Still connecting to the Internet via a fiber optic cable or Wi-Fi connection? That is so 2015. The Internet of the future will use airborne lasers to connect more people, more easily and more affordably, if a team of Facebook scientists and engineers has anything to say about it.

The team published a paper in the scientific journal Optica demonstrating the feasibility of using commercially available fluorescent materials to transmit data via laser beams through open space at speeds up to 2.1 Gbps. That's more than double the speed of the fastest download speeds possible over a 4G wireless connection.

High-Flying Data

It is no secret Facebook has been working on new ways to deliver Internet service to people living in areas too remote to be easily reached with more common telecommunications infrastructures. The company launched its Project Aquila program through its Connectivity Lab last year to develop high-altitude, long-endurance unmanned drones capable of staying airborne for months at a time.

The biggest obstacle to an airborne network of Internet connections is the limitations inherent in current wireless technologies, which rely on radio broadcast transmissions to send information through the air. Radio transmission offers only a limited spectrum of frequencies that can be used, limiting data rates. Companies also have to get permission from national governments to use those frequencies for commercial purposes.

“The use of optical carrier frequencies allows for many orders of magnitude more available spectrum, a high degree of spatial multiplexing, and the possibility to communicate at a high data rate in the absence of fiber network infrastructures, e.g., to space or high-altitude unmanned aerial vehicles,” the researchers wrote in Optica.

Speeds Up to 100 Gbps Possible

But while laser communication offers significant opportunities, there were several engineering obstacles the researchers had to overcome first. A signal from a light source is easily disrupted by atmospheric turbulence (the same reason stars seem to twinkle at night), which can cause data to be lost or corrupted thus limiting the effective transmission range. Meanwhile, even minor ground vibrations that are normally undetectable can cause a laser to miss its target.

The Facebook researchers addressed the problems by using a special type of dye known as a luminescent concentrator to effectively amplify the light signal received by the optical receiver. The materials have already been used in other applications, such as solar harvesting and high-energy physics experiments, but the researchers said this is the first time luminescent concentrators have been used in telecommunications systems.

The research team said the new technology could allow for data transmission ranges on the kilometer scale while lowering the cost of equipment deployment. While the team has already achieved transmission rates of more than 2.1 Gbps, the researchers said even higher rates could be achieved using different materials optimized for communication purposes. Combining those materials with more advanced signal collection and processing techniques could potentially increase transmission rates to the 100 Gbps range.