HFC超长距离传输解决方案

本文结合工程实际。比较系统的介绍在超长距离HFC传输网中。如何选用经济实用、可靠的技术方案。实现各光节点到总前端的上行和总前端对分前端及光节点的网管。     

利用量子几何相位制作光纤偏振旋转器

利用光纤中的量子几何相位(又称Berry相位),制作了单模光纤的线偏振光偏振面旋转器,并对器件进行了测量.实验数据表明,这种光纤偏振旋转器对光偏振面的旋转基本符合理论预计.对偏差进行处理后得到修正的定标公式,可更精确地反映出此光纤偏振旋转器的特性.     

几种“村村通”广播电视接收方案简介

一几种“村村通”电视传输方案介绍 根据目前电视传输的特点．可将电视传输分为三大类：卫星电视传输、有线电视传输和无线电视传输。卫星电视广播覆盖是跨地域的．覆盖区域最大、受众面最广，是大功率的数字压缩的电视广播．采用小口径卫星接收天线．可把卫星电视“接入户”。有线电视是为解决城市建筑物对电视波反射的问题而发展起来的、用电缆或光缆为用户提供电视信号的一种传输方式．该系统需要昂贵的电光设备及缆线．适合经济发达．人口居住较集中的城市。其最大优点是频带宽、传输节目多，能为今后的宽带综合应用打下基础。但投资大、施工周期长．尤其山区、河流、沙漠等地带更是不好实现。无线电视亦称地面广播．是以无线电波为载体来传送信号，需要搭建无线发射基站及相关配套设施。     

Ballistic transport and quantum interference in InSb nanowire devices

An experimental realization of a ballistic superconductor proximitized semiconductor nanowire device is a necessary step towards engineering topological quantum electronics. Here, we report on ballistic transport in In Sb nanowires grown by molecular-beam epitaxy contacted by superconductor electrodes. At an elevated temperature, clear conductance plateaus are observed at zero magnetic field and in agreement with calculations based on the Landauer formula. At lower temperature, we have observed characteristic Fabry–Pérot patterns which confirm the ballistic nature of charge transport.Furthermore, the magnetoconductance measurements in the ballistic regime reveal a periodic variation related to the Fabry–Pérot oscillations. The result can be reasonably explained by taking into account the impact of magnetic field on the phase of ballistic electron's wave function, which is further verified by our simulation. Our results pave the way for better understanding of the quantum interference effects on the transport properties of In Sb nanowires in the ballistic regime as well as developing of novel device for topological quantum computations.