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In fiber-optic communications, dark fiber or unlit fiber (or fibre) is the name given to individual fibers that have yet to be used within cables that have been already laid. They are hence not yet connected to any device, and are only there for future usage. Fiber-optic communication is a method of transmitting information from one place to another by sending light through an optical fiber. ...
Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ...
The term was originally used when talking about the potential network capacity of telecommunication infrastructure, but now also refers to increasingly common practice of leasing fiber optic cables from a network service provider. A network service provider (NSP) is a business or organization that sells bandwidth or network access by providing direct backbone access to the Internet and usually access to its network access points (NAPs). ...
Dark fiber for capacity expansion
One reason that dark fiber exists in well-planned networks is that much of the cost of installing cables is in so-called civils - the civil engineering work required in order to get the cables installed. This includes planning and routing, obtaining permissions, creating ducts and channels for the cables, and finally installation and connection. This work accounts for more than 60% of the cost of developing fiber networks, with only a relatively small proportion actually being invested in the optical fiber cable and high-tech networking infrastructure. [citation needed] The Falkirk Wheel in Scotland. ...
It therefore makes sense to plan for and install significantly more fiber than is needed for current demand, to provide for future expansion and provide for network redundancy in case any of the cables fail. In engineering, the duplication of critical components of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe, is called redundancy. ...
Additionally, many fiber optic cable owners such as railroads or power utilities have always added additional fibers for lease to other carriers.
In common vernacular, dark fiber may sometimes still be called "dark" if it's been lit by a fiber lessee and not the cable's owner.
Dark fiber overcapacity In the dot-com bubble, a large number[citation needed] of telephone companies (or telcos) built optical fiber networks, each with the business plan of cornering the market in telecommunications by providing a network with sufficient capacity to take all existing and forecast traffic for the entire region served. This was based on the assumption that telecoms traffic, particularly data traffic, would continue to grow exponentially for the foreseeable future. The dot-com bubble was a speculative bubble covering roughly 1995–2001 during which stock markets in Western nations saw their value increase rapidly from growth in the new Internet sector and related fields. ...
A telephone company (or telco) provides telecommunications services such as telephony and data communications. ...
In mathematics, exponential growth (or geometric growth) occurs when the growth rate of a function is always proportional to the functions current size. ...
The availability of wavelength-division multiplexing further reduced the demand for fiber by increasing the capacity that could be placed on a single fiber by as much as a factor of 100. As a result, the wholesale price of data traffic collapsed. A number of these companies filed for bankruptcy protection, or went bankrupt, as a result. This article or section does not cite its references or sources. ...
Notice of closure stuck on the door of a computer store the day after its parent company, Granville Technology Group Ltd, declared bankruptcy (strictly, put into administration—see text) in the United Kingdom. ...
Just as with the Railway Mania, the misfortune of one market sector became the good fortune of another, and this overcapacity created a new telecommunications market sector. Railway mania was the term given to the speculative frenzy in Britain in the 1840s. ...
The term Market Sector is used in economics and finance to describe a set of businesses that are buying and selling such similar goods and services that they are in direct competition with each other. ...
The dark fiber market For many years, incumbent local exchange carriers would not sell dark fiber to end users, because they believed selling access to this core asset would cannibalize their other, more lucrative services. Incumbent carriers in the US were required to sell dark fiber to competitive local exchange carriers as Unbundled Network Elements (UNE), but they have successfully lobbied to reduce these provisions for existing fiber, and eliminated it completely for new fiber placed for fiber to the premises (FTTP) deployments. ILEC, short for incumbent local exchange carrier, is a local telephone company in the United States that was in existence at the time of the break up of AT&T into the Regional Bell Operating Companies (RBOCs) also known as the Baby Bells. GTE was the second largest ILEC after...
A Competitive Local Exchange Carrier (CLEC), in the United States, is a telecommunications provider company (sometimes called a carrier) that competes with other, already established carriers (generally the incumbent local exchange carrier (ILEC)). Local exchange carriers (LECs) are divided into incumbent (ILECs) and competitive (CLECs). ...
Unbundled Network Elements (UNE) are a requirement mandated by the United States Telecommunications Act of 1996. ...
// Fiber to the premises (FTTP) is a form of fiber-optic communication delivery in which an optical fiber is run directly onto the customers premises. ...
Competitive local carriers were not required to sell dark fiber, and many do not, although fiber swaps between competitive carriers are quite common. This increases the reach of their networks in places where their competitor has a presence, in exchange for provision of fiber capacity on places where that competitor has no presence. This is a practice known in the industry as "coopetition". Coopetition or Co-opetition is a neologism coined to describe cooperative competition. ...
Meanwhile, other companies arose specializing as dark fiber providers. Dark fiber became more available when there was enormous overcapacity after the boom years of the late 1990's through 2001. The market for dark fiber tightened up with the return of capital investment to light up existing fiber, and with mergers and acquisitions resulting in consolidation of dark fiber providers.
In the U.S. Level(3) Communications acquired a number of dark fiber providers in 2005-2006, and took their dark fiber off the market. AboveNet still markets dark fiber and is one of the only national providers left. Not to be confused with L-3 Communications, a communications system company formed from the assets of the former Loral and Lockheed corporations before their merger. ...
