千家论坛_智能建筑与智能家居技术交流社区
标题:
无线光通信技术（要得来）
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作者:
babyvox1377
时间:
2007-1-9 10:10
标题:
无线光通信技术（要得来）
学到知识了就顶下
作者:
babyvox1377
时间:
2007-1-9 10:18
<p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 桂林三十四所、清华同方有限公司、中科院成都光电技术研究所、深圳飞通有限公司、上海光机所等几家单位，有比较成熟的样机。</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<span lang="EN-US"><p></p></span></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 桂林三十四所产品的主要性能参数有以下一些，传输速率：</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">8 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">34 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">，</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">155 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">；工作波长：</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">850 nm</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">；通信距离：</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">1~<chmetcnv wst="on" unitname="km" sourcevalue="4" hasspace="True" negative="False" numbertype="1" tcsc="0">4 km</chmetcnv></span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">；光发射功率：小于</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">40 mW</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 清华同方推出了面向未来的无线光链路的自由空间通信产品</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">OWLink E100</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">。清华同方在快速追踪系统具有自动校准功能获得了专利，其产品还遵循眼睛安全标准。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 中科院成都光电技术研究所，开发的产品主要性能参数有传输速率</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">:10 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">；工作波长：</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">850 nm</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">；通信距离：</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">1~<chmetcnv wst="on" unitname="km" sourcevalue="4" hasspace="True" negative="False" numbertype="1" tcsc="0">4 km</chmetcnv></span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">；发射功率：</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">3~30 mW</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 上海光机所承担的</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">"</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">无线激光通信系统</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">"</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">具有双向高速传输和自动跟踪功能。其传输速率可以达到</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">622 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">，通信距离可以达到</span><chmetcnv wst="on" unitname="km" sourcevalue="2" hasspace="True" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">2 km</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">。自动跟踪系统采用双波长同光路接收镜筒和高灵敏度位敏探测器，实现灵敏的伺服跟踪。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 深圳飞通有限公司开发出的样机，其速率有</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">155 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">622 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">以及</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">1.25 Gbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">几种，通信距离最远可达</span><chmetcnv wst="on" unitname="km" sourcevalue="4" hasspace="True" negative="False" numbertype="1" tcsc="0"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">4 km</span></chmetcnv><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> </span><b><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">6 FSO</span></b><b><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">研究的发展趋势</span></b><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> </span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">FSO</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">目前存在的问题主要集中在下面几个方面：</span><span style="FONT-SIZE: 10.5pt; COLOR: red; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">针对大楼摆动的瞄准问题</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">；</span><span style="FONT-SIZE: 10.5pt; COLOR: red; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">大气中粒子对光线的散射、吸收问题</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">；</span><span style="FONT-SIZE: 10.5pt; COLOR: red; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">提高传输速率问题</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">。