Optical Bus Planar Waveguide Inter-Core Communication

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Solution Overview

Problem

Current interconnect technologies, such as bus-based systems and fiber optics, are limited in their ability to efficiently communicate between multiple cores in processors, especially as the number of cores increases beyond 100, leading to constraints in computing power and energy efficiency.

Innovation Solution

An optical bus using a planar waveguide with a variable-thickness light-propagation layer and non-propagation layers, along with a light management system, enables selective and efficient data transfer between thousands of cores by leveraging spatial selectivity and total internal reflection, allowing each core to emit and receive light pulses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If wire networks are used to interconnect multiple cores, then communication between cores is achieved, but the system consumes precious space and energy while generating excess heat

Engineering Contradiction:
Improveinter-core communication speedVSAvoidenergy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent replaces electrical wire-based communication with optical communication using light pulses. Each core is equipped with optical emitters and detectors that transmit data through optical waveguides, substituting the mechanical/electrical wire network with an optical system that consumes less energy and generates less heat.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of signal transmission from electrical signals through wires to optical signals through waveguides. This parameter change enables higher data transmission rates while reducing energy consumption and heat generation associated with electrical resistance in wire networks.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If fiber optic technology is used for optical communication, then data transmission capacity is improved, but the one-dimensional nature limits transmission capacity for processors employing hundreds of cores

Engineering Contradiction:
Improvedata transmission capacityVSAvoidscalability to hundreds of cores
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent transitions from one-dimensional fiber optic transmission to two-dimensional planar waveguide transmission. The planar waveguides are configured in multiple layers and orientations, enabling light to propagate in multiple directions and dimensions, thereby providing the scalability needed for processors with hundreds of cores while maintaining high transmission capacity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If selective communication between cores is implemented using different light frequencies, then communication selectivity is achieved, but the complexity of managing multiple frequencies increases

Engineering Contradiction:
Improvecommunication selectivityVSAvoidlight management complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the optical communication system into dedicated waveguide paths between cores, where each core has its own set of optical emitters and detectors. This segmentation allows selective communication through spatial routing rather than frequency management, reducing the complexity of light management while maintaining communication selectivity.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution significantly increases data transfer rates between processor cores by a factor of 1000, enhancing computational power, reducing power consumption, and extending battery life in mobile devices by enabling reliable information transfer through encoded light.

Implementation Method 1

a planar waveguide providing substantially total internal reflection within a variable-thickness, light-propagation layer

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3658971B1Optical bus for a multi-core processor
Publication Date: 2021.05.19 YEDA RES & DEV CO LTD
  • EP3658971B1 patent drawingFigure 1~2
  • EP3658971B1 patent drawingFigure 3
  • EP3658971B1 patent drawingFigure 4

AI summary

An optical bus for multi-core processing providing optical data transfer between cores through a single planar waveguide employing a variable-thickness, light- propagation layer having a progressively changing effective refractive index in accordance with lateral position within the light-propagation layer such that light emission from a single light emitter in communication with one core is focused on each of multiple photodetectors in communication with its respective processer core.