高速准线性光传输系统非线性效应的仿真研究

推导了高速准线性光传输系统中信道内四波混频、信道内交叉相位调制等非线性效应方程,并根据方程进行计算机建模,从而实现高速准线性光传输系统的数值模拟.最后通过搭建仿真传输链路,比较了准分布式色散补偿方案和集总色散补偿方案的优劣,并对不同速率的准线性光传输系统的性能进行了分析,得到各非线性相互作用随速率变化的关系.     

色散补偿用啁啾光纤光栅

随着单信道传输速率的提高（10Gb/s、40Gb/s系统)和信号传输带宽的增加，光纤传输系统中的色散问题日益显著，目前的10Gb/s光传输系统中，主要采用色散补偿光纤（DCF）进行色散补偿。DCF具备能实现宽带补偿的优点，但也存在突出的缺点：非线性效应显著；损耗大（为补偿80km的光纤色散需增加8到10dB的附加损耗)，长度随不同的色     

40Gb/s长距离光纤传输系统的残余色散影响研究

伴随信息化进程的加速,WDM系统中的单信道传输速率普遍由10Gb/s扩容至40Gb/s,而单信道40Gb/s的长距离光纤传输系统对残余色散要求更为苛刻.就40Gb/s的WDM系统中的残余色散分别对MODB、CSRZ、DPSK和DQPSK光信号调制方式的影响进行了研究,发现残余色散大小对这4种光调制技术产生了不同的影响,并且DQPSK光信号调制技术在残余色散为正时具有更大的系统Q值和OSNR更适合长距离光纤传输系统.     

色散管理对高速准线性传输系统性能的影响

非线性效应对高速光纤通信系统的影响已成为限制系统性能的主要因素之一.作为高速光通信的一种优选方案,准线性光纤传输技术通过精细的色散管理设计,可将非线性效应降低到可忽略的程度.对160Gb/s高速准线性光传输系统设计了预补偿、后补偿和对称补偿三种色散管理方案,并对这三种方案进行了对比、分析和优化,最后根据各方案的Q值为依据得出优选方案,为实际系统的设计提供参考意义.     

准线性传输系统级联光栅色散补偿的研究

用耦合模理论和传输矩阵法对级联啁啾布喇格光纤光栅进行了分析,设计了一个大带宽、高反射率、大色散、低时延波纹的级联啁啾光纤光栅,并将其应用到一个8信道160Gb/s的高速准线性光传输系统中进行色散补偿.系统仿真结果表明,各个信道的Q值均在7.15 ～ 8.74之间,实现了级联啁啾光纤布喇格光栅的设计目标.     

基于10 Gb/s传输链路的40 Gb/s光传输实验研究

基于中国自然科学基金网(NSFCNet)的400 km×10 Gb/s光传输链路实现了40 Gb/s光传输,没有出现误码率(BER)平台,说明在常规的中短距离10 Gb/s系统可以直接升级至40 Gb/s系统,而不需要升级传输链路。但是,由于相对10 Gb/s系统而言40 Gb/s系统的色散容限非常小,在升级时必须精确补偿原有链路的色散,在接收机前一般需要加可调色散补偿单元。同时,还分析了光纤注入功率对系统性能的影响,结果表明在设计这种由10 Gb/s向40 Gb/s升级的系统时,不仅要考虑信号带宽增加带来信噪比要求的提高,而且必须充分考虑光纤非线性的影响。     

G.655光纤DWDM系统的DCF色散补偿方案比较

研究了NRZ-DPSK和NRZ-DQPSK G.655光纤40Gb/s DWDM通信系统中预补偿和逐段补偿两种色散补偿方案.通过仿真对比了这两种方案的色散性能和非线性性能,得出预补偿方案优于逐段补偿方案.在未来50GHz通道间隔40Gb/s DWDM系统中,采用预补偿能获得更好的传输性能.     

