SLALOM全光再生中继器加性噪声的抑制

本文分析了ＳＬＡＬＯＭ全光再生的传输特性，计算了ＳＬＡＬＯＭ对国性噪声的抑制能力，指出选择适当载流子寿命的ＳＬＡ和连续波注入功率可以提高再生器抑制加性噪声的能力，并给出了计算实例。     

双环结构级联型全光缓存器

提出了一种基于平行排列3×3耦合器的双环结构全光缓存器(DLOB)的级联方案,分析了单级和级联结构的缓存原理及读写方式,通过分析半导体光放大器(SOA)的噪声性能,得到光缓存器输出性能丰要由读写操作阶段注入的控制光功率及SOA的工作电流决定的结论,提出了在反馈式光缓存器中实现单级多圈和多级缓存的可能性,并搭建了一个两级的缓存系统,实验验证两级级联各缓存9圈时,输出信号光的功率几乎没有减少,信噪比(SNR)下降不到4 dB.理论分析和实验都表明,级联型光缓存器能够实现从纳秒级到毫秒级的缓存.可以满足未来光包交换(OPS)发展的需要.     

光放大与全光中继器

本文在综述和比较了各种正在研制中的光放大器的基础上,重点分析和阐述了掺铒光纤光放大器的工作原理和基本特征。用这种光放大器作光中继器替代现行的光-电-光转换式中继器是现代光纤通信技术的一大突破。它将在海底通信、超长距离通信、光孤子通信以及CATV、LAN、光交换等系统中得到重要应用。     

基于半导体光放大器的波长转换技术 及其在WDM 全光网络中的应用

本文在简单地介绍了各种波长转换技术之后,对基于半导体光放大器的交叉增益调制,交叉相位调制,以及四波混频效应的波长转换技术进行了深入地分析,为了阐明波长转换技术在WDM全光网络的中的应用,研究了一种分析模型。     

基于光子晶体光纤的全光再生理论和实验研究

提出了利用高非线性光子晶体光纤（PCF）的自相位调制效应（SPM）,实现对高重复率皮秒脉冲全光再生的方案,理论分析了再生器的传输特性和滤波器参量对再生特性的影响。此外,利用一段80m的非线性光子晶体光纤进行了全光再生实验,通过调节入射光纤的功率和可调谐滤波器的参量实现了对高传输速率脉冲的全光再生,实验结果与理论分析结果一致。     

环路型全光缓存器中噪声及动态增益的研究

针对基于半导体光放大器（SOA）的环路型全光缓存器的环路噪声累积问题，提出了用于分析噪声及输出信噪比的通用简化模型。从理论上给出了此类全光缓存器信噪比随缓存圈数变化的关系表达式，并且分析了在噪声影响下环路的动态增益特性。将连续光（CW）基座引入全光缓存器，其输出信噪比得到显著改善。和理论计算相一致的实验结果验证了该模型的正确性。     

RZ-DPSK全光再生技术的研究

提出了基于信号调制格式的转变来实现归零-差分相移键控信号(RZ-DPSK)全光再生的方案。首先通过偏振延时干涉仪将RZ-DPSK信号的相位噪声转变为幅度噪声,然后利用半导体光放大器(SOA)的非线性自增益调制效应对脉冲信号进行整形,最后利用起偏器实现信号相位再生。数值模拟比较了再生前后的信号,取得了良好的再生效果。     

基于三波长SLA的全光解复用器

工作在三波长状态下的SLA作为非线性元件,在光环形镜中实现OTDM信号的解复用,模拟计算表明,在保持光束功率为1W时,SLA恢复时间小于10ps,可从OTDM复用信号中提取出任一路信号,在控制脉冲功率为900mW时,带宽可达100GHz。     

全光半减器的研究进展

介绍了几种全光半减器的实现方案,分析了各方案的结构和工作原理,以及各自的优缺点,并展望了半减器的发展方向。     

全光波长变换技术的研究进展

全光波长变换技术是高速光纤通信网络的关键技术之一,是高速光纤通信系统中急需解决的问题.文章结合作者所研究的内容,对近年波长变化技术的研究情况进行了全面的回顾和总结,对几种全光波长变换技术的机制、特点和实现进行了比较分析.     

