SAN FRANCISCO: Light is better than radio waves when it comes to some wireless communications, according to Penn State engineers.

WiFi goes MiFi aka My WiFi

The scientists say that optical communications systems could provide faster, more secure communications with wider bandwidth.

The system uses a high-powered laser diode — a device that converts electricity into light — as the optical transmitter and an avalanche photo diode — a device that converts light to electricity — as the receiver. The light bounces off the walls and is picked up by the receiver.

The researchers tested infrared light, but the system will also work with visible light and ultraviolet light.

"The optical system we have offers a very large bandwidth thus a very high speed," said Fadlullah. "We can send one gigabit per second or more over a gigahertz band."

The researchers, including Mohshen Kavehrad, professor of electrical engineering, think this looks like an ideal system. Radio frequency systems do not require line of sight transmission, but can pass through some substances and so present a security problem.

Light, in a room without windows, will not escape the room, improving security, but also allowing the same frequencies to be used in adjacent rooms without interference. Multiple sensors could allow the light signal to pass from room to room or even from floor to floor. The system could also be set up to convert the signal to electricity, transfer it to another location and change it back to light.

"The safest security is physical layer security," said Mohshen Kavehrad. "If you first have to break into the building before you can attack the network it makes it very difficult."