Inside the schema, gifs, tables and a lot of interesting text.

You are ready?

Conditional classification

Unlike all of us familiar twisted pair, which, regardless of the place of use, has approximately the same design, fiber-optic communication cables can have significant differences based on the scope and place of installation.

The following main types of fiber-optic cables for data transmission can be distinguished based on the field of application:

• For laying inside buildings;
• for cable duct unarmored;
• armored for cable ducts;
• for laying in the ground;
• suspended self-supporting;
• with a cable;
• underwater.

The simplest design is possessed by cables for laying inside buildings and unarmored sewer cables, and the most complicated ones are for laying into the ground and underwater.

Indoor cable

Optical cables for laying inside buildings are divided into distribution cables, from which the network as a whole is formed, and subscriber cables, which are used directly for laying through the premises to the end user. Like twisted pair, optics are laid in cable trays, cable channels, and some brands can be extended along the outer facades of buildings. Typically, such a cable is wound up to the interfloor junction box or directly to the point of connection of the subscriber.

The construction of fiber optic cables for installation in buildings includes an optical fiber, a protective cover and a central strength element, for example, a bundle of aramid filaments. There are special requirements for optics installed in rooms with respect to fire safety, such as flame retardancy and low smoke emission, so they use polyurethane instead of polyethylene as a shell. Other requirements are low cable weight, flexibility and small size. For this reason, many models are lightweight, sometimes with additional moisture protection. Since the length of the optics inside buildings is usually small, the signal attenuation is insignificant and it does not affect the data transmission. The number of optical fibers in such cables does not exceed twelve.

There is also a kind of cross between a "bulldog and a rhinoceros" - a fiber-optic cable that contains, in addition, a twisted pair.

Unarmored sewer cable

Unarmored optics are used for laying in sewers, provided that they will not be exposed to external mechanical influences. Also, a similar cable is laid in tunnels, collectors and buildings. But even in cases of absence external influence on the cable in the sewer, it can be laid in protective polyethylene pipes, and installation is done either manually or using a special winch. Characteristic feature of this type fiber optic cable can be called the presence of a hydrophobic filler (compound), which guarantees the possibility of operation in sewage conditions and gives some protection from moisture.

Armored sewer cable

Armored fiber optic cables are used where high external loads, especially tensile stress, are present. Reservation can be different, tape or wire, the latter is subdivided into one- and two-line. Tape armored cables are used in less aggressive conditions, for example, when laying in cable ducts, pipes, tunnels, on bridges. Tape armor is a steel smooth or corrugated tube with a thickness of 0.15-0.25 mm. Shirring, provided that it is the only layer of cable protection, is preferred as it keeps rodents out of the fiber and generally increases the flexibility of the cable. For more severe operating conditions, such as burial or river bedding, wire-armored cables are used.

In-ground cable

For laying in the ground, optical cables with single-pivot or double-pivot wire armor are used. Reinforced cables with tape armor are also used, but much less often. The optical cable is laid in a trench or with the help of cable layers. This process is detailed in my second article on this topic, which provides examples of the most common types of cable layers. If the ambient temperature is below -10 ° C, the cable is preheated.

In wet soil conditions, a cable model is used, the fiber-optic part of which is enclosed in a sealed metal tube, and the armored wires are impregnated with a special water-repellent compound. Calculations immediately come into play: engineers working on cable laying should not allow tensile and compressive loads to be exceeded in excess of the permissible ones. V otherwise, immediately or over time, optical fibers can be damaged, rendering the cable unusable.

The armor also affects the value of the allowable tensile force. Fiber-optic cables with double-pivot armor can withstand forces from 80 kN, single-pivot cables - from 7 to 20 kN, and tape armor guarantees cable "survival" under a load of at least 2.7 kN.

Suspended self-supporting cable

Suspended self-supporting cables are mounted on existing poles of overhead communication lines and high-voltage transmission lines. It is technologically easier than laying a cable in the ground, but during installation there is a serious limitation - the ambient temperature during work should not be lower than - 15 ° C. Suspended self-supporting cables have a standard round shape, due to which wind loads on the structure are reduced, and the distance the span between the supports can reach one hundred or more meters. In the design of self-supporting suspended optical cables, there is always a CSE - a central power element made of fiberglass or aramid filaments. Thanks to the latter, the fiber-optic cable can withstand high longitudinal loads. Suspended self-supporting cables with aramid filaments are used in spans up to one kilometer... Another advantage of aramid threads, in addition to their strength and low weight, is that aramid is by its nature a dielectric, that is, cables made on its basis are safe, for example, in the event of a lightning strike.

