In the seventies it became very fashionable to have a night light in the bedroom, consisting of a hemispherical stand and a bundle of waveguides sticking out of it. In the dark, this design emitted dim light in the form of small dots burning on the tips of thin translucent fibers. This really beautiful thing was made from the waste products of a new kind of informational conductors. Their name is optical cables (otherwise - FOCL, that is, fiber-optic communication lines).
FOCL working principle
Any electrical conductor has resistance, not only active, but also reactive (capacitive and inductive). These physical parameters depend on the diameter of the wire, its wave properties and, of course, the length of the line connecting the signal sender to the receiving device. High-frequency channels are especially sensitive to the resistive qualities of a communication channel. Fiber-optic cable is devoid of this drawback, the losses in it are incomparably smaller than in conventional conductors, because the information carrier is light energy. The principle of the channel is quite clear and simple. A signal converted from electrical to optical is fed to the input of the communication line. At the output, it is demodulated, and it enters the receiving-information device in the form of usual voltage pulses.
Fiber Channel Benefits
In addition to immunity to noise and attenuation, optical cables have other very significant advantages. When transmitting information via fiber channels, it is much easier to maintain its confidentiality, since it is almost impossible to secretly connect to them. Another plus of this transmission method is economic in nature. Copper is a non-ferrous and expensive metal; waveguide materials have a more affordable price. The optical cable is made from quartz or special polymer compositions (fluorine-aluminate or fluorine-zirconate), which are also (third advantage) much lighter than metal conductors, which also need to be shielded.
Disadvantages of Optical Communication
Yes, optical cables, like everything in this world, are not without flaws.
Firstly, to restore communication when the line is broken, it is necessary to replace the entire damaged area, waveguides are not subject to splicing, thus, repair work is seriously more expensive.
Secondly, installation work is also not cheap. For their implementation, precision equipment is necessary, but it is expensive. And the qualifications of specialists require considerable, but they need to pay accordingly.
Thirdly, the aforementioned signal converters at the input and output of the line, as well as the connectors (devices providing switching), have very high requirements for reliability, optical loss, accuracy. The fact that quality costs money does not need to be explained to anyone.
Connection of the future
Nevertheless, there are more advantages. Optical cables can transmit a broadband signal, which significantly increases the speed of information exchange (measured already in Terabits per second). In this case, the attenuation is extremely small (at a wavelength of 1.55 microns, it is only 0.22 dB / km). In addition, the ability of light waves to move in opposite directions (with different polarizations) in one conductor increases the possibilities of fiber optic links. Their improvement continues.