Advancements in Nanolasers May Lead to an Optical Bus

Researchers using nanotechnology and lasers may provide us with a significant performance boost. Today, memory, graphics, and processor communications are done in the form of an electrical bus. Think of a bus as a multi-lane highway that delivers information from once device to the next.

However, the complexity and modern conductive materials cannot physically lead us to a significant increase in speeds. To get around this roadblock, researchers have resorted to using nanolasers as a faster alternative due to its potential to transmit data very close to the speed of light.

Researchers at the University of California, Berkeley have completed a work that inches the computer industry closer to this dream. They’ve developed a new process that will allow laser-emitting nanopillars to be directly grown onto silicon at milder conditions than in past work.

Connie Chang-Hasnain UC Berkeley professor of electrical engineering and computer sciences reminds of us previous efforts to make integrated nanolasers on a silicon chip:

Today’s massive silicon electronics infrastructure is extremely difficult to change for both economic and technological reasons, so compatibility with silicon fabrication is critical. One problem is that growth of III-V semiconductors has traditionally involved high temperatures – 700 degrees Celsius or more – that would destroy the electronics. Meanwhile, other integration approaches have not been scalable.

The research team at UC Berkeley can now fully integrate a nanolasers or “pillars” to transmit the information. The manufacturing process (aka growth process) now only involves 400 degrees Celsius to embed or “deposit” the laser onto a silicon chip. So, there is progress being made, but more work needs to be done. In addition, the process is much more affordable than previous efforts. Professor Chang-Hasnain tells us more:

This is the first bottom-up integration of III-V nanolasers onto silicon chips using a growth process compatible with the CMOS (complementary metal oxide semiconductor) technology now used to make integrated circuits. This research has the potential to catalyze an optoelectronics revolution in computing, communications, displays and optical signal processing. In the future, we expect to improve the characteristics of these lasers and ultimately control them electronically for a powerful marriage between photonic and electronic devices.

Don’t expect to see anything of this sort in the commercial area anytime soon. The transition to devices that have a hybrid of optical and electrical communications, specifically computer hardware, will take some time. Also, the power consumption of these nanolasers must be very low considering there are multiple buses within a modern computer (optical communication needs to prove that it is less power hungry than current electrical communication). A further practicality analysis is obviously needed.