Scientists claim wireless optical breakthrough

Wireless optical networks could replace Wi-Fi in home and commercial networks, according to engineers at Penn State University in the US.

The researchers believe optical systems could provide broader bandwidth, better security and would cause less interference in restricted areas such as hospitals.

“The optical system we have offers a very large bandwidth thus a very high speed,” said Jarir Fadlullah, an electrical engineer at Penn State. “We can send 1Gb/sec or more over a gigahertz band.”

Sending information via light waves either in physical light guides or wirelessly is nothing new, but existing wireless systems either require direct line of sight or are so diffused that they offer low signal strength.

The researchers say they have resolved the problem of weak signals by using multi-element transmitters and multi-branch receivers to create an artificially diffuse configuration. The system uses a high-powered laser diode as the optical transmitter and an avalanche photo diode to convert light back into electricity.

According to Fadlullah this means that the light will bounce around the room well enough to carry a signal in all but the dullest environments.

“Unless the walls are painted solid black, there is no need to worry about transmission within a room,” he said.

The Penn State team also claims that optical networks would bring other benefits, such as improved security, because unlike Wi-Fi signals the optical waves would not pass through walls.

“The safest security is physical layer security,” said Fadlullah. “If you first have to break into the building before you can attack the network it makes it very difficult. An optical system also can operate in locations where radio frequency transmission would interfere with other equipment, especially in hospitals and on planes.”

The researchers say the system remains a long way from market, but could be incorporated into a building’s lighting system to provide blanket coverage.