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Optical Performance Monitoring
Optical performance monitoring (OPM) is used for managing high capacity dense wavelength-division multiplexing (DWDM) optical transmission and switching systems in Next Generation Networks (NGN). OPM involves assessing the quality of data channel by measuring its optical characteristics without directly looking at the transmitted sequence of bits. It is a potential mechanism to improve control of transmission and physical layer fault management in optical transmission systems. In optical communications, typical roles for optical performance monitoring include ensuring correct switching in reconfigurable optical add-drop multiplexers, setting levels for dynamic equalization of the gain of optical amplifier An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback fro ...s, and providing system al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dense Wavelength-division Multiplexing
In fiber-optic communications, wavelength-division multiplexing (WDM) is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths (i.e., colors) of laser light. This technique enables Duplex (telecommunications), bidirectional communications over a single strand of fiber (also called wavelength-division duplexing) as well as multiplication of capacity. The term WDM is commonly applied to an optical carrier, which is typically described by its wavelength, whereas frequency-division multiplexing typically applies to a radio carrier, more often described by frequency. This is purely conventional because wavelength and frequency communicate the same information. Specifically, frequency (in Hertz, which is cycles per second) multiplied by wavelength (the physical length of one cycle) equals velocity of the carrier wave. In a vacuum, this is the speed of light (usually denoted by the lowercase letter, c). In glass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Communications
Optical communication, also known as optical telecommunication, is communication at a distance using light to carry information. It can be performed visually or by using electronic devices. The earliest basic forms of optical communication date back several millennia, while the earliest electrical device created to do so was the photophone, invented in 1880. An optical communication system uses a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal. When electronic equipment is not employed the 'receiver' is a person visually observing and interpreting a signal, which may be either simple (such as the presence of a beacon fire) or complex (such as lights using color codes or flashed in a Morse code sequence). Modern communication relies on optical networking systems using optical fiber, optical amplifiers, lasers, switches, routers, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Next Generation Networks
The next-generation network (NGN) is a body of key architectural changes in telecommunication core and access networks. The general idea behind the NGN is that one network transports all information and services (voice, data, and all sorts of media such as video) by encapsulating these into IP packets, similar to those used on the Internet. NGNs are commonly built around the Internet Protocol, and therefore the term all IP is also sometimes used to describe the transformation of formerly telephone-centric networks toward NGN. NGN is a different concept from Future Internet, which is more focused on the evolution of Internet in terms of the variety and interactions of services offered. Introduction of NGN According to ITU-T, the definition is: :A next-generation network (NGN) is a packet-based network which can provide services including Telecommunication Services and is able to make use of multiple broadband, quality of service-enabled transport technologies and in which ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reconfigurable Optical Add-drop Multiplexer
In optical communication, a reconfigurable optical add-drop multiplexer (ROADM) is a form of optical add-drop multiplexer that adds the ability to remotely switch traffic from a wavelength-division multiplexing (WDM) system at the wavelength layer. This is achieved through the use of a wavelength selective switching module. This allows individual or multiple wavelengths carrying data channels to be added and/or dropped from a transport fiber without the need to convert the signals on all of the WDM channels to electronic signals and back again to optical signals. The main advantages of the ROADM are: * The planning of entire bandwidth assignment need not be carried out during initial deployment of a system. The configuration can be done as and when required without affecting traffic already passing the ROADM. * ROADM allows for remote configuration and reconfiguration. * In ROADM, as it is not clear beforehand where a signal can be potentially routed, there is a necessity of power ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Amplifier
An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed. Optical amplifiers are important in optical communication and laser physics. They are used as optical repeaters in the long distance fiber-optic cables which carry much of the world's telecommunication links. There are several different physical mechanisms that can be used to amplify a light signal, which correspond to the major types of optical amplifiers. In doped fiber amplifiers and bulk lasers, stimulated emission in the amplifier's gain medium causes amplification of incoming light. In semiconductor optical amplifiers (SOAs), electron–hole recombination occurs. In Raman amplifiers, Raman scattering of incoming light with phonons in the lattice of the gain medium produces photons coherent with th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Signal-to-noise Ratio
Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to noise power, often expressed in decibels. A ratio higher than 1:1 (greater than 0 dB) indicates more signal than noise. SNR is an important parameter that affects the performance and quality of systems that process or transmit signals, such as communication systems, audio systems, radar systems, imaging systems, and data acquisition systems. A high SNR means that the signal is clear and easy to detect or interpret, while a low SNR means that the signal is corrupted or obscured by noise and may be difficult to distinguish or recover. SNR can be improved by various methods, such as increasing the signal strength, reducing the noise level, filtering out unwanted noise, or using error correction techniques. SNR also determines the maximum possible amount of data that can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Management
Network management is the process of administering and managing computer networks. Services provided by this discipline include fault analysis, performance management, provisioning of networks and maintaining quality of service. Network management software is used by network administrators to help perform these functions. Technologies A small number of accessory methods exist to support network and network device management. Network management allows IT professionals to monitor network components within large network area. Access methods include the SNMP, command-line interface (CLI), custom XML, CMIP, Windows Management Instrumentation (WMI), Transaction Language 1 (TL1), CORBA, NETCONF, RESTCONF and the Java Management Extensions (JMX). Schemas include the Structure of Management Information (SMI), YANG, WBEM, the Common Information Model ( CIM Schema), and MTOSI amongst others. Value Effective network management can provide positive strategic impacts. For ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
