Running from October 2012 to February 2017, UP-VLC is an ambitious EPSRC-funded £4.6 million Programme Grant which will explore the transformative technology of communications in an imaginative and foresighted way. The vision is built on the unique capabilities of gallium nitride (GaN) optoelectronics to combine optical communications with lighting functions, and especially on the capability to implement new forms of spatial multiplexing, where individual elements in high-density arrays of GaN based light emitting diodes (LEDs) provide independent communications channels, but can combine as displays. We envisage ultra-high data density - potentially Tb/s/mm2 - arrays of LEDs driven via CMOS control electronics in novel addressing and encoding schemes and in compact and versatile forms.
The project is a partnership between 6 research groups at 5 institutions. It is led by Professor M.D. Dawson of the University of Strathclyde and mentored by Professor P. Blood of Cardiff University. Some of the relevant technical expertise and background accomplishments brought by the partners of this project are illustrated in Fig.1.
(a) (b) (c) (d) (e)
Fig.1 (a) high-fill-factor chequerboard (square grid) GaN LED/CMOS clusters (Strathclyde/Edinburgh), (b) 1Gb/s eye diagram from 84μm-diameter GaN micro-pixel LED (Strathclyde), (c) flexible organic semiconductor grating arrays for hybrid LEDs (Strathclyde/St. Andrews), (d) multiple channel VLC link (Oxford), (e) 124Mb/s real time video VLC transmission demonstration (Edinburgh).
Recently, by integrating CMOS electronics with GaN based micro-LEDs, we have developed CMOS-controlled color-tunable smart displays. The color-tunable LED pixels in these displays have a modulation bandwidth of 100 MHz, thus providing simultaneously a wavelength-agile source for high-speed visible light communications. The programmable dynamic images generated from such a micro-display system are shown below (red ‘Tetris’ and green Firework).