OPTICAL FIBER AT HOME

The pooling of the optical fiber to the home (FTTH) explained here:

The optical fiber to the home (FTTH) is criticized for its delay and its long established. Many critics have made but few seek to understand and explain what happens. Here is an attempt to decrypt.

The optical fiber represents a significant investment, it is currently mainly for housing: buildings. The reason is quite simple: the deployment of fiber for several apartments, the costs are divided. So dense areas are targeted first by the operators. That is why the explanations that follow are based on the example of deployment for buildings and apartments. The principle of FTTH for houses is similar but the conditions are less explicit mutualisation by ARCEP and operators.

What is optical fiber to the home?

To begin a drawing which explains briefly the principle of optical fiber to the home. The scheme is explained in more detail in the following in particular about 2 types of architecture.





As you can see, the principle is quite simple: to link directly the apartment of the subscriber to the Internet via an optical fiber from the apartment to a room called NRO (Node Connection Optics ) which are all connected subscribers. The equivalent of the NRO in the current telephone infrastructure (telephone lines with a pair of copper of France Telecom) is the dispatcher or call NRA (Node Connection Subscriber). The fiber optic cable between the NRO and the home is called optical local loop (the copper telephone line is called local loop copper).

Where it becomes complicated is in the first place there are several technologies involved and there were several operators: therefore pooled investments: the work done and fiber deployed to reduce these investments (this could cover more area faster in particular).

The 2 families FTTH Technologies in the P2P FTTH PON and FTTH

There are basically two types of deployment of optical fiber to home deployments in P2P - Point to Point (Peer to Peer is in french, Peer to Peer or point to point) and deployments in PON (Passive Optical Network). With a roll-to-peer (P2P), each home has its own fiber optic up to NRO. With a deployment PON, an optical fiber from NRO and is divided into 64 fibers, 128 fibers and more fibers are connected to the homes of subscribers. The PON can be seen as a tree whose trunk is the optical fiber that is connected to the NRO and the branches are optical fibers connected the homes of subscribers. Some operators have opted for a technology rather than another and others are torn between two or believing that technology is more efficient in the city and the other more effective campaign.

The advantages and disadvantages of these 2 families technologies are the subject of endless debates. ARCEP (Autorité de Régulation des Communications Électroniques and Postcards) and the government chose not to settle for one of two technologies. As this is not the subject of these explanations, we will not go no more in this debate or in the details of these technologies.

The point is that the existence of these 2 technologies complicates sharing: share its infrastructure, it is impossible to use equipment on a P2P infrastructure PON. Against the opposite may be possible: it may well make the PON with a P2P infrastructure, the "cutting" is the level of NRO. It may very well be against sharing infrastructure point to point with another operator wants to point to point, this is addressed in a second time.

Comment on mutualisms then?

All is not lost! You can still share a good part of the investments necessary for the deployment of fiber optics. To switch from fiber to the home, it is NRO and it is up to the apartment. There are not many solutions: sewers (only in some large cities), the sheaths of France Telecom last few months and if you have to "open up" the streets to ask new fork. It is sometimes necessary.

Sharing fork

Small rapid definition of a sheath is a tube or a sleeve where you can get coaxial cables (used for example by Numericable), electric cables, telephone or fiber optics.

Regarding the fork of France Télécom, he currently serves in particular to bring the telephone lines into the home. In recent months, following the demand for Free and ARCEP, France Telecom provides operators offering fork which came into effect shortly. It allows alternative operators to use the existing fork from France Telecom for deployment of fiber to the home. France Telecom already used them before, and the alternative operators (Free & SFR) have used so far mainly sewers (only in some large cities) for deployment of fiber optics. France Telecom is the main operator holding a fork with Numericable to a lesser extent.

This sharing sheaths can be realized over the entire horizontal part of the deployment. The horizontal part means the part between the NRO and the foot of building. On this part of the fiber optic infrastructure may be different (P2P or PON), they can not be shared if they are of different types. Thus the fiber optic deployment is not shared on this part for operators deploying infrastructure types.