这些问题影响了传输的可靠性，所以对这些问题的研究成为</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">FSO</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">的发展方向。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> </span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">6.1 </span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">发射、接收的瞄准的研究</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 在大风中或因地震引起大楼的摆动，发射机发送的光信号对不准接收机，产生的误差大，甚至通信无法实现。目前的研究方向在于提高激光的瞄准，怎样利用非机械装置来实现精确的对准和快速瞄准；在接收机方面，散射光线也带有信息，接收散射光线越多，接收的信号能量越大，但同时接收的噪声也越大，所以尽量提高接收机接收信号总功率，又不能降低信噪比成为研究目标。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> </span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">6.2 </span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">减小大气对通信的影响</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 在不同的环境中不同波长的光线会有不同的传播特性，这些不同的特性导致了在不同环境下，不同波长的光线会有不同的吸收窗口、不同的散射函数以及不同的折射率，需要寻求一种最优波长，在通信链路中找出波长与性能的最优组合。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> </span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">6.3 </span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">传输速率的提高</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> </span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">FSO</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">相对于其他接入设备最大的优势之一就是带宽。现在</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">FSO</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">产品的速率从</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">2 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">开始，形成多个系列，比较典型的有</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">10 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">100 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">155 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">622 Mbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">。有的公司采用波分复用技术，速率可以达到</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">2.5 Gbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">10 Gbit/s</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 综上所述，</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<span lang="EN-US">FSO</span></span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">的发展方向是解决大楼的抖动引起的对不准问题、大气微粒的散射问题、大气湍流影响通信问题，提高系统可靠性，在此基础上提高传输速率，使</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">FSO</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">发挥最大优势。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> </span><b><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">7 </span></b><b><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">结束语</span></b><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p style="MARGIN: 0cm 15pt 3.75pt; WORD-BREAK: break-all; LINE-HEIGHT: 140%;"><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;"> 无线光通信已经成为现实，它是连接宽带网的一种快捷方法。文中详细地介绍了国内外目前对</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">FSO</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">的研究以及研究成果，分析了目前存在的问题，</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">如果这些问题能得到解决，那么必能发挥</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">FSO</span><span style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; mso-bidi-font-family: Arial; mso-ascii-font-family: Arial; mso-hansi-font-family: Arial;">的最大潜能和优势。随着无线光通信技术的不断完善，它一定可以得到广泛的应用。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: #181818; LINE-HEIGHT: 140%; FONT-FAMILY: Arial;">
<p></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman"> </font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman"> </font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman"> </font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p><font face="Times New Roman"> </font></p></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><b><span lang="EN-US" style="FONT-SIZE: 18pt; COLOR: red; mso-bidi-font-size: 12.0pt;"><p><font face="Times New Roman"> </font></p></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; LINE-HEIGHT: 150%;"><b><span style="FONT-SIZE: 18pt; COLOR: red; LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">自由空间光通信的现状与发展趋势</span></b><span lang="EN-US" style="COLOR: black; LINE-HEIGHT: 150%; mso-bidi-font-size: 10.5pt;"><br/><font face="Times New Roman">1 </font></span><span style="COLOR: black; LINE-HEIGHT: 150%; FONT-FAMILY: 宋体; mso-bidi-font-size: 10.5pt; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman";">前言</span><span lang="EN-US" style="COLOR: black; LINE-HEIGHT: 150%; mso-bidi-font-size: 10.5pt;"><font face="Times New Roman">
