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 overcome1,2,3 by using optical communications based on chip-scale electronic–photonic systems4,5,6,7 enabled by silicon-based nanophotonic devices8. 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 chips9,10,11 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 photonics12, 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 microprocessors13,14,15,16. 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.
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We thank S. Twigg, Q. Nguyen, and M. Moreto Planas for help with processor infrastructure, A. Srinivasan for help with photodetector characterization, and S. Han for help with chip photos. This work was supported by DARPA POEM award HR0011-11-C-0100, led by J. Shah and DARPA PERFECT award HR0011-12-2-0016, led by J. Cross. We thank M. Casper, J. Torneden, and the team at the Kansas City Plant for their support of our design submissions over the years leading up to this work. Support is also acknowledged from the Berkeley Wireless Research Center, UC Berkeley ASPIRE Lab, MIT CICS, National Science Foundation, FCRP IFC, Trusted Foundry, Intel, Santec, and NSERC. The views expressed are those of the authors and do not reflect the official policy or position of the DoD or the US Government.
An animated overview of the chip (starts at 0:05) and description of the test setup for the optical memory (starts at 0:59). The demonstration of the processor running programs starts at 2:36, with temperature changing events applied starting at 5:46, with and without the thermal tuning circuit enabled. This uploaded version is the 480p quality version, sized to be just under 30MB to not exceed the individual file size limit for supplementary information. We would like to point any readers to the full-quality 1080p version, accessible to only those with the following link: https://drive.google.com/file/d/0Bw4D2gUSMil1T3VrcVpybzh5dDg/view?usp=sharing
About this article
Scientific Reports (2018)