All-silicon chip laser demoed

Lasers made using the silicon wafers and manufacturing facilities of computer chips would be relatively inexpensive. Such lasers could also be easily integrated into computer chips, making high-speed optical connections between computers economically feasible.

Researchers from Intel Corporation have moved a step forward in the push to meld lasers and silicon chips.

Lasers stimulate the atoms of a gas or solid into emitting photons. The result is an intense beam of a single wavelength, or color, that remains narrowly focused.

Silicon chip lasers could eventually be used in portable biological and chemical sensors, to amplify communications signals, and to convert light to different wavelengths. Optical amplifiers are commonly used to strengthen communications signals that have weakened over distance.

The researchers' prototype silicon laser uses natural atomic vibrations in silicon to amplify light, a phenomenon known as the Raman effect. The prototype is a proof-of-concept that shows that it is possible to leverage the Raman effect to bring about light amplification and lasing in a silicon chip. The researchers' prototype produced short pulses that lasted around 100 billionths of a second, or nanoseconds.

The device consists of 4.8-centimeter-long S-shaped wave guide, or light channel, on a silicon chip. A pump laser fires light into the wave guide at one end. A reflective coating at the other end confines the light.

Researchers at UCLA recently produced a prototype that showed that it is possible to use the Raman effect in a silicon laser. The UCLA prototype, however, used an external optical fiber to contain the light.

The next step is achieving a continuous beam, according to the Intel researchers.

Photonic devices made from silicon could be ready for commercial use within five years, according to the researchers. The work appeared in the January 6, 2005 issue of Nature.