Depending on the structure of the core, several types of overhead cable are distinguished:

• A cable with a profiled core - contains optical fibers or modules with these fibers - the cable is resistant to stretching and compression;
• Twisted module cable - contains optical fibers, loosely laid, the cable is resistant to stretching;
• Cable with one optical module - the core of this type of cable does not have power elements, since they are in the sheath. Such cables have the disadvantage of being difficult to identify fibers. However, they are smaller in diameter and more affordable.

Fiber optic cable

Fiber optic cable is a type of self-supporting cable that is also used for overhead installation. In such a product, the cable can be load-bearing and winding. There are also models in which the optics are built into the lightning protection wire.

Reinforcement of an optical cable with a cable (profiled core) is considered sufficient effective method... The cable itself is a steel wire enclosed in a separate sheath, which in turn is connected to the cable sheath. The free space between them is filled with a hydrophobic filler. Often this design of an optical cable with a cable is called "eight" because of the external resemblance, although personally I have associations with overfed "noodles". "Eights" are used for laying overhead communication lines with a span of no more than 50-70 meters. There are some restrictions in the operation of such cables, for example, the "eight" with steel cable cannot be hung on power lines. I hope there is no need to explain why.

But cables with a winding lightning protection cable (ground wire) are quietly mounted on high-voltage power lines, while being attached to the ground wire. Lightning cable is used in places where there is a risk of damage to the optics by wild animals or hunters. It can also be used on long-distance spans than the usual "eight".

Submarine optical cable

This type of optical cables stands aside from all the others, since they are laid in fundamentally different conditions. Almost all types of submarine cables, one way or another, are armored, and the degree of armoring already depends on the bottom topography and depth of occurrence.

There are the following main types of submarine cables (according to the type of reservation):

• Not armored;
• Single (one-shot) booking;
• Enhanced (one-shot) booking;
• Reinforced rocky (two-point) armor;

More than a year ago, I considered the construction of a submarine cable in detail in this article, so here I will give only brief information with a picture:

1. Polyethylene insulation.
2. Mylar coating.
3. Double pivot armoring with steel wire.
4. Aluminum waterproofing tube.
5. Polycarbonate.
6. Central copper or aluminum tube.
7. Intra-modular hydrophobic filler.
8. Optical fibers.

Paradoxically, there is no direct correlation between the cable armor and the burial depth, since the reinforcement does not protect the optics from high pressures at depth, but from activity marine life as well as nets, trawls and anchors for fishing vessels. This correlation is rather the opposite - the closer to the surface, the more alarms, which is clearly seen from the table below:

Table of types and characteristics of submarine cables depending on the laying depth

Production

Now that we have got acquainted with the most common types of fiber-optic cables, we can talk about the production process of this whole zoo. We all know about fiber-optic cables, many of us dealt with them personally (as subscribers and as installers), but as it becomes clear from the information above, fiber-optic cables, especially trunk cables, can seriously differ from what you dealt with in the room.

Since it takes thousands of kilometers of cable to lay a fiber-optic backbone, entire factories are engaged in their production.

Fiber Optic Manufacturing

It all starts with the production of the main element - the fiber optic filament. This miracle is produced in specialized enterprises. One of the technologies for the production of an optical fiber is its vertical drawing. And it happens as follows:

• At a height of several tens of meters in a special shaft, two tanks are installed: one with glass, the second, down the shaft, with a special polymer material of the primary coating.
• From a precision workpiece feed unit or, more simply, the first reservoir with liquid glass, the glass thread is drawn.
• Below, the filament passes through a fiber diameter sensor, which is responsible for monitoring the diameter of the product.
• After quality control, the thread is wrapped in a primary polymer coating from a second reservoir.
• After going through the coating procedure, the thread is sent to another oven, in which the polymer is fixed.
• The fiber thread is pulled for another N-meters, depending on the technology, it is cooled and fed to a precision winder, in other words, it is wound on a bobbin, which is already transported as a blank to the place of cable production.

The most common fiber optic cable sizes are:

• With 8.3 micron core and 125 micron sheath;
• With a 62.5 micron core and a 125 micron sheath;
• With 50 micron core and 125 micron sheath;
• With 100 micron core and 145 micron sheath.

