Silicon chips land a lasting laser

It’s a basic rule of microelectronics: For components that generate and manipulate light, silicon is the wrong material. But rules, as the saying goes, are made to be broken.

Engineers in California now report that they’ve made a microchip silicon laser that they claim should be widely useful in circuits.

The development could enable circuit designers to replace many metal wires used to transmit signals in computer systems with optical fibers. And that, says electrical engineer Victor Krutul of Intel Corp. in Santa Clara, could rev up the flow of data to rates 100 times as fast as those possible today. Krutul is spokesperson for the Intel team that has made a prototype of the silicon laser.

This advance toward a practical silicon laser builds on a few earlier steps. Last fall, researchers at the University of California, Los Angeles unveiled the first silicon laser of any kind (SN: 10/30/04, p. 275: Available to subscribers at Laser Landmark: Silicon device spans technology gap), but it was too bulky to fit onto a chip.

In the Jan. 20 Nature, Intel’s Haisheng Rong and his colleagues reported the first microchip-size silicon laser. But it could emit light only in pulses because a buildup of electrons quickly extinguished the laser action. The latest incarnation, unveiled by the same Intel team in the Feb. 17 Nature, can stay on continuously.

All silicon lasers to date require a beam from another laser to power them. Optical engineers would prefer a laser that runs on electricity. Another route toward practicality, Krutul notes, could be to simultaneously energize many silicon lasers with the light from just one powerful laser.

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