Novel microprocessor chip uses light instead of electricity to efficiently transfer data

12/26/2015 - 22:01

Miloš Popović

Researchers at the University of Colorado Boulder, in collaboration with the University of California, Berkeley and the Massachusetts Institute of Technology (MIT), have developed a groundbreaking microprocessor chip that uses light, rather than electricity, to transfer data at rapid speeds while consuming minute amounts of energy.

Details of the new technology, which could pave the way for faster, more powerful computing systems and network infrastructure, were published today in the journal Nature.

“Light based integrated circuits could lead to radical changes in computing and network chip architecture in applications ranging from smartphones to supercomputers to large data centers, something computer architects have already begun work on in anticipation of the arrival of this technology,” said Miloš Popović, an assistant professor in CU-Boulder’s Department of Electrical, Computer, and Energy Engineering and a co-corresponding author of the study.


Ref: Single-chip microprocessor that communicates directly using light. Nature (24 December 2015) | DOI: 0.1038/nature16454


Data transport across short electrical wires is limited by both bandwidth and power density, which creates a performance bottleneck for semiconductor microchips in modern computer systems—from mobile phones to large-scale data centres. These limitations can be overcome by using optical communications based on chip-scale electronic–photonic systems enabled by silicon-based nanophotonic devices. However, combining electronics and photonics on the same chip has proved challenging, owing to microchip manufacturing conflicts between electronics and photonics. Consequently, current electronic–photonic chips are limited to niche manufacturing processes and include only a few optical devices alongside simple circuits. Here we report an electronic–photonic system on a single chip integrating over 70 million transistors and 850 photonic components that work together to provide logic, memory, and interconnect functions. This system is a realization of a microprocessor that uses on-chip photonic devices to directly communicate with other chips using light. To integrate electronics and photonics at the scale of a microprocessor chip, we adopt a ‘zero-change’ approach to the integration of photonics. Instead of developing a custom process to enable the fabrication of photonics, which would complicate or eliminate the possibility of integration with state-of-the-art transistors at large scale and at high yield, we design optical devices using a standard microelectronics foundry process that is used for modern microprocessors. This demonstration could represent the beginning of an era of chip-scale electronic–photonic systems with the potential to transform computing system architectures, enabling more powerful computers, from network infrastructure to data centres and supercomputers.