WASHINGTON, March 10—In the future, getting a broadband connection might be as simple as flipping on a light switch. In fact, according to a group of researchers from Germany, the light coming from the lamps in your home could one day encode a wireless broadband signal.
"The advantage is that you'd be using light that is already there," says Jelena Vučić of the Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institute in Germany. Vučić and her colleagues have found a way to get the most from this synergy of illumination and information and will be presenting their findings during the Optical Fiber Communication Conference and Exposition/National Fiber Optic Engineers Conference (OFC/NFOEC), which will take place March 21-25 in San Diego.
As of now, the majority of wireless in homes and businesses is achieved through a radio-frequency WiFi connection. But WiFi has limited bandwidth, and it's unclear where to find more in the already-crowded radio spectrum. By contrast, visible-frequency wireless has all the bandwidth one could want. The signal would be generated in a room by slightly flickering all the lights in unison. No one would be bothered by this because the rate of modulation would be millions of times faster than a human eye can see. Since visible light can't go through walls like radio, there would be no unwanted interference from stray signals and less worry of outside hackers.
Incandescent and fluorescent bulbs can't flicker fast enough, so all the lights would have to be LEDs. Although commercial LEDs have a limited bandwidth of only a few MHz, Vučić and her colleagues were able to increase this bandwidth ten-fold by filtering out all but the blue part of the LED spectrum. With the visible wireless system built in their lab, they downloaded data at a rate of 100 Mbit/s. They have now upgraded the system's receivers and are getting 230 Mbit/s, which is a record for visible wireless using commercial LEDs. Although state-of-the-art radio wireless can achieve comparable speeds, Vučić says they should be able to double their data rate again by employing a more sophisticated modulation signal.
The OFC/NFOEC 2010 talk, "230 Mbit/s via a Wireless Visible-Light Link Based on OOK Modulation of Phosphorescent White LEDs," presentation OThH3, will take place from 9:30 - 9:45 a.m. on Thursday, March 25 in the San Diego Convention Center.
The OFC/NFOEC Web site is http://www.ofcnfoec.org. In addition to comprehensive technical programming information, the site includes details on the trade show and exposition, where the latest in optical technology from more than 500 of the industry's key companies will be on display.
Members of the press who wish to attend the meeting should contact Angela Stark at firstname.lastname@example.org. More information can be found online at the OFC/NFOEC media center: http://www.ofcnfoec.org/media_center/index.aspx.
About OFC/NFOEC Since 1979, the Optical Fiber Communication Conference and Exposition (OFC) has provided an annual backdrop for the optical communications field to network and share research and innovations. In 2004, OFC joined forces with the National Fiber Optic Engineers Conference (NFOEC), creating the largest and most comprehensive international event for optical communications. By combining an exposition of approximately 500 companies with a unique program of peer-reviewed technical programming and special focused educational sessions, OFC/NFOEC provides an unparalleled opportunity, reaching every audience from service providers to optical equipment manufacturers and beyond. OFC/NFOEC is managed by the Optical Society (OSA) and co-sponsored by OSA, the Institute of Electrical and Electronics Engineers/Communications Society (IEEE/ComSoc) and the IEEE Photonics Society. Acting as non-financial technical co-sponsor is Telcordia Technologies, Inc.