并对中间采样点形成的9-QAM信号进行处理，利用提出的一套9-QAM信号恢复算法成功抑制了码间干扰（ISI）效应。11×112Gb/s DP-QPSK25GHz间隔Nyquist-WDM背靠背实验证明该方案在接收光信噪比方面比国际领先方案改善0.5dB。另外进行了3×112Gb/s DP-QPSK信号1120公里光纤传输实验，每信道被压缩至18GHz超窄带宽，信号传输后最小误码率达到1×10~(-4)
The high development of optical fiber communications is excited by the rapidincreasing demand of network services. Advanced phase modulation formats have beenattracting more and more attentions both from academic and industry as the higher bit rateand transmission length are required. The advantages of phase modulation format are: thesensitivity to receive phase modulated signal is superior to traditional intensity modulationby3dB. Phase modulation format can tolerate higher fiber nonlinearity effect in the fibertransmission. The deployment of Quadrature Phase Shift Keying (QPSK) decreases thesignal baud rate and releases the requirement of high speed electronic devices. Therefore,phase modulated signal generation, demodulation, and conversion become very importantresearch issues. Optical coherent detection has made revolutionary progress in recent years.Phase modulation formats are used more widely because the phase signal can be receivedby the coherent detection. Besides the transmission impairments can be compensatedthanks to the powerful digital signal processing techniques.
The optical signal generation, conversion and optical coherent detection with respectto the phase modulation formats are theoretical investigated and experimentally studied inthis thesis. The major research achievements and contributions of this dissertation aresummarized as follows:
(1) The optics modulation principle is investigated. The generation, demodulation, anddetection of Differential Phase Shift Keying (DPSK), QPSK and high level QuadratureAmplitude Modulation (QAM) are studied.
(2) We propose and demonstrate combining DPSK and duobinary (DB) transmissionfor the downstream in40Gb/s long-reach wavelength division multiplexed-passive opticalnetworks (WDM-PONs) in order to provide robust transmission performance in thebackhaul section and simple detection at the Optical Network Units (ONUs). DPSK isdeployed in the trunk span as it provides stronger robustness to fiber nonlinearity. DB isused in the access span where its higher chromatic dispersion tolerance relieves the need fordispersion compensation.4channel all-optical modulation format conversion from DPSKto duobinary is realized in a single Mach-Zehnder delay interferometer (MZDI) in the Remote Node (RN) to decrease system cost.
(3) A novel silicon based dual polarization DPSK (DP-DPSK) demodulation device isproposed. The polarization separation is realized based on the mode conversion and themulti-mode interference (MMI) structure. The orthogonal polarization DPSK signals aredemodulated based on only one microring resonator. We first time demonstrate the80Gb/sDP-DPSK polarization de-multiplexing and demodulation on chip.
(4) Ultra-wideband (UWB) generation based on the microring-coupled Mach-ZehnderInterferometer (MZI) is proposed. Microring-coupled MZI plays the role of high sensitivelinear discriminator. Two polarity Monocycle pulses are generated from Gaussianmodulated phase signal using silicon microring-coupled MZI device.
(5) Optical coherent detection principle and coherent receiver are investigated. Digitalsignal processing (DSP) algorithms for different modulation formats are studied in principleand simulation analysis. The performances of algorithms are presented for the experimentaldata recovery. We propose a novel cascaded adaptive blind equalizers based ondecision-directed modified least mean square (DD-MLMS) algorithm for polarizationseparation and carrier phase recovery. The algorithm is compatible with varioussquare-QAM formats. The experimental results of DP-QPSK and DP-16QAM back-to-backtransmission show that the performance is very close to the general algorithm but with abenefit of the reduced operation complexity.
(6) We propose9-QAM data recovery for DP-QPSK signal in presence of strongfiltering to approach Nyquist bandwidth in order to increase spectrum efficiency. Thedecision-directed least radius distance (DD-LRD) algorithm for blind equalization is usedfor9-QAM recovery and inter-symbol interference (ISI) compression.11×112Gb/sDP-QPSK25-GHz spaced Nyquist-WDM experiment result shows optical signal-to-noiseratio (OSNR) tolerance is improved by0.5dB at a bit error rate (BER) of1x10-3comparedto constant modulus algorithm (CMA) plus post-filter algorithm.3×112Gb/s DP-QPSKover1120km transmission is demonstrated. The BER can achieve1×10-4when thebandwidth per channel is strongly compressed to18GHz.
引文
[1] A. H. Gnauck, R. W. Tkach, A. R. Chraplyvy, et al. High-capacity opticaltransmission systems. J. Lightwave Technology,2008,26(9):1032-1045
[2] P. J. Winzer, G. Raybon, C. R. Doerr, et al.2000-km WDM transmission of10×107-Gb/s RZ-DQPSK. European Conference on Optical Communication(ECOC2006). Cannes,2006. Th4.1.3
[3] M. Hiroji, S. Akihide, K. Takayuki, et al.20.4-Tb/s (204×111Gb/s) transmissionover240km using bandwidth-maximized hybrid Raman/EDFAs. Optical FiberCommunication Conference (OFC2007). Anaheim,2007. PDP20
[4] X. Zhou, J. Yu, D. Qian, et al.8×114Gb/s,25-GHz-Spaced, PolMux-RZ-8PSKtransmission over640km of SSMF employing digital coherent detection andEDFA-Only amplification. Optical Fiber Communication Conference (OFC2008).San Diego,2008. PDP1
[5] X. Zhou, J. Yu, M.-F. Huang, et al.64-Tb/s (640×107-Gb/s) PDM-36QAMtransmission over320km using both pre-and post-transmission digital equalization.Optical Fiber Communication Conference (OFC2009). San Diego,2009. PDPB9
[6] A. Sano, H. Masuda, T. Kobayashi, et al.69.1-Tb/s (432×171-Gb/s) C-andextended L-band transmission over240km using PDM-16-QAM modulation anddigital coherent detection. Optical Fiber Communication Conference (OFC2009).San Diego,2010. PDPB7
