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Super-channel
A super-channel is an evolution in dense wavelength-division multiplexing (DWDM) in which multiple, coherent optical carriers are combined to create a unified channel of a higher data rate, and which is brought into service in a single operational cycle. Background From around the year 2010, coherent optical transmission at 40 Gbit/s and 100 Gbit/s began to be deployed in long-haul optical networks around the world. Coherent technology enables higher data rates to be sent over long haul (typically >2,000 km) optical transmission networks, compared to the historical modulation and detection technique, Intensity Modulation with Direct Detection (sometimes referred to as Non-Return to Zero, NRZ or On/Off Keying, OOK), which had been widely used for several decades. However, a coherent detector requires that the incoming phase modulation information is digitized before being sent to a high-performance digital signal processor (DSP). Within the DSP, optical impairments ... [...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] |
Coherence (physics)
Coherence expresses the potential for two waves to Wave interference, interfere. Two Monochromatic radiation, monochromatic beams from a single source always interfere. Wave sources are not strictly monochromatic: they may be ''partly coherent''. When interfering, two waves add together to create a wave of greater amplitude than either one (constructive Wave interference, interference) or subtract from each other to create a wave of minima which may be zero (destructive interference), depending on their relative phase (waves), phase. Constructive or destructive interference are limit cases, and two waves always interfere, even if the result of the addition is complicated or not remarkable. Two waves with constant relative phase will be coherent. The amount of coherence can readily be measured by the interference visibility, which looks at the size of the interference fringes relative to the input waves (as the phase offset is varied); a precise mathematical definition of the de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Signal Processor
A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on metal–oxide–semiconductor (MOS) integrated circuit chips. They are widely used in audio signal processing, telecommunications, digital image processing, radar, sonar and speech recognition systems, and in common consumer electronic devices such as mobile phones, disk drives and high-definition television (HDTV) products. The goal of a DSP is usually to measure, filter or compress continuous real-world analog signals. Most general-purpose microprocessors can also execute digital signal processing algorithms successfully, but may not be able to keep up with such processing continuously in real-time. Also, dedicated DSPs usually have better power efficiency, thus they are more suitable in portable devices such as mobile phones because of power consumption constraints. DSPs often use special m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatic Dispersion
Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Sometimes the term chromatic dispersion is used to refer to optics specifically, as opposed to wave propagation in general. A medium having this common property may be termed a dispersive medium. Although the term is used in the field of optics to describe light and other electromagnetic waves, dispersion in the same sense can apply to any sort of wave motion such as acoustic dispersion in the case of sound and seismic waves, and in gravity waves (ocean waves). Within optics, dispersion is a property of telecommunication signals along transmission lines (such as microwaves in coaxial cable) or the pulses of light in optical fiber. In optics, one important and familiar consequence of dispersion is the change in the angle of refraction of different colors of light, as seen in the spectrum produced by a dispersive prism and in chromatic aberration of lenses. Design of compound achr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarization Mode Dispersion
Polarization mode dispersion (PMD) is a form of modal dispersion where two different polarizations of light in a waveguide, which normally travel at the same speed, travel at different speeds due to random imperfections and asymmetries, causing random spreading of optical pulses. Unless it is compensated, which is difficult, this ultimately limits the rate at which data can be transmitted over a fiber. Overview In an ideal optical fiber, the core has a perfectly circular cross-section. In this case, the fundamental mode has two orthogonal polarizations (orientations of the electric field) that travel at the same speed. The signal that is transmitted over the fiber is randomly polarized, i.e. a random superposition of these two polarizations, but that would not matter in an ideal fiber because the two polarizations would propagate identically (are degenerate). In a realistic fiber, however, there are random imperfections that break the circular symmetry, causing the two p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog-to-digital Converter
In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a Digital signal (signal processing), digital signal. An ADC may also provide an isolated measurement such as an electronic device that converts an analog input voltage or Electric current, current to a digital number representing the magnitude of the voltage or current. Typically the digital output is a two's complement binary number that is proportional to the input, but there are other possibilities. There are several ADC hardware architecture, architectures. Due to the complexity and the need for precisely matched electronic component, components, all but the most specialized ADCs are implemented as integrated circuits (ICs). These typically take the form of metal–oxide–semiconductor (MOS) mixed-signal integrated circuit chips that integrate both Analogue electronics, anal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comb Filter
