A little theory


Conversion of electrical signals into optical signals by means of a transceiver Ethernet
The optical transceiver has as a function to convert electric impulses into optical signals conveyed in the middle of fiber. Inside both transceivers partners, the electrical signals will be translated into optical impulses by a LED and will be read by a phototransistor or a photodiode.
One uses a fiber for each direction of the transmission.
The transmitters used are of three types :
The LED Light-emitting diode which function in the visible red (850nM). It is what is used for the standard Ethernet FOIRL.
The diodes with infra-red which emit in the invisible one with 1300nM
Lasers, used for the monomode fiber, of which the wavelength is 1300 or 1550nM

Three types of fiberoptic

The step index fiber 200 ⁄ 380 consisted of a core and an optical sheath out of glass of various indexes of refraction. This fiber causes from the important section of the core, a great dispersion of the signals crossing it, which generates a deformation of the received signal.
The graded index fiber whose core consists of successive layers of glass having an index of close refraction. One approaches thus an equalization of the propagation times, which wants to say that one reduced nodal dispersion. Typical band-width 200-1500Mhz by km. It is this type of fiber which is used inside the buildings of the University (62.5 ⁄ 125) and between certain sites served by the postal and telecommunications authorities (50 ⁄ 125).
The monomode fiber whose core is so fine that the path of propagation of different the mode is practically direct. Nodal dispersion becomes almost null. The transmitted band-width is preque infinite (>10Ghz ⁄ km). This fiber is used primarily for the remote sites.
The small diameter of the core (10um) requires a great power of emission, therefore diodes with the laser which are relatively expensive.
Light propagation in the three types of fibers
The attenuation is constant whatever the Seule frequency luminous dispersion limits the busy bandwidth.
Constitution of a multimode fiberoptic
Light propagation in a step index fiber
The drawing above indicates how the reflection of the light signals according to their angle of emission occurs. What shows that the traversed path does not have the same length for all the radii. It is what one calls nodal dispersion.
Attenuation of the light according to the wavelength of the source
The attenuation of the light in fiber is function wavelength of the source. It is constant for all the frequencies of the transmitted useful signal. The drawing above shows that attenuation is more important in the red (850nM) that in the infra-red (1300-1550nM).

bar of glass to the cable multifibre

The images hereafter show how monomode fiber is manufactured. Each stage of manufacture is illustrated by a short filmed sequence.
The first stage consists of the assembly of a tube and a cylindrical bar of glass concentrically moved up. One heats the whole to ensure the homogeneity of the bar of glass.
A bar of glass a length of 1 m and a diameter of 10 cm makes it possible to obtain by stretching a monomode fiber approximately a 150 km length!
The bar thus obtained will vertically be installed in a tower located on the first floor and will be heated by slopes with gas. Glass will be stretched and to run in direction rez it to be rolled up on a reel.
One measures the thickness of the fiber (~10um) to control the speed of the engine of the roller, in order to ensure a constant diameter.

Then one will coat glass with a coating of protection (~230 um) and will assemble fibers to obtain the final cable with one or more strands.

connection of fiberoptic

There exists many connectors for fiberoptic. Most widespread are connectors ST and SC. For networks FDDI, one uses the connectors double MICS.
It is still necessary to quote connectors SMA (to be screwed) and connectors FCPC used for monomode fiber.
There are several manners to couple fiberoptic :
E coupling mechanical of two connectors put end to end by means of a part of precision. The drawing below watch union of two connectors ST, but there exist couplers ST ⁄ SC or ST ⁄ MIC.
Connection by Splicemécanique which is used for repairs following rupture or to connect a fiber and a connector already equipped with a few centimetres of fiber which one can acquire in the trade (Pig tail).
Fusion by means of an apparatus with called electric arc fusionneuse.