After a somewhat difficult start sharing fork by the incumbent operators others have recently noted the effective implementation of the reference offer of France Telecom on access to its fork. Mutualization is en route to this part of the deployments and ARCEP will continue to monitor developments in this offer and the conditions for its implementation.

Mutualisation of fiber on the horizontal part of the same type of infrastructure

As against, for operators wishing to make a deployment point to point (P2P), they can share their infrastructure, it is sufficient that the operator wants to use optical fibers already deployed its equipment installed in the NRO (or near). For example, the supply of mutualisation Free provides an offer of resale in NRO (in addition to sharing in building up).

Only PON deployments in the current state of things (this change may be in the future with shared wavelength discussed at the end of the article) do not allow sharing at the physical level of fiber deployed until 'length of building.

Pooling in the building: the end

If you look at a diagram of PON deployment, we can see that in the building (the part that is called back end of deployment), there is an optical fiber necessary per flat, like a P2P deployment. Finally! We can share the deployment in the building! Thus an operator is deploying optical fiber in each apartment building until the foot and the other operators can directly connect the foot of building.

During discussions between operators and ARCEP, Free has proposed a solution mutualisation in buildings: the multifibre. At first glance the solution and is amazing when you thought you just said that it may be a good solution.

What is Multi?

Caution: Because of the complexity of the topic, it is possible to believe that the Multifibre corresponds to a deployment and that the P2P monofibre corresponds to a PON deployment or it is not. The monofibre applies equally in both PON and P2P in the multifibre applies P2P that PON.

The Multifibre to exist between the foot of the building as the apartment and fibers to each subscriber that there are operators. Here, at first sight is astonishing: there is more sharing on the back end. One wonders then what it really is apart from increasing the cost of deployment at the end. Just imagine the life of the optical fiber over several decades beginning with the deployment and how many operators will be arriving in foot building.

On the number of operators arriving foot building is fairly simple to calculate if a point to point operator is already present in a building, another trader wishing to deploy point to point does not have much interest redeployed to go until the fiber foot building, it can connect directly to the NRO. As against an operator who deploys type PON infrastructure must go to building up and other operators may PON pool at the logical level (see below) with this operator since it is the solution generally adopted by pooling operators currently PON. This is an operator and an operator P2P PON foot building, or 2 operators and 2 fiber per apartment. Investments to go down the building is substantial and the number of buildings is also a result, one should not see 2 operators per building (may be in Paris and in some very dense).



This photo shows a box with 2 fiber fiber (below), so an installation multifibre

So when deploying fiber in the building, the operator raises 2 fibers per apartment, it connects to one of the two and the day when another operator arrives, it is sufficient to connect at the bottom of property to the remaining fiber for each apartment. It therefore does not require that a final foot building where an operator comes up building. No intervention (except for possible interventions SAV) will be required to foot building. Only the wiring is necessary to NRO and the connection to the proper perspective in the apartment of the subscriber (the subscriber can do with a box with 2 outlets), just as with the telephone lines currently, when you order ADSL, it is necessary that France Telecom makes a connection to the NRA.




This photo shows the components of a FTTH (Multi) with the subscriber box located in the flat (top left photo), fibers that descend into the riser of the building (right), and Finally enclosures operators (which is building up), 1 for each operator, each of 2 fibers from an apartment is connected to one of these boxes.

To further compare with the existing telephone lines, if you look at your phone box, you can see on your phone you have pairs of brass and more (even surplus). And this is reflected on the different parts of your telephone line leading to the telephone dispatcher. This allows for multiple phone lines (with couplers mother) or to use another pair of copper if a pair is faulty.

As against the single-fiber, whenever the subscriber changes its physical operator (operator at the foot of building), the intervention of a technician at the bottom of the building is necessary.

