A lightning switch

Developed as part of a Link research program sponsored by the Department of Trade and Industry in conjunction with Nortel, British Aerospace and Thomas Swan, the holographic light switch is attracting a great deal of attention.

Design of a 1xN switch. The data is routed into the different single-moded output fibres by varying the angle of diffraction generated at the liquid crystal phase hologram.

In essence, optical channels coming in on one optical fibre need to be diverted very precisely to another fibre. This can be achieved using holograms as follows. Hologram images are designed offline in a computer, and are then down-loaded onto an appropriate display device. The holographic light switches use a similar type of technology to that used for microdisplays, as detailed elsewhere on this web site. This combines liquid crystal technology with silicon chips.

Hologram device construction