Phase modulation with the next generation of liquid crystal over silicon technology

Abstract

Liquid crystal materials are fast becoming the de facto standard in modern commercial display technology and large amounts of research and development have gone into optimising the materials used in these many types of display. One of the most exciting technologies based on liquid crystal materials is the combination of their optical modulation characteristics with the power and compactness of a silicon VLSI backplane. The next generation of applications for liquid crystal over silicon technology are already starting to emerge in laboratories, however there are severe limitations as the liquid crystal materials have all been optimised for amplitude or intensity modulation when in fact the ability to modulate the phase of the light is more desirable. One example of such an application is adaptive optical interconnects. Data transmission within and between printed circuit boards is becoming more and more important as the data rates in electronic systems increase into the GHz region. One way of avoiding potential data bottlenecks in board to board interconnects is to use optical links to transmit the data. Recent research into free-space optical links has shown that a high level of manufacturing tolerance must be used to maintain the link, however, this can be avoided by incorporating a liquid crystal phase hologram as a beam steering element to compensate for movement between the boards and maintain the optical data path.