5704
Physics and Electro-Optics

OPTICAL BUS FOR A MULTI-CORE PROCESSOR (No. 1863)

Lead Researcher: Prof. Ulf Leonhardt

Summary

The exponential increase in computational power over the last decades is running into a bottle-neck – the only way of getting more computing power per chip is to integrate multiple-cores, but the problem with multiple-cores is the complex wiring system, used for inter-core communication. This technology, developed at the Weizmann Institute of Science propose a radically new idea that replaces wires and fibers altogether, by an appropriately designed integrated optical chip layer that serves the same purpose with less complexity. It eliminates the use of wires thus saving valuable space, reducing power consumption and subsequently internal heat production. It further allows for high number of interconnected processors on the same chip and improves inter-core connectivity by 100-1000-fold, ultimately increasing computational power.

Applications

The proposed innovation is applicable for a full range of markets integrating electronic technologies including:
·         Consumer electronics
·         Automatic car industry
·         Hardware for deep-learning networks
·         Robotics
·         Signal processing
·         Telecommunication
·         Information processing

Advantages

·         Direct and wireless inter-core communication
·         Waveguide fabrication is compatible with traditional CMOS fabrication technologies
·         Scaled-up connectivity of processor cores by 100-1000-fold
·         Increased computing power
·         Reduced electric power consumption
·         Reduced heat output
·         Space and energy efficient
·         Point-to-point communication without crosstalk

Technology's Essence

A single compact on-chip optical layer, compatible with CMOS fabrication technologies, that replaces the tangle of wires and fibers of existing bus systems.
 
This invention designed by transformation optics, involves a compact optical bus, comprised of a planar waveguide on silicon chips where light is confined in a layer by total internal reflection. The layer is made of silicon that has a high refractive index, sandwiched between layers of silica (glass) with a much lower index. The height of the highly refractive layer is carefully designed to provide a specific refractive index profile, dictated by the layer thickness. A light management system selectively activates specific illumination ports embedded within the waveguide; the emanating light is then focused onto reflectors, or Bragg mirrors, which lead to light ray emission at specific partner points.  In a similar manner, the light can be simultaneously focused onto a plurality of photodetectors within the waveguide, each of which communicates with a separate processor core. Bus geometry can be adjusted to match computer processor or core layout requirements.