title: Single-chip microprocessor that communicates directly using light.
abstract: 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.
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.|Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Chen
authors.initials: C
authors.lastname: Sun
authors.affiliation: University of Colorado, Boulder, Boulder, Colorado 80309, USA.
authors.forename: Mark T
authors.initials: MT
authors.lastname: Wade
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Yunsup
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Orcutt
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Luca
authors.initials: L
authors.lastname: Alloatti
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Georgas
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Waterman
authors.affiliation: University of Colorado, Boulder, Boulder, Colorado 80309, USA.
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Shainline
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Rimas R
authors.initials: RR
authors.lastname: Avizienis
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Sen
authors.initials: S
authors.lastname: Lin
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Moss
authors.affiliation: University of Colorado, Boulder, Boulder, Colorado 80309, USA.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kumar
authors.affiliation: University of Colorado, Boulder, Boulder, Colorado 80309, USA.
authors.forename: Fabio
authors.initials: F
authors.lastname: Pavanello
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Amir H
authors.initials: AH
authors.lastname: Atabaki
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Henry M
authors.initials: HM
authors.lastname: Cook
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Ou
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Leu
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Yu-Hsin
authors.initials: YH
authors.lastname: Chen
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Krste
authors.initials: K
authors.lastname: Asanović
authors.affiliation: Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Rajeev J
authors.initials: RJ
authors.lastname: Ram
authors.affiliation: University of Colorado, Boulder, Boulder, Colorado 80309, USA.
authors.forename: Miloš A
authors.initials: MA
authors.lastname: Popović
authors.affiliation: University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Vladimir M
authors.initials: VM
authors.lastname: Stojanović