[7] J. X. Cai, Y. Cai, C. R. Davidson, et al.20Tbit/s capacity transmission over6860km. Optical Fiber Communication Conference (OFC2011). Los Angles,2011.PDPB4
[8] J. Yu, Z. Dong, X. Xiao, et al. Generation, Transmission and coherent detection of11.2Tb/s (112×100Gb/s) single source optical OFDM superchannel. Optical FiberCommunication Conference (OFC2011). Los Angles,2011. PDPA6
[9] J. Sakaguchi, B. J. Puttnam, W. Klaus, et al.19-core fiber transmission of19×100×172-Gb/s SDM-WDM-PDM-QPSK signals at305Tb/s. Optical FiberCommunication Conference (OFC2012). Los Angles,2012. PDP5C.1
[10] T. J. Xia, G. Wellbrock, A. Tanaka, et al. High capacity field trials of40.5Tb/s forLH distance of1822km and54.2Tb/s for regional distance of634km. OpticalFiber Communication Conference (OFC2013). Los Angles,2013. PDP5A.4
[11] T. Hoshida, O. Vassilieva, K. Yamada, et al. Optimal40Gb/s modulation formats forspectrally efficient long-haul DWDM systems. J. Lightwave Technology,2002,20(12):1989-1996
[12] J. Yu, X. Zhou, L. Xu, et al. A novel scheme to generate100Gbit/s DQPSK signalwith large PMD tolerance. Optical Fiber Communication Conference (OFC2007).Anaheim,2007. JThA42
[13] D. van den Borne, S. L. Jansen, E. Gottwald, et al. DQPSK modulation for robustoptical transmission. Optical Fiber Communication Conference (OFC2008). SanDiego,2008.OMQ1
[14] A. Leven, N. Kaneda, U. Koc, et al. Coherent receivers for practical opticalcommunication systems. Optical Fiber Communication Conference (OFC2007).Anaheim,2007. OThK4
[15] J. Yu, X. Zhou, M. F. Huang, et al.400Gb/s (4×100Gb/s) orthogonalPDM-RZ-QPSK DWDM signal transmission over1040km SMF-28. Optics Express,2009,17(20):17928-17933
[16] X. Zhou, L. E. Nelson, P. Magill, et al. High spectral efficiency400Gb/stransmission using PDM time-domain hybrid32–64QAM and training-assistedcarrier recovery. J. Lightwave Technology,2013,31(7):999-1005
[17] X. Liu, S. Chandrasekhar, B. Zhu, et al.448-Gb/s reduced-guard-intervalCO-OFDM transmission over2000km of ultra-large-area fiber and five80-GHz-grid ROADMs. J. Lightwave Technology,2011,29(4):483-490
[18] X. Liu, A. H. Gnauck, W. Xing, et al. Athermal optical demodulator for OC-768DPSK and RZ-DPSK signals. IEEE Photonics Technology Letters,2005,17(12):2610-2612
[19] E. Ip, A. P. T. Lau, D. J. F. Barros, et al. Coherent detection in optical fiber systems.Optics Express,2008,16(2):753-790
[20] P. J. Winzer, R. J. Essiambre. Advanced modulation formats for high-capacityoptical transport networks. J. Lightwave Technology,2006,24(12):4711-4728
[21] P. J. Winzer, R. J. Essiambre. Advanced optical modulation formats. Proceedings OfThe IEEE,2006,94(5):952-985
[22] J. Zhang, N. Chi, P. V. Holm-Nielsen, et al. An optical FSK transmitter based on anintegrated DFB laser-EA modulator and its application in optical labeling. PhotonicsTechnology Letters,2003,15(7):984-986
[23] N. Chi, L. Xu, S. Yu, et al. Generation and transmission performance of a40Gb/spolarization shift keying signal. Electron. Lett.,2005,41(9):547-549
[24] G. P. Agrawal. Fiber-Optic Communication Systems. Third Edition, WileyInterscience,2002
[25] G. P. Agrawal. Nonlinear Fiber Optics. Four Edition, Academic Press,2006
[26] A. H. Gnauck, G. Raybon, S. Chandrasekhar, et al.2.5Tb/s (64×42.7Gb/s)transmission over40×100km NZDSF using RZ-DPSK format and all-Raman-amplified spans. Optical Fiber Communication Conference (OFC2002). Anaheim,2002. FC2
[27] R. A. Griffin, A. C. Carter. Optical differential quadrature phase-shift key (oQPSK)for high capacity optical transmission. Optical Fiber Communication Conference(OFC2002). Anaheim,2002. WX6
[28] M. Daikoku, I. Morita, H. Taga, et al.100-Gb/s DQPSK transmission experimentwithout OTDM for100G ethernet transport. J. Lightwave Technology,2007,25(1):139-145
[29] D. van den Borne, S. L. Jansen, E. Gottwald, et al.1.6-b/s/Hz spectrally efficienttransmission over1700km of SSMF using40×85.6-Gb/s POLMUX-RZ-DQPSK.J. Lightwave Technology,2007,25(1):222-232
[30] C. R. S. Fludger, T. Duthel, D. van den Borne, et al.10×111Gbit/s,50GHz spaced,POLMUX-RZ-DQPSK transmission over2375km Employing coherentequalisation. Optical Fiber Communication Conference (OFC2007). Anaheim,2007.PDP22.
[31] C. R. S. Fludeger, T. Duthel, D. van den Borne, et al. Coherent equalization andPOLMUX-RZ-DQPSK for robust100-GE transmission. J. Lightwave Technology,2008,26(1):64-72
[32] A. H. Gnauck, P. J. Winzer. Optical phase-shift-keyed Transmission. J. LightwaveTechnology,2005,23(1):115-130
[33] B. Mikkelsen, C. Rasmussen, P. Mamyshev, et al. Partial DPSK with excellent filtertolerance and OSNR sensitivity. Electronics Letters,2006,42(23):1363-1364
[34] Z. Zhang, L. Chen, X. Bao, et al. Partial bit delay correlative modulation used toimprove the dispersion tolerance of an optical duobinary system. Optics Express,2008,16(15):11344-11353
[35] I. Lyubomirsky, C.-C. Chien. DPSK demodulator based on optical discriminatorfilter. IEEE Photonics Technology Letters,2005,17(2):492-494
[36] I. Lyubomirsky, C.-C. Chien, Y.-H. Wang. Optical DQPSK receiver with enhanceddispersion tolerance. IEEE Photonics Technology Letters,2008,20(7):511-513
[37] L. Zhang, J.-Y. Yang, M. Song, et al. Microring-based modulation and demodulationof DPSK signal. Optics Express,2007,15(18):11564-11569
[38] X. Lin, L. Chao, W. Chiyan, et al. Optical differential-phase-shift-keyingdemodulation using a silicon microring resonator. IEEE Photonics TechnologyLetters,2009,21(5):295-297
[39] L. Zhang, J.-Y. Yang, Y. Li, et al. Monolithic modulator and demodulator ofdifferential quadrature phase-shift keying signals based on silicon microrings.Optics Letters,2008,33(13):1428-1430
[40] K. Xu, L. Wang, G. K. P. Lei, et al. Demodualtion of20Gbaud/s differentialquadrature phase-shift keying singals using wavelength-tunable silicon microringresonators. Optics Letters,2012,37(6):3462-3464
