Today we are going to talk about not very well known, but widely used fiber-optic connections. Another way to refer to them is as FOCLs or fiber-optic communication lines. Quite a long name, so in general circles more often used a simple abbreviation as “optics” or “fiber”. In fact, it’s not quite the same thing, but first things first.
Fibre optics are specialized communication lines, which transmit information by means of a beam of light in a certain coding. This technology is primarily used for data transmission in local and global networks for quite a long distance. But it is also used in the military industry, medicine and other non-networked areas.
How it works
And so we have already figured out what fiber-optic networks are, but how do they transmit information? Fiber optics is used in such networks. It consists of a central core and is small in size. The core is usually made, as you have probably already guessed, of glass. It is the core that is used to transmit the data with a beam of light.
But immediately the question arises – how to increase the transmission over a longer distance? To do this, the second layer of glass is used, which envelopes the central core and reflects light during the transmission of information. Earlier it was thought to use mirrors or similar mirror surfaces as a reflection – but as it turned out, such material would be very expensive.
Have you ever been to the sea or a lake at sunset. Remember how the light from the sun reflected off the water at a great angle. Although as you probably know, water is clear. But as the angle and density between the two materials increases – light begins to be reflected from different media.
This is exactly the technology that is used in fiber optic communication. The core and the outer shell have different densities and structures, which causes the beam of light to be reflected much farther away. A semiconductor or diode laser is used to transmit and reproduce light.
If we dip into history, the first works that laid the foundation for “optics” was the research of Daniel Colladon and Jacques Babinett. They primarily studied the possibilities of light refraction. But more precisely, the progenitor was Clarence Hasnell – he was the first to use light to transmit images through special tubes.
Different from twisted pair
If you go back to the 2000s, you may recall that back then the only thing used was aDLS-type Internet. There was nothing suitable to transmit information from computer to computer.
That’s when the idea of using old telephone wires came up. Let me remind you that these are just two ordinary wires with no braid and no extra protection. As a result the Internet was available, but at a very low speed. Also, many people complained about lags, interruptions, constantly dropping out of the Internet.
All of these problems were related precisely to the way of data transfer. It was very difficult to transmit data over two unbraided wires – since many packets were lost or changed as a result of electromagnetic interference. Telephone lines were replaced by twisted pair.
Twisted pairs are twisted pairs of wires in one outer braid. Most often twisted pair with 4 pairs (8 wires) is used. This type of communication is already much more reliable than telephone cable. As protection against radio waves a simple thing was invented – namely twisting.
One pair carries the same information. When the wire is twisted, it constantly changes its position. As a result, the first wire is on the outside and takes all the shock of the environment. The second wire hides behind it. So transmitted, the information across the pair of wires at the end adds up. As a result, interference is also subtracted.
The speed has increased several times. But there was a problem of rapid signal attenuation. Such wires can beat up to 100 meters, no further. And as the speed increased, the range would also drop.
That’s where fiber optic communications came in. The speed has increased even more, but the range of sending a packet has also increased. If before you had to install repeaters every 100 meters, then the transmission range with the help of “optics” has increased by several kilometers.
But the most interesting thing is that fiber-optic communication is almost completely protected from electromagnetic interference. Also, such wires are almost immune to temperature fluctuations and can work in both extreme heat and in the wild cold.
The transmission frequency with light is higher so the minimum speed starts at 1 Gbit per second. With twisted pair transmission, when all pairs are involved, the speed will be 1 Gbit per second. But the wire will be very expensive, because to achieve such a result it is necessary to protect each wire with a “screen” from the external environment.
Among the disadvantages of FOCL can be attributed only to the complexity of installation and welding. This requires special equipment and knowledge. When “welding” or otherwise connecting two optical cables – you need to achieve a perfect connection between the central cores and the outer glass. Otherwise the light will be attenuated in this area or the refractive index will not be correct.
Data transmission in networks
Everything happens in a similar way. Initially, the sending device encodes the information in the form of packets. Next, the data is converted into a format that can be transmitted by light over the FOCL. The information is then sent over the communication lines. Almost instantly, it reaches the receiver. It is left to him to translate the data into a format understandable to a computer, switch, router or other network equipment.
Today there are fiber optic networks in almost all cities. The houses are connected directly via “optics. The cable goes to a central switch. Then from there, twisted pair wires go to each house. Now some providers have started to connect customers via fiber optics. That is, instead of the same twisted pair, “glass” is used.
The speed of such connections is higher. At the same time the quality of communication and the Internet grows. Due to the higher reliability – the response value is lower and there are less lags. But here you need to take into account that to connect such a cable you need special routers.