The Fiber that Moves the Internet

This year, 5G will become a reality thanks to the experimental prototypes that are underway. For the first time in the history of mobile communications, speeds of one gigabyte per user will be reached, with a latency lower than 1ms. However, the dream of a totally mobile and wireless internet is only a utopia. While 5G will expand the bottleneck that prevents providers from meeting the demand for mobile speed, the limits of a finite and limited resource such as radio spectrum require the implementation of alternative technologies to support the growing global demand for bandwidth.

Why is Optical Fiber so Important for the Internet?

At the beginning of the 20th century, physicists Demetrius Hondros and Peter Debye tested equations applied to the controlled transfer of light pulses through glass cables, but it was not until the middle of that century that physicist Narinder Kapany conducted experiments that led to the invention of what we know today as optical fiber. It was not until April 1977 that finally a company, General Telephone and Electronics, sent the first telephone transmission through optical fiber.

Hardly the pioneers of this particular technology could have imagined that sending light through glass threads would literally change the future of communications and, consequently, of humanity.

Optical fiber is a type of flexible transparent fiber, resulting from the complex industrial process of drawing glass (silica) – although today it is also achieved with plastic – up to a diameter similar to that of a human hair. This hollow fiber serves as a guide for dielectric waves that operate at optical frequencies, in other words, binary light pulses. Each of its filaments consists of a central core of plastic or glass (silicon dioxide and germanium) that has a high refractive index, allowing light pulses to be converted into data and thus transmitting information.

During the first years of massification of optical fiber, its costs were very high and it was only used for large backbone networks that carried voice and data. However, as time went by, it became indispensable in data interconnection networks and its use became massive, not only on land, but also in extensive underwater transoceanic cables that today support the internet we use daily. With the exception of some satellite and microwave transmissions, all the backbone and internet interconnection networks are supported on optical fiber.

Why is Optical Fiber the Only One Capable of Loading the Insatiable Demand for Data Required by the Internet?

The answer is simple: there is nothing that travels faster than the speed of light and optical fiber uses light to transport information (although there is an average resistance ranging between 13% and 31% called latency, which is caused by the process of refraction when traveling through the fiber).

“As objects travel faster and faster, they get heavier and heavier – the heavier they get, the harder it is to achieve acceleration, so you never get to the speed of light. Photons are pretty special because they do not have to speed up, but the natural energy they possess is equivalent to their top speed, which we know as the speed of light, and in a strict sense we have not observed scientifically anything that can move as fast or faster than the Photons”.

Roger Rassool, physicist from the University of Melbourne, Australia

Only if the earth is flat might this latency be avoided, as an ultra-high-power laser signal might exceed the speed of the fiber optic signal. It could also be done by a laser transmission satellite, a technology currently available only in science fiction books.

Taking into account that the Internet speed is measured by the amount of bits per second that are moved from one network point to another and that the fiber optic uses photons as representations of those bits, what we finally have is a technology that allows the bits to travel almost at the speed of light (counting on the resistance mentioned before). Therefore, its capacity to transport becomes almost infinite; the only real limits are the latency and the capacity of conversion and processing that the terminals of transmission and reception of information have.

It is important to mention that there are research groups around the world working to reduce fiber optic latency. A study published in 2013 by scientists from the University of Southampton (United Kingdom) stated that it is possible to manufacture an optical fiber capable of transmitting data at a speed that reaches 99.7% of the speed of light in vacuum, which would end up reducing the latency by 0.3%.

This is why there is no technology for the telecommunications sector that involves a more appropriate long-term investment than optical fiber, because although every day more efficient and less resistant fibers will be produced, the reference values will end up being practically the same and will always be higher than any other non-optical technology.

Fiber Must Get to the Home

Nowadays all the backbone and interconnection networks used for the Internet are made of optical fiber, but this is not always the case with the Internet home networks, which in many cases are over copper networks (ADSL) or generally hybrid fiber coaxial networks (HFC). Although these technologies have proven to be functional, thanks mainly to the fact that DOCSIS has proven to be a system capable of permanently reinventing itself, the updates that they demand and their speed limitations require that the optical fiber finally reaches users’ homes, thus allowing them to support the high traffic demands, capacity and low-cost speed of the Internet we consume. However, it is understandable that large companies that still have a coaxial network deployed continue to seek to monetize this network before making the leap to fiber optic connections that reach homes.

You may also be interested in the article: The Extraordinary Capacity of DOCSIS to Reinvent Itself

The technology used to transport the fiber optic Internet to the user’s home is called FTTH (Fiber to The Home), which is part of the FTTx technology. The access network between the user and the backbone is usually done with one or two dedicated cables for each user (point-to-point connection / star topology) or a PON (Passive Optical Network), which uses a tree-like structure.

Thanks to the fiber that reaches the home, it is already common in Latin America to find providers that offer average speeds of 100 mbps, in some cases up to 250 mbps, while in developed countries these speeds average one gigabit per second. Although these are equivalent to the reference values promised by 5G, the big difference is the amount of data supported: this connection is permanent and practically unlimited thanks to fiber, while it will be on demand and with limited capacity in 5G.

Regarding costs, currently it is more economical for a telecom operator to design and implement a fiber network to homes than any other technology, including HFC. A study published in 2017 by the ILO estimated that practically all of the new Internet networks to be deployed in the coming years in developed countries will be FTTH.

In conclusion, no technology allows for as much speed, capacity, and availability of service to distribute the Internet as fiber optics, a system that uses light as a means to connect humanity regardless of the distance to be covered. In the next few years, it will go from being simply a backbone network to becoming the main means of transporting the Internet, even to and within homes.

By: Gabriel E. Levy B.