Now, if you have the settings, you can make a small calculation:

cost of installation monofibre (1 fiber between the apartment and the building up) + cost interventions technicians building up over tens of years (the local loop fiber is supposed to last) = total cost single fiber
cost of installation multifibre (2 fibers between the apartment and the building up) = total cost multifibre

Optical or coaxial, what to choose? :

In the "entry level", ie in very affordable prices, an optical cable has a good chance to be more effective because it is insensitive to electromagnetic interference, in fact the optical link uses the light, however, this process requires more than an RCA coaxial connection, adding a digital converter / optical output of dvd player (internal), a converter and optical / digital input of the amplifier (internal) and these converters have a maximum speed of 6Mhz (minimum) for most, which is sufficient for digital sound samples 48kHz (ie a DVD classic) but enough for a sampling of 96 or 192 kHz (DVD -audio, HD-DVD ...) and sometimes poor quality of these converters can result in distortions of the digital signal containing the flow of DTS or Dolby Digital.
Also note that for a long link (over 10m), it is preferable to use a coaxial connection for the power of light (Toslink transmitter) in this case is too small for larger lengths.

The advantages of the optical link:
- Insensitive to electromagnetic waves
- No transfer of masses (galvanic isolation with opto-electronic elements)
- An optical cable quality is significantly less expensive than coaxial cable RCA quality.

The disadvantages of the optical link:
- Sensitive to dust
- Significant loss factor (hence our advice to limit this type of cable to a length of 10m max)
- Speed limited
- Double conversion necessary
- Somewhat fragile
- Connectors Optical often of poor quality equipment on the entry.

With an RCA coaxial shielded cable of very good quality (OFC copper conductors, Gold plated connectors ...), there is a good chance that the sound quality is better because in this case it does not convert the signal twice, and therefore there is no limitation in speed 6Mhz minimum

The advantages of coaxial RCA connection:
- Flow rate well above the optical link:> 100 Mhz, therefore compatible with high sampling rate (192kHz).
- No galvanic isolation between the player and the amp, so there may be mass transfers.
- Attenuation of signal rather low (around 3 to 30 dB per km).

The disadvantages of the RCA coaxial connection:
- Bounces waves for cables longer than 15m when the connector impedance is 50 Ohms (often the case) instead 75 Ohms.
- Cable quality expensive.

In conclusion?

The optical link is theoretically superior to the coaxial connection but the optical connectors are often of very poor quality, and throughput is limited by the digital / optical and optical / digital coaxial cable can achieve better results in the vast majority of cases, including links lengths over 10m.

Among the best brands of RCA coaxial cables can include Cable Positive (Optimum Libra), QED (QUNEX series), or Audioquest.

How the information is transmitted through a fiber optic cable?

Whatever type of cable is used, information is transmitted in the same way. Because the interior of the fiber optic cable is coated with a reflection, total internal reflection is present in the fiber optics. In order to provide information within the fiber optic, analog information must first be converted into digital signals. Once this information is converted, lasers can transmit digital signals in the form of pulses of light.
Because there is total internal reflection within the fiber optics, information that is transmitted in the form of light is able to constantly bounce off the reflective surfaces of the fiber. This is important because even when the fiber optic cable is defined by an area which requires that bend or twist, the total internal reflection allows the light to continue traveling through the cable to its final destination.

Types of fiber optic cable

There are two main types of fiber optic cable, which are single mode and multi-mode.


Single mode: Single mode fiber is a small component that has only one mode of transmission. Single mode fiber is able to transmit at high speeds over long distances because of their small base. Because only mode fiber optic cable allows for transmission distances longer and faster than the rate of transmission of multi-mode fiber, it costs more fibers that are multi-mode.

Multi-mode: The reason that multi-mode has a lower single-mode because it has a large diameter. As a result of the larger diameter, multi-mode is capable of generating broadband high speed when it moves to the amounts of medium distances. However, in long distances, the large diameter can cause problems because the multiple paths of light can cause different types of distortion.