The advent



Fiberoptic for metropolitan area networks
The possibility of transporting light along fine glass fibers was exploited during first half of the XX ecentury. In 1927, Baird and Hansell tried to develop a device images of television using fibers. Hansell could make patent its invention, but it never was really used. A few years later, in 1930, Heinrich Lamm succeeds in transmitting the image of a filament of flashlight thanks to quartz a rudimentary fiber assembly. However, it was still difficult at that time to conceive that these glass fibers can find an application.
The first profitable application of fiberoptic took place to the beginning of the year 1950, when the flexible fibroscope was invented by van Heel and Hopkins. This apparatus allowed the transmission of an image along glass fibers. It was particularly used in endoscopy, to observe the interior of the human body, and to inspect weldings in engines of aircraft. Unfortunately, the transmission could not be made at a long distance being given the poor quality of fibers used. In 1957, the fibroscope (medical flexible endoscope) is invented by Basil Hirschowitz in the United States.
Telecommunications by fiberoptic remained impossible until the invention of the laser in 1960. The laser indeed made it possible to transmit a signal without losses at a long distance. In his publication of 1964, Charles Kao, Standard Laboratories Telecommunications, described a communication system with long distance and weak loss by making profitable the joint use of the laser and fiberoptic. A little later is in 1966, it showed in experiments, with the collaboration of Georges Hockman, who it was possible to transport of information at a long distance in the form of light thanks to fiberoptic. This experiment is often regarded as the first data transmission by fiberoptic.
However, the losses in this fiberoptic were such as the signal disappeared at the end of a few centimetres, not by loss of light, but because the various paths of reflection of the signal against the walls ended up making some lose the phase. That made it still not very advantageous compared to the traditional copper wire. The losses of phase driven by the use of a homogeneous glass fiber constituted the main obstacle with the current use of fiberoptic.
In 1970, three scientists of the company Corning Works Knell of New York, Robert Maurer, Peter Schultz and Donald Keck, produced first fiberoptic with sufficiently weak losses of phase to be used in the telecommunication networks (20 decibels per kilometer, today the conventional fiber displays losses of less than 0,25 decibel per kilometer for the wavelength 1550 Nm. used in telecommunications). Their fiberoptic was able to transport 65000 times more information than a simple copper cable, which corresponded to the report ⁄ ratio wavelengths used.
The first optical telephone communication system was installed with the downtown area of Chicago in 1977. In France, the DGT installed the first optical link in Paris between the telephone centres of Tileries and Philippe-Auguste. It is estimated that today more than 80% of the communications with long distance are transported along more than 25 million kilometers of cables with fiberoptics everywhere in the world.
The fiberoptic, in a first phase (1984 to 2000), was limited to the interconnection of the telephone centres, them-only requiring strong flows. However, with the fall of the costs driven by his mass production and needs increasing for the private individuals in very high banc, one considers since 2005 his arrival even at the private individuals

Principle of operation


The fiberoptic is a guide of wave which exploits the refracting properties of the light. It usually consists of a core surrounded by a sheath. The core of fiber has an index of refraction slightly higher (difference of some thousandth) that the sheath and can thus confine the light which is entirely considered multiple times at the interface between two materials (because of the phenomenon of total reflection interns). The unit is generally covered with a plastic sheath of protection.
When a luminous radius enters a fiberoptic to the one of its ends with an adequate angle, it undergoes multiple internal total reflections. This radius is propagated then until the other end of lossless fiberoptic, by borrowing a course in zigzag. The light propagation in fiber can be done with very few losses even when the fiber is curved.
A fiberoptic is often described according to two parameters:
the difference in standardized index, which gives a measurement of the jump of index between the core and the sheath : Δ = nc - ny ⁄ nc, where nc is the index of refraction of the core, and ng that of the sheath.
opening numerical of fiber (in numerical aperture), which is concretely the sine of the maximum angle of input of the light in fiber so that the light can be guided lossless, measured compared to the axis of fiber. The numerical opening is equal to sin θmax = √(n²c - n²g)

Principle of a fiberoptic with jump of index
There exist several types of fiberoptic. In step index fiber, the index of refraction changes brutally between the core and the sheath. In graded index fiber, this change of index is much more progressive. In fibers with photonic crystals, the variation of index between the various materials (in general silica and air) is much more important. Under these conditions, the physical properties of guidance differ appreciably from and gradient step index fibers of index.
In the field of optical telecommunications, the privileged material is silica very pure because it presents very weak optical losses. When the attenuation is not the principal selection criteria, one can also implement plastic fibers.
A fiberoptic cable contains several pairs of fibers in general, each fiber leading a signal in each direction. When a fiberoptic is not fed yet, one speaks about black fiberoptic.

