Optical Force Sensor Using Multi-Core Fiber and Tubular Structure
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Solution Overview
Problem
Current optical strain sensing technologies do not effectively measure forces at the distal region of instruments, such as medical instruments, where precise force detection is crucial for applications like tissue interaction to avoid damage.
Innovation Solution
An optical force sensor using a multi-core optical fiber with a tubular structure encasing the fiber's end, secured with epoxy, and connected to an optical interferometric system that processes reflected light without Bragg gratings to measure strain and forces at the distal region, employing swept wavelength interferometry for high-resolution strain profiling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical strain sensing technology is used to measure forces at the distal region, then measurement precision is improved, but device complexity increases due to the need for tubular structures, epoxy bonding, and interferometric systems
Solution Approach 1:
The optical fiber is nested within a tubular structure that is secured at the distal region of the instrument. The tubular structure encases the fiber end, creating a nested configuration where the fiber is protected and positioned within the tube, allowing force sensing at the distal region while maintaining a compact structure
Solution Approach 2:
Epoxy is used as an intermediary material to bond the optical fiber to the tubular structure. The epoxy transfers mechanical strain from the tubular structure to the optical fiber, enabling force measurement without direct mechanical connection between the fiber and the instrument structure
2Adaptability or versatility
If Bragg gratings are removed from the fiber portion within the tubular structure, then force measurement capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
Bragg gratings are selectively removed from the portion of the optical fiber that extends within the tubular structure. This extraction of the Bragg grating functionality from the sensing region allows the fiber to respond to axial strain forces without the wavelength-selective filtering effect of the gratings, enabling broadband force measurement
Solution Approach 2:
The optical fiber is functionally segmented into different regions: portions outside the tubular structure may retain Bragg gratings for other sensing functions, while the portion within the tubular structure has Bragg gratings removed to enable force sensing. This segmentation allows multiple sensing capabilities within a single fiber
3Measurement precision
If multi-core optical fiber is used instead of single-core, then measurement precision is improved through multiple independent strain signals, but device complexity increases
Solution Approach 1:
A multi-core optical fiber is used where multiple independent waveguides or cores are embedded within a single fiber. Each core can independently sense strain, allowing the single fiber to perform multiple sensing functions simultaneously - measuring different strain components or providing redundant measurement channels for improved precision
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
Enables precise measurement of forces at the distal region of instruments, providing detailed strain profiles and force feedback, enhancing the safety and effectiveness of medical procedures by accurately determining applied loads.
Implementation Method 1
an optical interferometric system which processes reflected light from a portion of the core included within the tubular structure that does not include Bragg gratings to produce a measurement of a force present at the distal region of the instrument
Implementation Method 2
employing swept wavelength interferometry for high-resolution strain profiling
Implementation Method 3
The epoxy transfers strain from the distal region of the instrument to the optical fiber
Data Source
AI summary
An optical force sensor along with an optical processing apparatus and method are disclosed. The optical force sensor includes an optical fiber, a core included in the optical fiber, an instrument including the optical fiber, the instrument having a distal region, and a tubular structure encasing an end of the optical fiber and secured to the first conduit at the distal region of the instrument. When an optical interferometric system is coupled to the optical fiber, it processes reflected light from a portion of the core included within the tubular structure that does not include Bragg gratings to produce a measurement of a force present at the distal region of the instrument.