Optical fiber: gasket, manufacturing features and specifications
Russian communications corporations are increasingly implementing fiber-optic solutions. This applies, in particular, to the B2C segment, in which Internet access services are provided for Citizens who connect to the "optical fiber", have the opportunity to access the Internet at the highest speeds - tens of megabits. Previously, this speed was considered quite incredible. The introduction of fiber-optic technology can also significantly accelerate business processes, and therefore commercial enterprises become active users of relevant solutions. What are the specifics of fiber optic cables as a communication solution? How much is building the appropriate infrastructure?
The main advantages of fiber
Optical fiber as a technology has several advantages in comparison with traditional types of cables. Among those:
- resistance to interference, electromagnetic fields;
- higher throughput;
- small weight and ease of transportation;
- there is no need to ground the singal transmitter and receiver;
- no short circuits.
This type of cable is capable of transmitting a signal over very long distances. Optical fiber as a resource for the organization of wired communications was actively introduced in developed countries in the 70s. Now the level of penetration of relevant technologies in Russia is one of the most dynamic in Europe.
We now examine what the main types of fiber optic solutions are.
Optical fiber can be used to build a communications infrastructure:
- within telephone networks;
- as part of intrazonal communications;
- within the backbone networks.
Recently, fiber has also been used as a tool for data transmission at the end sections of subscriber lines. Some experts distinguish the corresponding cable types into a separate category.Previously, DSL solutions and an Ethernet twisted pair cable were usually used at such sites. For the modern market of providing Internet access, subscriber has a fiber optic modem - a common practice.
It can be noted that in the market of communication solutions there are also hybrid types of cables combining fiber and traditional materials.
Features of the practical implementation of fiber optic solutions
Trunk cables are used to transmit data over long distances. Designed for simultaneous connection of a large number of subscribers. Most often, building a similar infrastructure involves a single-mode optical fiber.
Intra-zone cables are mainly used to provide multi-channel communication at distances within 250 km. In their structure most often fibers are used, classified as gradient.
City cables are used to provide communication between PBXs and various communication nodes. Designed for data transmission within 10 km and the organization of broadcasting with a large number of channels. In urban fiber optic systems, as a rule, gradient fibers are also used.
Above, we noted that single-mode fiber is most often used in the infrastructure of trunk cables. What is its specificity and difference from the other - multimode?
Singlemode and multimode cables
The term "fashion" in this case is technical. It denotes the set of light rays that form a particular interference structure. Modes of the lowest order are characterized by directionality on the surface of the distribution at a large angle. Those in a single amount pass single-mode cables. In turn, a multimode optical fiber is characterized by a larger value of the light guide channel. This makes it possible to pass a large number of modes.
Advantages of single mode cables
The main advantage of single-mode cables is that the signal level in them is, as a rule, more stable, and the data transfer rate with the same resource volumes is higher. The relevant solutions also have disadvantages. In particular, single-mode cables require significantly more powerful, and hence expensive, radiation sources than those used with multimode fibers.
The benefits of multimode fiber
In turn, the cables of the second type, which are designed to transmit a large number of modes, are characterized primarily by less labor-intensive installation, since the size of the light guide channel in them is larger. Regarding the emitters above, we noted that for multimode wires they are usually cheaper. At the same time, fiber-optic solutions of this type are poorly adapted for use in backbone networks due to insufficient bandwidth.
Optical communication cables are simple. The basis of the corresponding elements is fibers made of light-conducting quartz glass. These components are enclosed in a protective shell. If necessary, the cable can be supplemented with other elements - in order to give the structure greater strength. Optical fiber has a cylindrical shape. It is designed to transmit signals with a wavelength of 0.85-1.6 microns.
Optical fiber has a two-layer construction. It has a core as well as a shell with different refractive characteristics. The first component is used to transmit electromagnetic signals.The shell is designed to protect the channel from external interference, as well as to provide optimal conditions for the reflection of the luminous flux. The core of the cable is made most often from quartz. The shell in some cases may be polymeric.
How is fiber fabricated?
Consider how industrial production of optical fiber.