System of transmission

Any system of transmission of information has a transmitter and a receiver. For an optical link, two fibers are necessary. One manages the emission, the other the reception. It is also possible to manage emission and reception on only one strand but this technology is more rarely used because the equipment of transmission is more expensive.
The optical transponder has as a function to convert electric impulses into optical signals conveyed in the middle of fiber. Inside the two transponders partners, the electrical signals are translated into optical impulses by a LED and are read by a phototransistor or a photodiode.
The transmitters used are of three types:
the LED light-emitting diode (or electroluminescent diode) which function in the visible red (850 Nm)
lasers, used for the monomode fiber, of which the wavelength is 1300 or 1550 Nm
the diodes with infra-red which emit in the infra-red with 1300 Nm.
The receivers are:
the photodiodes PINE, most used because they are inexpensive and simple to use with a satisfactory performance,
photodiodes with avalanche.
For all the optical types of detectors, the principle of operation is the same one: the photoelectric effect.
Between the two transponders, information is carried by a physical support (the fiber) called the data communication channel. During its course, the signal is attenuated and deformed: repeaters and amplifiers placed at regular intervals make it possible to preserve the authenticity of the message. In general, the modulation of the optical signal is a modulation of luminous intensity obtained by the modulation of the electrical signal in the diode or the laser.
The attenuation and the deformation of the signal are direct consequences length of the data communication channel. In order to preserve the optical signal of the source, the systems of optical communication use three types of amplifiers:
Regeneration
Regeneration-Reshaping
Regeneration-Reshaping-Retiming
There exist repeaters with optical amplification (using doped glasses with rare earths) or repeater-regenerators electronic. The current connections use mainly optical amplifiers with doped fibers erbium and are entirely optical at distances being able to go up to 10.000 km.
As in all the systems of transmission, one seeks to transmit in same fiberoptic a maximum of communications of different origins. In order not to scramble the messages, one conveys them over different wavelengths: it is the multiplexing in wavelength or WDM (Wavelenght Division Multiplexing). There exist several techniques of multiplexing each one adapted to the type of transmission on fiberoptic (transmission long distance or loops local for example): Dense WDM (many signals at very brought closer frequencies), ultra WDM (even more), Coarse WDM (less less expensive channels but)
From now on, one can carry out networks all-optics, that is to say which are not fiberoptic assemblies connected the ones to the others by electric nodes. The switches, the multiplexers, the amplifiers exist in version all-optics. It is currently a real stake because the speed of the transmissions on fiberoptic is such as the bottlenecks are from now on in the electronics of the nodes of the networks.

Silica fiberoptic

The first stage is the realization of a preform: bar of silica very pure, a diameter of several centimetres. There exists a great number of processes to conceive a preform, interns like method PCVD (plasma chemical vapor deposition), or external like method VAD (vapor axial deposition). The next paragraph describes the method MCVD (modified chemical vapor deposition, chemical plating in vapor phase modified) which is used.
A tube substrate is placed in horizontal rotation in a turn glass-maker. Gases are injected inside and will settle inside under the effect of the heat produced by a blowtorch. These gases will modify the properties of glass (for example aluminum makes it possible to increase the index). The layers deposited are then vitrified in the passing of the blowtorch. Then the tube is heated with high temperature, and will be closed again on itself to form the preform.
The operation of manchonnage makes it possible thereafter to add a layer of silica around the preform to obtain the ration core/sheath wanted for future fiber.
The ALCATEL company developed a proprietary technology APVD (Advanced Plasma and Vapor Deposition) to replace the operation of manchonnage which is very expensive. Process APVD (commonly called refill plasma) consists in dissolving very pure natural quartz grains on the primary preform using a blowtorch inductive plasma.
The association of process MCVD and the refill plasma for the monomode manufacture of fiberoptics was the publication object in 1994 by the ALCATEL company. The process concerned primarily consists in nourishing plasma in natural or synthetic silica grains with a fluorinated or chlorinated additional compound mixed with a carrying gas (French Patent n° 2.760.449, Campion Jean-Florent and Al). This process of purification constitutes the only profitable known alternative to the techniques of external deposit.
At the time of the second stage, the preform is placed in top of a tower of fiber drawing of about fifteen meters height. The end of the preform is then in a furnace brought up to a temperature close to 2000 °C. It is then transformed into a fiber of several hundred kilometers, at a speed about the kilometer per minute. The fiber is then covered with a protective resin double-layer (this layer can be deposited by the tower of fiber drawing, just after the stretching) before being rolled up on a reel. This layer is particularly important to avoid any moisture, because the fiber becomes breakable under the effect of water: hydrogen interacts with silica, and any weakness or microcomputer-notch is amplified.