2.5Gbit/s光码分多址通信系统研究

以PTDS仿真实验平台为基础,对传输速率为2.5Gbit/s的光码分多址通信系统性能进行了研究.仿真研究了传输信道和光功率对光码分多址系统性能的影响,分析了传输距离、光纤色散系数、光纤衰减、入纤光功率等与误码率和Q值的关系.     

强色散补偿高速光通信系统中的信道内非线性效应

研究了强色散补偿高速光通信系统中的自相位调制(SPM)、信道内交叉相位调制(IXPM)和信道内四波混频(IFWM)等非线性效应，分析了SPM所致脉冲对称扰动、IXPM所致定时抖动和IFWM所致振幅抖动的规律，并通过数值仿真实现了强色散补偿系统中1600km的稳定传输。     

40Gb/s单信道光纤传输系统性能仿真分析

利用Optisystem仿真软件,对40Gb/s单信道传输系统中归零(RZ)调制和非归零(NRZ)调制两种格式进行仿真,并且对基于RZ调制格式下的单信道40Gb/s的色散补偿进行了仿真,比较了前置补偿、后置补偿和对称补偿的传输性能.仿真结果表明:在长距离传输时RZ调制格式优于NRZ调制格式,三种补偿方式中对称补偿效果最优.     

Coherent Optical OFDM Transmission Up to 1 Tb/s per Channel

Coherent optical frequency-division multiplexing (CO-OFDM) is one of the promising pathways toward future ultrahigh capacity transparent optical networks. In this paper, numerical simulation is carried out to investigate the feasibility of 1 Tb/s per channel CO-OFDM transmission. We find that, for 1 Tb/s CO-OFDM signal, the performance difference between single channel and wavelength division multiplexing (WDM) transmission is small. The maximum Q is 13.8 and 13.2 dB respectively for single channel and WDM transmission. We also investigate the CO-OFDM performance on the upgrade of 10-Gb/s to 100-Gb/s based DWDM systems with 50-GHz channel spacing to 100-Gb/s systems. It is shown that due to the high spectral efficiency and resilience to dispersion, for 100-Gb/s CO-OFDM signals, only 1.3 dB Q penalty is observed for 10 GHz laser frequency detuning. A comparison of CO-OFDM system performance under different data rate of 10.7 Gb/s, 42.8 Gb/s, 107 Gb/s and 1.07 Tb/s with and without the impact of dispersion compensation fiber is also presented. We find that the optimum fiber launch power increases almost linearly with the increase of data rate. 7 dB optimum launch power difference is observed between 107 Gb/s and 1.07 Tb/s CO-OFDM systems.      

用于高Gb／s光通信系统的新型时钟提取电路

新型时钟提取电路省去传统提取电路中的非线性处理电路，从而简化了接收设备。在利用这种电路的光通信系统中，在发送端，时钟脉冲叠加在数字信号上；在接收端，主放电路以后分成两个通路，一通路接有一个Ｎｙｑｕｉｓｔ滤波器，只允许信号脉冲通过，另一路则接有一窄带滤波器，实现时钟信号的提取。为了验证此方案的可实现性，研制出一套１．２４４Ｇｂ／ｓ光通信系统。本文从理论上分析这种光通信接收机的灵敏度与时钟脉冲调制度及时移的关系，并与实验结果相对比。另一方面，还建立了一个简单的公式计算所提取的时钟信号抖动值。     

Near Pseudolinear Regime in 10-Gb/s Single Sideband-Alternate Mark Inversion Systems Using Electrical Dispersion Precompensation

A 10-Gb/s optical single sideband (OSSB) system using alternate mark inversion return-to-zero and ideal electrical precompensation of dispersion is optimized numerically by means of an optical dispersion compensator at the receiver side. The transmission regime observed in the optimized system resembles the pseudolinear regime previously described for systems with bit rates of 40 Gb/s and above. Considering multichannel transmission, the OSSB system has a Q -factor penalty of 2 dB compared to an intensity modulated optical double sideband system with optimized optical dispersion map.     

