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.

Graphene photodetectors with a bandwidth >76 GHz fabricated in a 6″ wafer process line

“…We extract an upper value of 7.2 ps for the timescale in which the bolometric photoresponse in graphene is generated. The photodetectors were fabricated on 6" silicon-on-insulator wafers in a semiconductor pilot line, demonstrating the scalable fabrication of high-performance graphene based devices.Optical communication in general and especially chip integration of optic and electronic components has been considered as a promising way to significantly increase the performance of datalinks in terms of capacity, energy consumption, and costs [1][2][3]. The current bottleneck that hinders the mass production of chip integrated electro-optic components like modulators and photodetectors is the lack of a material that is compatible to established processing technology of chips while giving high performance devices.…”

Grating-Assisted Fiber to Chip Coupling for SOI Photonic Circuits

“…When considering high-density circuit, it is indispensable to reduce the footprint of these tapers. Since the taper length depends predominantly on the starting and ending waveguide width and effective index, the transition between a grating coupler and a single-mode photonic waveguide in any material platform is one of the largest [33][34][35][36][37]. Thus, it is extremely advantageous to have non-adiabatic tapers along with linear GCs for a compact spot-size converter.…”

Design of low bias voltage Ge/SiGe multiple quantum wells electro-absorption modulator at 1550 nm

“…However, the sharp filtering spectrum also makes the device highly sensitive to fabrication tolerance and operating temperature. To lock the resonating wavelength of the ring, a control circuit including a microheater was used in 9 and brought in extra complication and power consumption.…”