▷ Fiber optics: what it is, what it is used for and how it works

We are going to dedicate this article to learn more about fiber optics, we will explain what it is and how it works. We all know that this transmission element is used in data networks to connect to the Internet, but not everyone knows how to physically identify what fiber is, so we are going to be in trouble.

Index of contents

The creation of the Internet has undoubtedly been one of the most important information and communication technologies of our century. The Internet is of recent creation, we speak of 1991, when the World Wide Web was created, at which time the evolution in speed and accessibility began to skyrocket to this day. Precisely thanks to technologies such as fiber optics, the increase in data transfer capacity has reached extremely high levels of speed and distance.

What is fiber optics

As we have already mentioned, fiber optics is a means of data transmission by photoelectric impulses through a wire made of transparent glass or other plastic materials with the same functionality. These threads can become almost as fine as a hair, and are precisely the means of signal transmission.

Basically by these very fine cables a light signal is transferred from one end of the cable to the other. This light can be generated by means of a laser or an LED, and its most widespread use is to transport data over great distances, since this medium has a much greater bandwidth than metallic cables, lower losses and higher transmission speeds.

Another very important aspect that we must take into account is that the optical fiber is immune to electromagnetic interference, which is something that, for example, twisted pair cables suffer in all cases and contribute to the need for repeaters every certain distance. We must know that fiber optics does not transport electrical energy, only light signals.

But fiber optics is not only used for data transmission in networks, but also for high-quality audio connections. In addition, it is also a light source to provide visibility in tight spaces and even for decoration products, for example on Christmas trees and the like. Of course these fibers are constructed of plastic and are inexpensive, and have little to do with the cables used for data.

Parts of a fiber optic cable

Before we see how it works, we think it is important to know what are the parts that make up a fiber optic cable.

• Core: It is the central element of a fiber optic cable that is not always present. Its function is simply to provide a reinforcement to avoid cable breakage and deformation. Moisture drain: This element is also not present in all cables. Its function is to conduct possible humidity that the cable has so that it comes out through it. It is wound in the core. Fiber threads: it is the conductive element, light and data travels through it. They are made of high -quality silicon glass or plastic that create a medium in which light can reflect and refract correctly until reaching its destination. Buffer and Cladding (coating): basically it is the coating of the fiber optic threads. It consists of a dark-layer gel filler to prevent light rays from escaping from the fiber. In turn, the buffer is the external coating that contains the gel and the fiber. Mylar tape and insulating layers: basically it is an insulating coating that covers all the fiber buffers. Depending on the type of construction, it will have several elements, all of them made of dielectric (non-conductive) material. Flame Retardant Coating: If the cable is fire resistant, you will also need a coating capable of withstanding the flames. Armor: The next layer is the cable armor, which is always made of Kevlar wire in the highest quality. This material is light and highly resistant and fire retardant, we can see it in bulletproof vests and pilot helmets. Outer sheath: Like any cable, an outer sheath is required, usually plastic or PVC.

How fiber optics works

Being cables through which a light signal travels, the mode of transmission is not based on the transfer of electrons through a conductive material. In this case we attend to the physical phenomena of the reflection and refraction of light.

Reflection: The reflection of a light beam occurs when it strikes a surface separating two media and the direction of the wave changes, causing it to take a direction with an angle equal to the incidence angle. For example, if the light beam hits a 90 degree angle on a surface, it will bounce in the opposite direction, this is what happens when we stand in front of a mirror. If in another case the light beam hits a surface with 30 degrees, the beam will bounce with those same 30 degrees.

Refraction: in this case it is when a change of direction and speed occurs in a wave when passing from one medium to another. For example, it is what we see when light passes from air to water, we will see the same image, but at a different angle.

Through these two phenomena, the light will be transmitted along the fiber cable until it reaches its destination.

Fiber optic types and connectors

We already know how it works, but we still don't know how the light is transmitted inside these cables. In this case we must distinguish between singlemode fiber and multimode fiber.

In single-mode fiber, only one light beam is transmitted through the medium. This beam will be capable of reaching, at best, a distance of 400 km without the use of a repeater, and a high intensity laser is used to generate this beam. This beam is capable of transporting up to 10 Gbit / s for each fiber.

In the multimode fiber, on the other hand, several light signals can be transmitted on the same cable, which are generated by low intensity LEDs. It is used for shorter range transmissions, and is also cheaper and easier to install.

As for types of fiber optic connectors, we can find the following:

• SC: This connector is the one we will see most often, since it is used for data transmission in single-mode fiber connections. There is also an SC-Duplex version which is basically two joined SCs. FC: This is another of the most used and they look similar to a coaxial antenna connector. ST: It is also similar to the previous one with a central element of about 2.5 mm which is more exposed. LC: in this case the connector is square, although the central element remains the same configuration as the previous two. FDDI: It is a duplex fiber connector, that is, it connects two cables instead of one. MT-RJ: It is also a duplex connector and is not usually used for single-mode fibers.

Conclusions and advantages and disadvantages of using fiber optics

With this information we can form a fairly generic and complete idea of ​​what fiber optics is and how it is based on its operation. Domestic fiber optic connections are increasingly common, although sometimes instead of coming directly to us in fiber, it comes in the form of a coaxial cable if the network is hybrid. We will take advantage of another article to talk more about this type of cable.

Undoubtedly, the future that awaits us lies clearly in fiber optic networks, more and more relatively small population centers that have this type of high-bandwidth connectivity , since this is one of the main advantages. Furthermore, being based on light instead of electrical energy, it is totally immune to interference, and it does not produce it either. In the same way it supports very well the climatic changes and temperatures and is very light, being non-metallic elements.

But not everything is good in fiber optics, since one of the limitations is that the cables must be very firm and very well protected, to avoid fiber breakage. We also cannot transmit electricity, this is logical, so every element that needs electrical energy must have a nearby power source.

As for the installation and splicing of fiber cables, it is a quite complex process and great precision is necessary so that the signal is transferred from one cable to another without signal degradation. Transmitting and receiving devices are also much more expensive and complex, and in most cases light-to-electric energy conversion devices are needed to reach our homes.

This is all about fiber optic cables and connections. We trust that we have been able to solve the doubts you had about this technology and its use. If you are interested in other tutorials related to networks, here are some of them.

If you have questions or want to point out or add something, write us in the comments. We always try to improve the content as much as possible.