Comparison of nonlinear pulse interactions in 160-Gb/s quasi-linear and dispersion managed soliton systems

The understanding and development of 160-Gb/s transmission systems requires the study of the impact of different dispersion compensation schemes on pulse propagation in nonlinear fiber. In this paper, we present an investigation of 160-Gb/s optical transmission systems, focusing on optimal propagation regimes, and in particular, we analyze different transmission limitations and dominant nonlinear effects by comparing quasi-linear and dispersion managed soliton systems. Two quasi-linear systems, one using nonzero dispersion-shifted fiber (NZDSF) and the other single-mode fiber (SMF), and one short-period (1 km) dispersion managed soliton (DMS) system are studied, both for single-channel and wavelength-division-multiplexed (WDM) transmission. First, the performance of the two quasi-linear systems in single-channel transmission are compared and it is shown that the NZDSF and SMF systems allow similar error-free transmission distances with only small differences in the intrachannel four-wave mixing (IFWM) induced amplitude jitter. The effect of pulsewidth on transmission performance in this regime was investigated and the use of shorter pulses was found to result in lower amplitude jitter. We analyzed the behavior of the DMS system and showed that the reduced pulse broadening during transmission allowed a significantly longer single-channel transmission distance with a smaller impact of nonlinearities compared to quasi-linear propagation. The sensitivity of the DMS system performance to statistical fluctuations in the fiber dispersion was studied and the results show the level of accuracy in the dispersion management map which must be ensured in these systems. Finally, the performance of the DMS in WDM transmission was investigated and it was found that it was subject to very large penalties increasing the minimum channel spacing possible because of the strong impact of interchannel cross-phase modulation (XPM).     

System performance evaluation of the FSA submarine opticalamplifier system

The FSA submarine optical amplifier system developed for commercial use is designed to transmit 2.5 and 10 Gb/s signals flexibly; its repeater spacing is 90 km. It contains six line pairs to yield a maximum transmission capacity of 60 Gb/s. Its system configuration, and the characteristics of its fibers and optical amplifiers, which realize effective dispersion and optical passband management, are introduced. We discuss its performance with regard to the parameters significant in optically amplified transmission: evolution of zero dispersion wavelength (ZDW), polarization mode dispersion (PMD), and fiber nonlinearity induced impairments. Signal-to-noise ratios (SNR's) for 2.5 and 10 Gb/s signal transmission are measured and the improvements offered by polarization scrambling are also discussed. Finally, ZDW, PMD, and SNR characteristics of the system after installation are reported     

基于相干光正交频分复用的WDM传输系统及其性能分析

相干光正交频分复用由于其良好的传输性能成为近年来光传输领域的研究热点,波分复用技术可以在光纤中通过增加并行波长的数量来提高系统的容量,将CO-OFDM和WDM技术结合,可以构造出高速率、大容量、低成本的光传输网络。文章首先对基于CO-OFDM的WDM传输系统的理论模型和基本原理进行了研究,然后对基于CO-OFDM的100Gb/s×32-信道WDM传输系统进行了仿真分析。并研究了该系统的传输性能。结果表明：在没有任何光纤的色散及非线性补偿的情况下,当信号速率为3.2 Tb/s时,系统的Q因子高于16.0 dB,在标准单模光纤中的传输距离可达1500km。     

Greater than 200 Gb/s Transmission Using Direct-Detection Optical OFDM Superchannel

In this paper, we propose direct-detection optical orthogonal frequency division multiplexing superchannel (DDO-OFDM-S) and optical multiband receiving method (OMBR) to support a greater than 200 Gb/s data rate and longer distance for direct-detection systems. For the new OMBR, we discuss the optimum carrier-to-sideband power ratio (CSPR) in the cases of back-to-back and post transmission. We derive the analytical form for CSPR and theoretically verify it. A low overhead training method for estimating I/Q imbalance is also introduced in order to improve performance and maintain high system throughput. The experiment results show that these proposals enable an unprecedented data rate of 214 Gb/s (190 Gb/s without overhead) per wavelength over an unprecedented distance of 720 km SSMF in greater than 100 Gb/s DDO-OFDM systems.