Characteristics

The principal parameters which characterize fiberoptics used for the transmissions are the following:
Attenuation
Year Losses (dB ⁄ km) Wavelength (Nm) Company
1970 20   Corning Glass Work
1974 2 - 3 1060 ATT, Bell Labs
1976 0,47 1200 NTT,Fujikura
1979 0,20 1550 NTT
1986 0,154 1550 Sumitomo
2002 0,1484 1570 Sumitomo
The attenuation characterizes the attenuation of the signal during the propagation.
Are P0 and PL the powers at the entry and the exit of a fiber length L. the linear attenuation results then in an exponential decay of the power according to the length of fiber (Law of Beer-Lambert) : PL = P0e - Al where has is the linear attenuation coefficient. One often uses the coefficient adB expressed in dB ⁄ km and connected to by adB = 4,343a has.
The principal asset of fiberoptics is an extremely weak attenuation. The attenuation will vary according to the wavelength. The Rayleigh diffusion thus limits the performances in the field short lengths the wave (field of visible and the ultraviolet close relation). A peak of absorption, due to the presence of radicals - OH in silica, could also be observed around 1385 Nm. The most recent progress in the techniques of manufacture makes it possible to reduce this peak.
The silica fibers know a minimum of attenuation towards 1550 Nm. This wavelength of the infra-red close relation will thus be privileged for the optical communications. Nowadays, the control of the manufactoring processes makes it possible to usually reach an attenuation as weak as 0,2dB ⁄ km with 1550 Nm: after 100 km of propagation, there will thus remain still 1% of the power initially injected into fiber, which can be sufficient for a detection. If one wishes to transmit information on thousands of kilometers, it will be necessary to have recourse to a periodic reamplification of the signal, most generally via optical amplifiers which combine simplicity and reliability.
The signal will undergo additional losses with each connection between fibers, that it is by cross-pieces or by welding, this last technique reducing very strongly these losses.

Chromatic dispersion

Chromatic dispersion is expressed in PS (Nm·km) and characterizes the spreading out of the signal related to its spectral width (two different wavelengths are not propagated exactly at the same speed). This dispersion depends on the wavelength considered and results from the sum of two effects: dispersion specific to material, and the dispersion of the guide, related to the form of the profile of index. It is thus possible to minimize it by adapting the profile. For a silica fiber, the minimum of dispersion is towards 1300-1310 Nm.

Non-linear optics.

A data communication channel is known as nonlinear when its transfer function depends on the entry signal. The Kerr effect, the Raman diffusion and the Brillouin effect are the independent sources of nonlinearity in fiberoptics. Among the consequences of these non-linear effects, one can quote the automodulation of phase, mixtures with four waves intra- and inter-channel.

Modal dispersion of polarization (PMD)

The modal dispersion of polarization (PMD) is expressed in ps/km and characterizes the spreading out of the signal. This phenomenon is due to defects in the geometry of the fiberoptics which involve a difference in speed of group between the modes being propagated on various axes of polarization of fiber.

Monomode and multimode fibers


The fiberoptics can be classified in two categories according to the diameter of their core and the wavelength used: monomode and multimode fibers.

Multimode fibers

The multimode fibers (known as MF, for Multi Fiber Mode), were the first on the market. They have as characteristics to transport several modes (luminous ways). Because of modal dispersion, one notes a temporal spreading out of the signal proportional to the length of fiber. Consequently, they are used only for lower rates or short-hauls. Modal dispersion can however be minimized (with a given wavelength) by carrying out a gradient of index in the core of fiber. They are characterized by a diameter of core of several tens to several hundreds of micrometers (the cores into multimode are of 50 or 62,5 µm for lower rate). However the most recent fibers, of type OM3, make it possible to reach Gbit ⁄ s at distances about the km. The long distances can be covered only by monomode fiberoptics.

Fiberoptic flows and distances

Monomode fibers

For moreover long distances and ⁄ or moreover high bancs, one prefers to use monomode fibers (known as SMF, for Single Fiber Mode), which are technologically more advanced because finer. Their very fine core does not admit thus that a mode of propagation, most direct possible that is to say in the axis of fiber. The losses are thus tiny (less reflection on the interface core/sheath) than that is for very high flows and very long distances. The monomode fibers are of this fact adapted for the intercontinental lines (cables submarine). A monomode fiber does not have intermodal dispersion.
On the other hand, there exists another type of dispersion dispersion intramodale. Its origin is the finished width of the wave train of emission which implies that the wave is not strictly monochromatic: all the wavelengths are not propagated at the same speed in the guide what induces a widening of the impulse in fiberoptic. It is called also chromatic dispersion (cf higher chromatic Dispersion). These monomode fibers are characterized by a diameter of core of only some micrometers (the monomode core is of 9 µm for high banc).

