Asymmetry of Raman crosstalk in wavelength division multiplexing transmission systems

The Raman crosstalk in wavelength division multiplexing transmission systems is analysed in respect of modulation statistical property and dispersion walk-off effect. Both the mean nonlinear depletions/gains and crosstalk variances experienced by individual channels are found to be asymmetric for intensity-modulated systems. The asymmetry increases with the number of channels and input power.     

修旧如故重现风貌——上海历史建筑修缮保护的实践和思考

上海历史建筑历经百年沧桑,伴随着西方政治、宗教、经济、文化影响与中国特色相结合,已经成为上海独特的风貌景观和文化遗产。文章从实际出发,阐述上海历史建筑修缮保护的方式和还历史建筑的原真性的重要意义。     

高起点做好黄浦江两岸住宅布局规划

从黄浦江两岸四个重要开发地区着手，在规划范围，用地规模指标和建筑空间，景观，高度控制上，高起点做好浦江两岸住宅布局规划。     

Dual-fiber optical burst switching network: A novel architecture for metropolitan area networks

Fiber optic rings are widely deployed in metropolitan area networks (MAN). These rings currently employ architectures and protocols that are neither optimized for nor scalable to the network demand. Therefore, emerging technologies are being pushed to replace the traditional architectures. Among these technologies, optical burst switching (OBS) is an effective and promising technology. In this study, a novel architecture, dual-fiber OBS (DOBS), is proposed. This architecture has similar functions to those of fiber delay lines, partial wavelength conversion and deflection routing. A theoretical model is developed to evaluate the performance of DOBS, which is compared with single-fiber and simple two-fiber schemes by introducing them into ring and mesh MAN in simulations. The results reveal that DOBS can exponentially reduce the burst dropping probability. Moreover, since DOBS can be implement using commercially available devices and dark fibers, it is commercially viable in metro networks.     

复合静电驱动结构致动的内旋转微镜

报道了以体硅表面硅混合微加工工艺制作在SOI衬底上的一种新型复合静电驱动结构致动内旋转微镜,其中复合静电驱动结构由一个平板驱动器和一个垂直梳齿驱动器构成.实验表明,该新型驱动结构不仅能使微镜实现大范围连续旋转,而且能使微镜实现吸合效应致自发性90°旋转.微镜的连续旋转范围扩大到约46°,同时引发吸合效应的拐点电压也增大.对于具有1和0.5μm厚扭转弹性梁的微镜,实测拐点电压分别为390～410V和140～160V.当该微镜用作光开关时,测得光插入损耗为～1.98dB.     

适用于Pbit/s光分组交换网络的丢包率下限模型

文章针对通过优化路由来改善光分组交换网络性能这一方法进行了深入地分析。文章认为在输出光缓存结构下可以计算出网络丢包率下限的理论模型,通过将该模型得到的丢包率下限与在已有路由算法下由仿真得到的丢包率进行比较,能够预测出最佳路由算法下的丢包率,从而进一步预测通过优化路由所能获得的最大性能提升。     

Security performance analysis of an M-code keying OCDMA system

In this article, an M-code keying OCDMA system with parallel encoders/decoders is presented and its security performance is quantitatively analyzed. Under brute-force searching techniques, the formula about the average searching time is derived. The bit-correct-interception possibilities for tapping individual and multiple users’ signals are calculated, respectively. By analysis, it is shown that the security performance of an OCDMA system can be enhanced by employing M-code keying.     

适用于光码分多址通信系统的可调光编/解码器的一种新方案

提出了一种新的可调光编/解码器的实现方案。这种新结构的可调光编/解码器与以前文献中提出的结构相比,大大减少了所用2×2光开关数及光纤延时线的条数和长度,减小了硬件实现的复杂性,降低了成本和功耗,便于集成。     

A new family of 2-D optical orthogonal codes and analysis of its performance in optical CDMA access networks

A new family of two-dimensional optical orthogonal code (2-D OOC), one-coincidence frequency hop code (OCFHC)/OOC, which employs OCFHC and OOC as wavelength hopping and time-spreading patterns, respectively, is proposed in this paper. In contrary to previously constructed 2-D OOCs, OCFHC/OOC provides more choices on the number of available wavelengths and its cardinality achieves the upper bound in theory without sacrificing good auto-and-cross correlation properties, i.e., the correlation properties of the code is still ideal. Meanwhile, we utilize a new method, called effective normalized throughput, to compare the performance of diverse codes applicable to optical code division multiple access (OCDMA) systems besides conventional measure bit error rate, and the results indicate that our code performs better than obtained OCDMA codes and is truly applicable to OCDMA networks as multiaccess codes and will greatly facilitate the implementation of OCDMA access networks.     

光纤通信中集成滤光器的研究及实验

研究了４端集成滤光器和光开关在光纤通信中的应用特点，提出了对器件设计的要求和一些关键的设计方法，研制了器件，并进行了实例。实测结果表明，开和关的消光比为３２．３７ｄＢ，器件的插损小于４ｄＢ。