Instead of using microwaves to transmit data wirelessly, Facebook is considering using a built-in laser detector to offer connections with speeds of up to 2.1Gbps.
The Connectivity Lab at Facebook's internet.org believes that the laser approach could, along with the drones the company uses, help connect four billion people, especially those living in remote and rural areas.
Its researchers have described a new technique they call free-space optical (FSO) communication. The new technology can overcome the limitations of microwave data transmission by expanding the available spectrum to much larger sizes. They demonstrated that they could transmit data at a speed of 2Gbps using a bandwidth of 100 MHz.
The Facebook team borrowed a technique used to collect sunlight and applied it to data transmission.
The collector absorbs blue light and emits green light. Facebook notes the fast speeds are possible because less than two nanoseconds elapse between the absorption and emission of light.
“Optical fibers absorb light coming from any direction over a large area, and the emitted light travels inside the optical fiber, which channels it to a small, very fast photodetector.”
“The fact that these fluorescent optical fibers emit a different color than what they absorb makes it possible to increase the brightness of the light entering the system,” said Tobias Tiecke, project manager.
"This approach has been used in luminescent concentrators for harvesting sunlight, where the speed of color conversion is not important. We have shown that the same idea can be used for communication at very high speeds."
According to Tiecke, Facebook is trying to build a prototype of the idea to test it in reality and explore whether its use can be expanded as a commercial product.
