Fiber Optics, what it is and how it works
Fiber optic is interesting because it takes a very old concept that is the manipulation of light, it is nothing more than that, the controlled manipulation of light. If we go back to history, the Egyptians themselves controlled the light by means of mirrors to illuminate inside the incredible pyramids ... Precursors of the optical fiber?
Today the manipulation of the light is controlled within a cable, with special terminations and special plates that make the transmission possible and that I will detail throughout this humble note.
Structure of an optical fiber. To see in detail how optical fiber is composed, we will understand its advantages and disadvantages, and also, we will have a global vision of this medium. This example is about a cable composed of many parts, we must understand that there are many types of cables that adapt to different occasions (interior, exterior, etc.) but I took this as a reference because you can see in detail what elements may contain a cable. This will serve them because commonly in the catalogs of fiber optic cables, they specify that they are composed, cable internet companies
Structure of an optical fiber
1- Dielectric central element: this central element that is not available in all types of optical fiber, is a filament that does not conduct electricity (dielectric), which helps the consistency of the cable among other things.
2 - Moisture drainage thread: its purpose is that moisture comes out through it, leaving the rest of the filaments free of moisture.
3- Fibers: this is the most important part of the cable, since it is the medium through which the information is transmitted. It can be silicon (glass) or highly processed plastic. Here the physical phenomena of reflection and refraction occur. The purity of this material is what makes the difference to know if it is good to transmit or not. A simple impurity can divert the beam of light, causing it to be lost or not reach its destination. As regards the manufacturing process, it is very interesting and there are many videos and material in the network, but basically the threads (microns in width) are obtained by exposing glass tubes to extreme heat and by means of the dripping that occurs when melting. They get each one of them.
4- Loose Buffers: it is a small tube that covers the fiber and sometimes contains a gel that serves the same purpose, also making a dark layer so that light rays do not spread out of the fiber.
5- Mylar tape: it is a thin polyester layer that was used many years ago to transmit programs to PC, but in this case it only fulfills the role of insulation.
6- Flame barrier: is a cover that serves to protect the cable from heat and flame.
7- Kevlar synthetic yarns: these yarns help a lot in the consistency and protection of the cable, taking into account that the Kevlar is a very good flame retardant, besides supporting the stretching of its threads.
8- Tear thread: they are threads that help the consistency of the cable.
9 - Sheath: the upper layer of the cable that provides insulation and consistency to the set that has inside.
Now that we know how a cable is composed, let's see how it works. I'm not going to detail mathematically the operation because it's not the idea, I'm just going to talk about the two phenomena of optics that allow transmission and are the strawberries of this wonderful cake. Also in the network there is plenty of information to expand your knowledge.
The two physical principles by which fiber works are Reflection and Refraction. They are the guilty of carrying this forward.
Reflection of light in fiber optics Refraction: is the change of direction that waves carry when they pass from one medium to another. Simply and for better understanding, this is experienced when we put a spoon in a glass of water and it seems to move within it.
Reflection: it is also the change of direction of the wave, but towards the origin. This would be what happens when we look in the mirror without reflection, we could not comb or shave in front of the mirror.
Now that we know what are the physical principles that occur within the optical fiber, we go to a figure that details these phenomena in action:
We already know how it works, so let's talk a little about what types of fiber there are and what they are for. To do this we are going to group them in two ways. One is the single mode fiber and the other is multimode and this grouping is due to the way they transmit light inside the fiber.
Single mode: only one beam of light is transmitted inside the fiber. They have a transmission range of 300 km under ideal conditions, the light source being a laser.
Multimode: several light beams can be transmitted inside the fiber. Generally their source of light are IODOS of low intensity, having short distances of propagation (2 or 3 Km), but they are cheaper and easier to install.
We get to the point where we know what an optical fiber is like, what materials make them up and what types there are. It is the moment to know how to connect them between the devices and how are the network boards whose mission is to "transform" the light into binary code (photosensors) so that the device can interpret.
Types of fiber optic connectors Types of fiber optic connectors that go on the ends of the cables.
FC used in data transmission and telecommunications.
FDDI is used for fiber optic networks.
LC and MT-Array that are used in high data density transmissions, mostly used in servers or storage clusters.
SC and SC Duplex are used for data transmission.
ST or BFOC is used in building networks and security systems.
Once we have them connected, the plates emit light through different devices:
Laser: the most powerful and used in single-mode cable
LED: they are cheap, they do not have much power and they are used in multimode cables.
The network boards, in addition to giving us the connection interface, are in charge of "converting" the light impulses into binaries for the understanding of the PC. Basically they take the impulses in this way: Light impulse = 1, darkness = 0. This is how the binary forms. Also for more details, there is always the internet to deepen.
Finally I will give, to my way of seeing and understanding, the advantages and disadvantages that are worth knowing about fiber optics:
Advantage:
High bandwidth (tests gave almost 1 TB / s), making the transmission depend on the processing capacity of transmitter-receiver rather than the medium (which obviously is very fast)
Multiprotocol (TCP / IP, SCSI, etc.)
Scalable
Very safe since there is no way to access the transmitted data without breaking the fiber
The cable is very light and corrodes little
The signal is lost very little along the cable