FIBER OPTICAL WIRE COMMUNICATION

The discovery of the laser in 1960 has provided light sources suitable for the transmission and processing of information. Optical transmission has several advantages over radio transmission: speed (of light), high speed and a wider carrier frequency. It had one drawback: its price, but it becomes less and less true.


Operation of fiber: the preform (Bar glass 2 indices) is heated in a furnace, and stretched continuously by a cylinder which wraps around the fiber. Along the way, various systems adjust the speed of stretch and the oven temperature as a function of fiber diameter, measured by laser.



From 1960 to 1975, researchers, especially American, have worked to find a low attenuation. The single crystals, first approached, were abandoned in favor of glass, transparent material par excellence. The manufacturing techniques of fiber glass, and especially the research of high purity, were not without mentioning the manufacturing process of semiconductors. Therefore CNET (1) Lannion B, with his experience in semiconductors, decided to embark on the epic fiber.


20 Years of Progress

By applying the method to fibers called MCVD (Modified Chemical Vapor Deposition), obtained by CNET in 1975 silica fiber whose heart is enriched in germanium. The variation index between the glass heart and the sheath allows a reduced signal in the order of 5 decibels (2) per km for a laser wavelength of 0.85 m. Gradually improve the performance: in 80 years, the multimode beam, due to interference limitations, is replaced by a single. Currently, with a fiber laser and a 1.3 m or 1.5 m, the loss of signal strength is only 0.3 to 2 db / km, the wavelength chosen. This choice is based on the target application: for short distances at high speed information, use 1.3 m, where chromatic dispersion is the lowest, at the expense of a slightly more attenuation important. The other option is usually considered for international routes and especially the submarine links.


-> Booting the fiber.


A problem of connectivity

After some distance, the signal is very attenuated force: it has to be regenerated. So far, a device called a repeater transforming the optical signal into an electrical signal and amplify it back before the optical form. For the transatlantic TAT9, immerse it took a repeater every 50 km. A new system is currently under development: the optical amplifier. A laser is coupled to the fiber line, the signal passes through a fiber amplifier before reaching the fiber line. This system, returning a signal more faithfully than does the repeater, will link more than 500 km without connections.


The challenge of CNET

Optical fibers are material costs: about 1.20 francs per meter compared to 30 cents for copper. This hampers the development of optical transmission, despite its high speed performance and speed. To stand up to major Japanese and American, CNET strives to reduce production costs. Target: the fiber optic 40 cents per meter. For that, he worked closely with the company of Cables de Lyon. Stay tuned!



NOTES:

(1) CNET: Center National d'Etudes des Telecommunications.
(2) db = decibel is the optical equivalent decibel acoustics. It represents the signal attenuation, proportional to the ratio of the logarithmic power on the power recovered.

STEPS FOR INSTALLATION

It happens quite often to meet with individuals to install their own communications network in their house or apartment at rehabilitation or even when a building to which they are largely hand.

It is not so difficult to get started ... still need a few basics and roll their sleeves up.

The installation will take place in stages:

The VDI cables:

In a communication network, the infrastructure is designed in a star. That is to say that there is a cable that part of the table for each of the RJ45 sockets distributed throughout the dwelling. Thus there are so many cables that catch. The Voice Data Images cables are twisted pair cables covered most of the time one or more aluminum screens, all in a PVC sheath. Please allow for these cables in conduit diameter 20 mm or 22. Although measuring routes considering the appropriate passages (on average 15 to 20 m per connection in a home). Standardization ensures connections up to 50 m maximum. The cables should be marked and numbered at each end of the cable.

The installation of the table of communication:

Table of communication will be mounting against a wall or recessed in a form known as GTL (shafts Housing) where we find the electrical panel and platinum in particular EDF. It will bring to the table all the multimedia resources such as the arrival of the telephone line and internet, TV antenna, the access control system for example ... Each of these "resources" will own equipment to to connect and distribute on RJ45 sockets distribution. For example, a DTI and QFM for telephony and Internet, TV or Distributor coaxial splitter for the antenna .