Optics with a core diameter of 8.3 microns should be qualitatively soldered in field conditions, without high-precision equipment or the installation of hubs, it is not easy or almost impossible.

Great value has a control of the fiber diameter. It is this part of the installation that is responsible for one of the main parameters at all stages of thread production - the invariability of the diameter of the final product (standard - 125 microns). Due to the difficulties in welding filaments of any diameter, they tend to be made as long as possible. The linear footage of a fiber-optic "blank" on a reel can reach tens kilometers(yes, exactly kilometers) and more, depending on the customer's requirements.

Already at the enterprise itself, although this can be done at a glass factory, it all depends on the production cycle, for convenience, a colorless polymer-coated thread can be rewound onto another bobbin, dyeing it into its own in the process. bright color, by analogy with all the familiar twisted pair. What for? For the glory of sat .. for quick channel differentiation when, for example, repairing or welding a cable.

Making a cable

Now we have got the heart of our product - fiber optic filament. What's next? Next, let's look at the diagram of such an average underwater (yes, I like them the most) cable in the context:

At the plant, the resulting optical fibers are launched into machines, which together form a whole conveyor for the production of one type of cable. At the first stage of production of unarmored models, the threads are woven into bundles, which ultimately constitute the "optical core". The number of threads in a cable may vary, depending on the declared bandwidth. The bundles, in turn, are wound in a "rope" on special equipment, which, depending on its design and purpose. This equipment can also cover the resulting "cable" with a waterproofing material to prevent moisture ingress and tarnishing of optics in the future (in the diagram it is called "intra-module hydrophobic filler").

This is how the bundled bundles are twisted into a cable at the Perm fiber optic cable plant:

After the "tross" has been collected required amount fiber bundles, they are filled with polymer or laid in a metal or copper tube... Here, at first glance, it seems that there are no pitfalls and cannot be, but since the manufacturer seeks to minimize the number of joints and seams, everything turns out to be not entirely simple. Let's look at one specific example.

To create a tube-body, shown in the diagram above as a "central tube", a huge tape can be used from the material we need (steel, or copper). The tape is used so as not to toil with all the familiar and obvious rolling, and welding along the entire circumference of the joint. Agree, then the cable would have too many "weak" points in the design.

So that's it. The metal strip blank passes through a special machine that pulls it and has a dozen or two rollers that perfectly align it. Once the ribbon is aligned, it is fed to another machine where it meets our bundle of fiber optic filaments. The machine on the conveyor folds the tape around the stretched fiber, creating a perfectly shaped tube.

All this, still fragile, structure is pulled along the conveyor to a high-precision electric welding machine, which at high speed welds the edges of the tape, turning it into a monolithic tube, into which a fiber-optic cable is already laid. Depending on those. process, the whole thing can be filled with a hydrophobic filler. Or not to fill up, it all depends on the cable model.

In general, with the production, everything became more or less clear. Different brands of fiber optic, primarily trunk cable, may have some structural differences, for example, in the number of cores. Here the engineers did not invent a bicycle and simply combine several smaller cables into one large one, that is, such a trunk cable will have not one, but, for example, five tubes with fiber optic inside, which, in turn, are still filled with polyethylene insulation and, when necessary, are reinforced. These cables are called multi-module.

Sectional view of one of the multi-module cable models

Multimodal cables, which, for the most part, are used for long lines, have one more obligatory design feature in the form of a core, or as it is also called - a central power element. CSE is used as a "frame" around which tubes with fiber-optic cores are grouped.

By the way, the Perm plant "Inkab", the production process of which is shown on the gifs above, with its volumes of up to 4.5 thousand kilometers of cable per year is a dwarf, compared to the plant of the same infrastructure giant Alcatel, which can produce several thousand kilometers fiber optic cable in one piece, which is immediately loaded onto the cable-laying vessel.

The steel tube is the least radical optics armoring option. For non-aggressive operating and installation conditions, ordinary insulating polyethylene is often used. However, this does not negate the fact that after the manufacture of such a cable, it can be “wrapped” in an armouring winding made of aluminum or steel wire or cables.

Reservation of a PE-insulated cable at the same Perm plant

Output

As you can see from the material above, the main difference different types fiber-optic cable is their "winding", that is, that is, in which fragile glass strands are packed, depending on the field of application and the environment in which the cable will be laid.

