Optical free-space communication systems in the Mbps to Gbps range, suitable for industrial applications

For future short- and mid-range industrial applications, optical free-space communication systems are expected to play a major role. When moderate transmission rates (100 Mbps range) are required, optical wireless communications present a viable and promising technology supplemental to conventional radio wireless systems. Advanced approaches based on diversity techniques and adaptive signal processing show potential to achieve both high spatial coverage and high bit rates of more than 100 Mbps. Visible light communication systems using white phosphorescent LEDs present equally an interesting application potential, combining illumination with data transfer. When high data volumes (100 Gbps range) need to be transmitted, tailored optical data links provide a solution of choice. Exemplarily, a scalable (24 - 140 Gbps) optical data link is presented, developed for future implementation in maskless lithography systems. The link comprises a high-speed data buffer with synchronizable architecture and scalable throughput (N × 24 Gbps), an optical free space transmission solution, and, finally, a 45 channel low-noise optical receiver chip based on BiCMOS 0.6 µm technology.