Bell switches in free-space

17 Jun 2002

Bell Laboratories at Murray Hill has announced a column of 16 mechanical micro-mirrors to switch optical signals in telecommunications networks at microsecond speeds. It says that the free-space device will cost about US$ 1 compared with US$ 1000 for a faster integrated switch.

Each gold mirror, about 10 micrometres across, routes an individual wavelength of light carrying a message along an optical fibre. The multiplexed wavelengths are separated by a diffraction grating at the end of the fibre and imaged onto the mirrors fixed to microscopic silicon beams.

If an electrostatic force lifts a beam, the mirror deflects light into another fibre to continue its journey along the network. The process is known as wave division multiplexing.

The micro-electrical-mechanical system (MEMS) was announced at the Optical Fiber Communications conference in San Diego, California, at the end of February. JB