A team of University of California researchers has found a way to create tiny lasers on silicon, taking a significant step in the use of light to produce more powerful, energy-efficient microprocessors.
The advancement, published Sunday in the magazine Nature Photonics, points to the possibility of being able to build nanolasers on silicon within the current infrastructure for manufacturing processors. Chipmakers' investment in today's facilities for building products out of silicon is so high that most manufacturers would be unable to build new factories.
Researchers at U.C. Berkeley, have found a way to "grow" nanolasers directly on silicon at a relatively cool temperature of 400 degrees Celsius. The discovery is important because making the lasers using other techniques required a temperature of 700 degrees Celsius or more, which damaged the silicon-embedded integrated circuits.
Light particles, called photons, travel much faster than electrons on the nano-thin copper wiring used in today's processors, so scientists have been working for some time on introducing light for communications among the transistors that are used in processing data within a microprocessor. The U.C. researchers' contribution is in growing on silicon cylinders made of indium gallium arsenide, a material used in creating laser beams.
The cylinder, which is called an "optical cavity," amplifies light until it reaches a wavelength of 950 nanometers, which is near the intensity of an infrared laser. The U.C. team showed that once the 600-nanometer size cavities are made, they can produce laser beams at room temperature.
Connie Chang-Hasnain, the U.C. professor of electrical engineering who led the research team, says light doesn't have to be used throughout a microprocessor to be effective in dramatically boosting performance. The technology can be used in communications between just some components to be effective.
"It makes sense to use light because it's much more energy efficient, as well as power efficient," Chang-Hasnain told InformationWeek. "In addition, it has very high bandwidth."
The research has applications beyond microprocessors, such as in communications, electronic displays, and biochemical sensors. The Defense Advanced Research Projects Agency (DARPA) contributed funding to the work.
Research in the use of photonics in computing is being done in the marketplace, as well as in universities. Intel last July introduced a prototype of a high-speed optical data link that could transfer information at speeds of 50 gigabits per second, which is the equivalent of an entire high-definition movie every second.