[41] Y. Ding, J. Xu, C. Peucheret, et al. Multi-Channel40Gbit/s NRZ-DPSKdemodulation using a single silicon microring resonator. Journal of LighwaveTechnology,2011,29(5):677-684
[42] E. E. Basch, T. G. Brown. Introduction to coherent optical fiber transmission. IEEECommunication Magazine,1985,23(5):23-30
[43] J. R. Barry, E. A. Lee. Performance of coherent optical receivers. Proceedings OfThe IEEE,1990,78(8):1369-1394
[44] F. Derr. Optical QPSK transmission system with novel digital receiver concept.Electronics Letters,1991,27(23):2177-2179
[45] F. Derr. Coherent optical QPSK intradyne system: concept and digital receiverrealization. J. Lightwave Technology,1992,10(9):1290-1296
[46] J. Kahn, K.-P. Ho. Spectral efficiency limits and modulation/detection techniques forDWDM systems. J. Select. Topics Quantum Electron.,2004,10(2):259–272
[47] S. Tsukamoto, D.-S. Ly-Gagonon, K. Katoh, et al. Coherent demodulation of40-Gbit/s polarization-multiplexed QPSK signals with16-GHz spacing after200-km transmission. Optical Fiber Communication Conference (OFC2005).Anaheim,2005. PDP29
[48] D.-S. Ly-Gagonon, S. Tsukamoto, K. Katoh, et al. Coherent detection of opticalquadrature phase-shift keying signals with carrier phase estimation. J. LightwaveTechnology,2004,24(1):12-21
[49] M. Taylor. Coherent detection method using DSP for demodulation of signal andsubsequent equalization of propagation impairments. IEEE Photonics TechnologyLetters,2004,16(2):674-676
[50] E. Ip, J. M. Kahn. Digital equalization of chromatic dispersion and polarizationmode dispersion. J. Lightwave Technology,2007,25(8):2033-2043
[51] M. Kuschnerov, F. N. Hauske, K. Piyawanno, et al. DSP for coherent single-carrierreceivers. J. Lightwave Technology,2009,27(16):3614-3622
[52] S. J. Savory. Digital coherent optical receivers: algorithm and subsystems. J.Selected Topics in Quantum Eletronics,2010,16(5):1164-1179
[53] Y. Han, G. Li. Coherent optical communication using polarization multiple-input-multiple-output. Optics Express,2005,13(19):7527-7534
[54] S. J. Savory. Digital filters for coherent optical receivers. Optics Express,2008,16(2):804-817
[55] P. J. Winzer, A. H. Gnauck, C. R. Doerr, et al. Spectrally efficient long-haul opticalnetworking using112-Gb/s polarization-multiplexed16-QAM. J. LightwaveTechnology,2010,28(4):547-556
[56] H. Sun, K.-T. Wu, K. Roberts. Real-time measurements of a40Gb/s coherentsystems. Optics Express,2008,16(2):873-879
[57] K. Kikuchi. Coherent optical communications-history, state-of-the-art technologies,and challenges for the future-. Opto-Electronics and Communications Conference(OECC2008). Australia,2008.1-4
[58] K. Kikuchi. Eletronic post-compensation for nonlinear phase fluctuations in a1000-km20-Gbit/s optical quadrature phase-shift keying transmission system usingthe digital coherent receiver. Optics Express,2008,16(2):889-896
[59]顾畹仪. WDM超长距离光传输技术.(第一版).北京:北京邮电大学出版社,2006.26-31
[60] S. A. Gronemeyer, A. L. Mcbride. MSK and offset QPSK modulation. IEEETransactions On Communication,1976,24(8):809-820
[61] S. Pasupathy. Minimum shift keying: A spectrally efficient modulation. IEEECommunication Magazine,1979,17(4):14-22
[62] M. Ohm, J. Speidel. Optical minimum-shift keying with direct detection (MSK/DD).Asia-Pacific Optical Communication (APOC2003). Wuhan,2003.5281
[63] C. Lu, J. Mo, Y. Wen. Optical minimum-shift keying: property and implementation.Optical Fiber Communication Conference (OFC2006). Anaheim,2006. CFH1
[64] G.-W. Lu, T. Sakamoto, A. Chiba, et al. Optical MSK transmitter using amonolithically integrated quad Mach-Zehnder IQ modulator. European Conferenceon Optical Communication (ECOC2009). Vienna,2009.5.2.1
[65] L. N. Binh, T. L. Huynh. Single and dual-Level minimum shift keying opticaltransmission systems. J. Lightwave Technology,2009,27(5):522-537
[66] X. Wei, A. H. Gnauck, D. M. Gill. Optical π/2-DPSK and its tolerance to filteringand polarization-mode-dispersion. IEEE Photonics Technology Letters,2003,15(11):1639-1641
[67] J. Wang, J. M. Kahn. Conventional DPSK versus symmetrical DPSK: comparison ofdispersion tolerances. IEEE Photonics Technology Letters,2004,16(6):1585-1587
[68] A. Banerjee, Y. Park, F. Clarke, et al. Wavelength-division-multiplexed passiveoptical network (WDM-PON) technologies for broadband access: a review. J. Opt.Netw.,2005,4:737-758
[69] G.-K. Chang, A. Chowdhury, Z. Jia, et al. Key technologies of WDM-PON forfuture converged optical broadband access networks, J. Opt. Commun. Netw.,2009,1(4): C35-C50
[70] D. P. Shea, J. E. Mitchell. Long-reach optical access technologies. IEEE Networks.,2007,21(5):5-11
[71] D. P. Shea, J. E. Mitchell. Architecture to integrate multiple PONs with long reachDWDM backkhaul. IEEE J. on Selected Areas in Communications,2009,27(2):126-133
[72] R. P. Davey, D. B. Grossman, M. Rasztovits-Wiech, et al. Long-reach passiveoptical networks. J. Lightwave Technol.,2009,27:273-291
[73] C. H. Yeh, C. W. Chow, H. Y. Chen, et al. Using adaptive four-band OFDMmodulation with40Gb/s downstream and10Gb/s upstream signals for nextgeneration long-reach PON. Opt. Express,2011,19(27):26150-26160
[74] C. H. Yeh, C. W. Chow, C. H. Wang, et al. Using OOK modulation for symmetric40-Gb/s long-reach time-sharing passive optical networks. IEEE Photon. Technol.Lett.,2010,22(9):619-621
[75] C. W. Chow, C. H. Yeh.40-Gb/s downstream DPSK and40-Gb/s upstream OOKsignal remodulation PON using reduced modulation index. Opt. Express,2010,18(25):26046-26051
[76] I. P. Kaminow. Balanced optical discriminator. Appl. Opt.,1964,3(4):507-510
[77] C. W. Chow, H. K. Tsang. Polarization-independent DPSK demodulation using abirefringent fiber loop. IEEE Photon. Technol. Lett.,2005,17(6):1313-1315
[78] Y. Ding, H. Ou, and C. Peucheret. Wide-band polarization splitter and rotator withlarge fabrication tolerance and simple fabrication process. Optical FiberCommunication Conference (OFC2013). Los Angles,2013. OTh4I.2