AboveNet, Inc. ...
Dark fiber has been, and still is, available for sale on the wholesale market for both metro and wide area links, but it may not be available in all markets or city pairs. Prices for dark fiber may sometimes be lower than the price of a high speed leased line rental. In the UK there are few dark fibre providers, with the majority of carriers providing leased lines and network services over fibre. AboveNet own and operate a London based dark fiber network with lit services also offered. In addition, FibreSpan sell dark fiber metro and wide area network links, becoming a dominant player due to its microduct technology. A leased line is a symmetric telecommunications line connecting two locations. ...
AboveNet, Inc. ...
FibreSpan (Fibre Span) is a fibre solutions company with a national telecommunications licence. ...
Dark fiber capacity is typically used by network operators to build SONET and dense wavelength division multiplexing (DWDM) networks, usually involving meshes of self-healing rings. Now, it is also used by end-user enterprises to expand Ethernet local area networks, especially since the adoption of IEEE standards for Gigabit Ethernet and 10 gigabit Ethernet over single-mode fiber. Running Ethernet networks between geographically separated buildings is a practice known as "WAN elimination". Synchronous Optical Networking, commonly known as SONET, is a standard for communicating digital information over optical fiber. ...
The original version of this article was based on FOLDOC, with permission In telecommunications wavelength division multiplexing (WDM) is a technology which multiplexes several optical carrier signals on a single optical fibre by using different wavelengths (colours) of laser light to carry different signals. ...
A self-healing ring is a common configuration in telecommunications transmission systems. ...
Ethernet is a large, diverse family of frame-based computer networking technologies that operate at many speeds for local area networks (LANs). ...
The Institute of Electrical and Electronics Engineers or IEEE (pronounced as eye-triple-ee) is an international non-profit, professional organization incorporated in the State of New York, United States. ...
Gigabit Ethernet (GbE or 1 GigE) is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second, as defined by the IEEE 802. ...
10 Gigabit Ethernet or 10GbE or 10 GigE is the most recent (as of 2006) and fastest of the Ethernet standards. ...
In telecommunication, a single-mode optical fiber is an optical fiber in which only the lowest order bound mode can propagate at the wavelength of interest. ...
Wide Area Network (WAN) is a computer network that covers a broad area (i. ...
Other variations - Managed dark fiber is a form of wavelength-division multiplexed access to otherwise dark fiber where a simple "pilot" signal is beamed into the fiber by the fiber provider for management purposes using a transponder tuned to the assigned wavelength. DWDM systems generally require central management because their closely spaced wavelengths are subject to disruption by signals on adjacent wavelengths that are not within tightly controlled parameters, especially if amplification is required for signal transmission over 100 km.
- Virtual dark fiber using wavelength multiplexing allows a service provider to offer individual wavelengths ("lambdas" (λ) or "colors"), where access to a dark narrowband wavelength-division multiplexing (WDM) optical channel is provided over a wavelength division multiplexed fiber network that is managed at the physical level, but unlit by the network provider. This is typically done using coarse wavelength division multiplexing CWDM because the wider 20 nm spacing of the wave bands makes these systems much less susceptible to interference.
Look up Λ, λ in Wiktionary, the free dictionary. ...
Narrowband (narrow bandwidth) refers to a signal which occupies only a small amount of space on the radio spectrum -- the opposite of broadband or wideband. ...
This article or section does not cite its references or sources. ...
The original version of this article was based on FOLDOC, with permission In telecommunications wavelength division multiplexing (WDM) is a technology which multiplexes several optical carrier signals on a single optical fibre by using different wavelengths (colours) of laser light to carry different signals. ...
Butter's Law of Photonics According to Gerry/Gerald Butters,[1][2][3] the former head of Lucent's Optical Networking Group at Bell Labs, there is a law called, Butter's Law of Photonics,[4] a formulation which deliberately parallels Moore's law. Butter's Law [5] says that the amount of data coming out of an optical fiber is doubling every nine months. Thus, the cost of transmitting a bit over an optical network decreases by half every nine months. The availability of wavelength-division multiplexing DWDM and coarse wavelength division multiplexing CWDM is rapidly bringing down the cost of networking, further progress seems assured. Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) was the main research and development arm of the United States Bell System. ...
Gordon Moores original graph from 1965 Growth of transistor counts for Intel processors (dots) and Moores Law (upper line=18 months; lower line=24 months) For the observation regarding information retrieval, see Mooers Law. ...
The original version of this article was based on FOLDOC, with permission In telecommunications wavelength division multiplexing (WDM) is a technology which multiplexes several optical carrier signals on a single optical fibre by using different wavelengths (colours) of laser light to carry different signals. ...
The original version of this article was based on FOLDOC, with permission In telecommunications wavelength division multiplexing (WDM) is a technology which multiplexes several optical carrier signals on a single optical fibre by using different wavelengths (colours) of laser light to carry different signals. ...
References - Geert Lovink, Dark Fiber: Tracking Critical Internet Culture, MIT Press, Cambridge Mass, 2002 ISBN 0-262-12249-9
See also Optical fibers An optical fiber (or fibre) is a glass or plastic fiber designed to guide light along its length. ...
Front view of SFP module (LC connector). ...
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