What is fiber optics?

We explain what fiber optic is and how it works. In addition, what is it for, characteristics, advantages and disadvantages of optical fiber.

1. What is fiber optics?

The optical fiber is a physical means of transmission of information , usual in data networks and telecommunications, which consists of a thin filament of glass or plastic , through which pulses of laser or LED light travel, in which the data to be transmitted.

Through the transmission of these light pulses, information can be sent and received at important speeds through a cable run, safe from electromagnetic interference and with speeds similar to those of the radio. This makes fiber optic the most advanced cable transmission medium that exists.

The implementation of optical fiber is heir to centuries of research and experimentation on light and its properties, since ancient times when the Greeks communicated through the reflection of sunlight in small mirrors, the optical experiments of the Scientific Revolution , until the invention of optical telegraphy in 1792 by Claude Chappe, and the subsequent work of French physicists Jean-Daniel Colladon and Jacques Babinet, and the Irishman John Tyndall, all at the end of the 19th century.

The optical fiber as such would not enjoy the interest of the engineers until 1950 and in 1970 the first piece would be manufactured, using impurities of titanium on silica, by the work of Robert Maurer, Donald Keck, Peter Schultz and Frank Zimar. The first transmission of information through this medium was made on April 22, 1977 in Long Beach, California, and in the 1980s it was perfected and began to be implemented internationally.

2. What is fiber optic for?

Optical fiber is ideal for cable telecommunications , allowing the establishment of local and long-range computer networks, with a minimum of loss of information along the way.

Its applications are diverse in this field, allowing the obtaining of network material, fiber optic sensors (for temperature, pressure or light levels), lighting material (particularly effective since it does not require proximity to the light source), and being also useful for decoration (there are Christmas trees made of fiber optics) or as a component of translucent concrete.

3. How does fiber optic work?

The principle of operation of the optical fiber is that of Snell’s Law , which allows to calculate the angle of refraction of light when passing from one medium to another with a different index of refraction.

Thus, within the fiber, the light beams are trapped and propagating in the core, given the physical properties of the coating and the appropriate reflection angle, transporting the information sent to the destination. In the latter, it operates similarly to the telegraph.

4. Fiber optic characteristics

The optical fiber used today is composed of a plastic or glass core (silicon oxide and germanium) that has a high refractive index, covered with a similar plastic, but with a lower refractive index.

Thus, according to the mechanism of propagation of light inside, the optical fiber can be of two types:

• Single mode fiber . It allows the propagation of a single light mode, through the reduction of the diameter of the fiber core, allowing to send information over long distances and at a good transfer rate.
• Multimode fiber . It allows light beams to propagate in more than one way (more than a thousand different modes), which increases the margin of error and makes it not highly recommended for very long distance connections.

5. Fiber optic advantages

The optical fiber has the following advantages:

• It occupies little space , given its small size, but it is extremely flexible, which facilitates its installation.
• It is light , because it weighs eight times less than a conventional cable.
• It has great resistance , both mechanical and thermal, and resists corrosion well .
• It is greener , compared to waste left by conventional wiring.
• Immune to electromagnetic interference , given the nature of its components.
• Fast, efficient and safe . It is the best form of cable data transmission known.

6. Disadvantages of fiber optic

The disadvantages of optical fiber point to the following:

• They are fragile , since the glass inside is susceptible to breaking.
• It requires converters , to return the light energy to its informative sense.
• Splices are difficult , especially in rural areas.
• It does not transmit electricity , so it requires complex transmitters and transmitters, whose power supply cannot be taken from the line itself.
• Aging in the presence of water , which limits its worldwide application.
• There are no optical memories.