一种只需单个判决阈值的全光误码指示新方法

提出了一种基于自相位调制和带通滤波的全光误码指示新方法. 放大后的原比特流经过高非线性光纤的自相位调制和带通滤波器的带通滤波后输出误码指示信号流, 原比特流中的误码对应误码指示信号流中的高峰值功率脉冲, 而原比特流中的“1”码和“0”码对应误码指示信号流中的低峰值功率脉冲, 并且误码指示信号流与经过光延迟线的原比特流同步. 因此, 仅需在误码指示信号流中设置一个阈值就能判定原比特流中误码的位置. 通过数值实验, 我们对速率为80 Gb/s的归零码系统进行了验证. 该方法可作为未来采用归零码型的超高速光传输系统中误码指示的一种可选途径.     

Wavelength Assignment in WDM Optical Networks with Limited-range Wavelength Conversion

According to previous studies, limited range wavelength conversion (LWC) can improve the performance of optical network. In this paper, the effects of FWM (Four Wave Mixing) and XGM (Cross-Gain Modulation) conversion are both examined. It is found that the performance difference between LWC and full conversion becomes quite remarkable with the increase in numbers of wavelengths per-link. So in order to improve the performance of optical network with limited conversion in the case of large number of wavelengths, three simple dynamic wavelength assignment algorithms (LUWC, FUWC and WSM) are proposed. Simulation results show that the algorithms greatly reduce the blocking probabilities of networks with LWC. Moreover, the algorithms require no global information of network.     

An Effective Method for Guaranteed Shared Protection in WDM Optical Networks

0　IntroductionToday’sWDMopticalnetworkscanprovidehugebandwidthtotheirclientsandarebecomingauniquecan didateforthefutureInternettransportinfrastructure .However ,networkfailurewillinducelargetrafficlossbe causeallthelightpathsinopticalnetworkcarryalargevolumeofinformation .Soitisverynecessarytoprovideprotectionforworkinglightpaths .Theprotectionapproachescanbeclassifiedintopathprotectionandlinkprotectiondependingonwhethertheend to endorthelocalprotectionisused .Theycanalsobesortedintodedica…     

Method for Guaranteed Shared Protection in WDM Optical Networks

Previous dynamic resource allocation methods (Separate Path Select, SPS) for survivable networks are always separated into two steps, that is, to determine an optimal primary path first and then select a backup path for the primary path. But SPS cannot achieve a good network performance. In this paper we analyze the drawback of the traditional SPS technique and propose an efficient shared protection method called M _ SPS. Instead of rejecting an arrival call immediately when a backup lightpath for the optimal primary lightpath cannot be found, M _ SPS continue to try the sub-optimal one until a legal primarybackup pair can be selected. We apply M SPS to CERNET_ Like and NSFNET networks. The results show that M _ SPS improves the network performance remarkably.