A filtering approach for reducing timing jitter due to the acousticeffect

We introduce a signal processing approach to compensate for the timing jitter produced by the acoustic effect in soliton communications. The other main sources of timing jitter, the Gordon-Haus effect and the polarization effect, are inherently stochastic. By contrast, the acoustic effect is deterministic and becomes the dominant source of bit error rates in standard soliton systems when the bit rates are more than 10 Gb/s and the transmission distance is more than several thousand kilometers. We exploit the deterministic nature of the acoustic effect to introduce a scheme that predicts the amount of timing jitter as a function of the previous transmitted bits and uses the information to adjust the sampling period of the received soliton pulses. We demonstrate successful application of the scheme by simulations and discuss implementation issues     

一种基于序列调制的自适应抖动抑制方案

针对指针调整将会在SDH网络与PDH网络交界处引起大幅度的低频抖动的问题,文章在现有研究成果的基础上,提出了一种基于序列调制的自适应抖动抑制方案,该方案采用新的基于统计预测和缓存监测相结合的比特泄漏周期自适应调制方法,可以有效地避免相同极性的网络工作模式转换所造成的缓存器溢出损伤;给出了实现序列调制的设计原理,计算了网络在非劣化模式和劣化模式下的比特泄漏周期指标和序列调制时间指标.仿真与实际应用表明,该方案可以简单而有效地解决指针调整抖动的抑制问题.     

锁模光纤激光器中的矢量孤子簇

为了研究锁模光纤激光器中矢量孤子的动力学特征,利用非线性偏振旋转锁模机制,实验获得了矢量孤子及矢量孤子簇。矢量孤子簇表现出来的动力学特点与抽运功率与偏振设置有关。抽运功率越高,由矢量孤子裂变所形成的矢量孤子簇对数越多。而且,孤子簇脉冲序列在时域上显示出强度周期调制现象。实验中观察到强度周期调制的4阶和7阶脉冲矢量孤子簇。结果表明,强度周期调制的矢量孤子簇输出是非线性偏振旋转锁模光纤激光器偏振调制的本征属性,孤子簇周期强度调制现象归因于腔内偏振相关隔离器对孤子簇的周期偏振调制的结果。     

A new edge detector for CMI optical fiber transmission withimproved jitter tolerance

An edge detecting scheme for coded mark inversion (CMI) line codes which can reject wrong slot errors is proposed. This scheme looks at data transitions over one-and-a-half symbol durations and makes a binary decision based on the most likely transition pattern. An analysis and measurement results for the bit-error-rate performance of this scheme over an optical fiber link which show improvements in the detector tolerance against symbol timing jitters are presented     

Influence of Stochastic High-Order Perturbations on Soliton Transmission System

The influence of stochastic high-order perturbations on soliton transmission system is studied by self-companying operator method. Arrival time jitters variation induced by stochastic third-order dispersion is approximately proportional to three powers of transmission distance, that by stochastic nonlinear dispersion and self-steeping are approximately proportional to the transmission distance.     

量子密钥分配系统中非线性偏振耦合的研究

受传输光纤非线性偏振影响,量子密钥分配系统本振光与信号光耦合率下降,使形成偏振复用信号的抖动增强,系统的稳定性和安全性下降.为了提高量子光学中偏振编码技术的性能,经过理论分析和数值模拟,给出可操作性的实验方案,解决了光纤非线性偏振耦合导致的偏振抖动问题.结果表明,在同等条件下,以分光检测结果反馈控制本振光和信号光的非线性偏振耦合率,可增强偏振复用信号的稳定性,将系统传输容量提高61%.该结果有利于偏振编码技术在量子密钥分配系统的实际应用.     

Acoustic effect and the polarization of adjacent bits in solitoncommunication lines

The excitation of radial and torsional-radial acoustic modes by solitons is analyzed depending on light polarization. The theoretical study of the timing jitter and bit error rate caused by the acoustic effect in soliton communication lines for co- and counter-polarized adjacent bits is presented. The influence of guiding filter on the acoustically induced timing jitter is calculated     

具有滑频滤波器的光孤子通信系统时间抖动的研究

本文通过微扰理论，对采用滑频滤波器控制的孤子系统的时间抖动进行了研究。结果表明，滑频滤波器的引入，导致幅度和频率、幅度和滑频滤波器三阶项间的耦合，使得孤子传输系统的时间抖动增大，影响系统的传输极限。研究了滑频滤波器三阶项对滑频速率的影响，讨论和比较了具有滑频滤波器、固定频率滤波器和不加任何控制时的系统对由放大器的ＡＳＥ噪声产生的时间抖动的抑制结果。采用滑频滤波器是一种较好地抑制时间抖动的方法。     

The Choice of Dispersion Managed Schemes in Standard Single-Mode Fiber

In this paper, the three allocated schemes of dispersion-managed soliton are proposed on standard single-mode fiber. Adopting variational method and on the proposed schemes, the timing jitter introduced from the perturbations of amplifier spontaneous-emission (ASE) and cross-phase modulation in wavelength-division multiplexing is studied. Compared with performances of different system schemes, the principles of optimal allocated dispersion management are obtained, which can be used to optimal allocated dispersion managed soliton system.     

色散随机变化对暗孤子传输系统时间抖动的影响及抑制

运用守恒量扰动法，研究了色散随机变化对暗孤子传输系统的影响。结果表明：色散随机变化增大了暗孤子到达检测窗口的时间抖动方差而降低了暗孤子传输系统的容量。引入非线性增益可以有效地抑制色散随机变化对暗孤子到达时间抖动的影响。