Optical Fiber Bend Detection via Reflected Power Threshold

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Solution Overview

Problem

During the insertion of a catheter, optical fibers can experience strong bending, leading to light leakage at curved portions, which reduces the optical power reaching the treatment site and can result in unintended ablation. Existing techniques do not accurately measure bending loss or detect bends in optical fibers during operation.

Innovation Solution

An optical fiber state detection system that includes a first light source for monitor-related light, a reflection mechanism, a light receiving part, a tap coupler, and a control part. This system accurately measures bending loss by detecting changes in received optical power and determines the presence or absence of bends in the optical fiber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the catheter diameter is reduced to minimize invasion, then the optical fiber becomes more prone to bending and breaking, but increasing the catheter diameter increases patient trauma

Engineering Contradiction:
Improvecatheter diameterVSAvoidoptical fiber integrity
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The system performs preliminary detection of bending loss before ablation treatment begins. The monitor-related light source continuously monitors the optical fiber state during insertion and positioning, allowing the system to detect bends before they cause treatment failures or safety issues.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements real-time feedback by monitoring the received optical power of reflected light and comparing it against threshold values. When bending loss exceeds the threshold, the control part immediately shuts down the ablation-related light source, providing continuous feedback to maintain both safety and treatment effectiveness.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If the optical fiber is strongly bent during insertion to reach difficult positions, then the catheter can access remote treatment sites, but light leaks at the curved portion reducing optical power delivery

Engineering Contradiction:
Improvecatheter flexibilityVSAvoidoptical power delivery
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The system performs preliminary detection of bending loss before ablation treatment begins. The monitor-related light source continuously monitors the optical fiber state during insertion and positioning, allowing the system to detect bends before they cause treatment failures or safety issues.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements real-time feedback by monitoring the received optical power of reflected light and comparing it against threshold values. When bending loss exceeds the threshold, the control part immediately shuts down the ablation-related light source, providing continuous feedback to maintain both safety and treatment effectiveness.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If traditional curvature detection techniques are used for the catheter, then the curved shape can be estimated, but bending loss of the optical fiber cannot be accurately measured

Engineering Contradiction:
Improvecurvature detection accuracyVSAvoidbending loss measurement
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The system uses an intermediary monitor-related light source with a specific wavelength to detect bending loss. This separate monitoring light allows indirect measurement of the optical fiber's bending state without interfering with the ablation process, providing information that cannot be obtained through direct curvature measurement alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces mechanical curvature measurement methods with optical-based detection. By using optical properties (light reflection and transmission) to detect bends, the system can simultaneously measure both the curved shape and the actual bending loss affecting light delivery, rather than relying solely on mechanical position tracking.

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

4Reliability

If a separate detection system is added to monitor optical fiber bends, then bending loss can be measured, but the system complexity increases

Engineering Contradiction:
Improvebend detection capabilityVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system merges the detection function with the existing ablation system by using the same optical fiber and integrating the monitor-related light source into the existing catheter structure. The tap coupler combines monitoring and ablation light paths, allowing both functions to share common components and reduce overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical fiber serves multiple functions: it delivers both the monitor-related light for detection and the ablation-related light for treatment. The same fiber acts as both the sensing element and the treatment delivery channel, eliminating the need for separate detection fibers and reducing system complexity.

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

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 system effectively measures bending loss and detects bends in optical fibers, preventing light leakage and ensuring accurate ablation by shutting down the ablation-related light source when a bend is detected.

Implementation Method 1

a reflection mechanism that reflects the monitor-related light propagated through the optical fiber

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a wave multiplexer that multiplexes the monitor-related light and the ablation-related light; and a control part, wherein the first light source and the second light source are connected to the wave multiplexer, the wave multiplexer and the light receiving part are connected to the tap coupler, the monitor-related light and the ablation-related light are different from each other in wavelength

Methodology Applied
Scientific EffectWavelength division multiplexing:

Data Source

PatentEP3949887B1Optical fiber state detection system
Publication Date: 2025.05.07 FURUKAWA ELECTRIC CO LTD
  • EP3949887B1 patent drawingFigure 1
  • EP3949887B1 patent drawingFigure 2~3
  • EP3949887B1 patent drawingFigure 4~5

AI summary

It is an object to provide an optical fiber state detection system that can accurately measure the bending loss of an optical fiber in operate and determine the presence or absence of a bend on the optical fiber. An optical fiber state detection system 1 includes a monitor-related LD 11 that outputs a monitor-related light TL for monitoring a state of an optical fiber 50, a reflection mechanism 31 that reflects the monitor-related light TL propagated through the optical fiber 50, a monitor PD 12 that receives a reflected light RL reflected by the reflection mechanism 31, a tap coupler 13 provided between the reflection mechanism 31 and both the monitor-related LD 11 and monitor PD 12 and such that the monitor-related LD 11 and monitor PD 12 are connected thereto, and a control part 60, wherein, when the control part 60 detects that a received optical power of the reflected light RL has become lower than a predetermined threshold, it is determined that a bent has occurred on the optical fiber 50.