[79] D. Dai, Y. Tang, J. Bowers. Mode conversion intapered submicron silicon ridgeoptical waveguides. Opt. Express,2012,20(12):13425-13439
[80] Y. Ding, H. Ou, C. Peucheret. Wideband polarization splitter and rotator with largefabrication tolerance and simple fabrication process. Optics Letters,2013,38(8):1227-1229
[81] J. Yao, F. Zeng, Q. Wang. Photonic generation of ultrawideband signals. J.Lightwave Technol.,2007,25(11):3219-3235
[82] J. Dong. Ultrawideband monocycle generation using cross-phase modulation in asemiconductor optical amplifier. Opt. Lett.,2007,32(10):1223-1225
[83] Q. Wang, J. Yao. Switchable optical UWB monocycle and doublet generation usinga reconfigurable photonic microwave delay-line filter. Optics Express,2007,15(22):14667-14672
[84] E. Zhou. A power-efficient ultra-wideband pulse generator based on multiplePM-IM conversions. IEEE Photon. Technol. Lett.,2010,22(14):1063-1065
[85] S. Pan, J. Yao. Switchable UWB pulse generation using a phase modulator and areconfigurable asymmetric Mach–Zehnder interferometer. Opt. Lett.,2009,34(2):160-162
[86] Y. Dai, J. Du, X. Fu, et al. Ultrawideband monocycle pulse generation based ondelayed interference of π/2phase-shift keying signal. Optics Letters,2011,36(14):2695-2697
[87] F. Liu. On-chip photonic generation of ultra-wideband monocycle pulses. Electron.Lett.,2009,45(24):1247
[88] S. Darmawan, L. Y. M. Tobing, T. Mei. Coupling-induced phase shift in amicroring-coupled Mach-Zehnder interferometer. Optics Letters,2010,35(2):238-240
[89] B. Guha, B. B. C. Kyotoku, M. Lipson. CMOS-compatible athermal siliconmicroring resonators. Optics Express,2010,18(4):3488-3493
[90] M. Seimetz, C. M. Weinert. Options, feasibility, and availability of2×490°hybridsfor coherent optical systems. J. Lightwave Technology,2006,24(3):1317-1322
[91] L. G. Kazovsky, L. Curtis, W. C. Young. All-fiber90°optical hybrid for coherentcommunications. Applied Optics,1987,26(3):437-439
[92] D. N. Godard. Self-recovering equalization and carrier tracking in two dimensionaldata communication systems. IEEE Transactions on Communications,1980,28(11):1867-1875
[93] C. R. Johnson, P. Schniter, T. J. Endres, et al. Blind equalization using constantmodulus criterion: a review. Proceedings of The IEEE,1998,86(10):1927-1950
[94] M. J. Ready, R. P. Gooch. Blind equalization based on radius directed adaptation.International Conference on Acoustics Speech and Signal Processing (ICASSP1990),1990,3:1699-1702
[95] I. Fatadin, D. Ives, S. J. Savory. Blind equalization and carrier phase recovery in a16-QAM optical coherent system. J. Lightw. Technol.,2009,27(15):3042-3049
[96] A. J. Viterbi, A. M. Viterbi. Nonlinear estimation of PSK-modulated carrier phasewith application to burst digital transmission. IEEE Trans. Inf. Theory,1983,29(4):543-551
[97] A. Leven, N. Kaneda, U. V. Koc, et al. Frequency estimation in intradyne reception.IEEE Photonics Technology Letters,2007,19(6):366-368
[98] M. Selmi, Y. Jaouen, P. Ciblat. Accurate digital frequency offset estimator forcoherent PolMux QAM transmission systems. European Conference on OpticalCommunication (ECOC2009), Vienna,2009. P3.08.
[99] T. Nakagawa, M. Matsui, T. Kobayashi. Non-data-aided wide-range frequency offsetestimator for QAM optical coherent receivers. Optical Fiber CommunicationConference (OFC2011). Los Angles,2011. OMJ1
[100] M. Seimetz. Performance of Coherent Optical square-16-QAM-systems based onIQ-transmitters and homodyne receivers with digital phase estimation. Optical FiberCommunication Conference (OFC2006). Anaheim,2006. NWA4
[101] M. Seimetz. Laser linewidth limiattions for optical systems with high-ordermodulation employing feed forward digital carrier phase estimation. Optical FiberCommunication Conference (OFC2008). San Diego,2008. OTuM2
[102] T. Pfau, S. Hoffmann, R. Noe. Hardware-efficient coherent digital receiver conceptwith feedforward carrier recovery for M-QAM constellations. J. Lightw. Technol.,2009,27(8):989-999
[103] O. Gerstel, M. Jinno, A. Lord, et al. Elastic optical networking: a new dawn for theoptical layer?. IEEE Commun. Mag.,2012,50(2): s12-s20
[104] H. Y. Choi, T. Tsuritani, I. Morita. BER-adaptive flexible-format transmitter forelastic optical networks. Opt. Express,2012,20(17):18652-18658
[105] R. Borkowski. Experimental study on OSNR requirements for spectrum flexibleoptical networks. J. Opt. Commun. Netw.,2012,4(11): B85-B93
[106] Y.-K. Huang. High-capacity fiber field trial using terabit/s all-optical OFDMsuperchannels with DP-QPSK and DP-8QAM/DP-QPSK modulation. J. Lightw.Technol.,2013,31(4):546-553
[107] K. Roberts, M. O’Sullivan, K.-T. Wu, et al. Performance of dual-polarization QPSKfor optical transport systems. J. Lightw. Technol.,2009,27(16):3546-3559
[108] P. J. Winzer, A. H. Gnauck, S. Chandrasekhar, et al. Generation and1,200-kmtransmission of448-Gb/s ETDM56-Gbaud PDM16-QAM using a single I/Qmodulator. European Conference on Optical Communication (ECOC2010), Torino,2010. PDP2.2
[109] X. Zhou.64-Tb/s,8b/s/Hz, PDM-36QAM transmission over320km using bothpre-and post-transmission digital signal processing. J. Lightw. Technol.,2011,29(4):571-577
[110] J. Yu, Z. Dong, H.-C. Chien, et al.7-Tb/s (7×1.284Tb/s/ch) signal transmission over320km using PDM-64QAM modulation. IEEE Photon. Technol. Lett.,2012,24(4):264-266
[111] X. Xu, B. Chatelain, D. V. Plant. Decision directed least radius distance algorithmfor blind equalization in a dual-polarization16-QAM system. Optical FiberCommunication Conference (OFC2012). Los Angles,2012. OM2H
[112] R. Schmogrow, M. Winter, M. Meyer, et al. real-time Nyquist pulse generationbeyond100Gbit/s and its relation to OFDM. Opt. Express,2012,20(1):317-337
[113] G. Bosco, A. Carena, V. Curri, et al. Performance limits of Nyquist-WDM andCO-OFDM in high-speed PM-QPSK systems. IEEE Photon. Technol. Lett.,2010,22(5):1129-1131
