Jitter accumulation in optical transmission systems

Jitter accumulation on a high-bit-rate submarine optical link has been investigated through signal circulating experiments. One-, 6- and 12-repeater loops exhibit similar accumulation. The variance of the systematic jitter increases as the number of repeaters and the random jitter tends to saturate.     

Reduction of Gordon-Haus jitter in soliton transmission systems byoptical phase conjugation

The effect of optical phase conjugation on Gordon-Haus jitter in long-distance soliton communication systems is considered. In-line optical phase conjugation at an optimal point two-thirds of the way down the system reduces the rms jitter by a factor of three. A post-transmission-line compensation scheme based on optical phase conjugation and soliton-supported dispersion compensation reduces the rms jitter by a factor of two     

20 Gbit/s soliton transmission using alternating dispersionarrangement in standard fibre systems

An alternating dispersion arrangement is proposed for soliton systems with dispersion compensation to improve soliton stabilisation. A transmission experiment at 20 Gbit/s over 2600 km long singlemode fibre was successfully demonstrated by employing this novel dispersion arrangement     

Infinite-distance soliton transmission with soliton controls in time and frequency domains

It is shown by computer runs and simple analysis that one hundred million km soliton transmission is possible by means of soliton transmission controls in the time and frequency domains. This means that limitless transmission is possible. The key to success is to reduce noise by the synchronous modulation technique which can also reduce timing jitter and nonlinear interaction forces. The accumulated noise converges to a fixed low level even after limitless transmission.<>     

光孤子传输系统

阐述了光孤子传输系统主要特征及其关键技术,探讨了光孤子传输系统的构成及其实用方案,与传统的线性通信系统相比,被称为非线性通信系统的光孤子传统系统将逐步显示出优越的发展前景。     

Analysis of power jitter induced by interchannel interactions indispersion-managed optical soliton transmission systems

Collision-induced power jitter is theoretically and numerically examined in dispersion-managed wavelength-division multiplexed optical soliton transmission systems. The variational method is mainly used to develop a time efficient jitter calculation approach. The power jitter causes a serious problem for a singly periodic dispersion managed line having almost zero average dispersion, which can be reduced by applying doubly periodic dispersion management     

Polarisation guiding in ultralong distance soliton transmission

Signal polarisation rotation due to polarisation dependent loss has been observed for the first time in an optical communications transmission system. In particular its effect as a limiting factor in solitonic polarisation multiplexed systems is discussed. An analytic expression for the degree of rotation is presented and experimentally verified. Additionally, 5 Gbit/s solitons have been transmitted a distance of 11000 km without transmission control     

超高速光孤子传输技术

当前光通信技术研究中的一个热点课题是光孤子传输。文章介绍了采用光孤子实现超高输的设计思路，有限变换短光脉的产生技术，以及采用多重极化波的８０Ｇｂ／ｓ，８０ｋｍ光孤传输实验。     

光孤子传输特性研究综述

在分别研究了高阶色散、五阶非线性、孤子振幅、孤子相位及孤子间隔对其传输特性的影响之后,对诸多因素的综合影响及其在某种程度上的相互制约关系进行了综述,给出了孤子保形传输的数值计算结果.     

利用光时分复用技术实现5Gb／s的孤子传输

利用光纤环激光器作为孤子源和光时分复用技术成功地进行了５Ｇｂ／ｓ的孤子传输实验。研究了在相同的入纤工上，光脉冲的波工对孤子的传输性能的影响，在实验的波长范围内的测量表明，波长越长出纤脉冲的时域宽度越窄，但脉冲的频谱的变化基本与波无关，对实验结果进行了数值模拟分析，实验结果基本与数值模拟的一致。     

Long-distance optical soliton transmission with lumped amplifiers

A soliton transmission method using lumped amplifiers is presented which is named the preemphasis method. An N=1 soliton with relatively high amplitudes (1.2<A<1.4), which is used as an input soliton, plays an important role in the lumped-gain soliton transmission system. The initial soliton pulse width can be preserved after propagation over long distance despite the existence of fiber loss. It is shown that with the lumped gain, the soliton pulse can propagate over more than 9000 km when the repeater spacing is 31 km and fiber loss is 0.22 dB/km     

Amplified spontaneous emission in soliton transmission systemsemploying sliding filters