<p></p></font></span></p><p style="LINE-HEIGHT: 150%;"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">20</span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">世纪<span lang="EN-US">90</span>年代后期，随着全光接入网的发展，人们对传输速率的要求越来越高；随着通信范围的延伸，人们对快捷通信链路建立的兴趣进一步提高。自由空间光通信技术因其具有独到的优势，在固定无线宽带技术中，能为宽带接入的快速部署提供一种灵活的解决方案，又得到了极大的关注。其应用范围已从军用和航天逐渐迈入民用领域，其技术本身也在不断的完善中。<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">自由空间光通信可在以下一些范围发挥重要作用。<span lang="EN-US">1</span>）可以作为光纤通信和微波通信冗余链路的备份；<span lang="EN-US">2</span>）可以应用于移动通信基站间的互连，无线基站数据回传；<span lang="EN-US">3</span>）应用于城域网的建设以及最后<chmetcnv wst="on" unitname="公里" sourcevalue="1" hasspace="False" negative="False" numbertype="3" tcsc="1">一公里</chmetcnv>接入；<span lang="EN-US">4</span>）在技术上或经济上不宜敷设光缆的地区，在不宜采用或限制使用无线电通信的地方；<span lang="EN-US">5</span>）在军事设施或其他要害部门需要严格保密的场合<span lang="EN-US">6</span>）在企业内部网互连和数据传输。<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">2 </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">自由空间光通信的基本原理及其特点<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">自由空间光通信系统（<span lang="EN-US">FSO</span>）是以大气作为传输媒质来进行光信号的传送的。只要在收发两个端机之间存在无遮挡的视距路径和足够的光发射功率，通信就可以进行。<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">系统所用的基本技术是光电转换。在点对点传输的情况下，每一端都设有光发射机和光接收机，可以实现全双工的通信。光发射机的光源受到电信号的调制，并通过作为天线的光学望远镜，将光信号经过大气信道传送到接收端的望远镜。高灵敏度的光接收机，将望远镜收到的光信号再转换成电信号。由于大气空间对不同光波长信号的透过率有较大的差别，可以选用透过率较好的波段窗口。光的无线系统通常使用<span lang="EN-US">850nm</span>或<span lang="EN-US">1550nm</span>的工作波长。同时考虑到<span lang="EN-US">1500nm</span>的光波对于雾有更强的穿透能力，而且人眼更安全，所以<span lang="EN-US">1550nm</span>波长的<span lang="EN-US">FSO</span>系统具有更广阔的使用前景。<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">自由空间光通信与微波技术相比，它具有调制速率高、频带宽、不占用频谱资源等特点；与有线和光纤通信相比，它具有机动灵活、对市政建设影响较小、运行成本低、易于推广等优点。自由空间光通信可以在一定程度弥补光纤和微波的不足。它的容量与光纤相近，但价格却低得多。它可以直接架设在屋顶，由空中传送。既不需申请频率执照，也没有敷设管道挖掘马路的问题。使用点对点的系统，在确定发收两点之间视线不受阻挡的通道之后，一般可在数小时之内安装完毕，投入运行。在考虑到当地气象的条件以后，光无线系统一般可得到<span lang="EN-US">99.9%</span>的可用性。如果采用其他系统构成主备用，甚至可达到<span lang="EN-US">99.999%</span>电信级的可用性要求。<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">另外自由空间光通信系统与网络的连接，还有如下的优点：<span lang="EN-US">1</span>）对运行的协议透明。现在通信网络常用的<span lang="EN-US">SDH</span>、<span lang="EN-US">ATM</span>、<span lang="EN-US">IP</span>等都能通过。<span lang="EN-US">2</span>）可组成点对点、星形、和网格形结构的网络。<span lang="EN-US">3</span>）可灵活拆装、移装至其他位置。<span lang="EN-US">4</span>）易于扩容升级，只需稍作接口的变动就能改变容量。 自由空间光通信存在的主要问题有以下几点：<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">（<span lang="EN-US">1</span>）<span lang="EN-US">FSO</span>是一种视距宽带通信技术，传输距离与信号质量的矛盾非常突出，当传输超过一定距离时波束就会变宽导致难以被接收点正确接收。目前，在<chmetcnv wst="on" unitname="km" sourcevalue="1" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">1km</span></chmetcnv>以下才能获得最佳的效果和质量，最远只能达到<chmetcnv wst="on" unitname="km" sourcevalue="4" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">4Km</span></chmetcnv>。多种因素影响其达不到<span lang="EN-US">99.999%</span>（五个<span lang="EN-US">9</span>）的稳定性。<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">（<span lang="EN-US">2</span>）<span lang="EN-US">FSO</span>系统性能对天气非常敏感是<span lang="EN-US">FSO</span>的另一个主要问题。晴天对<span lang="EN-US">FSO</span>传输质量的影响最小，而雨、雪和雾对传输质量的影响则较大。据测试，<span lang="EN-US">FSO</span>受天气影响的衰减经验值分别为：晴天，<span lang="EN-US">5-15db/km</span>、雨，<span lang="EN-US">20-50db/km</span>、雪，<span lang="EN-US">50-150db/km</span>、雾，<span lang="EN-US">50-300db/km</span>。国外为解决这个难题，一般会采用更高功率的激光器二极管、更先进的光学器件和多光束来解决。<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">（<span lang="EN-US">3</span>）城市内，由于建筑物的阻隔、晃动将影响两个点之间的激光对准。<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">（<span lang="EN-US">4</span>）激光的安全问题也会影响其使用，超过一定功率的激光可能对人眼产生影响，人体也可能被激光系统释放的能量伤害。所以产品要符合眼睛安全标准。<span lang="EN-US"><p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">3 </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">国外研究现状<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">在自由空间光通信（<span lang="EN-US">FSO</span>）领域，国外已经开始了将近<span lang="EN-US">10</span>年的研究，但是<span lang="EN-US">FSO</span>产品真正投入使用也就是最近几年的事情。