Graded-Index Lens for Multi-Axis Optical Coupling

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Solution Overview

Problem

Optical coupling between integrated circuits and other components, such as fibers or cabling, often results in data degradation due to ineffective light propagation, leading to slower or inefficient data transfers.

Innovation Solution

A graded-index lens with a variable refractive index and a contoured surface is used to focus light along multiple axes, enabling efficient coupling by transforming rapidly diverging light rays into collimated or converging beams, which can be precisely aligned and fabricated using MEMS techniques for high precision and repeatability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional optical coupling methods are used, then the coupling structure is simple, but light propagation is ineffective causing data degradation

Engineering Contradiction:
Improvedata transfer efficiencyVSAvoidcoupling structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the refractive index distribution within the coupling medium. A graded-index profile is implemented where the refractive index varies continuously from the center to the edges of the coupling region, enabling precise control of light propagation paths and improving coupling efficiency without excessive structural complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs curved surfaces in the coupling structure, specifically spherical or aspherical lens surfaces, to focus and guide light rays. This curvature enables effective light propagation by converging divergent rays from the integrated circuit onto the fiber core, resolving the data degradation issue while maintaining a relatively compact structure

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Speed

If light rays are allowed to diverge naturally, then the coupling structure is simple, but data transfer speed decreases due to ineffective propagation

Engineering Contradiction:
Improvedata transfer speedVSAvoidlight control mechanism complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The graded-index parameter distribution is specifically designed to counteract natural light divergence. By creating a refractive index gradient that is highest at the center and decreases toward the edges, the structure actively guides divergent rays back toward the optical axis, maintaining beam quality and enabling high-speed data transfer

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The graded-index coupling medium acts as an intermediary between the integrated circuit light source and the optical fiber. This intermediate structure modifies the light propagation characteristics, transforming rapidly diverging rays into controlled beams that efficiently couple into the fiber, thereby enabling high-speed data transfer without requiring complex active control mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution effectively enhances data transfer efficiency by accurately focusing light beams in multiple dimensions, ensuring efficient coupling between integrated circuits and fibers, suitable for various applications including optical transceivers and short-distance interconnects.

Implementation Method 1

The lens may use a material having a variable refractive index to focus rays of light along first axis

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

a curved surface to focus the rays of light along a second axis

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP3170042B1Method of obtaining a multi-axis graded-index photonic coupling
Publication Date: 2022.09.14 CISCO TECHNOLOGY INC
  • EP3170042B1 patent drawingFigure 1
  • EP3170042B1 patent drawingFigure 2A~2B
  • EP3170042B1 patent drawingFigure 3A~3B

AI summary

An optical coupling may involve orienting a waveguide and a lens such that light rays are focused on a surface. The lens may involve the use of a material having a variable refractive index to focus rays of light along first axis and a curved surface to focus the rays of light along a second axis.