Wavelength of cut and standardized frequency

The wavelength of cut is the wavelength C in lower part of which the fiber is not monomode any more. This parameter is connected to the standardized frequency, noted V, which depends on the wavelength in vacuum 0, of the radius of core has fiber and indices of the core nc and sheath ng.
V = (2πa√n²c - n²g0
A fiber is monomode for a standardized frequency V lower than 2.405. Abacuses provide the constant of standardized propagation, noted B, according to the frequency standardized for the first modes.
The standardized frequency gives a direct indication on the number of modes M which a multimode fiber can contain via the approximation opposite : M = V2 ⁄ 2.

Special fibers

It is possible to add certain characteristics with fibers:
the doped fibers contain rare earth ions
fibers with maintenance of polarization
photosensitive fibers.

Use for telecommunications

The fiberoptic thanks to the advantageous performances that it allows, is used more and more inside the telecommunication networks. With the boom of Internet and numerical exchanges its use spreads gradually until coming to the private individual.
Because of their need, the operators and the companies were the first fiberoptic purchasers. She is particularly appreciated in the soldiers for her insensitivity to the IEM (Interferences electromagnetic) but also for her lightness.
Should however be distinguished the multimode and monomode fibers. The multimode fibers are reserved for the data-processing networks at short-hauls (datacenter, companies and others) whereas the monomode fibers are installed for networks with very long distances. They are in particular used in the underwater cables which connect part of the continents. While arriving in the dwellings via network FTTH, fiberoptic brings a revolution in telecommunications directly to the private individuals.
At the base a fiberoptic is a guide-wave. It is thus the wave which is propagated in the fiberoptic which is modulated to contain information. The light signal is coded in variation of intensity. For the short-hauls, and an optics at low-cost, a simple LED can play the part of transmitting source while on high-speed networkings and with long distance, it is a laser which is preferably used.

Use in the data-processing networks

Historically, data-processing networks local or LAN, which made it possible to connect data-processing stations which until there could not communicate between them, were built with cables networks containing copper wires. The great disadvantage of these cables is that they are very sensitive to the electromagnetic interferences in any kind (elevators, high tension currents, transmitting,...). In mediums with strong concentration of waves, it thus became difficult to use this type of cables even by protecting them by a shielding. But especially, main drawback: the electrical signal that they transport attenuates very quickly. If one wants to connect two distant equipment would be this only of a few hundred meters (to connect two buildings between them for example), that becomes complicated because the signal almost perceptible any more once did not arrive at the other end of the cable.
Except particular cases dependant in particular on specific electromagnetic constraints, the lans (a few tens of meters) are generally carried out on copper. When the distance between two machines increases, it becomes interesting to use a fiberoptic. A fiberoptic can in particular connect two buildings, or constitute a link of a data-processing network local, regional, continental, or intercontinental.
The fiberoptic was very quickly introduced into the data-processing networks to mitigate the weak points of the copper cables. Indeed, the light which circulates there is not sensitive to the electromagnetic interferences and it attenuates much less quickly than the electrical signal transferred onto copper. One can thus easily connect distant equipment several hundreds of meters, even several kilometers. It remains effective in disturbed environments and this, with flows at least ten times superiors with the simple cables networks. Only disadvantage: its sometimes dissuasive price according to the selected type of fiber.

Types of fiberoptics



Multimode fiber used in a connection
In the data-processing networks, as with the pair of copper the fibers often go by two : the interface of a machine uses a fiber to send data and other fiber to receive some. However it is possible to carry out a bidirectional connection on only one fiberoptic.
Several types of fiberoptics are used today in the data-processing networks:
monomode or multimode,
with sizes of core and sheath variables. Most common : the 50 ⁄ 125, multimode fiber, has a core 50 microns in diameter for a sheath of 125 microns
with types of different connectors: ST (round section to screw), SC (square section clipsable), LLC (small square section clipsable), or MTRJ (small square section clipsable).

Optical amplification


The doped fibers are used to amplify a signal. One also finds them in the laser with fibers. The fibers with double-sheath are used more and more for the optical pumping of high power.