If you liked this material, then you can safely ask questions in the comments, based on which I will try to prepare another article on this topic.

Thank you for the attention.

And a dozen years ago and at the end of 2013, the optical fiber produced by the industry is standardized and has many types and subtypes. The main types of OV are considered on the pages
Optical fiber types and standards
Optical fiber types

The most drastically different fibers multimode and singlemode.

The theory of transmission along them is discussed on the pages Modal propagation in fibers. The number of mods. Formula. Multimode stepped and stepped refractive index fibers

By outward appearance optical fibers are no different. That is, without the appropriate devices, it is impossible to figure out which fiber optic fell into your hands. The appearance, color, and some properties of optical fibers are given by a special coating. Several OB sizes are standardized.

250 microns the same glass covered with lacquered insulation. Varnish is usually used in different colors, and in addition to insulating properties, the color of the fiber determines its conditional number in the module. (Color counting of fibers, identification by color in optical cables). The lacquer finish provides additional resistance to bending. This fiber is similar to fishing line and can withstand bends with a radius of 5mm (see photo)

900 μm optical fiber in a buffer polymer coating. Used in making cords and connecting fiber optic crosses. The color of the coating often determines the type of fiber. (Color counting in fiber optic cables)

Optical fiber with varnish (125 microns) and polymer (900 microns) coating,
below the connector is closed with a cap (All photos)

Optical fiber and cable production

Most of the fiber is produced by Fujikura (Japan) and Corning (USA). But more and more technological lines appear, including in Russia, producing one or another type of optical fibers. Some of the steps and principles of this process are described on the pages
Fiber optic technology. Fiber optic preforms
Fiber extraction from preform

Further, the optical fiber on special drums is supplied to cable factories, where it is used in the production of optical cables. Since cables for fiber-optic communication lines differ in purpose and method of laying, they accordingly have a different number of armor covers and differ in profile.

Optical cable marking

There are many manufacturers of fiber optic cables in the CIS countries, and at the same time, each enterprise develops its own technical conditions(TU) for its products and labels it in its own way. Marking systems are different and the following pages are devoted to the analysis of this problem.
Fiber Optic Labeling and Assignment Handbook
Alphabetical List of Possible Fiber Optic Labels
Fiber optic labeling sorted by manufacturer

Laying of fiber-optic communication lines (FOCL)

FOCLs are laid along overhead power lines, in the ground, cable ducts, along the walls of buildings and indoors. The following official documents are devoted to the laying of fiber-optic cables over overhead power lines:
Rules for the design, construction and operation of fiber-optic communication lines on overhead power lines with a voltage of 0.4-35 kV
Rules for the design, construction and operation of fiber-optic communication lines on overhead power lines with a voltage of 110 kV and above

Other types of laying almost do not differ from the methods of laying cables with metal conductors and their features are described on the page from the "SLSMSS Manual": Features of laying optical cables

Installation of couplings and terminal devices for fiber-optic communication lines

Enlarge photo

Fiber optic cables are similar in appearance to conventional cables. All the complexity of "optics" is precisely in the connection of optical fibers with each other. It will not be possible to connect them "on the knee"; for any type of connection of an optical fiber, specialized tools and devices are required. The pages
FOCL terminal devices. Connectors
Fiber optic attenuators for FOCL
Fiber optic cleaver. Gel connectors for FOCL
Welding of optical fiber FOCL. Types of welding machines
Description of installation of fiber optic couplings and optical crosses

In the next photo, optical fibers are stacked in a fiber optic splice cassette.

Fiber optic in cassette coupling (Enlarge photo)

Fiber measurements

Measurements of optical fibers are made before installation (control of drums with cable), during the installation of fiber-optic couplings and crosses, and during the FOCL process. C measurements are made by two types of instruments: measurement with fiber optic testers and optical reflectometers (OTDR). RH measurements are devoted to the pages
Types of FOCL measurements. Fiber measurements
Measurements of fiber-optic cable (FOCL) during installation

This topic is discussed in even more detail on the pages of the book Hardwood Reflectometry of optical fibers.
Loss measurement with optical testers
How the OTDR works
OTDR assignment

Aging of fiber optic (optical) cables

FOCL documentation

Installation of fiber optic couplings and crosses, as well as all measurements of optical cables must be documented in the appropriate protocols and passports. Below are links to the official rules and guidelines for building communications links.
Protocol for measuring the attenuation of optical fibers of face-to-face length, serial number "n" before laying (incoming control)