[114] K. Kikuchi, Y. Ishikawa, K. Katoh. Coherent demodulation of optical quadratureduobinary signal with spectral efficiency of4bit/s/Hz per polarization. EuropeanConference on Optical Communication (ECOC2007). Berlin,2007.9.3.4
[115] I. Lyubomirsky. Quadrature duobinary for high-spectral efficiency100G transmission. J.Lightw. Technol.,2010,28(1):91-96
[116] F. Machi, M. S. Alfiad, M. Kuschnerov, et al.111-Gb/s polMux-quadratureduobinary for robust and bandwidth efficient transmission. IEEE Photon. Technol.Lett.,2010,22(1):751-753
[117] J. Li, E. Tipsuwannakul, T. Eriksson, et al. Approaching Nyquist limit in WDMsystems by low-complexity receiver-side duobinary shaping. J. Lightw. Technol.,2012,30(1):1664-1676
[118] J. Li, M. Sjodin, Magnus, P. A. Andrekson. Building up low-complexity spectrally-efficient Terabit superchannels by receiver-side duobinary shaping. Opt. Express,2012,20(9):10271-10281
[119] Z. Dong, J. Yu, Z. Jia, et al.7×224Gb/s/ch Nyquist-WDM transmission over1600-km SMF-28using PDM-CSRZ-QPSK modulation. IEEE Photon. Technol.Lett.,2012,24(13):1157-1159
[120] J. Yu, Z. Dong, H.-C. Chien, et al. Transmission of200G PDM-CSRZ-QPSK andPDM-16QAM with a SE of4b/s/Hz. J. Lightw. Technol.,2013,31(4):515-522
[121] H.-C. Chien, J. Yu, Z. Jia, et al. Noise-suppressed Nyquist-WDM for Terabitsuperchannel transmission. J. Lightw. Technol.,2012,30(24):3965-3971
[122] M. Oderder, H. Meyr. Digital filter and square timing recovery. IEEE Transac.Commun.,1988,36(5):605-612
[123] E. Ip, J. M. Kahn. Feedforward carrier recovery for coherent optical communications. J.Lightw. Technol.,2007,25(9):2675-2692
[2] P. J. Winzer, G. Raybon, C. R. Doerr, et al.2000-km WDM transmission of10×107-Gb/s RZ-DQPSK. European Conference on Optical Communication(ECOC2006). Cannes,2006. Th4.1.3
[3] M. Hiroji, S. Akihide, K. Takayuki, et al.20.4-Tb/s (204×111Gb/s) transmissionover240km using bandwidth-maximized hybrid Raman/EDFAs. Optical FiberCommunication Conference (OFC2007). Anaheim,2007. PDP20
[4] X. Zhou, J. Yu, D. Qian, et al.8×114Gb/s,25-GHz-Spaced, PolMux-RZ-8PSKtransmission over640km of SSMF employing digital coherent detection andEDFA-Only amplification. Optical Fiber Communication Conference (OFC2008).San Diego,2008. PDP1
[5] X. Zhou, J. Yu, M.-F. Huang, et al.64-Tb/s (640×107-Gb/s) PDM-36QAMtransmission over320km using both pre-and post-transmission digital equalization.Optical Fiber Communication Conference (OFC2009). San Diego,2009. PDPB9
[6] A. Sano, H. Masuda, T. Kobayashi, et al.69.1-Tb/s (432×171-Gb/s) C-andextended L-band transmission over240km using PDM-16-QAM modulation anddigital coherent detection. Optical Fiber Communication Conference (OFC2009).San Diego,2010. PDPB7
[7] J. X. Cai, Y. Cai, C. R. Davidson, et al.20Tbit/s capacity transmission over6860km. Optical Fiber Communication Conference (OFC2011). Los Angles,2011.PDPB4
[8] J. Yu, Z. Dong, X. Xiao, et al. Generation, Transmission and coherent detection of11.2Tb/s (112×100Gb/s) single source optical OFDM superchannel. Optical FiberCommunication Conference (OFC2011). Los Angles,2011. PDPA6
[9] J. Sakaguchi, B. J. Puttnam, W. Klaus, et al.19-core fiber transmission of19×100×172-Gb/s SDM-WDM-PDM-QPSK signals at305Tb/s. Optical FiberCommunication Conference (OFC2012). Los Angles,2012. PDP5C.1
[10] T. J. Xia, G. Wellbrock, A. Tanaka, et al. High capacity field trials of40.5Tb/s forLH distance of1822km and54.2Tb/s for regional distance of634km. OpticalFiber Communication Conference (OFC2013). Los Angles,2013. PDP5A.4
[11] T. Hoshida, O. Vassilieva, K. Yamada, et al. Optimal40Gb/s modulation formats forspectrally efficient long-haul DWDM systems. J. Lightwave Technology,2002,20(12):1989-1996
[12] J. Yu, X. Zhou, L. Xu, et al. A novel scheme to generate100Gbit/s DQPSK signalwith large PMD tolerance. Optical Fiber Communication Conference (OFC2007).Anaheim,2007. JThA42
[13] D. van den Borne, S. L. Jansen, E. Gottwald, et al. DQPSK modulation for robustoptical transmission. Optical Fiber Communication Conference (OFC2008). SanDiego,2008.OMQ1
[14] A. Leven, N. Kaneda, U. Koc, et al. Coherent receivers for practical opticalcommunication systems. Optical Fiber Communication Conference (OFC2007).Anaheim,2007. OThK4
[15] J. Yu, X. Zhou, M. F. Huang, et al.400Gb/s (4×100Gb/s) orthogonalPDM-RZ-QPSK DWDM signal transmission over1040km SMF-28. Optics Express,2009,17(20):17928-17933
[16] X. Zhou, L. E. Nelson, P. Magill, et al. High spectral efficiency400Gb/stransmission using PDM time-domain hybrid32–64QAM and training-assistedcarrier recovery. J. Lightwave Technology,2013,31(7):999-1005
[17] X. Liu, S. Chandrasekhar, B. Zhu, et al.448-Gb/s reduced-guard-intervalCO-OFDM transmission over2000km of ultra-large-area fiber and five80-GHz-grid ROADMs. J. Lightwave Technology,2011,29(4):483-490
[18] X. Liu, A. H. Gnauck, W. Xing, et al. Athermal optical demodulator for OC-768DPSK and RZ-DPSK signals. IEEE Photonics Technology Letters,2005,17(12):2610-2612
[19] E. Ip, A. P. T. Lau, D. J. F. Barros, et al. Coherent detection in optical fiber systems.Optics Express,2008,16(2):753-790
[20] P. J. Winzer, R. J. Essiambre. Advanced modulation formats for high-capacityoptical transport networks. J. Lightwave Technology,2006,24(12):4711-4728
[21] P. J. Winzer, R. J. Essiambre. Advanced optical modulation formats. Proceedings OfThe IEEE,2006,94(5):952-985
[22] J. Zhang, N. Chi, P. V. Holm-Nielsen, et al. An optical FSK transmitter based on anintegrated DFB laser-EA modulator and its application in optical labeling. PhotonicsTechnology Letters,2003,15(7):984-986
[23] N. Chi, L. Xu, S. Yu, et al. Generation and transmission performance of a40Gb/spolarization shift keying signal. Electron. Lett.,2005,41(9):547-549
[24] G. P. Agrawal. Fiber-Optic Communication Systems. Third Edition, WileyInterscience,2002
[25] G. P. Agrawal. Nonlinear Fiber Optics. Four Edition, Academic Press,2006