Among the most common methods for the production of the relevant material is the deposition from the gas phase through a chemical reaction. This procedure is implemented in several stages. On the first one, a quartz billet is made, on the second - a fiber is formed from it. This process involves the use of the following substances: chlorinated silica, oxygen, pure silica. The considered fiber production method is characterized, first of all, by the ability to provide high chemical purity of the material. In some cases, the gradient fibers with target refractive characteristics are also formed at the factory. It is possible to ensure them by using various additives during the manufacture of optical fiber - titanium, phosphorus, germanium, boron.
So, we have studied the basic characteristics of optical fibers, and the characteristics of their manufacture. Let us now consider the variants of the structural implementation of the corresponding cables.
The parameters defining the features of the respective configurations depend on the specific application of the optical fiber. With all the variety of structural approaches there are 3 main categories of cables:
- concentric twist;
- with the core of a figured form;
- flat tape type.
Fiber optic cables of the first type have a structure that is generally similar to that of electrical cables. The number of fibers in such solutions is most often 7, 12, or 19. The second type of cables therefore have a core — usually plastic — in which the light-conducting channels are placed. Contains this type of optical cable 8 fibers, in some cases - 4, 6 or 10. Ribbon cables have in their structure, respectively, the tape, which contain a certain number of light guide channels. As a rule - 12, in some cases - 6 or 8. It can be noted that in some cases the indicator under consideration, which characterizes an optical cable, is 16 fibers.This characteristic can be predetermined by standards adopted in the country in which the fiber is manufactured.
The specifics of laying fiber optic cables
We now examine the main features that characterize the laying of optical fiber. Experts recommend to adhere to the following basic rules when solving the corresponding task:
- it is necessary to make sure that the cable radius is larger than the required minimum that is set for bending;
- Avoid using channels or trays with sharp edges;
- cables should be laid on a flat surface;
- if possible, do not connect cables at an angle of 90 degrees;
- Avoid twisting the wire.
The minimum bend radius is usually fixed in the technical characteristics of the cable provided by its manufacturer. Specialists during the installation recommend to adhere to the rule: optical fiber with a diameter of not more than 2 cm should not go beyond the minimum radius, if it does not exceed 30 cm.
Cable Management Tools
For the laying of the cables in question, will require a variety of tools.Among those - optical fiber cleaver. It is designed to prepare the appropriate materials for welding. Its essence is in the connection of the light-conducting elements of two different wires due to high-temperature processing. Welding optical fiber also requires the use of a special apparatus.
How much does fiber deployment cost?
Earlier there was a popular point of view that the installation of fiber optic cables is not very cost-effective due to the high cost of the light-conducting media themselves, as well as the work on their installation. Such a thesis was probably relevant at that period of market development, when there was not a sufficiently high demand for appropriate communications. Now, as we noted above, optical fiber is no longer a rarity for ordinary subscribers of urban networks.
But how much is the implementation of the solutions in question? Very much depends on the specific types of wires. Moreover, the price set by the manufacturer for a particular fiber (optical cable) is a very superficial measure of the costs associated with the implementation of the relevant infrastructure.It is very important to consider it in conjunction with the labor costs and other resource requirements that are required for laying the fiber-optic network. Thus, we will try to estimate how much appropriate solutions will be implemented with regard to total costs - not only for optical fiber, the price of which, as we noted above, can vary considerably, but also for attracting specialists for cable installation and purchasing other necessary infrastructure components. in question.
Above, we classified fiber-optic solutions based on criteria such as network scale. So, if we talk about trunk lines, then laying 1 km of optical fiber will cost about 100-150 thousand rubles. As for the functioning of the city communications center - the cost of solving this problem will be about 100 thousand rubles. Building a distribution infrastructure based on optical fiber for an individual district will cost approximately 150 thousand rubles. One communication center, designed to connect subscribers, will cost approximately 30 thousand rubles. In turn, the installation of equipment and cables for 100 subscriber lines will cost approximately 30 thousand rubles.
If the provider decides to provide equipment for its customers free of charge - in particular, fiber-optic modems, then each of the corresponding devices will cost about 1000 rubles. Note that, due to the continuing dependence of the RF communication market on fiber imports, the corresponding prices may vary in correlation with the ruble exchange rate.
Thus, in some cases, optical fiber may indeed require significant investments. However, as the number of subscribers increases, the corresponding investments will pay off. Many modern Russian providers are counting on this by modernizing traditional communication lines and introducing high-tech fiber-optic solutions.