在<span lang="EN-US">FSO</span>这个领域里，国外几个大的<span lang="EN-US">FSO</span>厂家，包括<span lang="EN-US">LightPointe</span>公司，<span lang="EN-US">AirFiber </span>公司，<span lang="EN-US">Canon </span>公司，<span lang="EN-US">Terabeam </span>公司。<span lang="EN-US">LightPointe</span>收到<span lang="EN-US">Corning</span>和思科系统公司的投资款<span lang="EN-US">3</span>千多万美元（现已增值至<span lang="EN-US">5</span>千多万美元），而<span lang="EN-US">AirFiber</span>则获得大概来自北电网络的<span lang="EN-US">5</span>千万美元（现已增值至<span lang="EN-US">9</span>千多万美元），朗讯科技则投资了<span lang="EN-US">4</span>亿<span lang="EN-US">5</span>千万美元的巨款在<span lang="EN-US">Terabeam</span>身上（现已增值至<span lang="EN-US">5</span>亿<span lang="EN-US">8</span>千多万美元）。几个公司的研究现状分别介绍如下：<span lang="EN-US">
<p></p></span></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">（<span lang="EN-US">1</span>）<span lang="EN-US">Lucent98</span>年<span lang="EN-US">3</span>月开始开发，<span lang="EN-US">99</span>年<span lang="EN-US">3</span>月发布<span lang="EN-US">WaveStar OpticAir system </span>产品。单波长，传输速率<span lang="EN-US">2.5 Gb/s, </span>四波长<span lang="EN-US">10 Gb/s, </span>距离<chmetcnv wst="on" unitname="km" sourcevalue="5" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">5Km</span></chmetcnv>，<span lang="EN-US">99 </span>年<span lang="EN-US">12</span>月，<span lang="EN-US">Global Crossing Ltd. </span>现场使用。<span lang="EN-US">TeraBeam</span>，<span lang="EN-US">Lucent</span>宣布组建<span lang="EN-US"> TeraBeam Internet Systems</span>，产品是基于<span lang="EN-US">IP </span>的无光纤点到多点网络，发送和接收机，固定在办公室窗户上小卫星碟。这些卫星碟型天线的波束与安装在楼内的基站相连。<span lang="EN-US">Lucent</span>投入资金、研究开发资源，知识产权，价值<span lang="EN-US">450</span>百万美元的自由空间光产品。<span lang="EN-US">TeraBeam </span>的产品都用<span lang="EN-US">Lucent </span>的商标，光元件，网络设备和服务优先选用<span lang="EN-US">Lucent </span>的。<span lang="EN-US">TeraBeam</span>拥有<span lang="EN-US">70%</span>的股份<span lang="EN-US">,</span>可以使用技术和销售客户。<span lang="EN-US">
<p></p></span></span></p><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">2</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">）</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">LightPointe</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">公司将自由空间光学技术用于创造、设计和制造电信公司等级的光传输设备，向电信服务商提供比传统光缆传输速度更快、成本更低的高速通讯解决方案。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">LightPointe</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">的系统以超快的带宽速度提供安全可靠的无线传输，速度最高可达</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">2.5Gb/s</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">，产品适应性强，可解决城市地区的连接问题。公司拥有多项正在申请专利的专有技术，可提供电信公司等级的网络可用性。</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">LightPointe</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">的自由空间光传输（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">FSO</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">）产品在第一层（物理层）工作，可适应任何协议（</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">SONET</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">SONET/SDH</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">ATM</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">、</span><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: "Times New Roman"; mso-fareast-font-family: 宋体; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">FDDI</span><span style="FONT-SIZE: 10.5pt; COLOR: black; FONT-FAMILY: 宋体; mso-font-kerning: 1.0pt; mso-bidi-font-family: "Times New Roman"; mso-ascii-font-family: "Times New Roman"; mso-hansi-font-family: "Times New Roman"; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA;">、以太网、快速以太网）。</span>
作者:
babyvox1377
时间:
2007-1-9 10:21
<span lang="EN-US"><p><font face="Times New Roman"><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;"><font face="宋体">产品包括各种<span lang="EN-US">"</span>飞行自由空间光传输解决方案<span lang="EN-US">"</span>，其中有<span lang="EN-US">FlightLite</span>、<span lang="EN-US">FlightPath</span>、<span lang="EN-US">FlightSpectrum</span>。速度最高可达<span lang="EN-US">1.25 Gb/s</span>，提供兆位级以太网通讯能力，工作波长为<span lang="EN-US">850</span>纳米（<span lang="EN-US">nm</span>）。<span lang="EN-US">2003</span>年秋季将开始向市场提供<span lang="EN-US">2.5 Gb/s Flight Spectrum</span>，其使用半径为<chmetcnv wst="on" unitname="米" sourcevalue="1000" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">1000</span>米</chmetcnv>，采用<span lang="EN-US">1550nm</span>波长。 <span lang="EN-US"><p></p></span></font></span></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;"><font face="宋体">产品<span lang="EN-US">LightStation </span>的特点有以下一些：<span lang="EN-US">