[26] A. H. Gnauck, G. Raybon, S. Chandrasekhar, et al.2.5Tb/s (64×42.7Gb/s)transmission over40×100km NZDSF using RZ-DPSK format and all-Raman-amplified spans. Optical Fiber Communication Conference (OFC2002). Anaheim,2002. FC2
[27] R. A. Griffin, A. C. Carter. Optical differential quadrature phase-shift key (oQPSK)for high capacity optical transmission. Optical Fiber Communication Conference(OFC2002). Anaheim,2002. WX6
[28] M. Daikoku, I. Morita, H. Taga, et al.100-Gb/s DQPSK transmission experimentwithout OTDM for100G ethernet transport. J. Lightwave Technology,2007,25(1):139-145
[29] D. van den Borne, S. L. Jansen, E. Gottwald, et al.1.6-b/s/Hz spectrally efficienttransmission over1700km of SSMF using40×85.6-Gb/s POLMUX-RZ-DQPSK.J. Lightwave Technology,2007,25(1):222-232
[30] C. R. S. Fludger, T. Duthel, D. van den Borne, et al.10×111Gbit/s,50GHz spaced,POLMUX-RZ-DQPSK transmission over2375km Employing coherentequalisation. Optical Fiber Communication Conference (OFC2007). Anaheim,2007.PDP22.
[31] C. R. S. Fludeger, T. Duthel, D. van den Borne, et al. Coherent equalization andPOLMUX-RZ-DQPSK for robust100-GE transmission. J. Lightwave Technology,2008,26(1):64-72
[32] A. H. Gnauck, P. J. Winzer. Optical phase-shift-keyed Transmission. J. LightwaveTechnology,2005,23(1):115-130
[33] B. Mikkelsen, C. Rasmussen, P. Mamyshev, et al. Partial DPSK with excellent filtertolerance and OSNR sensitivity. Electronics Letters,2006,42(23):1363-1364
[34] Z. Zhang, L. Chen, X. Bao, et al. Partial bit delay correlative modulation used toimprove the dispersion tolerance of an optical duobinary system. Optics Express,2008,16(15):11344-11353
[35] I. Lyubomirsky, C.-C. Chien. DPSK demodulator based on optical discriminatorfilter. IEEE Photonics Technology Letters,2005,17(2):492-494
[36] I. Lyubomirsky, C.-C. Chien, Y.-H. Wang. Optical DQPSK receiver with enhanceddispersion tolerance. IEEE Photonics Technology Letters,2008,20(7):511-513
[37] L. Zhang, J.-Y. Yang, M. Song, et al. Microring-based modulation and demodulationof DPSK signal. Optics Express,2007,15(18):11564-11569
[38] X. Lin, L. Chao, W. Chiyan, et al. Optical differential-phase-shift-keyingdemodulation using a silicon microring resonator. IEEE Photonics TechnologyLetters,2009,21(5):295-297
[39] L. Zhang, J.-Y. Yang, Y. Li, et al. Monolithic modulator and demodulator ofdifferential quadrature phase-shift keying signals based on silicon microrings.Optics Letters,2008,33(13):1428-1430
[40] K. Xu, L. Wang, G. K. P. Lei, et al. Demodualtion of20Gbaud/s differentialquadrature phase-shift keying singals using wavelength-tunable silicon microringresonators. Optics Letters,2012,37(6):3462-3464
[41] Y. Ding, J. Xu, C. Peucheret, et al. Multi-Channel40Gbit/s NRZ-DPSKdemodulation using a single silicon microring resonator. Journal of LighwaveTechnology,2011,29(5):677-684
[42] E. E. Basch, T. G. Brown. Introduction to coherent optical fiber transmission. IEEECommunication Magazine,1985,23(5):23-30
[43] J. R. Barry, E. A. Lee. Performance of coherent optical receivers. Proceedings OfThe IEEE,1990,78(8):1369-1394
[44] F. Derr. Optical QPSK transmission system with novel digital receiver concept.Electronics Letters,1991,27(23):2177-2179
[45] F. Derr. Coherent optical QPSK intradyne system: concept and digital receiverrealization. J. Lightwave Technology,1992,10(9):1290-1296
[46] J. Kahn, K.-P. Ho. Spectral efficiency limits and modulation/detection techniques forDWDM systems. J. Select. Topics Quantum Electron.,2004,10(2):259–272
[47] S. Tsukamoto, D.-S. Ly-Gagonon, K. Katoh, et al. Coherent demodulation of40-Gbit/s polarization-multiplexed QPSK signals with16-GHz spacing after200-km transmission. Optical Fiber Communication Conference (OFC2005).Anaheim,2005. PDP29
[48] D.-S. Ly-Gagonon, S. Tsukamoto, K. Katoh, et al. Coherent detection of opticalquadrature phase-shift keying signals with carrier phase estimation. J. LightwaveTechnology,2004,24(1):12-21
[49] M. Taylor. Coherent detection method using DSP for demodulation of signal andsubsequent equalization of propagation impairments. IEEE Photonics TechnologyLetters,2004,16(2):674-676
[50] E. Ip, J. M. Kahn. Digital equalization of chromatic dispersion and polarizationmode dispersion. J. Lightwave Technology,2007,25(8):2033-2043
[51] M. Kuschnerov, F. N. Hauske, K. Piyawanno, et al. DSP for coherent single-carrierreceivers. J. Lightwave Technology,2009,27(16):3614-3622
[52] S. J. Savory. Digital coherent optical receivers: algorithm and subsystems. J.Selected Topics in Quantum Eletronics,2010,16(5):1164-1179
[53] Y. Han, G. Li. Coherent optical communication using polarization multiple-input-multiple-output. Optics Express,2005,13(19):7527-7534
[54] S. J. Savory. Digital filters for coherent optical receivers. Optics Express,2008,16(2):804-817
[55] P. J. Winzer, A. H. Gnauck, C. R. Doerr, et al. Spectrally efficient long-haul opticalnetworking using112-Gb/s polarization-multiplexed16-QAM. J. LightwaveTechnology,2010,28(4):547-556
[56] H. Sun, K.-T. Wu, K. Roberts. Real-time measurements of a40Gb/s coherentsystems. Optics Express,2008,16(2):873-879
[57] K. Kikuchi. Coherent optical communications-history, state-of-the-art technologies,and challenges for the future-. Opto-Electronics and Communications Conference(OECC2008). Australia,2008.1-4
[58] K. Kikuchi. Eletronic post-compensation for nonlinear phase fluctuations in a1000-km20-Gbit/s optical quadrature phase-shift keying transmission system usingthe digital coherent receiver. Optics Express,2008,16(2):889-896
[59]顾畹仪. WDM超长距离光传输技术.(第一版).北京:北京邮电大学出版社,2006.26-31
[60] S. A. Gronemeyer, A. L. Mcbride. MSK and offset QPSK modulation. IEEETransactions On Communication,1976,24(8):809-820
[61] S. Pasupathy. Minimum shift keying: A spectrally efficient modulation. IEEECommunication Magazine,1979,17(4):14-22