Sensors

Following research tasks in the Eighties, the fiberoptics can be used in the field of the sensors:
the gyrometer with fiberoptic is an instrument used by the ships, the submarines, the aircraft or the satellites to give the angular velocity. It contains fibers with maintenance of polarization
a network of Bragg registered in a fiberoptic can give information of constraint or temperature.

Field of lighting

As of the years 1970, the fiberoptic was used in decorative luminaries with variation of color. As from the years 1990, the fiberoptic is used to convey the light on a way of a few tens of centimetres since a source towards the object to be emphasized, making it possible to obtain specific and discrete lightings, being able to be elegantly integrated into a window of presentation, and offering the advantage of radiating very little infra-red, thus limiting the risk of rise in temperature inside the window, harmful to art works.

Diagram showing how FTTx architectures
vary according to the distance enters
the fiberoptic and the installation of the customer.
On the left the building of the operator or NRO.
On the right a residential building

FTTX

FTTx consists in bringing fiberoptic to more close to the user, in order to increase the quality of service (in particular flow) of which this one will be able to profit. One speaks also sometimes about FITL, for Fiber In The Loop (fiber in the loop, implication local).
Often, when one speaks about connection of the users to fiberoptic, it acts in the facts of a bringing together of the optical fiber network to the customer via a pair of copper (telecom operators) or of a coaxial cable (cable television operator).
The flow provided via a fiberoptic is independent of the distance, whereas the flow provided via the last meters (or hectometers) of copper depends on the length of the pair of copper (attenuation of the signal).
FTTN : Fiber to the district
FTTC : Fiber to the pavement
FTTN : Fiber to the distribution frame
FTTB : Fiber to the building
FTTCab : Fiber to the under-distribution frame
FTTP: Fiber to the buildings - companies
FTTH : Fiber to the residence
FTTO : Fiber to the office - companies
FTTLA : Fiber to the last amplifier

FTTN

Technology of deployment of the networks high-flow consisting in equipping the cupboards with the under-distribution frames (SR) of active equipment high-flow (DSLAM).
This technology is used by the majority of the world operators, when it is a question of improving the service road high-flow of existing networks. It has the following advantages and disadvantages:
Advantages:
Re-use the pair of copper of the last kilometer decreasing in a considerable way the quantity of civil engineering necessary.
It makes it possible to increase provided flow ADSL considerably, by reducing the length of the copper wire connecting the customer to fiber, while remaining within the limits of the ADSL2+
It allows a deployment of the networks much faster
The entire investment for the operator lies between 1/4 and 110 of the FTTH (because of civil engineering), if it re-uses existing copper. Indeed, civil engineering would account for 50% of investment FTTH by subscriber. The economy is inversely proportional to the population density.
Disadvantages:
The operating costs are higher, because mainly of the need for the electric connection of the SR (last technologies into 2008 make it possible to feed SR via the network telecom, making the FTTN much more competitive
The flow is limited more (between 10 and 20 Mbits for the ADSL2+ according to the distance from copper) that the FTTH. Prolongation in FTTH perhaps made in the second time according to the needs.
In France, the opening to the competition of SR is a precondition to the deployment of this technology. The Leroy amendment of the law of modernization of the economy liberalizes the market of the local subloop completely.
In France, 50% of the phone lines are limited to a flow lower than 5Mbits. This technology FTTC thus starts to be looked at seriously, taking into account the costs, and especially of the times of deployment of the FTTH announced by the 3 dominant operators.
As many one have good information over the lengths copper wires connecting the French hearths, as much one does not have reliable information on the distribution lengths of coppers to the SR, which would make it possible to consider the flows accessible on France, via deployments FTTC.
Another factor limiting the deployment of this technology is the cost of the subscription which is, in France, independent of the real flow provided to the customer (between 0,5 Mbits and 20 Mbits). The operators thus are little incited to improve the flow of the customers via the FTTC, whereas they hope to increase the price of the subscription via the FTTH.