The connection of RJ45 outlets communication:

We Connect the RJ45 communication on both sides of a connection, one at the table and the other in one of the housing. The RJ45 sockets to connect using a cable convention specific and standardized at the international level: EIA TIA 568 B. Just follow the instructions carefully when connecting the color codes are fundamental. It is imperative to have numbered each take in order to navigate and not waste time.

Commissioning:

The installation and validation, it should choose the place of its multimedia equipment in the house and connected by cords brewing facing each resource involved. Compliance with a color-coded by type of resource will allow for better visual reading of the installation in the table (red cords for the TV, computer blue, ivory for telephony, for its black, yellow for the doorman , green for other functions ...) The company provides Casanova, for the most courageous, a help in the design and costing and sales training free.

Conditions of installation of the Fiber Optics.

Decrees 2009-52 and 2009-54 for implementing the LME (Law of Modernization of the Economy) establish the conditions for installing the fiber optics.

Here are some selections not so trivial as this:

"Buildings must be equipped with electronic communication lines at very high speed optical fiber serving each dwelling. These lines connect each dwelling with at least one fiber per unit at a connection point in the building, accessible and providing access to several electronic communication networks. (...) Each dwelling is equipped with indoor installation such as to enable the service to each of the major "


Fiber optics will be the support of several networks such as television, telephony and the Internet by example and lead to an array of communication for dissemination of these services (high speed) throughout the house.
"Installation, maintenance, replacement and management where appropriate lines are at the expense of the operator signatory to the Convention. (...) The agreement authorizes the use by other operators of reception facilities for electronic communication lines installed by the signatory operator. "


The building will have an owner operator of the facility, signed an agreement with the landlord or the condominium, but the network should be shared open to other operators.


"The signatory operator serves the housing (...) by a continuous path from the optical fiber connection point and leading to a termination device installed within each dwelling. (...) The operator complies with the rules of the building, as well as standards and rules. "
The operator will make at its expense the work of building riser must respect the norms and rules of the art wiring. Fiber optics will reach an array of communication (brassable) and multimedia services are distributed within the housing by a star-wiring and sockets RJ45 communication.

Advantages of fiber optics over Copper

The optical fiber has advantages in compared to copper:
- The spread signal undergoes low relief and has no need to be frequently reamplified;
- You can perform data transmission to very high speeds (currently up to 160 Gbit/s laboratory);
- The signals are insensitive to electromagnetic perturbations ;
- It is possible to multiplex several spectrally data types on a single fiber, it transmits multiple channels, each with its own "Color" (or wavelength, or "lambda");
- The optical fiber cables are easier to handle, they can stand ups are important and lighter and more flexible than copper

Optical technology

Optical transmission technology which made its appearance in 70 years, spread over a
ten years in the networks represented in the form of optical fibers. In 2004, 55million km of fiber have been made by operators in the world, and this phenomenon continues each year. That is why there is an increased supply fiber Optical black at the expense of leased lines in most part of Europe. Optical technologies haveemerged through their capacity to carry data at high speed, their flexibility allocation of resources and the simplicity of their interfaces by over SDH technology (Synchronous Digital Hierarchy).






A dedicated fiber optic communications for long distance is a "bar" very fine (125 m) glass extremely pure, which gives the property to behave as a guide light on several hundreds of kilometers. Fiber, wrapped in a layer of plastic, is consisting of a core and a sheath of glass, of clues different environment. A phenomenon
total internal reflection allows the light to spread along the core of the fiber.

WDM technology

The majority of optical networks are currently based on spectral multiplexing WDM
(Wavelength Division Multiplexing), is injected in a same fiber signals dedicated to several applicationsor different users and it performs a correspondence between the colors of beams light and interfaces Client ends
optical links.
Each node in the network, it has the possibility to extract or insert at channel of choice.
Recommendations of the ITU (International Telecommunications) define very precisely the characteristics of channels to use, including their central wavelength and width of each beam.