[62] M. Ohm, J. Speidel. Optical minimum-shift keying with direct detection (MSK/DD).Asia-Pacific Optical Communication (APOC2003). Wuhan,2003.5281
[63] C. Lu, J. Mo, Y. Wen. Optical minimum-shift keying: property and implementation.Optical Fiber Communication Conference (OFC2006). Anaheim,2006. CFH1
[64] G.-W. Lu, T. Sakamoto, A. Chiba, et al. Optical MSK transmitter using amonolithically integrated quad Mach-Zehnder IQ modulator. European Conferenceon Optical Communication (ECOC2009). Vienna,2009.5.2.1
[65] L. N. Binh, T. L. Huynh. Single and dual-Level minimum shift keying opticaltransmission systems. J. Lightwave Technology,2009,27(5):522-537
[66] X. Wei, A. H. Gnauck, D. M. Gill. Optical π/2-DPSK and its tolerance to filteringand polarization-mode-dispersion. IEEE Photonics Technology Letters,2003,15(11):1639-1641
[67] J. Wang, J. M. Kahn. Conventional DPSK versus symmetrical DPSK: comparison ofdispersion tolerances. IEEE Photonics Technology Letters,2004,16(6):1585-1587
[68] A. Banerjee, Y. Park, F. Clarke, et al. Wavelength-division-multiplexed passiveoptical network (WDM-PON) technologies for broadband access: a review. J. Opt.Netw.,2005,4:737-758
[69] G.-K. Chang, A. Chowdhury, Z. Jia, et al. Key technologies of WDM-PON forfuture converged optical broadband access networks, J. Opt. Commun. Netw.,2009,1(4): C35-C50
[70] D. P. Shea, J. E. Mitchell. Long-reach optical access technologies. IEEE Networks.,2007,21(5):5-11
[71] D. P. Shea, J. E. Mitchell. Architecture to integrate multiple PONs with long reachDWDM backkhaul. IEEE J. on Selected Areas in Communications,2009,27(2):126-133
[72] R. P. Davey, D. B. Grossman, M. Rasztovits-Wiech, et al. Long-reach passiveoptical networks. J. Lightwave Technol.,2009,27:273-291
[73] C. H. Yeh, C. W. Chow, H. Y. Chen, et al. Using adaptive four-band OFDMmodulation with40Gb/s downstream and10Gb/s upstream signals for nextgeneration long-reach PON. Opt. Express,2011,19(27):26150-26160
[74] C. H. Yeh, C. W. Chow, C. H. Wang, et al. Using OOK modulation for symmetric40-Gb/s long-reach time-sharing passive optical networks. IEEE Photon. Technol.Lett.,2010,22(9):619-621
[75] C. W. Chow, C. H. Yeh.40-Gb/s downstream DPSK and40-Gb/s upstream OOKsignal remodulation PON using reduced modulation index. Opt. Express,2010,18(25):26046-26051
[76] I. P. Kaminow. Balanced optical discriminator. Appl. Opt.,1964,3(4):507-510
[77] C. W. Chow, H. K. Tsang. Polarization-independent DPSK demodulation using abirefringent fiber loop. IEEE Photon. Technol. Lett.,2005,17(6):1313-1315
[78] Y. Ding, H. Ou, and C. Peucheret. Wide-band polarization splitter and rotator withlarge fabrication tolerance and simple fabrication process. Optical FiberCommunication Conference (OFC2013). Los Angles,2013. OTh4I.2
[79] D. Dai, Y. Tang, J. Bowers. Mode conversion intapered submicron silicon ridgeoptical waveguides. Opt. Express,2012,20(12):13425-13439
[80] Y. Ding, H. Ou, C. Peucheret. Wideband polarization splitter and rotator with largefabrication tolerance and simple fabrication process. Optics Letters,2013,38(8):1227-1229
[81] J. Yao, F. Zeng, Q. Wang. Photonic generation of ultrawideband signals. J.Lightwave Technol.,2007,25(11):3219-3235
[82] J. Dong. Ultrawideband monocycle generation using cross-phase modulation in asemiconductor optical amplifier. Opt. Lett.,2007,32(10):1223-1225
[83] Q. Wang, J. Yao. Switchable optical UWB monocycle and doublet generation usinga reconfigurable photonic microwave delay-line filter. Optics Express,2007,15(22):14667-14672
[84] E. Zhou. A power-efficient ultra-wideband pulse generator based on multiplePM-IM conversions. IEEE Photon. Technol. Lett.,2010,22(14):1063-1065
[85] S. Pan, J. Yao. Switchable UWB pulse generation using a phase modulator and areconfigurable asymmetric Mach–Zehnder interferometer. Opt. Lett.,2009,34(2):160-162
[86] Y. Dai, J. Du, X. Fu, et al. Ultrawideband monocycle pulse generation based ondelayed interference of π/2phase-shift keying signal. Optics Letters,2011,36(14):2695-2697
[87] F. Liu. On-chip photonic generation of ultra-wideband monocycle pulses. Electron.Lett.,2009,45(24):1247
[88] S. Darmawan, L. Y. M. Tobing, T. Mei. Coupling-induced phase shift in amicroring-coupled Mach-Zehnder interferometer. Optics Letters,2010,35(2):238-240
[89] B. Guha, B. B. C. Kyotoku, M. Lipson. CMOS-compatible athermal siliconmicroring resonators. Optics Express,2010,18(4):3488-3493
[90] M. Seimetz, C. M. Weinert. Options, feasibility, and availability of2×490°hybridsfor coherent optical systems. J. Lightwave Technology,2006,24(3):1317-1322
[91] L. G. Kazovsky, L. Curtis, W. C. Young. All-fiber90°optical hybrid for coherentcommunications. Applied Optics,1987,26(3):437-439
[92] D. N. Godard. Self-recovering equalization and carrier tracking in two dimensionaldata communication systems. IEEE Transactions on Communications,1980,28(11):1867-1875
[93] C. R. Johnson, P. Schniter, T. J. Endres, et al. Blind equalization using constantmodulus criterion: a review. Proceedings of The IEEE,1998,86(10):1927-1950
[94] M. J. Ready, R. P. Gooch. Blind equalization based on radius directed adaptation.International Conference on Acoustics Speech and Signal Processing (ICASSP1990),1990,3:1699-1702
[95] I. Fatadin, D. Ives, S. J. Savory. Blind equalization and carrier phase recovery in a16-QAM optical coherent system. J. Lightw. Technol.,2009,27(15):3042-3049
[96] A. J. Viterbi, A. M. Viterbi. Nonlinear estimation of PSK-modulated carrier phasewith application to burst digital transmission. IEEE Trans. Inf. Theory,1983,29(4):543-551
[97] A. Leven, N. Kaneda, U. V. Koc, et al. Frequency estimation in intradyne reception.IEEE Photonics Technology Letters,2007,19(6):366-368
[98] M. Selmi, Y. Jaouen, P. Ciblat. Accurate digital frequency offset estimator forcoherent PolMux QAM transmission systems. European Conference on OpticalCommunication (ECOC2009), Vienna,2009. P3.08.