Buy fiber-optic cable from Layta at an attractive price.
For the convenience of customers, the description of the equipment is provided with reviews from other buyers, characteristics, certificates, instructions, passports, photographs, and accessories.
You can buy a fiber-optic cable both through the website and by phone.
If you have any questions about the choice, delivery or warranty, then you can always consult with specialists by phone.
Delivery is made to Moscow, St. Petersburg, Kazan, Saratov, Rostov, Krasnodar, Stavropol, Yekaterinburg, Novosibirsk, Voronezh, Volgograd and other cities of Russia

It's hard to imagine security system without wires and cables. Their variety, variations and performance are very diverse, which is why it is not so easy to choose a high-quality fiber-optic cable. Variety of models and technical characteristics allows you to create unique security systems, however, in order to buy a fiber-optic cable, you need to understand its features and understand what it is.

Fiber optic cable Is a cable consisting of fiber-type light guides and used as an optical signal transmitter. A feature of this cable option is the ability to transmit a signal over a decent distance without loss of image quality, therefore, fiber-optic cables are perfect for video surveillance systems in places with large areas and increased remoteness of cameras from the control center. Also, the fiber-optic cable is characterized by increased resistance to interference: even with a long cable length, the signal goes with minimal interference.

The scope of fiber-optic cable is so wide that it can rightfully be called the leader among analogs. This type of cable is widely used in almost all areas: from standard computer networks to intercontinental lines. This widespread popularity of the product is due to its superior performance.

Manufacturers today offer great amount modifications and variations of fiber-optic cables, depending on the purpose of their use. When you are going to buy a fiber-optic cable, decide on the scope of its application: temperature differences, location inside a building or on the street, maximum loads, interaction with environment etc.
Fiber optic cable models are used even under extreme conditions - special purpose fiber optic cable is designed for non-standard option applications: underground or water, as well as in areas with increased risks. The main difference between fiber-optic cables lies in the sheath, thanks to which the products can easily cope with their tasks, even in non-standard conditions.

Despite the high cost of fiber optic cable (this is due to the high price of fiber optic) and its fragility, the presence of a number of positive qualities made it almost irreplaceable. Fiber optic models transmit high quality signal, reduced attenuation and high data rates. All these advantages allow you to achieve the clearest picture required to create a high-quality and efficient video surveillance system.

At Light's company you can always buy a fiber-optic cable at favorable terms and at an attractive price. Competent specialists will select the right model for you that meets all standards and requirements. Having decided on the model and type of cable, special attention should be paid to its installation. Properly selected and installed equipment is guaranteed to provide you with reliable operation for years to come.

Fiber optic communication lines (FOCL) firmly hold their positions and develop intensively thanks to the distribution optical cable as the main transport for the transmission of information.
There are several prerequisites for this:

• firstly, the optical cable has a very low signal attenuation, a large bandwidth, a high degree of noise immunity (immunity to electromagnetic interference), low weight and volume, long term operation, galvanic isolation of equipment and other advantages in comparison with copper cable
• secondly, fiber optic cables are becoming cheaper than copper cables every day.

Fiber-optic communication cable is made on the basis of optical fiber. Optical fiber is an optical dielectric waveguide designed to transmit broadband optical signals over long distances. Optical fibers can be classified into two types: multimode and singlemode.

Single mode fiber (SMF, Single Mode Fiber) used in telephony, for the manufacture of television cables and the creation of information networks.

Multimode Fiber (MMF, Multi Mode Fiber) it is mainly used to transfer information and in local networks.

Structurally these fibers primarily differ in the ratios of the diameters of the core and the fiber itself: standard core diameters of multimode fibers - 50 and 62.5 µm, single-mode fiber in the range of 5 - 10 µm.

The diameter of the silica cladding of the fiber is also standardized and amounts to 125 µm.

To standardize the characteristics of optical fibers, the International Telecommunication Union (ITU) has developed and adopted a number of Recommendations (G651, G652, G653, G654, G655, G656, G 657). These guidelines describe the geometric, optical and mechanical parameters that modern optical fibers must satisfy.