Two main types of WDM exist:
- The CWDM (Coarse WDM) is used to multiplex simple and inexpensive way to eighteen
lambdas on access networks, or metropolitan on a spectrum ranging from 1270 to 1610 nm.
The spacing between each lambda is important (20 nm), the temperature of each laser is not controlled and the wavelengths plants can therefore suffer no significant deviations from about 6 or 7 nm.
The scope of such a system has limited the lack of function of re-amplification, 80 km at most.
- The DWDM (Dense WDM) is a solution to transport of several dozen high lambdas
flow over long distances, the spacing between lambdas can vary from 1.6 nm (200 GHz) to 0.1 nm (12.5 GHz).
An enslavement of laser temperature necessary to avoid any deviation of the lengths
wave.
The use of electronics and photonics accuracy that results justify the cost differences between CWDM and DWDM.

The DWDM channels are located on the C and L bands, it is known technically amplifier, distances transmission can reach several thousand km.

Conference OFC / NFOEC 2008

Conference OFC / NFOEC 2008, which focuses on optical communications (Optical Fiber Communication / National Fiber Optic Engineers Conference), held in San Diego, California at the end of February. This annual conference focuses on current U.S. transportation optical telecommunications, a sector which is highly holder, with the explosion of multimedia content on the Internet. Each year this conference is becoming increasingly international. In fact, traffic on the Internet constantly double every 16 months: daily trade in 9000 reaching peta-bytes (9 billion gigabytes) and should reach 21 000 peta-bytes in 2012.
The major theme of discussion in the previous edition focused on the adoption of 40Gigabit / s (Gbps), and in particular whether it should not work directly on the next generation (100Gbit / s). This year, the 40Gbit / s and 100Gbit / s have been assimilated into the same category and, despite the relatively slow for these components, they have been a major focus of this conference. The market for components for ultra high speed is estimated at $ 900 million for the year 2012, representing 10% of components for optical telecommunications.
Thus, many components to 40Gbit / s were presented at the exhibition (of high power lasers to modulators and demodulators via fleas specific treatments), and showed that the technology was mature and treated. Moreover, these transfers are already used in some deployments of FTTH (Fiber To The Home).
Another very popular technology on the show was the SFP + technology for new optical connectors. Smaller than its competitors and more recently standardized, this technology can increase the number of optical ports and card supports the new standards and 10Gbit / s in contrast to his predecessor (SFP).
Since the technology 40Gbit / s are developed, the main discussions focused on the development of technologies 100Gbit / s and beyond, and the specification of standards along with these innovations.
The conference was also a scientific meeting, several research papers were presented during those few days. So Alcatel-Lucent and its group of Bell Labs research showed how they had managed to develop a transmission reaches record 16.4 Terabit / s (16 400 Gbit / s), over 2 550 km using 164 channels to 100Gbit / s multiplexed and this sets a new speed record.
This demonstration, along with three other articles on Bell Labs circuits transmissions 100Gbit / s (on a receiver on a bipolar modulator and another modulator) showed that this new technology and Ethernet 100Gbit / s approaching commercialization.
This market is still developing and has gone bearer for the coming years with new innovations.

Multiplexing, modulation WDM, DWDM

In any transmission, it is interesting to move at the same time in the same conductor (here a single fiber) up communications companies, neither of which comes another scramble. They are therefore each carries a different wavelength is multiplexing.
Multiplexing and its inverse are given by Mux / Demux. The different wavelengths are generally assembled and separated by means of optical filters such as thin films (the most commonly prevalent).
A bit like on a combined technology "common rail" a new generation of diesel engines more efficient, combining the different modulation types for different types of fiber optic transmission, and it is possible to choose a type of modulation for the same material, or need to know the physical principle to use in the SI.

For information, here are some words:

WDM (Wavelength Division Multiplexing) (G.692): several trains of digital signals at the same speed of modulation, but each to a separate wavelength.

