Optical Waveguide Index Tuning for Propagation-Time Compensation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing imaging waveguides, particularly those with twisted optical fibers, suffer from significant propagation time differences and phase distortions, limiting their ability to provide high-resolution, three-dimensional imaging and effective transmission of femtosecond pulses, especially in minimally invasive medical endoscopes.

Innovation Solution

A method and device that adjust the effective refractive index of optical fibers within imaging waveguides using high-energy electromagnetic radiation, specifically ultra-short pulses and UV radiation, to arbitrarily reduce propagation time differences and implement a desired propagation time profile, utilizing subsets of fibers and controlled exposure to gases like H2 and N2 to enhance refractive index changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the diameter of the endoscope is reduced to enable minimally invasive procedures, then the flexibility and invasiveness are improved, but the propagation time differences and phase distortions in the optical fibers increase

Engineering Contradiction:
Improveendoscope diameterVSAvoidpropagation time difference
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by systematically adjusting the effective refractive indices of individual optical fibers through controlled exposure to high-energy electromagnetic radiation. By modifying the refractive index parameter of each fiber, the propagation time is adjusted to compensate for differences caused by the reduced endoscope diameter and fiber twisting, thereby resolving the contradiction between small diameter and propagation time precision.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If complex distal imaging optics are added to increase spatial resolution, then the imaging quality is improved, but the endoscope diameter increases beyond the minimally invasive threshold

Engineering Contradiction:
Improvespatial resolutionVSAvoidendoscope diameter
Core Design Contradiction:
Measurement precisionVSLength of moving object

Solution Approach 1:

The patent replaces the mechanical imaging optics system with a wavefront correction approach using high-energy electromagnetic radiation to adjust fiber propagation characteristics. Instead of adding physical lenses and mirrors at the distal end, the invention uses optical field manipulation through refractive index modification, eliminating the need for complex distal optics while maintaining high spatial resolution.

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

3Length of stationary object

If the length of the optical fiber bundle is increased to reach deeper anatomical structures, then the imaging depth is improved, but the propagation time differences and pulse spreading increase

Engineering Contradiction:
Improvefiber lengthVSAvoidpropagation time difference
Core Design Contradiction:
Length of stationary objectVSLoss of time

Solution Approach 1:

The patent applies parameter changes by systematically adjusting the effective refractive indices of individual optical fibers through controlled exposure to high-energy electromagnetic radiation. By modifying the refractive index parameter of each fiber, the propagation time is adjusted to compensate for differences caused by the reduced endoscope diameter and fiber twisting, thereby resolving the contradiction between small diameter and propagation time precision.

Inventive Principle:
Principle #35Parameter changes

4Power

If high pulse power density is used to enable nonlinear endomicroscopy, then the imaging capability is improved, but the fiber damage risk increases

Engineering Contradiction:
Improvepulse power densityVSAvoidfiber damage
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-adjusting the propagation time characteristics of the optical fibers using high-energy electromagnetic radiation before performing nonlinear endomicroscopy. This preliminary wavefront correction optimizes the fiber bundle performance, allowing for better control and distribution of high pulse power density, thereby enabling nonlinear imaging while reducing the risk of fiber damage through improved energy management.

Inventive Principle:
Principle #10Preliminary action

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 approach effectively compensates for propagation time differences and phase distortions, enabling high-resolution, three-dimensional imaging with reduced fiber damage and improved transmission of femtosecond pulses, suitable for medical endoscopes with diameters less than 0.5 mm.

Implementation Method 1

changing the effective refractive indices of optical fibers by means of high-energy electromagnetic radiation

Methodology Applied
Scientific EffectPhotosensitivity: Photochromism

Implementation Method 2

The state of the art also includes camera endoscopes. These offer high flexibility because the camera and an illumination unit are located at the distal end

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 3

utilizing subsets of fibers and controlled exposure to gases like H2 and N2 to enhance refractive index changes

Methodology Applied
Scientific EffectHydrogenation: Hydrogenation

Data Source

PatentEP4621454A1Method for compensating the difference in propagation time of optical waveguides
Publication Date: 2025.09.24 TECHNISCHE UNIVERSITAT DRESDEN
  • EP4621454A1 patent drawingFigure 1~3
  • EP4621454A1 patent drawingFigure 4~6
  • EP4621454A1 patent drawingFigure 7~8

AI summary

The invention relates to a method and a device for compensating for the propagation time differences of imaging waveguides and/or for implementing a desired propagation time profile, as well as the use of the method and the device. The method comprises changing the effective refractive indices of optical fibers by means of high-energy electromagnetic radiation encompassed by an imaging waveguide. Possible areas of application of the method and the device include, but are not limited to, cancer diagnostics, nonlinear endomicroscopy, optical coherence tomography (OCT), swept-source optical coherence tomography, the uninterrupted transmission of femtosecond pulses, and/or the correction of propagation time differences that occur in imaging waveguides comprising twisted optical fibers.