When choosing an optical cable, it is necessary to take into account the main parameters: the type of fiber and its size, the maximum attenuation depending on the wavelength of the light wave, the minimum bandwidth, chromatic dispersion, as well as great importance also have mechanical characteristics: resistance to static and dynamic tensile forces, bending, axial twisting, crushing forces, impacts, etc.

In this section we are pleased to offer you a wide range of products:

we also offer cable accessories:

• , and
• Other elements of cable accessories

In our store you can choose and buy an optical cable of both single-module and multi-module design, with a removed load-bearing element, and self-supporting.

Hot selling - cables of the type - lightweight and inexpensive cables, single-module construction, steel wire as bearing element is a great solution for the last mile. Also a great offer for indoor cables. Special attention should be given to self-supporting fully dielectric cables ( ), a wide range of fibers with different fibers up to 144 fibers , as well as for each type of cable are selected mounts made specifically for this type of cable.

In chapter Cable fastenersYou can find everything you need to install an optical cable -

In the modern world, it is necessary to transmit information efficiently and quickly. Today there is no more perfect and effective way data transmission than fiber optic cable. If someone thinks that this is a unique development, then he is deeply mistaken. The first optical fibers appeared at the end of the last century, and work is still underway to develop this technology.

Today we already have a transmission material that is unique in its properties. Its use has gained widespread popularity. Information is of great importance in our time. With the help of it, we communicate, develop the economy and everyday life. In this case, the speed of information transfer must be high in order to provide the required rate modern life... Therefore, now many Internet providers are introducing fiber optic cable.

This type of conductor is intended only for the transmission of a pulse of light that carries part of the information. Therefore, it is used to transfer informative data, and not to connect power. Fiber optic cable makes it possible to increase the speed several times, in comparison with metal wires. During operation, it has no side effects, deterioration of quality at a distance, overheating of the wire. The advantage of a cable based on optical fibers is the impossibility of influencing the transmitted signal, therefore it does not need a screen, stray currents do not act on it.

Classification

Fiber optic cable is very different from twisted pair, based on the area of ​​application and installation location. There are the main types of cables based on optical fiber:

• For internal installation.
• Installation in cable ducts, without armor.
• Installation in cable ducts, armored.
• Laying in the ground.
• Suspended without a cable.
• Suspended, with a cable.
• For underwater installation.

Device

The simplest device has a fiber-optic cable for indoor installation, as well as a conventional cable without armor. Most complex construction for cables for underwater installation and for installation in the ground.

Indoor cable

Internal cables are divided into subscriber cables for laying to the consumer, and distribution cables to create a network. Optics are carried out in cable channels, trays. Some varieties are laid along the facade of the building to the distribution box, or to the subscriber himself.

Indoor fiber optic device is composed of optical fiber, special protective coating, power elements, for example, a cable. Fire safety requirements are imposed on the cable laid inside buildings: resistance to combustion, low smoke emission. The cable sheath material is polyurethane, not polyethylene. The cable should be lightweight, thin and flexible. Many fiber optic cable designs are lightweight and waterproof.

Indoors, the cable is usually laid over short distances, so there is no question of signal attenuation and the effect on the transmission of information. In such cables, the number of optical fibers is no more than twelve. There are also hybrid fiber optic cables with twisted pair cables.

Unarmored cable for cable ducts

Optics without armor are used for installation in cable ducts, provided that there are no mechanical influences from the outside. This version of the cable is used for tunnels and collectors of houses. It is laid in polyethylene pipes, manually or with a special winch. A feature of this cable design is the presence of a hydrophobic filler that guarantees normal operation in the cable duct and protects against moisture.

Armored cable for cable ducts

Armored fiber optic cable is used when external stresses, such as tensile stress, are present. The armor is done in different ways. Armor in the form of a tape is used if there is no effect of aggressive substances, in tunnels, etc. The armor structure consists of steel pipe(corrugated or smooth), with a wall thickness of 0.25 mm. Corrugation is performed when it is one layer of cable protection. It protects the optical fiber from rodents and increases the flexibility of the cable. Under conditions with great risk damage use wire armor, for example, at the bottom of a river, or in the ground.

In-ground cable

For installation of the cable in the ground, fiber optic with wire armor is used. Reinforced tape armored cables can also be used, but they have not found widespread use. A cable-laying machine is used to lay the fiber into the ground. If installation in the ground is carried out in cold weather at temperatures less than -10 degrees, then the cable is heated in advance.

