Researchers from Facebook's Connectivity Lab have demonstrated a conceptually new approach that can in the future make light-based wireless communications.
The technology is far more superior than the ones based on radio frequencies or microwaves and could pave the way for fast optical wireless networks capable of delivering cheap internet to regions of the world with no access to it at all.
Tobias Tiecke, who led the research team, said that a large section of people don't connect to the Internet because the wireless communications infrastructure is not easily available in their location, mostly in very remote areas of the world.
Bringing Internet signals to new locations is normally done using wireless because it’s much more cost-effective than running cables. However, the conventional wireless comes with speed limitations and needs radio spectrum that are often purchased from the government.
Having experienced such limitations, researchers have increasingly eyed sending data from point-to-point over laser beams as they do not require any special spectrum or permission, and several systems can work in the same area without interfering with each other.
The Connectivity Lab at Facebook's internet.org expects that its laser approach, along with its drone tech could possibly connect the next four billion people, mainly those who live in far-flung and rural areas.
In a new paper, the researchers outlined the technique they used. Called free-space optical communications or light-based wireless communication, it offers an effective way to bring the Internet to locations where optical fibres and cell towers can be challenging to base in a cost-effective way.
Making use of laser light to send information across the atmosphere can potentially provide very high bandwidths and data capacity, but sending high-speed signals using lasers isn't simple. The major challenge has been how to accurately point a very small laser beam carrying the data at a tiny light detector that is some distance away.
The researcher team used fluorescent materials instead of regular optics to collect light and concentrated it onto a small photodetector. They consolidated the light collector, which had 126 so cm of the surface that can collect light from any direction over a large area, with current telecommunications technology to achieve data rates of more than 2 gigabits-per-second (Gbps).
The new light collector utilizes plastic optical fibres containing organic dye molecules that absorb blue light and emit green light. This format substitutes the classical optics and motion platform normally required to point the light to the collection area.
The high speeds are possible because of less than two nanoseconds lapse between the blue light absorption and the green light emission.
Facebook’s Connectivity Lab says the technology could be applied both indoors and outdoors. It could be used to transfer high-definition video to mobile devices around the home and the same technology could be used outdoors to establish low-cost communications links of a kilometer or more in length.
Additionally, by integrating a signal modulation method called orthogonal frequency division multiplexing, or OFDM, the researchers beamed more than 2Gbps in spite of the system's bandwidth of 100MHz and the company thinks it can go faster.