Optical fiber transmission: operation and available technologies

The wait for the construction of a single optical fiber network in our country seems to be over. In fact, a summit was held in recent days which saw the main owners of the network infrastructure as protagonists, such as TIM and the subsidiary Enel, Open Fiber . The meeting will certainly have interesting economic implications on the country's economy and on the level of connectivity of users. You can find an in-depth analysis on what has happened in recent days here .

Fiber optic transmission represents the future of telecommunications.
Credit: www.corriere.it. The possibility of introducing a single optical fiber connection in our country is a much debated topic due to the need to improve the Internet connection of the population which, in some cases, is still seen as a mirage.

What exactly is the technology we are talking about, however, we find out below.

How fiber optic transmission takes place

Communication via optical fiber consists in transferring data through the propagation of optical signals (i.e. light) using optical fiber as the transmission medium. In other words, the propagation of the signal takes place by exploiting the reflection properties of light.

For optical fiber , therefore, we mean a cable made up of very thin transparent filaments of very pure silicon glass fiber , held together by an insulating sheath. Each cable is composed of two concentric elements, the core from the transparent and pure material and the cladding which is opaque in nature. The propagation of light occurs in the core by exploiting the property of the refractive index . The refractive index is a property of the material that is crossed by electromagnetic radiation and quantifies the decrease in the speed of propagation of the signal when it passes through this material.

Since the refractive index of the core is greater than that of the cladding, an angle of incidence greater than a limit angle is imposed on the light pulse. In this way the ray undergoes a total reflection and propagates in the core for multiple reflections. In this way there is also no dispersion of radiant energy towards the outside since one works in the absence of refraction.

The fiber optic transmission takes place through successive reflections.
Credit: http://usandthem.altervista.org. The propagation of the light pulse occurs through a sequence of reflections in the core filament of the optical fiber.

The diameters of the core and cladding filaments are very small in the order of tens and hundreds of μm respectively.

The footprint of an optical fiber is minimal, almost equal to that of a hair!

The external coatings serve on the one hand to ensure insulation of the material but also to protect these cables which in themselves tend to be not very resistant to shocks. This is a different technology than the previous ones (for example ADSL) in which the transmitted signal was electrical and the material used was copper. Using optical fiber, the signal losses are significantly lower than those that could occur using an ADSL connection.

The structure of the optical fiber cable consists of two concentric elements (core cladding) that deal with the effective transfer of the light pulse and two external casings that act as insulation and protection.
Credit: https://www.tradetelecomunicazioni.com. The structure of the optical fiber cable consists of two concentric elements (core and cladding) that deal with the effective transfer of the light pulse and two external casings that act as insulation and protection.

Current linking technologies

Once you understand the technical functioning of this type of transmission, you may be interested in activating a fiber optic subscription for your home. You will surely have read some acronyms next to the speed indicators that should be explored.

Let's clarify these terms too.

  • FTTH (Fiber to the Home) . The optical fiber connects the control panel directly to one's home. It is the only one able to guarantee a transmission speed of up to 1 Gigabit per second, both in download and upload, thus allowing maximum performance .
FTTH is the link that brings the fiber directly into the home
  • FTTC (Fiber to the Cabinet) . In this mode, the optical fiber connects the control unit only up to the street cabinet (cabinet) installed near the house. The connection from the cabinet to the home is ensured by the copper network (twisted pair) . In this situation the length of the copper line can affect the connection speed although the street cabinets are capillary.
The FTTC allows to obtain the fiber connection from the control unit to the street cabinet
  • FWA (Fixed Wireless Access) . The data travels through the 4G / 4G + network arriving directly at the home, which uses it in the same way as a fixed line service. The success of this technology lies in allowing a high-speed Internet connection where there is not yet the "physical" optical fiber, ie the one lying underground along the roads.
The FWA uses the 4G / 4G + radio links to reach homes where there is no fiber

Future prospects

The agreement signed in recent days will allow for the improvement of the network infrastructure at a national level, allowing a greater portion of the population to have a fiber optic connection directly at home.

The article Fiber Optic Transmission: Operation and Available Technologies comes from TechCuE .