Research Update: Chip electrically controls the speed of light
By Matthew Miller -- EDN, January 5, 2006
Researchers at IBM have fabricated the first optical chip that electrically controls the speed of light. The chip works by electrically altering the effective index of the refraction of an integrated photonic-crystal waveguide. The component could one day enable tunable optical delay-line chips, optical buffers, high-extinction optical switches, and highly efficient wavelength converters. The device, along with other components, could also eliminate the telecom industry's reliance on bulky and costly optical-to-electrical and electrical-to-optical converters. The chip can variably slow light by a factor of 300, under active control by a signal that consumes less than 2W and changes in less than 100 nsec. IBM built the chip on silicon-on-insulator CMOS.
The active element is a 250-micron-long photonic-crystal waveguide formed with a nanoscale version of micromachining that perforated a 223-nm-thick membrane with 109-nm-diameter holes spaced at a 437-nm pitch. As a result, the waveguide slows light passing through it in a 20-nm bandwidth at the communications wavelength of 1620 nm. Click here for more information, including an animated demonstration. For an animation of how the technique works, click here.
EIBM Corp, www.ibm.com.