[99] T. Nakagawa, M. Matsui, T. Kobayashi. Non-data-aided wide-range frequency offsetestimator for QAM optical coherent receivers. Optical Fiber CommunicationConference (OFC2011). Los Angles,2011. OMJ1
[100] M. Seimetz. Performance of Coherent Optical square-16-QAM-systems based onIQ-transmitters and homodyne receivers with digital phase estimation. Optical FiberCommunication Conference (OFC2006). Anaheim,2006. NWA4
[101] M. Seimetz. Laser linewidth limiattions for optical systems with high-ordermodulation employing feed forward digital carrier phase estimation. Optical FiberCommunication Conference (OFC2008). San Diego,2008. OTuM2
[102] T. Pfau, S. Hoffmann, R. Noe. Hardware-efficient coherent digital receiver conceptwith feedforward carrier recovery for M-QAM constellations. J. Lightw. Technol.,2009,27(8):989-999
[103] O. Gerstel, M. Jinno, A. Lord, et al. Elastic optical networking: a new dawn for theoptical layer?. IEEE Commun. Mag.,2012,50(2): s12-s20
[104] H. Y. Choi, T. Tsuritani, I. Morita. BER-adaptive flexible-format transmitter forelastic optical networks. Opt. Express,2012,20(17):18652-18658
[105] R. Borkowski. Experimental study on OSNR requirements for spectrum flexibleoptical networks. J. Opt. Commun. Netw.,2012,4(11): B85-B93
[106] Y.-K. Huang. High-capacity fiber field trial using terabit/s all-optical OFDMsuperchannels with DP-QPSK and DP-8QAM/DP-QPSK modulation. J. Lightw.Technol.,2013,31(4):546-553
[107] K. Roberts, M. O’Sullivan, K.-T. Wu, et al. Performance of dual-polarization QPSKfor optical transport systems. J. Lightw. Technol.,2009,27(16):3546-3559
[108] P. J. Winzer, A. H. Gnauck, S. Chandrasekhar, et al. Generation and1,200-kmtransmission of448-Gb/s ETDM56-Gbaud PDM16-QAM using a single I/Qmodulator. European Conference on Optical Communication (ECOC2010), Torino,2010. PDP2.2
[109] X. Zhou.64-Tb/s,8b/s/Hz, PDM-36QAM transmission over320km using bothpre-and post-transmission digital signal processing. J. Lightw. Technol.,2011,29(4):571-577
[110] J. Yu, Z. Dong, H.-C. Chien, et al.7-Tb/s (7×1.284Tb/s/ch) signal transmission over320km using PDM-64QAM modulation. IEEE Photon. Technol. Lett.,2012,24(4):264-266
[111] X. Xu, B. Chatelain, D. V. Plant. Decision directed least radius distance algorithmfor blind equalization in a dual-polarization16-QAM system. Optical FiberCommunication Conference (OFC2012). Los Angles,2012. OM2H
[112] R. Schmogrow, M. Winter, M. Meyer, et al. real-time Nyquist pulse generationbeyond100Gbit/s and its relation to OFDM. Opt. Express,2012,20(1):317-337
[113] G. Bosco, A. Carena, V. Curri, et al. Performance limits of Nyquist-WDM andCO-OFDM in high-speed PM-QPSK systems. IEEE Photon. Technol. Lett.,2010,22(5):1129-1131
[114] K. Kikuchi, Y. Ishikawa, K. Katoh. Coherent demodulation of optical quadratureduobinary signal with spectral efficiency of4bit/s/Hz per polarization. EuropeanConference on Optical Communication (ECOC2007). Berlin,2007.9.3.4
[115] I. Lyubomirsky. Quadrature duobinary for high-spectral efficiency100G transmission. J.Lightw. Technol.,2010,28(1):91-96
[116] F. Machi, M. S. Alfiad, M. Kuschnerov, et al.111-Gb/s polMux-quadratureduobinary for robust and bandwidth efficient transmission. IEEE Photon. Technol.Lett.,2010,22(1):751-753
[117] J. Li, E. Tipsuwannakul, T. Eriksson, et al. Approaching Nyquist limit in WDMsystems by low-complexity receiver-side duobinary shaping. J. Lightw. Technol.,2012,30(1):1664-1676
[118] J. Li, M. Sjodin, Magnus, P. A. Andrekson. Building up low-complexity spectrally-efficient Terabit superchannels by receiver-side duobinary shaping. Opt. Express,2012,20(9):10271-10281
[119] Z. Dong, J. Yu, Z. Jia, et al.7×224Gb/s/ch Nyquist-WDM transmission over1600-km SMF-28using PDM-CSRZ-QPSK modulation. IEEE Photon. Technol.Lett.,2012,24(13):1157-1159
[120] J. Yu, Z. Dong, H.-C. Chien, et al. Transmission of200G PDM-CSRZ-QPSK andPDM-16QAM with a SE of4b/s/Hz. J. Lightw. Technol.,2013,31(4):515-522
[121] H.-C. Chien, J. Yu, Z. Jia, et al. Noise-suppressed Nyquist-WDM for Terabitsuperchannel transmission. J. Lightw. Technol.,2012,30(24):3965-3971
[122] M. Oderder, H. Meyr. Digital filter and square timing recovery. IEEE Transac.Commun.,1988,36(5):605-612
[123] E. Ip, J. M. Kahn. Feedforward carrier recovery for coherent optical communications. J.Lightw. Technol.,2007,25(9):2675-2692