Connecteurs

SMA
SMA cane métal
Fibers of 100 with 1500µm
naked, cabled, protected
Montage modulable
Fiber métal
One Shot
SMA Probes
Single use medical
Easy installation
SMA PowerShot
End coppers
Assembly power
Medical probes
Single use
Simplified assembly
SMA Puissance
Connecteurs modified of standard
SMA
Pour specific fibers of diamêtre of 100µm
à 1500µm
Montages pour
optimization injection of power
SMA Nova
Cane coppers
For fiber Silica/Silica of 200
with 1000µm of heart
Specific assemblies for
optimization injection of
power
SMA Supernova
Cane coppers
Radiator for high dissipation
thermics
For fiber Silica/Silica of 200
with 1000µm of heart
Specific assemblies for
optimization injection of strong
power
4Power
Standard connector Mitsubishi
Cane diameter 4mm
For fibers of diameter of 200µm
with 1000µm
Specific assemblies for
optimization strong injection
power
Nanoptic
Connection fiber to fiber
Compactness
Monomode fibers
Multimode fibers Gradient of Index
Immersed connection
Applications Hte T°
Canes
Ceramic canes
Canes polymer
Metal ends derived from
standard SMA
Needles
Microptic
Connections fiber to fiber
Multimode fibers Gradient of Index
Fibers in large heart of 100µm with
940µm
Connectors fibers HCS
For fiber HCS200, HCS400
SMA, ST, V-PIN
Assembly by fracture/setting
Severe Roboptic environment
Robotics applications
Severe environments and
dusty
ST
Centering and positioning of
fiber by ceramic cane or metal
Locking of connection by
bayonet
Angularly indexed cane
Great facility of assembly on site
SC
Monomode connectors or
multimode
Ceramic or polymeric cane
Conform to standard TIA/EIA 604
Exist in Duplex version
LLC
Miniature connector
Cane with a diameter 1,25 mm
Multimode or monomode
Simplex or duplex
FC
Connectors of utmost precision
Ceramic cane or metal
Body, nut metal
Locking by threading
For monomode or multimode fiber
Maintenance of Polarization
Monomode connectors FC or SC
Tunable version
FC High Reliability
FC high efficiencies
Qualification NASA
CATV
network Telecom
Equipements of test optique
Réseaux locaux
Les networks étendus
Traitement of the data Networks
   

Couplers

Couplers General information
Abrasion ⁄ joining
Fusion/drawing
Integrated optics
Monomode couplers
Fusion/drawing
Monomode standard or with
maintenance of polarization
Length D? wave 633,820,1310,
or 1550nm
Multimode couplers
Multimode couplers,
achromatic
1x2, 1x4, 1x8, 1x16
Balanced or unbalanced
Couplers short wavelengths
Of 633nm with 1060nm
Couplers fusion drawing
Couplers with lenses selfoc
Special couplers monomode
Couplers with maintenance of
polarization
Couplers of taking away TAP
   

Leak-tight penetrations

Leak-tight penetrations
Bulkhead unions
Interface FC, SMA or ST
Simplified leak-tight penetrations
Bulkhead unions
Version SMA
Version FC
Version ST
Leak-tight penetrations ATEX
Leak-tight penetrations for
use in atmospheres
explosives according to the Standard
European NFEN 60079-1
Version SMA or FC
Leak-tight penetrations HV and UHV
Version HV High Vacuum with
flange KF
Version UHV Ultra High Vacuum
with flange CF
Monomode or multimode fiber
Multifibre leak-tight penetrations
M16 version
M30 version
Multifibre: to 61 fibers
loose tube
50 naked fibers
   

Multiplexers

Monomode multiplexers
Monitoring OTDR
Certified Bellcore 1209
1550nm ⁄ 1625nm
1310nm + 1550nm/1625nm
Multimode multiplexers
Mono or bidirectional
800 with 900nm and 1200 with 1600nm
Fibers multimode

Collimators

Collimators, concentrators
Collimators with lenses selfoc
Collimators with lenses
traditional
Standard monomode fibers
special or GI
Beams gaussien
Maintaining of polarization
Adjustable focus
treatments VIS (375 Nm with 1.600 Nm)
In a generic way one calls collimator a component which will modify the angle of a beam to obtain at a distance specifies (focal distance) a given diameter. When the beam obtained is parallel, this collimating component will be called, when the beam is convergent one calls it concentrator. The Selfoc lenses are bars with gradient of index which one will position directly in contact with fiber, the focal point is then almost at this contact point. The length of this bar is adapted by very precise polishing to the wavelength of fiber. This polishing in skew optimizes the rate of reflection, but a treatment by deposit of anti-reflecting filter is proposed in option. The Selfoc lenses are with relatively short length of focal distance and the typical diameters of beams obtained are of 300µm with 400µm. They thus are generally reserved for fibers of small diameter, monomode or multimode with gradient of index.

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