Silicon chip laser goes continuous

Researchers from Intel Corporation have improved their all-silicon laser so that it produces a continuous beam of light.

Useful lasers made from silicon would make it possible to move data between and within computer chips using light rather than electricity. This would make for faster chips that could be more tightly integrated with optical communications equipment.

Silicon lasers also promise to be relatively inexpensive because they can be produced using existing chip-making facilities.

The silicon laser takes advantage of the Raman effect, which takes place when photons scatter off of energized atoms. The Raman effect is 10,000 times larger in silicon than in an ordinary glass fiber.

The researchers previously produced a pulsed silicon laser. They optimized the design of the silicon waveguide that serves as the cavity that amplifies light by sandwiching it between areas of silicon that are altered, or doped, to favor positive or negative electric charges. This forms a type of diode that reduces the amount of energy lost by absorption into the silicon.

The continuous silicon laser could eventually be used in optical amplifiers, optical switches, networking, and medical, sensing and chemical analysis applications, according to the researchers.

It is difficult to predict when the silicon laser will be ready for practical use, according to the researchers. The work appeared in the February 17, 2005 issue of Nature.