DWDM (Dense Wavelength Division Multiplexing) technology is known as dense WDM spacing when used between two wavelengths is equal to or less than 100 GHz. It works now for long-distance transmissions. In practice, this means that we put in a lot of fiber signals carried by frequencies very close to each other.

U-DWDM (Ultra - Dense Wavelength Division Multiplexing) allows up to 400 channels.

CWDM (Coarse Wavelength Division Multiplexing) only 8 to 16 channels, but a less expensive technology used in particular for local loops (MAN).

Protocols
Protocols transmitted over fiber optics include:

SONET / SDH
ATM
Ethernet,
ESCON,
FICON,
Fiber Channel.


CWDM
DWDM technology has relatively high costs.
• high performance fiber
• cooled lasers
• fine wavelengths very close to each other.

Technology CWDM (Coarse Wavelength Division Multiplexing) is a WDM economy. The channels are removed (coarse). In fact, according to its quality, we only have 8 or 16 channels per fiber. The material used, a moderate cost and use without constraints, allows for installation in the equipment end (local loops, business).

Advantages of fiber optics

The interest of this method of transmission through optical fiber, a priori exotic, are numerous:
signal loss over long distances much smaller than in an electric conductor in a metal
transmission speeds very high,
low weight per meter (this is important, both to reduce the weight exerted the complex installations in buildings to reduce the traction of long cables at their ends),
insensitivity to external interference (near a neon or a high-voltage cable, for example)
no heating (high frequency copper boiler, it must be cool to get high data rates).
A case of mode
Optical mode is the number of paths (for simplicity).
In a multimode fiber, light can take many paths (see diagram). In a fiber, it is trapped in a direct way. It retains speed and consistency. The fiber is a fiber better than multimode fiber, but requires the use of light sources (laser) very powerful.




Multimode fiber

Multimode fiber, or MMF (MultiMode Fiber) is mainly used in local area networks (a few hundred meters). Its diameter is relatively large (50 to 85 microns). It uses an LED to generate the signal.
The establishment of this type of transmission poses few problems and does not require expensive equipment or complex to implement.
We distinguish fibers low or step index (flow rate limited to 50 Mb / s) and fiber graded index (flow rate limited to 1 Gb / s).
See the file "Fiber optic local area network."
Singlemode optical fiber
The fiber or SMF (Single Mode Fiber) is used for metropolitan networks or long-distance operators. His heart is extremely thin (a few microns). The data transmission is ensured by lasers emitting wavelengths from 1300 to 1550 nanometers and optical amplifiers at regular intervals.
We can distinguish several categories of more efficient, both in speed that distance:
• G.652 - fiber dispersion shifted not the most common. It enables transmission to 2.5 Gbps maximum.
• G.653 - dispersion shifted fiber: for submarine cables.
• G.655 - fiber to non-zero dispersion (NZDF: Non Zero Dispersion Fiber): designed for applications such as WDM (Wavelength Division Multiplexing) amplified (see below).
• G.692 - more recent, it is compatible with DWDM multiplexing. It helps to support the high speeds over distances of 600 to 2000 km (submarine cables).
It should be noted that over the distance is, the less the flow may be high.

Principle of fiber optics

Overall, fiber is composed of :

Over a glass of very fine, the heart (a few microns), a single, sometimes very long (up to several hundreds of km)
a sheath that traps light in the heart reflecting virtually without loss (generally, a transparent envelope of a refractive index lower (some will remember their physics courses),
a protective sheath that can meet several tens to several hundreds of fibers,
a system of very specific connection (if not exposed to the light ends and not out).
The lifetime of such a driver is estimated to be at least 20 years.
The electrical signal to be transmitted, originally led by drivers metal is transformed into light signal with a transceiver. The transceiver uses an LED (Light Emitting Diode - Light Emitting Diode) or a laser to produce light.
For the reverse, to convert the light signal into an electrical signal, using a detector. Usually a photodiode.