Add-drop multiplexer
生活随笔 会计服务 货运公司 功率放大器 笔记本维修 软件著作权申请 新胜达 断桥铝合金 花卉租摆 温度控制器 阳光房 素食 北京保洁公司 压路机 北京物流 工商注册 电脑回收 温控器 航空货运 代理记帐 电脑租赁 展览展示 吹膜机 鱼鳞病 升降平台 kvm 仓储货架 汽车租赁 铜门 铜窗 铜装饰 铜扶手 生活随笔 会计服务 货运公司 功率放大器 笔记本维修 软件著作权申请 新胜达 断桥铝合金 花卉租摆 温度控制器 阳光房 素食 北京保洁公司 压路机 北京物流 工商注册 电脑回收 温控器 航空货运 代理记帐 电脑租赁 展览展示 吹膜机 鱼鳞病 升降平台 kvm 仓储货架 汽车租赁 铜门 铜窗 铜装饰 铜扶手 生活随笔 会计服务 货运公司 功率放大器 笔记本维修 软件著作权申请 新胜达 断桥铝合金 花卉租摆 温度控制器 阳光房 素食 北京保洁公司 压路机 北京物流 工商注册 电脑回收 温控器 航空货运 代理记帐 电脑租赁 展览展示 吹膜机 鱼鳞病 升降平台 kvm 仓储货架 汽车租赁 铜门 铜窗 铜装饰 铜扶手
An add-drop multiplexer (ADM) is an important element of optical fiber networks. A multiplexer combines, or multiplexes, several lower-bandwidth streams of data into a single beam of light. An add-drop multiplexer is a multiplexer that has the capability to add one or more lower-bandwidth signals to an existing high-bandwidth data stream, and at the same time can extract or drop other low-bandwidth signals, removing them from the stream and redirecting them to some other network path. This is used as a local "on-ramp" and "off-ramp" to the high-speed network.[1]
ADMs can be used both in long-haul core networks and in shorter-distance "metro" networks, although the former are much more expensive due to the difficulty of scaling the technology to the high data rates and dense wavelength division multiplexing (DWDM) used for long-haul communications. The main optical filtering technology used in add-drop multiplexers is the Fabry-Pérot etalon.
A recent shift in ADM technology has introduced so called "multi-service SONET/SDH" (also known as a multi-service provisioning platform or MSPP) equipment which has all the capabilities of legacy ADMs, but can also include cross-connect functionality to manage multiple fiber rings in a single chassis. These new devices can replace multiple legacy ADMs and also allow connections directly from Ethernet LANs to a service provider's optical backbone.
In the end of 2003, sales of multiservice ADMs exceeded those of legacy ADMs for the first time, as the change to next-generation SONET/SDH networks accelerated.
An emerging variety of ADMs that is becoming popular as the carriers continue to invest in metro optical networks are reconfigurable optical add-drop multiplexers (ROADMs).
References
See also
 | This article needs additional citations for verification. (July 2007) |