Harald Haas: Progress in LED technology removes barriers for LiFi communication

Using light for communication is something most of us are familiar with -- from wireless remotes using infrared, to the light within a fiber optic cable bringing the Internet to our homes and offices. Even Alexander Graham Bell transmitted voice over a distance using sunlight and a mirror with his photophone before he invented the telephone. Like Bell, University of Edinburgh professor Harald Haas wants to use available light to transmit communications.

"What really made the change was the advent of the high brightness white LED," says Haas in this SPIE interview from Photonics West 2017. "With that, we suddenly could not only cover a point-to-point link, we could cover an entire room, an entire street.So the light that is emitted by these high brightness lights could cover much more area in an environment and suddenly the idea of using light for mobile communications became possible and that gave rise to what we then called LiFi."

By using LED lights and a process called spatial modulation, Haas has shown the ability to transmit data at speeds similar to traditional wifi. Having first coined the term "LiFi" in 2011, Haas has since started the company PureLiFi and continues to work on improving the public's awareness and support of the technology.

"The response is always positive, because it's such an easy-to-understand idea for people - using light for data communication," says Haas.

"The point of getting beyond that excitement is to then show people how it works and I've seen this many times. When I have people in my lab and show them a gigabit of data transmit from a tiny little micro LED over 10m, it creates an additional wow effect."

When SPIE interviewed Professor Haas at Photonics West, he was happy to report that most of the technical roadblocks have been removed and that driving adoption and showcasing the technology's many potential applications was now key.

Since light doesn't leak or penetrate through walls like traditional radio signals, the security LiFi offers is one of the features Haas sees as key to some of the initial applications such as corporate boardrooms and manufacturing facilities. Additional potential applications include industry 4.0, the Internet of Things, increasing available bandwidth in large public setting (think airports and stadiums), medical devices, and even underwater transmission. The imagination can go wild when envisioning a future with LiFi.

"The applications are one of the most exciting aspects of LiFi, because they are almost limitless," Haas adds. "Everywhere you have an LED light, imagine you have a data transmitter, and obviously you could also have a photo detector and a receiver integrated and you have a bi-direction communication link. Until we get to the state where everything is connected by LED light, we will have intermediate stages."

Harald Haas currently holds the Chair of Mobile Communications at the University of Edinburgh, and is founder and Chief Scientific Officer of pureLiFi Ltd as well as the Director of the LiFi Research and Development Center at the University of Edinburgh. His main research interests are in optical wireless communications, hybrid optical wireless and RF communications, spatial modulation, and interference coordination in wireless networks.