The growth of the amplified spontaneous emission (ASE) noise in a soliton line employing sliding filters is studied. An analytical expression of the integrated ASE power is given for constant line dispersion. For large dispersion variations caused by the combined effect of sliding and third-order dispersion of the line, an optimal sliding rate exists that minimizes the amplified spontaneous emission. Methods to reduce the spontaneous emission at the line output are proposed     

色散管理孤子系统的调制不稳定性

为了探究色散管理孤子系统抗微小扰动的能力,从色散管理孤子的调制不稳定性出发,利用孤子传输满足的非线性薛定谔方程,采用线性稳定性分析和数值模拟,得到色散管理系统中调制不稳定性的增益谱;得出色散管理孤子各阶调制不稳定性的增益曲线,并分析了基阶调制不稳定性起主导作用的条件,讨论了色散图中路径平均色散值。结果表明,色散深度对基阶调制不稳定性增益谱有影响,在平均色散为负值的情况下,平均色散值βav(βav0)越大,色散波动幅度越小,基阶调制不稳定性的增益越小,更有利于抑制调制不稳定性增益;但将平均色散值降至更小时,调制不稳定性增益谱不再连续。     

Stable soliton transmission in the system with nonlinear gain

It is shown that the linear-wave growth in bandwidth-limited-amplified soliton transmission can be suppressed by a selective amplification of solitons by means of nonlinear gain that can be realized by using fast saturable absorbers. Numerical simulations assuming the use of nonlinear amplifying loop mirrors (NALM's) as the nonlinear-gain element show that 20 Gb/s soliton trains can be transmitted over transoceanic distances, Wavelength-division multiplexing is also feasible if demulti/multiplexers are used just before and after the NALM     

Timing jitter in ultrahigh-speed dispersion-managed soliton systems

An analytical theory is presented which demonstrates the timing jitter induced by amplifier noise in ultrahigh-speed dispersion-managed soliton systems when the Raman effect and third-order dispersion (TOD) are considered. The analysis indicates that Raman jitter remains a potential problem for picosecond and subpicosecond pulses. Positive residual TOD can enhance the timing jitter caused by the combined action of TOD and Raman effect, while vice versa for negative residual TOD.     

High-bit-rate soliton transmission using distributed amplificationand dispersion management

We show through numerical simulations that the use of distributed amplification together with dispersion management can permit single-channel speeds of 40 Gb/s over transoceanic distances while maintaining 100-km spacing between pumping stations. We achieve this performance by using a bidirectional pumping scheme and optimizing the dopant density such that the peak-power variations over each fiber span remain below 0.4 dB. The required pump power is less than 80 mW for a dopant density of 200 ions/μm³     

光孤子传输控制方案的探讨

文章首先分析了光孤子通信系统的限制因素,包括光纤损耗、孤子间的相互作用、各种高阶效应以及参量随机变化等.然后在此基础上,讨论了光孤子通信系统的传输控制方案,并分析比较了这些方案的优缺点,对光孤子系统设计具有参考价值.     

La transmission par solitons sur fibre optique soliton transmission on optical fibres

Optical amplification has fundamentally changed the design of optical fibre transmission systems, especially transoceanic and other such long-haul systems. These changes have made it necessary to consider the cumulative effects of chromatic dispersion and self phase modulation as well as the effect of amplified spontaneous emission (ase) noise. In this context, transmission using solitons is an attractive alternative for high bitrate transmission. Its practical implementation is subject to limitations, however, due primarily to non-linear interaction between signal and noise. Current research work is focused on overcoming these limitations, in particular through the introduction of on-line optical processing techniques of varying degrees of sophistication. This article looks at results achieved by cnet.     

Influence of noise in optical pulse source on soliton transmission

This paper performed a 10-Gb/s optical soliton transmission experiment in a sliding frequency recirculating loop and found that the noise in the optical pulse source decreased error-free distance. This is because the mean frequency of soliton at the pulse source is modulated by the noise which results in the increase of timing jitter at the receiver even in a strong sliding frequency controlled soliton transmission line. Jitter in arrival time of transmitted solitons was theoretically analyzed to verify experimental results     

Timing jitter in soliton transmission with up- anddown-sliding-frequency guiding filters

We derive an analytical expression for the variance of the timing jitter of a soliton transmission system using sliding-frequency guiding filters, taking into account the third-order filter term. An improved analytical result for the upper limit of the sliding rate for stable soliton propagation is also obtained. We show that the variance of timing jitter is significantly increased by the sliding action. As a consequence of the third-order filter contribution, the timing jitter is lower in a system with down-sliding compared with the up-sliding regime at the same sliding rate