10 Gbit/s all-optical regenerator

A 10 Gbit/s optical data stream has been regenerated all-optically by clock recovery and remodulation. The regenerator consists of a fibre ring laser, modelocked by the incoming data stream, and a Kerr shutter acting as an all-optical AND gate to recode the ring laser pulses with the incoming data. Error ratio measurements for an all-optical regenerator are presented for the first time and the future potential of all-optical regeneration is discussed     

The suppression of optical regenerator employing semiconductor laser amplifier loop mirror on the additive noise

In this paper, transmission properties of the regenerator employing a semiconductor laser amplifier loop mirror (SLALOM) are discussed. The ability of the regenerator to suppress the additive noise in the input data train is calculated. It’s shown that the regenerator can greatly suppress noise in communication system and improve their communication capacity by choosing suitable semiconductor laser amplifier(SLA) and the power of injected continuous wave.     

基于光纤非线性效应的全光再生器研究

本文对光纤非线性效应的物理机理做了理论分析,并在此基础上,利用optisystem仿真平台和matlab编程软件联合仿真实现了基于光纤非线性效应的几种全光再生方案,仿真结果与理论分析吻合。     

Penalty-free error-free all-optical data pulse regeneration at 84Gb/s by using a symmetric-Mach-Zehnder-type semiconductor regenerator

Penalty-free data-pulse regeneration at 84 Gb/s was achieved down to an error rate level of 1×10^-11 by using a data pattern length of 2³¹-1. A symmetric-Mach-Zehnder-type all-optical polarization-insensitive semiconductor regenerator was used     

On the optimization of regenerator parameters in a chain of 2R all-optical regenerators

The dependence of the bit-error ratio (BER) along a 2R all-optical regenerator chain on the nonlinearity threshold and degree is investigated numerically using the rigorous distribution and the Gaussian distribution for the optical power. It is shown that, for high nonlinearity degree, the optimum nonlinearity threshold has a weak dependence on the number of regenerators and, for low nonlinearity degree, increases with the number of regenerators. Numerical results show that the Gaussian distribution may under-estimate or over-estimate the BER and fails to indicate the optimum regenerator parameters.     

Optical 3R regenerator using wavelength converters based onelectroabsorption modulator for all-optical network applications

The optical 3R regenerator using electroabsorption modulators was evaluated at 10 Gbit/s in terms of the all-optical network application. Its reset of impairments induced by the fiber transmission was confirmed by carrying out the multiple recirculating loop experiment. The experimental result shows that the transmission distance could be extended by almost 1.5 times compared to the case when it was not used, inserting the optical regenerator between the two recirculating loops     

Enhancing speech degrated by additive noise or interfering speakers

The author examines some of the ways that speech signals, subjected to certain degradations (e.g. additive noise, interfering speakers, bandlimiting, single-channel data), can be processed to increase the likelihood of being correctly understood. He concentrates on applications that involve monaural listening. He treats spectral and time-domain subtraction techniques, methods involving fundamental frequency tracking, and enhancement by resynthesis     

利用变形镜抑制光纤模态噪声

光纤模态噪声限制了下一代高精度视向速度光谱仪的测量精度。特别是当使用相干光源进行波长定标时,模态噪声会引起视向速度测量误差,降低视向速度测量精度。为了抑制光纤模态噪声,提出了一种基于变形镜的动态改变散斑花样的技术方法,该方法是在单次曝光时间内通过动态改变变形镜的面型,平滑光纤引起的散斑花样,提高定标光谱的质心稳定性,从而保证视向速度的测量精度。通过实验,利用632.8 nm 氦氖激光器作为定标光源,验证了该方法的有效性。实验结果表明,单次曝光图像包含约105个变形镜形变模式时,可以有效抑制光纤模态噪声。针对分辨率R=100000的光谱仪,单根定标谱线的情况下,光纤模态噪声引起的视向速度定标误差约为19.8 cm/s,与国际上其他技术方法的精度持平,该方法不仅可以提高能量利用率,且不影响光纤的使用寿命。     

Jitter reduction in 40 Gbit/s all-optical 3R regenerator using integrated MZI-SOA switches

Root-mean-square-phase jitter reduction from 4 to 1 ps in an all-optical 3R regenerator module operating for continuous and different length data packets at 40 Gbit/s is presented. The circuit is based on hybrid integrated Mach-Zehnder interferometric switches. Error-free operation is demonstrated with 2.5 dB power penalty improvement.     

One million pulse circulations in a fiber ring using a SLALOM forpulse shaping and noise reduction

The distinctly nonlinear input-output characteristics of a nonlinear element consisting of a semiconductor laser amplifier (SLA) in a loop mirror configuration (SLALOM) that may be utilized for pulse shaping and noise reduction is described. As an example, it is shown that nearly unlimited circulations of optical pulses in a fiber ring are possible