Tiny Lasers Speed up Computers

We all want faster and more powerful computers and devices that consume less and less energy to save battery power. So far, researchers and manufactures were able to produce ever smaller microprocessors that doubled in performance every year and so followed a predicted trajectory of performance increase commonly known as Moore’s law.

However, as circuits on microprocessors reached the nanometer scale, the problems of further miniaturization accumulated due to increasing heat buildup and reduced reliability. Some scientists see the limit of miniaturization at about 2-3 manometers which should be reached by about 2020 and constitutes a natural limit of traditional microprocessor technology due to unpredictable quantum effects.

To further increase the speed and performance of computers and devices, new strategies and technologies are required. Beside the use of quantum technology, implementation of laser guided data transfer has been a recent research focus.

Tiny Laser Breakthrough

Now, there has been a breakthrough in the world of lasers. An international group of scientists was able to place tiny lasers directly onto silicon. This has not been possible before and has opened exciting new opportunities in the semiconductor industry and provides a development platform for new super-fast microprocessors.

“Putting lasers on microprocessors boosts their capabilities and allows them to run at much lower powers, which is a big step toward photonics and electronics integration on the silicon platform.”

Professor Kei May Lau from Hong Kong University of Science and Technology

Usually, lasers used for commercial applications are pretty big, with the average size of 1 mm x 1 mm. Lasers smaller than this typically suffer from large mirror loss, which made it very difficult to get fully functional lasers at a smaller size. However, the group of scientists figured out a way!

They used “tiny whispering gallery mode lasers” which were 1 micron in diameter. That’s 1,000 times shorter in length and 1 million times smaller in area than the typical, commercial lasers used today! Current “whispering gallery mode lasers” have already been used for on-chip optical communications, chemical sensing, and other data processing applications. With those new tiny lasers, the integration of light based data transfer in all kind of electronic devices seems now feasible.

“Photonics is the most energy-efficient and cost-effective method to transmit large volumes of data over long distances. Until now, laser light sources for such applications were ‘off chip’ — missing — from the component,” Lau explained. “Our work enables on-chip integration of lasers, an [indispensable] component, with other silicon photonics and microprocessors.” It is expected we will see their tech coming into the market within the next decade.

Laser Integration on Silicon Chips

The group of scientists was able to integrate subwavelength cavities (which was the main makeup for their tiny lasers) onto silicon, meaning they could then create high-density on-chip light-emitting elements, or lasers. For this process to work, they had to first find a way to fix silicon crystal lattice flaws until the cavities were basically equal to cavities grown on lattice-matched gallium arsenide, GaAs, substrates. These Nano-patterns they created on silicone to fix the flaws on the GaAs templates made them nearly flawless. This made lasing possible on the new templates because the electrons were confined within the quantum dots grown there.

After they got the nearly perfect templates, they were able to use optical pumping. Optical pumping is a process where light, not electrical currents, “pump” electrons from an area of lower energy levels in an atom (or molecule), to an area with higher levels. This shows whether or not the device can work as a laser, and they demonstrated their product could indeed function as a laser.

Future Applications

Now that tiny, high-performance lasers have been able to be placed directly on silicon wafers, a new world has been opened up. Next-gen microprocessors will be able to run even faster and consume less power. This is possible because of both the lasers size and performance capabilities. Because the lasers are small, they take up less power while putting out just as high-performance levels. When you put lasers on a microprocessor, their capabilities will instantly be boosted and able to run at a lower power, which is a giant step for photonics and electronic integration using silicon as the platform.

This new breakthrough has big implications for all things electronic. It is expected that these new, high-performance lasers will be immediately picked up by the high-speed data communication industry. Gaming could be much faster, data transfers could be done in the blink of an eye, the possibilities are limitless and Moore’s law remains intact for now.

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