In signal processing, a comb filter is a Filter (signal processing), filter implemented by adding a delayed version of a signal processing, signal to itself, causing constructive and destructive Interference (wave propagation), interference. The frequency response of a comb filter consists of a series of regularly spaced notches in between regularly spaced ''peaks'' (sometimes called ''teeth'') giving the appearance of a comb. Comb filters exist in two forms, ''feedforward'' and ''feedback''; which refer to the direction in which signals are delayed before they are added to the input. Comb filters may be implemented in discrete time or continuous time forms which are very similar. Applications Comb filters are employed in a variety of signal processing applications, including: * Cascaded integrator–comb filter, Cascaded integrator–comb (CIC) filters, commonly used for anti-aliasing filter, anti-aliasing during interpolation and decimation (signal processing), decimation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthogonal Frequency-division Multiplexing
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission used in digital modulation for encoding digital (binary) data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL internet access, wireless networks, power line networks, and 4G/ 5G mobile communications. OFDM is a frequency-division multiplexing (FDM) scheme that was introduced by Robert W. Chang of Bell Labs in 1966. In OFDM, the incoming bitstream representing the data to be sent is divided into multiple streams. Multiple closely spaced orthogonal subcarrier signals with overlapping spectra are transmitted, with each carrier modulated with bits from the incoming stream so multiple bits are being transmitted in parallel. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Labs
Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. As a former subsidiary of the American Telephone and Telegraph Company (AT&T), Bell Labs and its researchers have been credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B (programming language), B, C (programming language), C, C++, S (programming language), S, SNOBOL, AWK, AMPL, and others, throughout the 20th century. Eleven Nobel Prizes and five Turing Awards have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telepho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infinera
Infinera Corporation was an American vertically integrated manufacturer of Wavelength-division multiplexing (WDM)-based packet optical transmission equipment based in San Jose, California. It was also a manufacturer for IP transport technologies, for the telecommunications service provider market. It was a pioneer in designing and manufacturing of large-scale photonic integrated circuits (PICs). The company sold hardware and software networking options for Tier 1 carrier, Internet content provider, cable operator, government, and enterprise networks. In June 2024, Nokia acquired Infinera for $2.3 billion. History Infinera was founded in 2000 as Zepton Networks by Drew Perkins, Jagdeep Singh and David Welch. It raised its first round of funding in April 2001. The startup remained in stealth mode until its first products were launched in 2004, although a few early media articles did describe the company's component technology - a photonic integrated circuit in indium phosphi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcatel-Lucent
Alcatel-Lucent S.A. () was a multinational telecommunications equipment company, headquartered in Boulogne-Billancourt, Paris, France. The company focused on Fixed line telephone, fixed, Mobile phone, mobile and telecommunications convergence, converged networking hardware, Internet Protocol, IP technologies, Telecommunications convergence#Telecommunication convergence business support systems, software and services, and operated between 2006 and 2016 in more than 130 countries. The American company Lucent Technologies was acquired by the France-based Alcatel in 2006, after which the latter renamed itself to Alcatel-Lucent. Lucent was a successor of AT&T's Western Electric and a holding company of Bell Labs. In 2014, the Alcatel-Lucent group split into two: Alcatel-Lucent Enterprise, providing enterprise communication services, and Alcatel-Lucent, selling to communications operators. The enterprise business was sold to China Huaxin Post and Telecom Technologies in the same year, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Huawei
Huawei Technologies Co., Ltd. ("Huawei" sometimes stylized as "HUAWEI"; ; zh, c=华为, p= ) is a Chinese multinational corporationtechnology company in Longgang, Shenzhen, Longgang, Shenzhen, Guangdong. Its main product lines include telecommunications equipment, consumer electronics, electric vehicle self-driving car, autonomous driving systems, and rooftop solar power products. The company was founded in Shenzhen in 1987 by Ren Zhengfei, a veteran officer of the People's Liberation Army (PLA). Initially focused on manufacturing stored program control, phone switches, Huawei has expanded to more than 170 countries to include building telecommunications network infrastructures, providing equipment, operational and consulting services, and manufacturing communications devices for the consumer market. It overtook Ericsson in 2012 as the largest telecommunications equipment manufacturer in the world. Huawei surpassed Apple Inc., Apple and Samsung Electronics, Samsung, in 2018 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