<p></p></span></font></span></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">a. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">数据率从<span lang="EN-US">1 Mbps</span>到<span lang="EN-US">1.25 Gb/s </span>；传输距离达<chmetcnv wst="on" unitname="km" sourcevalue="2.5" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">2.5Km</span></chmetcnv><span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">b. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">分布<span lang="EN-US">SNMP</span>监视采用光接口<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">c. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">信号高度安全<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">d. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">协议透明（<span lang="EN-US">IP, ETHERNET, ATM, SONET, FDDI</span>）；容易集成到现存的网络<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">e. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">内置望远镜和信号强度表<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">f. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">微调控制；内部装有加热器，具有镜头防霜功能<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">g. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">采用自动微波备份交换技术，可使用率达<span lang="EN-US">99.999%</span>，采用<span lang="EN-US">LightPointe Patent Pending FORCE? </span>技术（<span lang="EN-US">Free-space Optical Radio Communication Equipment</span>）可补偿纯光通信带来的限制。使用无须许可证的扩展频谱<span lang="EN-US">ISM</span>频带的<span lang="EN-US">LBS 100/10</span>微波备份交换产品，可克服有雾天气的限制。<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;"><font face="宋体">（<span lang="EN-US">3</span>）<span lang="EN-US">AirFiber</span>公司位于美国加洲<span lang="EN-US">San Diego</span>，<span lang="EN-US">98</span>年<span lang="EN-US">5</span>月成立，主要服务于大城市大楼宽带接入。它的产品称为<span lang="EN-US">OptiMesh</span>，网络结构为网眼状拓扑结构，冗余备份短距离<span lang="EN-US">622Mb/s</span>无线光传输系统。产品特点有：<span lang="EN-US">
<p></p></span></font></span></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">a. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">运行中心由交换，路由，服务平台，<span lang="EN-US">NMCs</span>，网关到载体<span lang="EN-US">ISRs <p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">b. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">主干传输由光纤环，<span lang="EN-US">ADMs, </span>光纤<span lang="EN-US">/</span>铜线分布，微波链路等<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">c. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">从核心网到初级用户网包括<span lang="EN-US">AirFiber </span>节点，楼房<span lang="EN-US">POP</span>，初级<span lang="EN-US">NTU</span>或服务平台<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><font face="宋体"><span lang="EN-US" style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">d. </span><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;">基础服务提供用户<span lang="EN-US">LAN, PBX,</span>布线，终端设备，电话，计算机<span lang="EN-US">
<p></p></span></span></font></p><p style="LINE-HEIGHT: 150%;"><span style="FONT-SIZE: 10.5pt; COLOR: black; LINE-HEIGHT: 150%;"><font face="宋体">（<span lang="EN-US">4</span>）<span lang="EN-US">Canon</span>是世界著名生产光学仪器的公司，利用在光学系统方面的优势，也踏足自由空间光通信系统的领域。主要产品有：<span lang="EN-US">Canobeam DT-50</span>，速率从<span lang="EN-US">25Mb/s</span>到<span lang="EN-US">622Mb/s. </span>可连接<span lang="EN-US"> FastEthernnet,FDDI, ATM</span>。特点是具有自动跟踪系统，调整探测器件的位置以检测激光束的光轴，所以不因建筑物的摆动和震动而使传输中断。同时，镜头自动跟踪特性增加传输距离达<chmetcnv wst="on" unitname="km" sourcevalue="2" hasspace="False" negative="False" numbertype="1" tcsc="0"><span lang="EN-US">2km</span></chmetcnv>。<span lang="EN-US">Canobeam III</span>：数据率达到<span lang="EN-US">622Mb/s</span>，有不同的网络接口，如<span lang="EN-US">ATM, FDDI, Fast Ethernet</span>，并可选择<span lang="EN-US">SNMP </span>的<span lang="EN-US">TCP/IP</span>。<span lang="EN-US"><p></p></span></font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><span lang="EN-US"><p> </p></span></p><p style="LINE-HEIGHT: 150%;"></p></font></p></span>
作者:
buddie
时间:
2007-1-9 20:28
要大众化使用恐怕较难，正如上文所说的存在的四个问题。
作者:
david-risbo
时间:
2007-1-10 00:40
Terabeam公司并购美国Proxim无线通信，成为全球无线行业的巨头，产品线包括了从无线网卡、无线MESH、Wi-Fi WiMAX、无线光通信等系列，在中国地区的产品总代理：瑞赛博 010-51659153
作者:
苏州天平
时间:
2007-1-10 09:27
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