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Researchers Are Working on Fiber-to-the-Living Room

March 9, 2015 By Finley Engineering in

Telecom companies have long been using light to transmit data across the Internet and other information networks. More recently, fiber-to-the-home (FTTH) initiatives have extended that by using optical fiber and light waves to transport data and information right into homes and businesses.

Researchers at Oxford University are taking optical networking technology the next step forward, using “LiFi-like” signals to wirelessly beam data inside homes and buildings to computers or TVs. The system takes the light waves from fiber connections, amplifies them and beams them across a room to consumer electronics (CE) devices at super-fast speeds of over 100 gigabits per second (Gbps), according to an IEEE Spectrum news report.

Oxford’s LiFi-like technology could address a couple of big challenges facing wireless network providers and consumers. Using the technology, potential data transfer rates reach over 3 terabits per second (Tbps) as compared to about 7 Gbps for Wi-Fi networks, researchers said. Using light to transmit digital data offers a practically unlimited amount of data-carrying capacity.

That offers wireless providers a means of solving issues of limited wireless spectrum. “If you’re in the optical window, you have virtually unlimited bandwidth and unlicensed spectrum,” Ariel Gomez, Oxford University Ph.D. student and author of a paper describing the system in IEEE Photonics Technology Letters, was quoted as saying.

To make the system work, Oxford University researchers install a base station capable of sending and receiving data via light waves on the ceiling of a room. The ability to focus the beams of light precisely is the critical factor that makes the technology work effectively.

An optical fiber is only 8-9 micrometers, or microns (10-6 meters), in diameter, IEEE Spectrum’s Neil Savage points out. The research team, which also included researchers from University College, London, was able to achieve equivalent light beam focusing by using “holographic beam steering.”

An array of liquid crystals creates a programmable diffraction grating that reflects light in the desired direction. This is a device that is akin to those used in projectors, an Oxford photonics engineer and research project leader commented.

The light diffusion grating acts like a prism, deconstructing the light beams into their component wavelengths and colors. Total bandwidth supported depends on field of view. With a field of view of 36º, in contrast, aggregate bandwidth of 112 Gbps over three channels was reached; with a 60-degree field of view, total throughput was 224 Gbps over six channels, researchers said.

Oxford’s LiFi-like system does require a direct line of sight, however. Researchers are now working to develop a tracking and location system so users wouldn’t have to keep their laptops in the same location all the time.

For all its promise, Gomez doesn’t believe the LiFi-like system will replace Wi-Fi, “though it could certainly find its uses,” he said.