Fiber Bragg Grating Interferometer for Microvascular Tool Sensing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In minimally invasive surgery, particularly endovascular procedures, there is a challenge in accurately measuring bending, temperature, and pressure at the tip of microvascular tools due to distorted haptic feedback, which can lead to vessel injury and complications like dissection or perforation, especially in patients with preexisting arterial diseases.

Innovation Solution

An optical measurement device using Fiber Bragg Gratings embedded in a silicon dioxide single-mode fiber, multiplexed at specific locations to distinguish and quantify strain, temperature, and bending, utilizing a Fabry-Perot Interferometer setup with tuned reflectivity to enhance signal interference and enable simultaneous measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If instruments are migrated further into the vessel to reach the desired region, then the ability to access distant lesions is improved, but the resistance and haptic feedback distortion increase due to increasing surface area contact

Engineering Contradiction:
Improveinstrument migration distanceVSAvoidhaptic feedback quality
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The patent replaces mechanical haptic feedback sensing with optical sensing using Fiber Bragg Gratings. The FBG sensors detect strain, temperature, and bending through optical wavelength shifts, eliminating the need for mechanical force sensing at the instrument tip. This substitution provides accurate remote sensing without the distortion inherent in mechanical haptic feedback transmission through long instrument shafts.

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

Solution Approach 2:

The patent introduces Fiber Bragg Grating sensors as intermediary elements embedded within the instrument structure. These FBG sensors act as remote proxies that directly sense conditions at the instrument tip and transmit information back through the fiber optic cable, providing accurate feedback without requiring direct mechanical coupling between the operator and the distant instrument tip.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If more force is applied to overcome increasing resistance, then the ability to navigate to the desired region is improved, but the risk of vessel injury increases due to elastic compression and springlike behavior

Engineering Contradiction:
Improveapplied force for navigationVSAvoidvessel injury risk
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The patent implements real-time feedback through FBG sensors that continuously monitor strain, temperature, and bending at the instrument tip. This feedback is transmitted to the operator, enabling them to detect early signs of excessive force application or vessel compression and adjust accordingly, preventing elastic compression and springlike behavior that could lead to sudden instrument leaps and vessel injury.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent enables preliminary detection of adverse conditions through the FBG sensing system. By monitoring strain and bending before critical thresholds are reached, the system allows operators to take preventive action by reducing applied force before elastic compression occurs, thereby preventing the harmful springlike behavior and associated vessel injury risks.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If multiple sensors are multiplexed in the fiber to measure strain, temperature and bending, then the measurement capability is improved, but the device complexity increases

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidsensor multiplexing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs Fiber Bragg Gratings that serve multiple sensing functions simultaneously. A single FBG structure can detect strain, temperature, and bending through different spectral characteristics, eliminating the need for separate dedicated sensors for each parameter. This multi-functionality reduces the number of discrete components needed while maintaining comprehensive measurement capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes the spectral dimension of light to encode multiple measurement parameters. Different sensing information (strain, temperature, bending) is represented by different wavelength shifts or spectral features of the FBG, allowing multiple parameters to be transmitted through a single fiber optic channel without spatial or temporal multiplexing complexity.

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

4Adaptability or versatility

If the fiber diameter is reduced to enable use in small vessels, then the adaptability to small vessels is improved, but the signal strength and measurement precision may deteriorate

Engineering Contradiction:
Improvecompatibility with small vesselsVSAvoidsignal measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent uses optical sensing with Fiber Bragg Gratings that are inherently suitable for thin fiber implementations. The FBG sensors detect changes through optical wavelength shifts rather than mechanical displacement, maintaining high measurement precision even in fibers with diameters small enough for use in delicate intracranial vessels.

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

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 device provides accurate and simultaneous measurement of bending, temperature, and pressure, even in small vessels, reducing the risk of unintentional instrument movement and vessel injury by detecting strong compression early, suitable for MRI environments and enhancing safety in minimally invasive surgeries.

Implementation Method 1

at least two Fiber Bragg Gratings as a Fabry Pero-Interferometer are arranged in the fiber allowing for reflection of light emitted by the light source into the fiber, back through the fiber towards the optical spectrum analyzer

Methodology Applied
Scientific EffectFiber Bragg Grating reflection: Reflection

Implementation Method 2

at least two Fiber Bragg Gratings as a Fabry Pero-Interferometer are arranged in the fiber allowing for reflection of light

Methodology Applied
Scientific EffectFabry-Perot Interferometer interference: Interference

Implementation Method 3

allowing for simultaneous measurement of bending, temperature and pressure

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

Fiber Bragg Gratings embedded in a silicon dioxide single-mode fiber, multiplexed at specific locations to distinguish and quantify strain, temperature, and bending

Methodology Applied
Scientific EffectPhotoelasticity: Photoelasticity

Data Source

PatentEP4636362A1An optical measurement device for enabling simultaneous measurement of temperature, pressure and bending
Publication Date: 2025.10.22 TECHNISCHE UNIVERSITÄT HAMBURG (TUUH) KÖR
  • EP4636362A1 patent drawingFigure 1a~2
  • EP4636362A1 patent drawingFigure 3a~4
  • EP4636362A1 patent drawingFigure 5(A)~6CII

AI summary

The invention pertains to an optical measurement device for enabling simultaneous measurement of temperature, pressure and bending, comprising a broadband light source (Q), a fiber (F), and an optical spectrum analyzer (OSA), whereby in the fiber (F) at least two Fiber Bragg Gratings as a Fabry-Perot Interferometer are arranged allowing for reflection of light emitted by the light source (Q) into the fiber (F), back through the fiber (F) towards the optical spectrum analyzer (OSA), whereby reflection is depending of the temperature, pressure and bending applied to the fiber (F) in the region of the Fiber Bragg Grating Fabry-Perot Interferometer, whereby by use of the at least two Fiber Bragg Gratings Fabry-Perot Interferometer additional correlation features are produced allowing for separation of temperature, pressure and bending. The invention also pertains to a method using said optical measurement device and the uses in medicine.