For wet ground use a cable with sealed optical fiber in a metal tube, and wire armor is impregnated with a water-repellent compound. Experts make calculations for cable laying. They determine the allowable stretching, compressive loads, etc. Otherwise, after a certain time, the optical fibers will be damaged and the cable will become unusable.

The armor has an effect on the amount of permissible tensile load. Fiber optic with wire armor can withstand loads up to 80 kN, with tape armor the load can be no more than 2.7 kN.

Suspended fiber optic cable without armor

Such cables are installed on poles of communication and power lines. This makes installation easier and more convenient than into the ground. At the same time, there is an important limitation - during installation, the temperature should not fall below -15 degrees. The cross-section of the cable is round. This reduces the wind load on the cable. The distance between the supports should be no more than 100 meters. The structure has a load-bearing element in the form of fiberglass.

Thanks to the power element, the cable can withstand heavy loads directed along it. Power elements in the form of aramid threads are used at distances between posts up to 1000 meters. The advantage of aramid threads, in addition to low weight and strength, are the dielectric properties of aramid. If lightning strikes the cable, there will be no damage.

The cores of overhead cables are divided according to their type into:

• Profile-core cable, fiber optic resistant to crush and stretch.
• The cable with twisted modules, the optical fibers are freely laid, there is resistance to stretching.
• With an optical module, the core contains nothing other than fiber. The disadvantage of this design is that it is inconvenient to identify the fibers. The advantage is small diameter, low cost.

Fiber optic cable with rope

Tether fiber is self-supporting. Such cables are used for laying through the air. The rope can be load-bearing or winding. There are cable models in which the optical fiber is located inside the lightning protection wire. The cable, reinforced with a profile core, has sufficient efficiency. The cable consists of a sheathed steel wire. This jacket is connected to the cable braid. The free volume is filled with a hydrophobic substance. Such cables are laid with the distance between the poles not exceeding 70 meters. The limitation of the cable is the impossibility of laying on the power line.

Cables with a wire rope for lightning protection are installed on high-voltage lines with fixing to ground. Rope cable is used when there is a risk of damage by animals, or over long distances.

Underwater fiber optic cable

This type of fiber is isolated from the rest, because it is laid under special conditions. All submarine cables have armor, the design of which depends on the depth of installation and the bottom topography of the reservoir.

Some types of submarine fiber for the execution of armor with:

• Single armor.
• Reinforced armor.
• Reinforced double armor.
• No armor.

1 ›Polyethylene insulation.
2 ›Mylar coating.
3 ›Double wire armor.
4 ›Aluminum waterproofing.
5 ›Polycarbonate.
6 ›Center tube.
7 ›The filler is hydrophobic.
8 ›Fiber optic.

The size of the armor does not depend on the depth of the gasket. Reinforcement protects the cable only from the inhabitants of the reservoir, anchors, ships.

Fiber Optic Welding

Used for welding welding machine special type. It contains a microscope, clamps for fixing fibers, arc welding, a heat shrink chamber for heating the sleeves, a microprocessor for control and monitoring.

Brief technical process of fiber optic welding:

• Removing the shell with a stripper.
• Preparation for welding. Sleeves are put on the ends. The ends of the fibers are degreased with alcohol. The end of the fiber is cleaved with a special device at a certain angle. The fibers are packed into the apparatus.
• Welding. The fibers are aligned. At automatic control the position of the fibers is automatically set. After confirmation by the welder, the fibers are welded by the machine. With manual control, all operations are carried out manually by a specialist. When splicing, the fibers melt with an arc electric current are combined. Then the place to be welded is warmed up to avoid internal stresses.
• Quality checking. The welding machine analyzes the picture of the welding place using a microscope, determines the assessment of the work. An accurate result is obtained with an OTDR, which detects discontinuities and attenuation in the weld line.
• Processing and protection of the welded place. The put on sleeve is shifted for welding and put into the heat-shrink oven for one minute. After that, the sleeve cools down, lays down in the protective plate of the coupling, and a spare optical fiber is applied.

Fiber Optic Advantages

The main advantage of optical fiber is the increased speed of information transmission, there is practically no signal attenuation (very low), as well as the safety of data transmission.

• It is impossible to connect to the optical line without authorization. Any connection to the network will damage the optical fibers.
• Electrical safety. It increases the popularity and application of such cables. They are more and more used in industry when there is a danger of explosions in production.
• It has good protection from interference natural origin, electrical equipment, etc.